G rin d in g in th e c e m e n t in d u s tr y . N. C. Rock-
wood (Rock Products, 1938, 60—63).—The introduc
tion of closed-circuit grinding is tho greatest recent advance. Tho rate of passage of cement is accelerated by eliminating diaphragms in mills, different-sized grinding media being segregated by special linings, or by the form (e.g., conical) of th e mill. There is a distinct tendency towards coarser cement, although a proportion of “ flour ” is essential. G. H . C.
[G rin d in g of] d ic a lc iu m s ilic a te [in P o r tla n d c e m e n t]. A. I. Korschunova (Trans. Union Res.
In st. Cements, U.R.S.S., 1937, No. 17, 34—39).—
The functions of 2C a0,Si02, 3C a0,Si02, alite, belite, and celite in P ortland cement are briefly discussed.
Belite cements should be ground more finely th an high-grade alite cements, their resistance to
com-pression being thereby greatly increased. Separating mills, giving a const, output of fine dust, should be
used. D. G.
D e te rm in a tio n of th e sp ecific s u rfa c e of P o r t la n d c e m e n t r a w m ix tu r e s b y m e a n s of tb e W a g n e r tu r b id im e te r . T. Asano (Rock Products, 1936, 39, No. 2, 34—36).—Gradation by wt. obtained with the Wagner apparatus agreed well w ith air- elutriation and sedim entation-pipette results. The best results were obtained with aq. suspensions, using N a2S i03 as dispersing agent. Ch. Ab s. (e)
T h e o ry of b u rn in g of P o r tla n d c e m e n t in a u to m a tic s h a ft k i l n s . Y. N. Young (Trans. Union Res. Inst. Cements, U.R.S.S., 1937, No. 17, 3—33).—
A comparison is made of the conditions of burning of clinkers in shaft and rotary kilns and the wide technical dissim ilarity between the two processes is pointed out. The chemical reactions which take place a t various points in a shaft kiln are discussed and cross-sectional diagrams, showing compositions of different layers and analyses of th e gas phase, are
given. D. G.
F e r r a r i c e m e n t. F. Ferrari (Zement, 1938, 27, 1—6).—A sum mary of its history, m anufacture, and properties, and a bibliography are given.
G. H. C.
S o d iu m s ilic a te c e m e n ts . F. D. Snell (Chem.
and Ind., 1938, 62—63).—Reference is m ade to H 20- and acid-resistant cements described in B.P. 401,522 and 470,890 (B., 1934, 98; 1938, 379). Typical mixings are : aggregate 100, “ dry ” N a2S i0 3 (Na20 / S i0 2 1 : 2, and 20% of H 20) 25, N a2S iF 6 23 pts., mixed with H 20 ; aggregate 100, N a2S iF 6 9-4, liquid Na2S i03 (Na20 /S i0 2 1 : 3-25, 38% solid content) 70 pts. The tim e of workability of the la tte r is 15—20 min. and becomes im practicably short if the alkalinity of the N a2Si03 is < 1 : 3-25. ' J . A. S.
R e fra c to ry c e m e n ts a n d m o r ta r s . I I I . S.
Nagai and J . Katayama (J. Jap an . Ceram. Assoc., 1937, 45, 447—458; Zement, 1938, 27, 176; cf.
B., 1938, 378).—The resistance of various commercial cements to attack by slags etc. was tested by moulding a mixture of cement and slag into a cone and observing its collapse in the furnace. A new type of cement was evolved, containing 70—90% of crushed diaspore (or a fused mass of mullite and corundum), 10—30% of hydraulic cement (CaO, A120 3 or 3Ca0,5Al20 3) made from A120 3 and CaC03, and 0—5% of bentonite or
other plasticiser. G. H. C.
D e te rm in a tio n of free lim e [in P o r tla n d c e m e n t] b y th e E m le y m e th o d . P. D. Katze-
nelenbogen and N. A. Toropov (Trans. Union Res.
Inst. Cements, U.R.S.S., 1937, No. 17, 52—55).—
Clinkers giving on analysis by the Em ley method
>1-0% of free CaO, i.e., a harmless q uantity of CaO, were nevertheless found to be unsatisfactory. Micro
scopical investigation showed th a t th ey contained a considerable no. of free CaO crystals, and attention is therefore drawn to the inaccuracy of this method.
Modifications are suggested. ' D. G.
