T h e Journal of In d u stria l a n d Engineering Ghemistry
P u b l i s h e d by T H E A M E R I G A N G H E M I G A L S O G I E T Y
V o lu m e III O C T O B E R , 1911 No. 10
BOARD OF ED ITORS.
Editor: M. C. W hitaker.
Associate E d ito rs:
Geo. P. Adam son, E . G. B ailey, H. E. Barnard, C. A . Brow ne, G. E. B arton, W m . B rady, W m . Cam pbell, F. B.
Carpenter, V irgil Coblentz, Francis I. Dupont, W . C. E baugh, W m . C. Geer, W . F . H illebrand, W . D. H om e, K arl Langenbeck, A . D. L ittle, C. E . Lucke, P. C. M cllh iney, E . B. M cCready, W m . M cMurtrie, J. M erritt M at
thews, T . J. Parker, J. D. Pennock, W. D. Richardson, Geo. C. Stone, E rnst T w itchell, R obt. W ahl, W m . H.
W alker, W . R. W hitney, A. N. Wright.
Pub lish ed m o n th ly . Subscription p ric e to n o n -m e m b e rs of th e A m erican C hem ical S ociety , $6.00 y early . F o reig n postage, sev en ty -fiv e c e n ts, C an a d a . C u b a a n d M exico excep ted .
E ntered at th e Post-O ffice, E a s to n , P a ., as Second-class M a tte r.
EDITORIALS
THE CONSERVATION OF RESEARCH.
The presidental address of Sir William R am say before the British Association for the A dvancem ent of Science at its eighty-first annual meeting is rich in suggestions of great and important problem s for scientific research and development, and also points directly a t some of the issues of so-called conservation.
Sir W illiam declared th at if the stored-up energy in a ton of radium could be utilized in a space of th irty years instead of the inevitable period of 1,700 years, it w ould propel a 15,000 ton ship w ith a force of 15,000 horse-power a t the rate of fifteen knots during the entire th irty years.
This prospect, however, is dimmed by the fa ct th at the production of radium does not exceed half an ounce a year.
T h e stu d y of radium and its compounds has finally led M adame Curie to establish beyond a doubt its id en tity as a chem ical elem ent which conform s to a position in the periodic system under barium . The establishm ent of radium as an element and the deter
m ination of its atom ic w eight and periodic relations are im portant m atters from a chemical standpoint.
These discoveries are also important from the stand
point of establishing a foundation upon which further researches into the peculiar properties of this elem ent m ay be undertaken.
T h e potential possibilities of radioactive substances w ith stored-up energy and the transm utation in
clinations displayed b y them &nd their associates will alw ays be an inviting field for research. Some of this research will be inspired by p u rely scientific m otives; some b y commercial needs. W e m ay rest assured th at all these research results w ill be e x ploited b y the prom oters and amateur conservation
ists.
T urning to the more directly practical subject of
energy from coal, Sir W illiam declared th a t if the rapid increase in the output of coal mined in the B ritish Isles continued, the supply w ould be e x hausted in a hundred and seventy-five y e a rs --a v e ry brief space in a n ation ’s life. He urged th a t the present reckless w aste should be discontinued and th at ev ery possible means of econom izing should be adopted.
Specific suggestions for its conservation were the use of turbines, gas engines, creation of power at the p it m outh and its distribution electrically, the abandon
m ent of w asteful dom estic fires in open hearths and the substitution of central heating plants. He even w ent so far as to recomm end legislation to control the expenditure of the n ation’s fuel supply.
The conservation of the coal pile is as im portant to A m erica as it is to G reat Britain. It is im portant to the fa cto ry m anager from the standpoint of econom y in production, im portant to the mine owner from the standpoint of perm anence of investm ent, and im
portan t to hum an ity a t large if th e y have a regard for the future.
These and m an y other reasons m ake im provem ent in coal econom y an im portant field for research.
The resources of chem istry and physics alone will not produce the highest attainable efficiency in the conservation of coal. M any w o rth y inventions fail through fa u lty business adm inistration, soitap p ears th at h u m an ity is not doing its best w ith the adm inistra
tion of know ledge placed a t its disposal for the con
servation of the w orld ’s fuel supply.
It is an easy m atter to show the loss in energy in converting coal into pow er or light, b u t how about the loss due to failure to utilize the n atural pow er facilities of the cou n try which elim inate the use of coal altogether?
T he conservationist who “ p ro te cts” a great w ater
fall from being utilized for producing pow er does not
7i4 T H E J O U R N A L O F I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y . Oct., i 9u consider the function of power and its relations to the
great problems of conserving the fuel supply and the industrial developm ent of the country. He does not understand industrial economics and its relation to human wealth, life and com fort, and m ay even be suspected of not understanding conserva
tion.
Conservationists m ay be divided into two classes:
sentim ental conservationists and scientific conserva
tionists. The loudest of these is the sentimental conservationist.
The ruins of the Tem ple of Philae were “ s a v e d ” at the expense of an increased cap acity of the Assuan dam which would have irrigated and rendered fertile and productive thousands of acres of the Nile V alley, to the great relief of an impoverished nation and race.
G reat w aterfalls are “ p rotected ” a t the expense of our coal deposits and power-using industrial enter
prises.
The warnings of the scientific conservationists like Sir W illiam R am say, are usually ignored and the scientific facts th ey adduce are sw ept aside b y the impassioned eloquence of the sentim ental conserva
tionist or reformer.
W hile the chemical and physical investigator is working w ith unselfish devotion to solve problems which will conserve the w orld’s resources for the benefit of mankind, w h y should not the people en
trusted w ith the adm inistration of the results of these investigations conserve them on a basis of scientific facts unm ixed w ith sentim entality?