M o d ified eth y len e g ly co l m e th o d fo r d e te r m in in g fre e lim e in [P o rtla n d ] c e m e n t c lin k e r. S.
Ro r d a m (Rock Products, 1937, 72—74).—I n place of pure (CH2'OH)2 (I), a m ixture of 30 ml. of (I) and 15 ml. of abs. MeOH is used. The flask is heated so th a t the MeOH refluxes, thereby m aintaining const, temp, and excluding 0 2, which oxidises (I). After boiling for 30 min., the liquid is filtered, washed with MeOH, and titrated with 0-In-HCI (to bromothymol- blue). I t is easier to ru n p ast th e end-point and back- titrate with O-lN-NaOH. Addition of BaCl2 as in the usual procedure leads to high results. G. H. C.
S tr u c tu r e of tb e g la s s y p h a s e in P o r tla n d c e m e n t c lin k e r. L. T. Brownmiller (Amer. J . Sci., 1938, [v], 35,241—259).—The effect of instantaneous, normal, and delayed quenching of various ternary and quaternary systems involving CaO, A120 3, S i0 2, and Fe20 3 has been examined. A t cooling rates inter
mediate between those which produce glasses and crystals, m etastable phases separate which, though similar to true glasses, give rise to X -ray diffraction lines. The diffraction p attern is const, over a wide range of compositions and is alm ost identical with th a t due to cryst. 3Ca0,Al20 3, even when A120 3 is absent. There is no evidence th a t the m etastable phase is an unstable modification of 4Ca0,Al20 3,Fe20 3, for it has been shown th a t the la tte r compound passes from th e liquid state (glass) into the cryst. state without any interm ediate m etastable arrangements. The properties of th e m etastable phase depend on th e rate of cooling, Tj of the m elt, and its composition.
C. R . H.
E v a lu a tio n of [c e m e n t] c lin k e r. K . Wurzner
(Zement, 1938, 27, 59—63).—W hen the d of clinker is determined in a sp.-gr. bottle, with turpentine, slowly increasing vals. are obtained as the liquid enters the pores, bu t never rising to the val. found for ground clinker. When the bulk d is corr. to a const, proportion of voids, different clinkers show little variation. Likewise re-sintering has little effect on the interior pore vol. of clinker particles. The sieve fraction between 5 and 7 mm. is found to contain particles th e masses of which vary over a 2 :1 range, and the proportion of voids in this fraction depends m ostly on the relative nos.-of heavy and light particles which happen to be present; different results are obtained w ith round- and square-mesh sieves. Since bulk d depends m ainly on the voids and interior porosity of th e clinker, Anselm’s claim (B., 1936, 1095), th a t this is a measure of degree of burning and thence of quality, is discredited. G. H . C.
E v a lu a tio n of [c em en t] c lin k e r. W. Anselm
and K . Schindler (Zement, 1938, 27, 137— 140).—
Critics are considered to have misunderstood the m ethod (cf. Mussgnug, B., 1938, 59; W urzner, preceding abstract). The empirically found relation
ship is upheld, and the method does not depend on the selection of a particular sieve fraction. G. H. C.
B u lk d e n sity a n d [c em en t] c lin k e r e v a lu a tio n . K . Burgedorf (Zement, 1938, 27, 205).—An example from practice is given to show th a t Anselm’s pro
cedure (cf. preceding abstract) cannot replace any existing means of control or test. G. H. C.
P e tr o g r a p h ic s tu d y of c lin k e r p ro d u c e d b y th e K r a m a to r s k c e m e n t w o rk s . L. M. Tkatschenko
Cl. IX .—B U ILD IN G MATERIALS. 655 and N. S. Kostzov (Trans. Union Res. Inst. Cements,
U.R.S.S., 1937, No. 17, 61—78).—Microscopical investigations are described. The variation in mineral composition and characteristic structure of the clinkers with changes in conditions of m anufacture is investigated. The clinkers are, on the whole, const, in composition. They contain alite in pre
ponderance, belite (5—20%), celite (15—20% );
decomp. products of alite and sometimes of belite are also found together w ith a certain quantity of an amorphous, dark-coloured mass. Tables are givon showing chemical compositions and results of mechan
ical tests on various clinkers. D. G.
A c c e le ra te d te s ts of s tr e n g th s of c e m e n t p ro d u c ts . W. Hunter, J. M. Jackson, and R.
Budeiri (J. Roy. Tech. Coll., 1938, 4, 276—284).—
The effects of the normal curing process of cements, which occupies 7 days, were approx. reproduced by curing a t 100° for 6 hr. Accelerated curing by steam under pressure developed high strengths rapidly, but was unsuitable for reproducing the effects on strength which are caused by changes in H 20 -c em en t ratio and cement content under normal curing conditions.
A. K. G. T.
T e s tin g la b o r a to r y e x p e rim e n ts : w a te r -c e m e n t r a tio in -c e m e n t -c o n -c re te . D. S. Ve n-
kanna and R. Srinivasan (Current Sci., 1938, 6, 386—387).—Any variation of the H 20 -cem ent ratio from an optimum val. for a given fineness modulus m arkedly reduces the strength of 1 : 2 : 4 cement concrete. D ata are recorded, and the need for an exact H 20 -cem en t ratio in preparing concrete is emphasised. Cement concrete increases rapidly in strength during the first week and then less rapidly
for 6 months. L. S. T.
R ole of i n e r t m a te r ia ls in c o n c re te . M. A.
Caquot (M6m. Soc. Ing. Civ. France, 1937, 90, 562—
582).—The problem of granulometric composition is one of finding a grading to give min. voids. For coarse m aterial the grain sizes should fall in the order 0-4,1-6, 6-3, 25 mm., and some tolerance is permissible.
The quantity of fine m aterial must be fixed more exactly. More uniform concrete is produced when the grains < 2 mm. are rounded th an when angular.
Various grading curves are discussed. T. W. P.
C h e m is try a n d p h y sic s of c o n c re te s h rin k a g e . R . W. Carlson (Proc. Amer. Soc. Test. M at., 1935, 35, 370—382).—The shrinkage of m ortar and concrete was > would be expected from a knowledge of the shrinkage of tho cement paste. The increase was attrib u ted to presence of voids. The shrinkage per unit of small bars was th a t of larger specimens.
Ch. Ab s. (e) C o lo rim e tric d e te r m in a tio n of silic a in a lim e m o r t a r . E. I. Nagerova and A. D. Petrova
(Trans. Union Res. Inst. Cements, U.R.S.S., 1937, No. 17, 56-—60).—A m ethod of determining S i02, based on the form ation of a coloured Mo complex, probably H 8Si(Mo20 7)6, by addition of a small quantity of acid (NH4)2Mo04 is described. Picric acid solutions are used as standards. Results obtained compare very favourably with gravimetric methods.
D. G.
C o rre la tio n of e le c tric a l a n d t h e r m a l p r o p e r tie s of b u ild in g b ric k . J. S. Johnson (J. Amer.
Ceram. Soc., 1938, 21, 79—85).—Measurements of therm al and electrical conductivities and porosities were m ade on a series of light-wt. firebrick and building brick. The conductivities decrease hyperbolically with increase in porosity. Tho initial val. of k decreases w ith tim e to a degree depending on tho porosity, and tho mechanism of the conductivity appears to be by ionic movement. The ratio of the electrical conductivity to k increases approx. linearly with increase in porosity. J. A. S.
P ro b le m s co n n e c te d w ith p o ro u s b u ild in g m a te r ia ls . D. R. G. Bonnell (Chem. and Ind., 1938, 195—198).—Problems of H 20 in the pores of building m aterials aro discussed, w ith particular reference to frost action, crystallisation of salts, and moisture movement (i.e., shrinkage and swelling on
drying and wetting). T. W. P.
R a p id s ta in in g in g r a n ite s u s e d in civ il en g in e e rin g w o rk . B. H. and R. G. Knight (J. Inst.
Civil Eng., 1937—8, 545—552).—Chemical and microscopical tests aro described on granites which acquired a pink colour after a few days’ exposure.
The pink staining was caused by an unstablo dark mica, identified in th in sections by its optical proper
ties ; it was a surface phenomenon and had no struc
tu ral significance. Accelerated chemical tests with
H N 0 3 are described. T. W. P.
M a s tic flo o r tile . C. Ellis (Ind. Eng. Chem., 1938, 30, 20—23).—Tho use of asphalt, plasticised coumarone, and S resins is discussed and the general manufacturing processes are described. S. M.