A workm an w ith a bed, a bath, and a steady job is infinitely more im portant to hum anity and to industry, and more inspiring to look a t than a de
cayed temple. A factory using natural power and furnishing em ploym ent for hundreds of men and women under clean, light, sanitary conditions is certain ly a better exam ple of proper conservation of the researches of science than the dissipation of thousands of horse-power of energy b y the reserva
tion of a w aterfall to satisfy the gaping curiosity of a few tourists.
THE RELATION OF CHEMISTRY TO HIGH W AY ENGI
NEERING.
U ntil v e ry ' recently there has been but little need upon the p art of highw ay engineers to call upon the chem ist for aid in the science of road building. Earth, gravel and broken stone had been for m any years practically the only m aterials necessary to success
fu lly meet the requirements of country and sub
urban traffic, and previous experience had shown th a t the chem ical analysis of these m aterials was of bu t slight assistance in determining their value for practical work. W ith com paratively few exceptions, highw ay engineers in this country had received little or no scientific education in road construction, and the few highly trained men engaged in such work found th at sufficient inform ation regarding the prop
erties of m aterials em ployed could be obtained from a few simple physical tests and the use of the m icro
scope. A v e ry small num ber of chemists were en
gaged in investigating the reason w h y certain classes of rock proved to be better road materials than others, when physical properties alone would not explain m atters, b u t such work was in no sense of a com
m ercial nature and was conducted alm ost exclusively in governm ent laboratories.
These conditions m aintained until a few years ago when the constan tly increasing use of motor vehicles caused the subject to be considered from an entirely different point of view . The rapid destruction of m any of our best and most carefully built macadam roads soon proved th at broken stone as previously used was inadequate to meet the requirements of this new kind of traffic, and highw ay engineers found them selves confronted with a ve ry serious problem.
The rock dust necessary to bond together the coarser fragm ents of the m acadam j-oad, and preserve its integrity, was being removed b y the passage of even' autom obile and this dust becom ing a nuisance to those who used and lived near the road caused an insistent dem and from the public not on ly for more lasting roads but for dustless roads as well. The highway engineer was thus forced to search for new materials of construction. A fter much experim enting he has found that the conditions of m odem traffic may be successfully m et b y em ploying a variety of sub
stances as binders for the road materials previously used. These new substances he has termed “ dust p reve n tives” and “ road binders.” The great m ajority of these m aterials come under the classifica
tion of bitum ens, but a num ber of cheap by-products from various industrial sourccs have also been utilized for this purpose. Most of these dust preventives and road binders are extrem ely variable in com
position and it has become practically impossible for the m odem highw ay engineer to intelligently conduct his work w ithout the assistance of the chemist.
The field thus opened is p ractically a new one in chem istry, although in its broadest sense it includes the chem istry of paving m aterials as practiced in connection w ith m unicipal work. For the purpose of illustrating the wide scope of this new field, some of the more im portant m aterials m ay be mentioned.
These consist of petroleum s and petroleum products, including residual- petroleums, fluxes, oil-asphalts, and fluxed or cut-back oil asphalts; malthas; native asphalts and other solid native bitum ens and asphaltic cements produced b y fluxing them ; coal tars and w ater gas tars, their distillate^ and residues; mixtures of tar w ith petroleum or asphalt products, bituminous emulsions, and fictitious asphalts; bituminous aggregates, including rock asphalts or bituminous rocks, bitum inous concrete and asphalt or other bitum inous topping; waste sulphite liquors; sucrates of certain inorganic bases; soluble silicates; calcium and magnesium chlorides; and various organic by
products from industrial processes.
The m ost im portant class of materials at present, the bitum ens, alone offer an inexhaustible field oi research in connection w ith their utilization in road construction. These products m ust be considered and exam ined as th ey exist and as they are offered
by manufacturers. It is true th at the immense amount of stu d y accorded this class of m aterials by chemists throughout the world is responsible for a very large portion of our knowledge of organic chemistry, b u t most of the work so far accomplished has been devoted to the isolation of certain organic compounds present in the crude m aterial or to the preparation of new compounds, and this w ork is of little value in the field mentioned, which is obliged to deal w ith an endless va rie ty of the most com plex mixtures, solutions and emulsions of hydrocarbons and their derivatives, m any of which are unstable and are undergoing constant changes, which affect their value as road materials.
Comparatively few chemists have as yet entered this field and those who have so far obtained rec
ognition for their work m ight alm ost be countcd on the fingers of both hands. Methods of exam ina
tion and analysis a t present em ployed are more or less crude, and a va st am ount of work w ill be neces
sary to establish this branch of chem istry upon a satisfactory basis. The field is a most im portant one, however, and should prove attractive to m any chemists and chem ical engineers for whom it will most surely offer em ploym ent in the near future.
Already its im portance has been recognized b y high
way engineers of this and all of the progressive E uro
pean countries as evidenced b y the proceedings of the Permanent International Association of R oad Con
gresses. The Am erican Society for Testing Materials has established a Com m ittee on the Testing of R oad Materials, and the Am erican Society of Civil Engineers has devoted much tim e and consideration to the sub
ject. This branch of work will be recognized a t the Eighth International Congress of A pplied Chem istry under the section on Fuels and Bitum inous Materials.
Numerous chem ical road m aterial industries have recently sprung into existence, and m any of those devoted to the m anufacture of paving m aterials have widened the scope of their production to include various classes of dust preventives and road binders.
Chemists are needed to control and perfect these processes, to inspect, analyze and specify products which are to be used and to carry on investigations relative to the utilization of by-products for road treatment and construction, to im prove old and devise new methods of exam ination, and to determine the effect of certain constituents upon the value of
®aterials for this work. Innum erable problems m ight he mentioned for the consideration of the chem ist engaged in this line of work, for instance the effect light, heat, and atm ospheric exposure upon various types of bitum ens, accurate qu antitative methods for the determ ination of paraffin scale in native bitumens and of naphthalene in tars and tar prod
ucts; an accurate qu antitative method for separating tars from petroleum s and asphalts in bitum inous
®xtures; a qu an titative method for determ ining the Presence of w ater gas ta r in coal ta r products, an
^solute method for recovering bitum ens unaltered
■rom bituminous aggregates, and so on ad infinitum.
h order th a t the w ork of the chem ist should be of
greatest value in highw ay construction, it is, of course, essential th at he have a thorough knowledge of how the m aterials which he examines are actually used and w hat effect peculiar local conditions and con
ditions controlled b y the highw ay engineer w ill have upon the results obtained in practice. In like manner it is necessary for the modern highw ay engineer to be informed in regard to the chem ical and physical properties of the m aterials which he uses. During the com ing w inter a post-graduate course in highw ay engineering w ill be offered, b y Colum bia U niversity, which will include instruction in the chem istry of road m aterials. It is therefore evident th at the de
mand has already arisen for a new product of chem ical and engineering sciences— “ The Chemical H ighw ay E n gineer” — to whom the country m ust look for in
form ation and assistance in the intelligent expenditure of a va st am ount of public money. This can best be realized from the fa ct th at a t the close of 1911 it is estim ated that approxim ately one hundred and fo rty million dollars will have been spent b y this country in the construction and m aintenance of highw ays during the year and subsequent annual expenditures will probably far exceed this amount.
Pr é v o s t Hu b b a r d.
INTERNATIONAL CONGRESS OF APPLIED CHEMISTRY.
T en tative rules governing the presentation and publication of papers before this body a t its meetings in September, 1912, have been issued, and in order th at there m ay be no m isunderstandings, all prospec
tiv e authors should carefully read the rules th at follow, subm itting in w riting an y criticisms th ey m ay have to offer, together w ith suggested remedies for such criticisms.
1. A ll papers m ust be in duplicate and legibly written, preferably typew ritten.
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7i ö T H E J O U R N A L O F I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y . Oct., i 9n
or offered to any other Society, Association or publica
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members desiring cloth-bound sets can obtain them at an advanced charge over the S5.00 membership fee; such advanced charge will be announced later, b u t will probably be S2.50; delivery of these cloth- bound sets will be about 90 days later than of the paper-bound sets. A uthors of papers received be
fore the close of June 30, 1912, m ay publish those papers in a n y publication th ey m ay elect .after the paper is read or after the Congress has adjourned.
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It is contem plated to announce the final and definite rules governing the subject m atter of this sum m ary during- December, 19 11; criticism s received before December 1, 1911, w ill be duly considered.
IHE DIRECT PRODUCTION OF MOLYBDENUM STEEL IN TH E ELECTRIC FU R N AC E .1
B y E . T . Di t t u s a n d R . G. Bo w m a n. R eceived O cto b er 1, 1911.
P R E F A C E .
It is the intention of the authors to present in the following paper a brief résumé of the properties, uses and m ethods of production of m olybdenum steel, and to describe in detail a series of experim ents on the production of m olybdenum steel, direct from iron ore and m olybdenite, in the electric furnace.
The use of a sulphide ore of so active a m etal as molybdenum in connection w ith the m anufacture of steel presents a num ber of problems. Forem ost among these are the com plete reduction of the m olyb
denum w ithout serious loss, the diffusion of the m olyb
denum through the steel to form a homogeneous product and the elim ination of the sulphur from the steel. The process em ployed was one based on a reaction described b y F. M. B ecket in U. S. Paten t 855»157. and is believed to be new.
The authors wish to express their h earty apprecia
tion and thanks to Professor W . G. H aldane and others for the encouragem ent and assistance th ey have given in carrying out the experim ental investigations.
The desirable properties of m olybdenum steel and the expense involved in its m anufacture b y the methods at present in use, led the authors to search for some reaction upon which cou;d be based a process for its direct production from its most common ore. W ith out such a process an y extended use of m olybdenum steel, instead of tungsten steel, is v e ry im probable.
The reaction described b y B ecket appeared the most simple and was, therefore, made the subject of the investigations.
The production of steel direct from ore in the electric furnace is easily accomplished where the ore is pure.
Certain impurities, p articularly sulphur, are, however, Verv difficult to remove from the m etal. Sm all amounts m ay be rem oved b y the use of a basic slag hut this m ethod is lim ited in its application since the fusibility of the slag decreased rapidly w ith in
creasing basicity. F or the reduction of m olybdenite 10 the presence of m olten iron it is necessary to have Present some substance which has a greater affinity for sulphur than either m olybdenum or iron. The compound formed b y the desulphurizing agent and the sulphur must either pass into the slag or be vo la tilized as soon as formed. The tw o m etals which seem best adapted for use as desulphurizers, under these conditions, are manganese and silicon.
1 Paper p resen ted a t th e G eneral M eeting of A m erican E lectrochem ical Society, T oronto, S e p t., 1911.
The final rules so adopted w ill be published in the four official languages of the Congress, and w ill then be binding on all contributors to the Congress, and all papers offered to the Congress m ust be offered subject to those rules.
Manganese in the form of m etal or as the ferro alloy reacts w ith sulphides a t high tem peratures according to the following reaction :
î M n + R S = R + 2M11S.
The manganese sulphide forms a slag resembling iron sulphide. If the above reaction takes place in a b ath of molten steel or iron the resulting m etal is ap t to contain small included masses of manganese sulphide. Sulphur in this form has little effect on the properties of steel. This reaction m ight be applied to the production of alloy steels, such as m olybdenum steel, b y adding a m ixture of m olybdenite and ferro
manganese to the bath of molten steel ju st before tapping. This w ould result in the form ation of ferro- m olybdenum and manganese sulphide, the former alloying w ith the steel and the latter passing into the slag.