P r o g r e s s in b ric k - ro a d r e s e a rc h . H. Z. S ch o
field (Ohio Ceram. Ind. Assoc., Preprint, Nov. 2,
1935, 5 pp.).—Two new fillers are described : (a) S 60, graded sand 30, and Thiokol 10% ; (b) a 1 : 1 m ixture of asphalt and S. (a) had th e advantage th a t the finished joint was perfectly filled, bonding was tenacious, and a firm resilient state was m aintained over the year’s temp, range. Disadvantages were tho cost and the difficulty of application. Type (b) m aintained a uniform consistency in summer and winter and showed greater resistance to shear or tension th an did asphalt alone. Ch. Abs. (e)
A d h e sio n of b itu m in o u s b in d e r s to r o a d a g g r e g a te s . B. H. Knight (Inst. Mun. Co. Eng. J ., 1938, 64, 1401— 1421; R oad Abs., 1938, 5, No. 148).
—Results from th e Riedel and W eber test and the mineral composition, grain size, and surface texture of the tested aggregates are compared. Mineral composition is im portant only in so far as it affects surface texture, but th e grain size of the constituent minerals is a factor in adhesion. Slags are an excep
tion to this. Adherent coatings {e.g., linjonite) improve adhesion. A m ethod of measuring the degree of roughness of a surface, in which a magnified projection of the edge of th e aggregate is compared with one of a series, is described. Stones classed as unsatisfactory by the Riedel-W eber test require further testing by the modified Oberbach test.
T. W. P.
B io c h e m is try of d ry - ro t in w ood. I I I . P r o d u c ts of decay of p in e w o o d r o tte d b y M eru lhis lach rym an s. J . G. Boswell (Biochem. J ., 1938, 32, 218—229; cf. A., 1931, 886).—Two fractions of rotted pine wood (probably P. resinosa), one of which was in an advanced stage of decay, have been investig
ated and tho properties of the E tO H , H 20 , and dil.
NaOH extracts and of th e cellulose in each have been examined in detail. The ro tted sample contained only slightly more lignin th an the sound wood, whilst tho more rotted p a rt contained 40% of lignin.
In the early stages of the fungal attack, th e destruc
tion of cellulose proceeds very quickly and the process is one of hydrolysis, whilst th e smaller units so produced, which are not smaller th a n trisaccharides, are not attacked so quickly. The dil. alkali extract on progressive hydrolysis gave : (a) a fraction hydro
lysed by dil. acid to mannose, xylose, and an u n identified acid, (b) one which had a uronic acid content and yielded glucose when hydrolysed by fuming HCl, and (c) an insol. fraction which resembled lignin.
From the H 20-sol. fraction, four substances with strong reducing properties were isolated as the following 2 : 4-dinitrophenylhydrazones : C2aH20O13N &, m.p. 2S0°, C2J I 2ZOv N 8, m .p. 147°, 8, m.p.
182°, and m .p. 116°. J . N. A.
K iln -se a so n in g tr e a tm e n ts of te a k a n d th e ir effects on i ts w e a rin g q u a litie s a s flo o rin g . I.
R. A. G. Knight and A. R. Dean. I I . F. H. Arm
strong (Dept. Sci. Ind. Res. Forest Products Res.
Rec., 1938, No. 23, 14 pp.).—I. A general drying schedule for teak is suggested, covering a moisture range in inlet samples of 40—10%.
II . The floor-wearing qualities, max. bending strength, and resistance to indentation of teak are not affected by the use of kiln tem p, of 95° and 45—
60°. Resistance to shock is lowered by drying a t
higher tem p. E . A. R .
T e s tin g of w o o d tr e a te d w ith fire r e ta r d a n t s . C. R . Brown (Proc. Amer. Soc. Test. M at., 1935, 35, 674—704).—The procedure of testing is described.
The moisture content of specimens has no effect within tho normal range. Treatm ents which reduce combustibility do not necessarily retard flame pene
tration. D ata aro correlated and discussed.
Ch. Abs. (e) A c id p ro o f s ta in [for w o o d ]. C. F . Scribner
(Ind. Finishing, 1935,11, No. 5, 46).—Two coats of a solution containing CuS04,5H20 1 pt., KC103 1, and H aO S pts. are appliod, followed by 2 coats of 15%
aq. N H 2Ph,HCl. After thorough drying raw linseed
oil is rubbed in. Ch. Abs. (e)
B le a c h in g a c tio n of a lk a lin e h y d ro g e n p e ro x id e on w o o d . W. G. Campbell and G. Swann (Bio
chem. J ., 1938, 32, 702—707).—Many woods can be bleached by H 20 2 in presence of N H 3 or dil. aq.