Silicon reacts w ith sulphides to form silicon sulphide SiS2 and liberates the m etal of the original sulphide.
T his is the reaction described b y B ec k et.1 The reaction has been investigated b y Fielding3 who produced a yellow powder which sublimed at 1 5 0 0 ° C.
and which decomposed w ater w ith the form ation of HjS and silicic acid. This compound did not corre
spond to the form ula SiS,. Sabatier3 describes a some
w hat sim ilar com pound and suggests the formula Si2S4. The heat of form ation of SiS2 is given b y Sabatier3 as +40.4.
This reaction m ight be applied to the production of m olybdenum steel in the same m anner as the m an
ganese reaction described above. The silicon, in the form of ferro-silicon, and the m olybdenite should be reduced to powder, intim ately m ixed in the proper proportion to produce the reaction and added to the steel in the furnace before tapping. The m ixture m ight be added in a soft iron tube or in small bri
quettes m ade up w ith a binder of sodium silicate.
A ddition in the ladle during tapping would probably result in -raising the sulphur content of the m etal on account of the absence of slag, which in the furnace w ould rem ove small am ounts of sulphur which might tend to pass into the steel.
E X P E R I M E N T A L W O R K .
The. experim ental w ork of this thesis was under
taken w ith a view to determine the feasib ility of ap
plying the B ecket process to the production of m olyb
denum steel direct from iron ore and m olybdenite in the electric furnace. The problem s presented were: first, the design and construction of a suitable furnace; second, the production of a carbon steel b y
1 Elec. Chcm. a n d M et. In d ., A ug., 1909.
2 B u ll, de Soc. C hitn., P a ris. 2, 38, 153.
3 C om pt. rend., 90, 819.
ORIGINAL PA PERS.
7*8 T H E J O U R N A L O F I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y . Oct.,.1911 direct sm elting from iron ore; third, the addition of
m olybdenum to the steel and the elim ination of the sulphur of the m olybdenite from the bath of metal.
Of these the third presents b y far the greatest diffi
culty.
F U R N A C E .
T o accomplish the results desired it was necessary th at the furnace fulfil the following requirements:
the crucible walls should be of a neutral or basic m ate
rial, free from carbon; the furnace should be easily charged and operated ; the electrodes should be capable of a v a rie ty of adjustm ents; the furnace should be capable of being readily dism antled for the purpose of relining or m aking alterations. Since the best m ethod of heating could be determined only b y e x periment, it was thought best to design a furnace capable of being operated as a Girod, or w ith slight alteration, as a H^roult furnace.
W ith the above-m entioned requirem ents in view , tw o furnaces were designed. These were essentially the same in principle b u t differed in the proportions of* the crucible and in certain minor details. A de
tailed description of the design illustrated in Fig. i will suffice, since this was the furnace finally adopted and used in the investigations.
The crucible is elliptical in cross section and measures 6 inches X 9 inches X 8 inches (15 X 23 X 20 cm.) deep. The total volum e of the crucible is about 360 cubic inches (5.5 liters), the volum e of the sm elting zone about 90 cubic inches (1.4 liters). The walls have a slight bosh to effect a concentration of heat at the base of the crucible. The crucible lining is of burned magnesite obtained b y crushing magnesite brick to pass 10 mesh (2.5 mm.). The magnesite was m ixed w ith ta r to form a paste and rammed in hot around a central wooden form. The ta r was burned out in the heating up of the furnace.
The walls are built up of eight fire-brick sections of special design, luted together w ith fire-clay and encircled b y steel bands. These rest on a foundation
made up of tw o courses of standard fire-brick, with the joints filled w ith fire-clay.
The cover for the crucible is a solid elliptical fire
brick section 17 inches X 20 inches .and 2*/, inches (43 X 50 X S3 cm .) thick, encircled b y a steel band.
The electrodes enter through the slot in the center of the cover. This slot adm its of considerable lateral or angular m ovem ent of the electrodes. The under side of the cover is slightly concave. An as
bestos gasket is placed under the cover where it rests on the top of the furnace, and small asbestos washers encircle the electrodes where th ey pass through the cover.
The tap-hole is i '/ ( inches (3 cm.) in diameter, and is well rounded a t its point of entrance to the crucible.
A small hole 1 inch (2.5 cm.) in diam eter extends diagonally from the top of the outer wall to the smelting zone for the purpose of pyrom eter readings and for the escape of gases.
E L E C T R O D E S .
The hearth electrode consists of six x/2-inch (1.3 cm.) rods of Swedish iron screwed into a J/,-inch (0.9 cm.) plate of the same m aterial. The plate is embedded in the lining of the bottom of the crucible in such a position th at the upper ends of the rods are flush w ith the inner surface. A copper strap Vh inch (0.5 cm.) thick and 1.5 inches (4 cm.) wide, bolted to the plate, extends outside the furnace for connection to the source of current.
The two m ovable electrodes are supported on a frame above the furnace. The supporting frame is entirely independent of the furnace proper and is therefore unaffected b y expansion or contraction of the walls.
The electrodes are cylindrical graphite rods 1.25 inches (3 cm.) in diam eter and 11 inches (28 cm.) long.
Each electrode is attached to a brass rod by means of a collar clamp and cotter pin. The rod carries a rack which meshes w ith a pinion mounted on the electrode support. The electrode supports are mounted to slide from right to left on the supporting frame.
This facilitates adjustm ent of the electrode while the furnace is in operation, and also allows the electrode to be pushed back out of the w ay when relining the crucible. The support is so constructed th at the electrode m ay be swung about it as a center and in
clined at any angle. O rdinary pipe fittings were used as much as possible in the con
struction of the frame and supports, since these give a light, strong construction, and require no special castings or forgings. An electrode support built entirely of pipe and fittings is illustrated in Fig. 2.
The furnace illustrated in Figs. 2 and 3 differs from th at described above m having a crucible of double the depth described, i. e., 16 inches (40 cm.), and a different arrangem ent of the rods in the bottom of the crucible. This furnace was designed to operate continuously with a column of cold charge resting on the molten material, as in a shaft furnace.
F ie. 3.
electrodes alternately a t intervals of tw o or three minutes, which caused the arcs to alternate from one electrode to the other.
The cap acity of the furnace as described is about 1000 gram s of m etal per charge, or approxim ately 2000 gram s of raw charge. A charge of 1000 grams w as em ployed in several runs. This yielded 500 gram s of m etal, b u t this am ount is too small to make clean tapping possible.
Single-phase alternating current at 60 cycles, 25 furnace as a H iro u lt steel furnace, the points of the rods in the hearth electrode are covered w ith a layer of magnesite, and the two m ovable electrodes are con
nected in series w ith the circuit. The magnesite covering for the hearth electrode need not be of a n y great thickness, since there is but a slight tendency for the current to cross through the iron plate after the charge becomes molten.
electrode w ith the opposite side. The m ovable electrodes m ay then be placed parallel vertically, thus forming tw o arcs, or set to converge to a single central point forming bu t one arc. T o operate the
R U N N I N G O F T H E F U R N A C E .
The furnace is charged a t the beginning of a run b y rem oving the cover and distributing £he charge w ith a trough or funnel. A dditional m aterial m ay be added through the opening in the cover while the furnace is running.
The small am ount of coke in the charge used was found to be sufficient to m ake the cold charge slightly conducting, the resistance rapidly decreases w ith rise of tem perature, and the furnace m ay thus be readily started on a cold charge, providing the walls of the crucible are hot. The electrodes are forced down through the charge to within a short distance of the bottom of the crucible a t starting. A s the charge becomes hot, the electrodes are gradually raised until the charge is reduced and the arcs p lay between the ends of the electrodes and the surface of the slag. W ith the current available it was found impossible to maintain arcs below both electrodes sim ultaneously for any length of time. The best results were obtained b y raising and lowering the This type of furnace m ay be operated as a Girod
steel furnace b y connecting the tw o m ovable electrodes in parallel with one side of the circuit and the hearth
720 T H E J O U R N A L O F I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y . Oct., i 9n
volts, was em ployed. The amperage varied through
out the run, but averaged 250 w ith the arcs running steadily.
A n opening for pyrom eter readings was provided in the furnace, b u t no readings were taken. In a furnace of this' size a variation of tem perature from cold ore to the m axim um sm elting heat m ay be found in a space of a few inches; such a variation would make pyrom eter readings irregular and of little value.
T he generator used in supplying current for the experim ent was a General E lectric alternating current composite-wound, having both slip rings and a rectifier com m uter for supplying direct current to the series
field. The name plate gives the following data:
No. 2044, T yp e A, Class 10-30— 1500. No load voltage 1040, Full load voltage 1155, Thompson- Houston System .
The transformers were made b y the General Electric Co. No. 423,052, T yp e H, Cycles 60, Form G, V olts 1200, 2400, 120,240. The transform ation ratio was 10 -1. The primaries were connected in series w ith the line and the tw o coils in parallel w ith each other, the secondaries all in parallel w ith the line. This com bination gave the best results. The amperage ranged from 0-500 w ith an average of 250, the voltage averaged 25.
The sw itchboard consisted of tw o ammeters in parallel w ith each other and in series w ith the line, a voltm eter in parallel, a circuit breaker, and recording w attm eter. The amm eters were made b y W esting- house E lectric Co., 7,200 alt. circuit, cap. 300 amps.
The voltm eter was a Thom pson Portable machine, the circuit breaker an I. T. E . typ e W . 500 amps.
The w attm eter was a Thom pson recording, No.
104,114, T yp e M, Class 100-200 Form D s.
During all the work the generator was run w ith the series coil short-circuited across the brushes.
This protected the machine because any overload or short would cause the voltage to drop due to the arm ature reaction, and reactance. A dead short would thus cause the voltage to drop to zero and thus no harm could be done to the machine.
The connections of the various pieces of apparatus are illustrated in the accom panying diagram (Fig. 5).
O R E S A N D F L U X E S .
The iron ore em ployed was a good grade of hematite from the mines of the Colorado Fuel and Iron Co.
a t Sunrise, W yom ing. Tw o separate lots were used, the analyses of which were as follows:
P e r cent.
F e ... 6 6 .0 6 AloOs... 1.52 S i0 2... 4 .1 2 P ... 0 .0 4 S ... 0 .0 4
The ore was crushed to pass eight mesh (3 mm.) and the fines were retained.
M O L Y B D E N IT E .
A q u an tity of v e ry pure m olybdenite from York6s Peninsula, A ustralia, w as obtained from the Foote Mineral Co.
A nalysis showed the m aterial to be practically pure MoS2 w ith only a trace of im purity in the form of copper sulphide.
F E R R O -S IL I C O N .
Tw o lots of ferro-silicon were used, the analyses of which were as follows:
P e r cent.
F e . ... 4 9 .7 0 S i... 5 0 .0 0 S ; ... 0.005 C... 0 .2 0
The ferro-silicon and m olybdenite were ground to pass th irty mesh (0.85 mm.) and intim ately mixed in the proper proportions to bring about the reaction
MoSj + Si '= Mo + SiS2.
The proper am ount of this m ixture to give the desired m olybdenum content in the steel was enclosed in a small paper tube and added to the bath of metal ju st before reduction was complete.