NaOH a t room tem p., the final colour of the wood being fairly perm anent provided th a t drying is effected a t low temp. The wood is first darkened and a dark extract obtained, following which both wood and extract aro bleached w ith evolution of gas.
P . G. M.
H e a t-in s u la tin g m a te r ia ls .-—See I. W ood fo r d is tilla tio n p la n ts . P r o d u c ts f r o m th e r m a l d e
co m p . of w o o d . F lo w p ro p e r tie s of a s p h a lts .—
See II . W ood s u b s ta n c e s .—See V. H y d ra u lic lim e s . B u r n t C aO .—See V II. S ilic a te s in in d u s try . D e te rm in in g -t] of s la g s y s te m s . A l- c o a te d g la s s .—See V III. S e rv ic e of p a in t on w o o d .—See X III.
Patents.
C e m e n t a n d p l a s t e r m a te r ia l. J . W. Phillips, Assr. to F. J . Lindquist (U.S.P. 2,071,263, 16.2.37.
Appl., 28.9.34).—To th e gauging H ,0 of a hydraulic cement are added tung oil (blown, if desired) and a drier and the whole is emulsified with tho aid of a sol. soap, and of N(C2H 4*OH)3 if desired.
B. M. V.
C alcin ed m a g n e s ite c o n c re te . M. L evi (B.P.
473,953, 5.3.37).—
-A
light concrete is m ade from calcined magnesite, with or without sand, sawdust, or cement, mixed with an aggregate consisting of whole seed husks (e.g., rice husks) and MgCl2 solution.The husks are n o t ground, in order th a t air pockets m ay exist in the concrete. T. W. P .
C e m e n t m o r t a r s a n d c o n c re te s, a n d m o n o lith s o r b lo c k s m a d e th e re fro m . R. Barker, G. Brier, R . F o x , L. V. F o x , E. Jukes, and A. M. Smith (B.P.
474,085, 1.5. and 27.7.36).—A concrete m ade from Portland cement, granulated or powdered slate, and granulated or powdered b u rn t blue bind or shale, gauged with the supernatant liquid obtained from a suspension of CaO in H 20 w ith added soap, is claimed.
A m ethod for malting blocks from this composition in which a glass facing is mado to adhere is also claimed.
T. W. P.
P r o d u c tio n of lig h t-w e ig h t sto n e s . K. I. A.
Eklund (B.P. 480,681, 25.7.36. Swed., 27.7.35 and
13.1.36).—To form a stone resistant to weather, a m ixture is mado of free CaO, w ith or w ithout cement, b u t not slag cement, finely-ground silicious m aterials with sugar or the like as plasticiser, and, if desired, aggregate. Tho min. of H 20 necessary to form a homogeneous m ixture is used, and induration effected
by steam. B. M. V.
P ro d u c tio n of p la s tic c o m p o s itio n s [fo r b u ild in g p u rp o s e s ]. A. G. R odwell and S. H. Colton
(B.P. 4S0,793, 3.9.36).—Hydraulic cement, Portland cement, CaO- or CaS04-plaster is mixed with H 20 (sufficient to hydrate it completely b u t > 10% in excess of this quantity) and, before setting occurs, rubber latex or other aq. colloidal dispersion of natural or synthetic rubber is added. The whole is th en allowed to set, giving plastics suitable for roads, floors, walls, and, particularly, layers between steel frames and wooden decks of ships. S. S. W.
O b ta in in g c o n s tru c tio n m a te r ia ls f o r r o a d s , e m b e d d e d in a n o rg a n ic b in d e r. Soc. Franq. D u Vialit (B.P. 481,404, 24.7.37. Ger., 25,7.36).—
A m ixturo of fragm ents of stone and org. binder, preferably m anufactured hot, is rendered non
agglomerating in storage by presence of a suspension of a filler in a liquid which is not a solvent of either tho binder or th e filler. The m aterial is laid cold and the extra pressure of th e roller is sufficient to break
Cl. X.—METALS; METALLURGY, INCLUDING ELECTROMETALLURGY. 657 down the film of filler, which m ay comprise 10% of
calcareous stone or 15% of coal dust in H 20 . B. M. V.