C O K E .
The coke used was from Trinidad, Colorado, and was obtained from the N orth Am erican Smelting Co., of Golden, Colorado, from whom the analysis was also obtained.
A n a lysis:
P e r cent.
F ix e d c a rb o n ... 77.70 Vol. an d co m b u st, m a t ... 2 .8 0 A sh ... 18.66
FezO ... 1 2 3
AI2O3... • • • 1 -41 C aO ... 1 30 Si0 2... 6 .5 9 . S ... 0.47 M oisture... ... 0.8 4
The coke was crushed to pass eight mesh (3 mm.) and the fines retained.
LIME.
Ordinary builders’ lime was used as flux. The analy
sis was as follows:
P e r cent.
C aO ... 92.76
MgO...
FejO j. A lsO;... 1-90 S i0 2... 1 -34 P ... ft. 96
The lime was crushed to pass eight mesh (3 mm ) and the fines retained.
R E C O R D O F F U R N A C E R E S U L T S . R U N N O . 5.
Charge:
Iro n o re ... 3,025 gm.
■* C oke... 660 gm.
L im e . ... 412 gm.
C alcu lated iro n c o n te n t... 2,000 gm . L e n g th of r u n ... 1 h r. 30 m in.
M ean a m p e re s... 200 M ean v o lts ... 25 K . W ... 5 M etal o b ta in e d ... 1,700 gm.
C alculated m o ly b d en u m c o n te n t...2.5 p e rc e n t.
Iron turnings were spread over the bottom of the crucible and covered b y a layer of coke, lime and silica to form slag and protect the iron. The m etal m elted in 25 minutes b u t was kept m olten in the furnace for 15 minutes after fusion in order to b u m out the tar from new portions of the lining. This m etal was tapped cleanly and a charge sufficient for 500 grams of metal was added. This reduced in 20 minutes.
Molybdenite-ferro-silicon rrfixture sufficient to give a content of 5 per cent. Mo in the m etal was added in a paper tube ju st before reduction was complete.
The tap hole was opened but the m etal was level w ith the tap and only slag flowed out. The tap hole was again plugged and a charge sufficient to give 1000 grams of m etal was charged.
Reduction was rapid and the charge was entirely reduced in 30 minutes. M olybdenite m ixture sufficient to give a m olybdenum content of 2.5 per cent, in the metal ¿vas added ju st before final reduction of the charge. Since the bottom of the crucible appeared to be sinking constantly, another charge equivalent to 500 grams of m etal was added and reduced in 15 minutes. This gave a total of 2000 gram s of m etal (calculated) in the furnace, w ith sufficient m olyb
denum to yield 2.5 per cent, in the total.
The tap hole was opened and slag flowed out freely but no m etal was obtained. The current was shut off and the furnace allowed to cool. A solid mass of metal level w ith the tap hole was found in the bottom of the crucible.
The furnace was taken down and the entire lining and bottom electrode removed. A solid mass of metal weighing 1700 gram s was obtained. The m etal was malleable and tough, and was broken w ith great difficulty. W hen broken across the center the fracture was very fine-grained and dense at the center of the mass and coarsely crystalline and full of small blow holes at its outer edges.
A section 0/ the central portion of the mass, polished and etched w ith picric acid, showed a netw ork of a bright w hite constituent, prob ably a double carbide of molybdenum and iron. A section in the coarsely crystalline portion of the mass showed a coarsely granular structure.
Analysis:
P e r cent.
C ... 0 .6 2 S i... 0 .91 M o... 1.15 P ... 0 .0 8 S \ ... 0 .3 7
R U N N O . 6 .
C harge:
Iro n o re ... 756 gm.
C oke... 163 gm.
L im e ... 103 gm.
C alculated iron c o n te n t... 500 gm.
C alcu lated m o ly b d en u m c o n te n t... 2 p e rc e n t.
L e n g th of r u n ... 30 m in.
M ean a m p e re s... 300 M ean v o lts ... 25 K . \V ... 7 .5 M etal ta p p e d ...
Description of run:
The furnace was rebuilt and arranged as in Run 5. The tap hole was given a sligh tly'g reater inclina
tion.
Iron turnings were placed on the bottom of the crucible and were m elted in 30 minutes. The tar in the new lining burned out v e ry slow ly and the m olten m etal was, therefore, allowed to remain in the furnace for one and one-half hours w ith the arcs running.
W hen the greater p art of the tar was burned out the m etal was tapped and the charge added.
Reduction was rapid and m olybdenum m ixture sufficient to give a m olybdenum content of 2 per cent, w as added. The walls of the crucible were crumbling and the crucible was rapidly becom ing too large to heat properly. The magnesite from the lining made the fused charge thick and pasty. An attem pt was made to tap the m etal b u t nothing was obtained.
The crucible was now too large to work properly but since the bottom seemed to be sinking it was thought advisable to fill the crucible up to the proper level b y the reduction of a large charge of ore. A charge corresponding to 2000 gram s of m etal was added in small am ounts w ith the arcs running. R eduction was rapid b u t not uniform, owing to the increased size of the crucible. B y continual poking of the charge the whole mass was finally fused but was not suffi
ciently liquid to tap. The furnace was allowed to cool and a mass of m etal level w ith the tap hole was found em bedded firm ly in the bottom . A small portion of this m etal was rem oved w ith tongs and proved to be ve ry soft and m alleable and easily sawed or cut.
A polished section etched with picric acid showed a netw ork of bright white lines in a ground of pearlite.
A n alysis:
P e r cen t.
C ... 1 .1 4 S i... 1.23 P ... ... 0 .0 3 S ... 0 .0 3 M o... 0 .4 5
R U N N O . 7
Charge:
Ir o n o re ...
C o k e...
L im e ...
C alcu lated iro n c o n te n t...
L e n g th of r u n ...
M ean a m p e re s ...
M ean v o lts ...
K . W ...
M etal ta p p e d ...
The crucible was relined. The electrodes were p artially consumed and, since no more of the same
1,512 gm.
326 gm.
206 gm.
1,000 gm .
’. 60 m in.
300 25 7 .5
722
size were a t hand, were rem oved and replaced b y i 1/ , inches (3 cm.) rods. The arcs were started on the mass of m etal rem aining from Run 6. W hen the furnace was hot and this m etal was molten, a charge was added and quickly reduced. The tap-hole was opened, bu t only a portion of the m etal was obtained.
The charge was then found to have formed a scaffold across the crucible. It was found impossible to smelt down the semi-fused mass forming the scaffold w ith the small electrodes a t hand; the furnace was, there
fore, allowed to cool and the m aterial picked out.
The m etal obtained in tapping had a coarse crystal
line structure and was extrem ely hard and tough.
A polished section etched with picric acid and magnified 180 diameters showed irregular branching figures of a bright white constituent in a ground of g ra n u la r p earlite.
A nalysis :
P e r cent.
C ... 0 . 7i S i... 2 .1 4
(L arge a m o u n t of scale in sam ple.)
P ... 0 .0 4 S ... 0 .0 2 5 M o ... 1.95
R U N N O . 8 .
Charge :
Ir o n o re ... 1,512 gm.
• C o k e ... 326 gm.
L im e ... 206 gm.
C alculated iro n c o n te n t ... 1,000 gm.
C alculated Mo c o n te n t... 5 p e rc e n t.
L e n g th of r u n ... 60 m in.
M ean a m p e re s... 300 M ean v o lts ... 25 K . W ... 7 .5 E lec tro d e co n su m p tio n ... 6 5 .0 gm.
M e ta l t a p p e d ... ... . . . .
The fu m acc was started on a small am ount of wrought iron punchings, covered b y a little powdered coke. These m elted rapidly, and a sm all charge was thrown in in small portions w ith the arcs running freely. When the m etal was all melted, the entire charge was added and the electrodes embedded in the cold m aterial. The sm all rods em ployed in E x periment 7 had been replaced b y full-size electrodes.
Reduction of the charge was rather slow. A t the end of six ty minutes an attem pt was m ade to tap.
Slag flowed out freely and filled the mould, b u t the m etal would not flow. The tap-hole was closed and a strong arc started to m elt the mass of metal. Upon tapping, a portion of the m etal was obtained. This was tough and m alleable and had a v e ry fine-grained structure.
The m olybdenum m ixture was added as usual just before reduction was complete. W hen the arc was started on the surface of the m etal after tapping the slag, a w hite sublim ate formed on the electrodes and the under surface of the cover. This was probably MoO„ formed b y the oxidation of the. m etallic m olyb
denum in the steel, which was unprotected b y slag.
A polished section of the m etal tapped, when etched w ith picric acid and exam ined under a m agni
fication of 180 diameters, showed a coarse netw ork of the characteristic bright white constituent in a mass of pearlite.
O c t., 1911 A nalysis:
P e r cent.
C ... 0 .9 2
P ... 0.0 4 3 S i... . ... 1.10 M o... 2 .1 5 S ... 0 .0 3 6
R U N N O . 9 .
C harge:
Ir o n o re ... 756 gm.
C o k e ... ... 163 gm.
L im e... 103 gm.
C alcu lated iro n c o n te n t... 500 gm.
L e n g th of r u n ... 60 m in.
M ean a m p e re s... 300 M ean v o lts ... 25 K . W ... 7 .5 M etal ta p p e d ...
C alcu lated m o ly b d en u m c o n te n t... 0 .6 p e rc e n t.
The furnace was started on the m etal remaining in the crucible. W hen the crucible was well heated, the charge was added, and reduction was rapid. At the end of six ty minutes an attem p t was made to tap.
Slag flowed out freely, b u t the m etal would not flow.
This was due to a dam of m etal formed ju st outside the tap-hole from a leak in the clay plug.
The furnace was allowed to cool, and a mass of metal weighing about 450 gram s was taken from the crucible w ith tongs. This m etal was ve ry malleable and tough and could be easily sawed and cut.
A polished section, etched w ith picric acid and exam ined under a m agnification of 190 diameters, showed the characteristic net-work of double carbide and in addition a mass of needles of a white constituent resem bling the carbide.
A n a lysis:
. P e r cent.
C ... 0 . 5 4 S i... 1 . 6 5 M o... 0 . 4 5 P ... 0 . 0 7 S ... 0 . 0 5
R U N N O . IO .
M olybdenum steel from m olybdenite concentrates.
Analysis of concentrates (W ood’s Flotation Process):
P e r cent.
M o... 1 1 . 1 0 C u ... 0 . 7 2 S ... 1 5 . 0 0 S i0 2... 6 5 . 0 0
M olybdenum m ixture (equivalent to 0.66 per cent.
Mo in calculated iron).
G ram s.
C o n c e n tra te s... 1 0 0 S i-F e ... 9 . 2 8 L im e ... 6 5 . 0 0
C h arge:
A s in previous runs, equivalent to 1500 grams calculated iron.
L e n g th of r u n ...4 0 m in.
M ean a m p e re s... 2 5 0
M ean v o lts ... 2 5 K . W ... 6 . 2 5 M etal ta p p e d ... 1 , 3 7 0 gm.