P u tty c o m p o sitio n s. St o r r y, Wit t y, & Co., Lt d., and G. F. Ho l d c r o ft (B.P. 481,332, 17.3.37).—
W hiting (85% of the whole), linseed oil, and one or more other fa tty acids (< 1 0 % of the oil) are pre
mixed together and shortly before use an oxide of a bi- or m ulti-valent m etal (Cr20 3, about 1% of the whole) and an oxidising agent (about 10% of the
oxide) are mixed in. B. M. V.
S im u lta n e o u s ly s e a so n in g a n d t r e a tin g w a te r- sw o lle n fib ro u s m a te r ia ls [g reen w o o d e tc .].
A. J . Stam m (U .S .P . 2,060,902, 17.11.36. Appl., 9.5.34).—The m aterial, e.g., green wood, is im pregnated with a H 20-miscibIe solvent (I), b.p.
preferably >100° {e.g., OH'fCHJj'OEt) and the H sO removed by distillation under reduced pressure. I t is then further impregnated with a m olten substance, e.g., wax, resin, oil, etc., which is miscible with (I) but insol. in H 20 , (I) finally being removed by vac.
distillation. Im pregnation with tho reagents is assisted by the alternate application of reduced and normal pressures. W arping and excessive shrinkage
are prevented. R. J . W. R.
W ood p re s e rv a tio n a n d m o d e of tr e a tm e n t.
R . H . W h i t e , jun., and J . A. V a u g h a n , Assrs. to I n d u s t r i a l R e s . C o rp . (U.S.P. 2,054,399 and 2,054,400, 15.9.36. Appl., [a ] 13.10.33, [b] 31.12.34.
Renewed [a ] 29.5.36).— (a) The H 20 content of tim ber is raised to 30—45% of its dry wt., and preservative oil (creosote) containing 0-25—2 (1)% of a phosphat
ide (lecithin) (which has the effect of lowering the y and increasing the penetration of the oil) is intro
duced a t 66—82°/125—200 lb. per sq. in. The wood is again treated with H 20 made slightly alkaline with NaOH, so th a t the ratio of retained moisture (above the fibre-saturation point) : oil = 2 : 3. (b) The use of the above oil is claimed. The m ethod is stated to prevent loss of oil by bleeding and evaporation from
the surface. L . C. M.
M a n u fa c tu re of c o m p re s s e d la m in a te d w ood . Soc. d’In v e n t io n s Ae r o n a u t iq u e s e t Me c a n iq u e s
(S .I .A .M .) (B.P. 480,638, 27.5.37. F r., 27.5.36).—
Each lam ina is dried, im pregnated with a polymeris
able m aterial, and pressed a t 300 kg./sq. mm. and a t a tem p, high enough to polymerise the im pregnant.
The plies are united by glueing with a polymerisable solution under pressure < the above. B. M . V.
M a c h in e s fo r t r e a tin g s a n d e tc .—See I. P r o d u c tio n of p ig F e a n d P o r tla n d c e m e n t.—See X.
P la s tic c o m p o sitio n s. P ro te c tiv e c o a tin g s fo r ex p o se d s u rfa c e s .—See X III. L in o le u m a d h e siv e .—See XV.
X . - M E T A L S ; M ET A LL U R G Y , INCLUDING ELECTROM ETALLURG Y.
C u p o la p ra c tic e . S. E. Da w s o n (Found. Tr. J ., 1938, 58, 97—98, 100).—Factors governing the dimensions of cupolas are discussed. An apparatus for obtaining cooling curves on cast-Fe test bars is
described. R . B. C.
z z (b.)
P r o g r e s s in s te e l-p la n t fu rn a c e s. AnOn. (In - dustr. Heating, 1938, 5, 31—52).—A review.
R. B. C.
E x is tin g m e ta llu r g ic a l k n o w le d g e of th e m e lt
in g of s te e l a n d c a s t iro n . P. Ba r d e n h e u e r
(Giesserei, 1938, 25, 129—-137).—A review.
R. B. C.
P ro d u c tio n of c o m m o n -q u a lity b a s ic [steel]
b ille ts f r o m th e e le c tric fu rn a c e . A. G. Ro b ie t t e
(Iron Steel Ind., 1938,11,119— 121).—Recent changes in arc-furnace design, and operating practice and
(Iron Steel Ind., 1938,11,119— 121).—Recent changes in arc-furnace design, and operating practice and