Furnace started on m etal in bottom. Charge added in two portions and reduced rapidly. A tap was attem pted after the addition of the first charge, b u t the m etal would not flow. The molybdenum T H E J O U R N A L O F I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y .
mixture w as added in tw o equal portions and was reduced alm ost instantly. The trap was clean and the ingot obtained was sound and free from large blow holes. The increase in m olybdenum content in the -metal over th at calculated was prob ably due to a concentration of the m olybdenum in the m etal reduced.
A polished section, taken from the center of the ingot, when etched w ith picric acid and exam ined under a magnification of 180 diameters, showed a fine network of the double carbide and sm all isolated patches of the same constituent all in a ground mass of pearlite.
Analysis:
P e r cen t.
C ...i ... 0 .7 0 S i0 2... *... 1.2 0 M o... 0 .7 0 P ... 0 .1 0 S ... 0 .4 5
C O N C L U S IO N S .
Since the results of the experim ents herein described, with the exception of runs Nos. 5 and 10, were quali
tative rather than qu antitative, further experim ents would be necessary in order to determine the loss and distribution of m olybdenum.
Since no analyses were made upon the slag, it is impossible to determine w hat proportions of the sul
phur were rem oved b y the ferro-silicon and the slag.
(1) Molybdenum steel can be made in the electric furnace b y the direct reduction of iron ore and the addition of m olybdenum -in the form of m olybdenite, MoSj.
(2) M olybdenum steel of low su lp h u r c o n te n t can be produced from m oly b d en ite b y th e use of ferro- silicon as a desulphurizer.
(3) M olybdenum steel of low su lp h u r c o n te n t can be produced .from m oly b d en ite in th e form of low- grade co n cen trates b y th e use of ferro-silicon as a desulphurizer.
With regard to the design of a furnace for small scale operations, the foregoing experim ents would indicate th at:
(1) The Girod principle as used was superior to the Hiroult.
(2) A tilting furnace would be more effective than a stationary furnace.
(3) The tap-hole on a station ary furnace should be made short, w ith a steep inclination. Am ple provision for heating the tap-hole should be made.
(4) T ar does n o t m ake a satisfa c to ry b in d in g m aterial for crushed m agnesite.
Co l o r a d o Sc h o o l o f Mi n e s, Go l d e n, Co l o r a d o.
c o n c e n t r a t io n a n d p u r i f i c a t i o n o f i r o n o r e, h i g h IN SULPHUR, B Y ROASTING IN A RO TAR Y K IL N .1
B y Ja m e s Ot i s Ha n d y a n d Jo h n M . Kn o t e. R eceiv ed J u ly 14, 1911.
While the am ount of high-grade iron ore still un- mmed is va st in quantity, the deposits of low er grade
1 Read b y Ja m e s O tis H a n d y a t In d ia n a p o lis M eeting A. C. S., J u n e , 1911.
are receiving serious attention. W ater concentration, m agnetic separation or roasting are being used as means of elim inating in part sulphur, phosphorus and silica and raising the iron content so th at the ore becomes com m ercially valuable. This paper is con
cerned w ith the solution of a problem of concentration b y roasting.
T H E O R E .
The ore consisted of approxim ately the following m ixture of minerals:
M ag n etite (F e304) 32.6 p e r c en t. «« 23.66 p e r c en t, m etallic iron S id erite (FeCOs) 27.1 p e r c en t. “ 13.50 p e r c en t, m etallic iron P y r ite (FeS2) 7.5 p e r c en t. 3.50 p er c en t, m etallic iron C alcite (CaCOs) 13.2 p e r c en t. — 7.4 p e r c en t, calcium oxide M agnesite (MgCOa) 10.8 p e r cent. *=* 5.1 p e r c en t, m agnesium oxide M anganous oxide (M nO) 2.5 p e r c e n t . *=* 1.95 p e r c en t, m anganese
Silica (S i0 2) 6.3 p e r cent. =
An a l y s i s o f Ca r g o Sa m p l e.
P e r cent.
Ir o n ... 4 0 .6 6 M anganese... 1.95 L im e... 7 .40 M agnesia... 5 .1 0 C arbon d io x id e ... 2 1 .8 0 A lu m in a ... 1.25 Silica... 6 .3 2 S u lp h u r... 4 .0 1 P h o sp h o ru s ... 0 .0 1 5
No doubt the carbonates of calcium and magnesium were com bined as dolomite.
The advan tage of the roasting process over other concentration processes was obvious; the valuable fluxing agents would be retained and if the expulsion of sulphur could be made com plete enough, even the iron in the pyrite would be available.
L A B O R A T O R Y E X P E R I M E N T S .
An average sample of the iron ore, obtained b y diamond drilling, was used. It was crushed to pass a J/a-inch screen. The first experim ents were in roasting in a muffle furnace a t a tem perature of 650-750° C. which is usually considered favorable for the elimination of sulphur from p y rite .1 H ardly more than 2 per cent, of sulphur (about one-half) could be roasted out at this tem perature even when ore finer than x/j inch was used. T he tem perature was gradually increased w ith ve ry slight gain until n o o ° to 1150° C. had been reached when the sulphur percentage dropped rapidly from about 1 per cent.
to_ less than o. 1 per cent, and in some cases the sul
phur was entirely eliminated.
The most successful experim ents were those in which the ore was introduced into a muffle having a tem pera
ture of 1150° C. The door was closed after 15 minutes. The heating then continued for an hour a t a tem perature of 1x50° C. The ore had fused or sintered slightly, and contained from 0.032 per cent, to no sulphur.
A pparently it was necessary to raise the roasting tem perature above the point where sulphates could exist or where lime could hold sulphur. Although the successful experim ents w ith small lots of ore in a closed b u t not sealed muffle seemed to indicate oxida
tion of sulphur b y oxygen in the ore itself, subsequent tests showed th at half or less of the sulphur could
1 L unge, S u lp h u ric A c id and A lk a lit l f I , 340 (1903).
