B urnin g of cem en t in k iln s w ith g ra tes. E . Schirm (Tonind.-Ztg., 1938, 6 2 , 367—372).—Lellep’s preheating grate is applicable only to dry-process plants, b u t arrangements are described for drying slurry with similar devices, such as rocking stepped grates, rotating frames festooned w ith loops of chain which dip into a pool of slurry, rotating cylindrical grates with a radial flow of hot gases, and circular flat grates with rotating radial vanes. Vac. dew ater
ing on a moving belt is also used, b u t is possible only w ith those types of raw m aterial which do not choke filters. A kiln is described in which the actual burning of the clinker is carried out on a chain grate.
The H 20 content of slurry m ay be reduced without excessive r) by foaming with air. G. H. C.
M agn esite lin in g s in k iln s. W. F. R o c h o w (Rock Products, 1938,4 1 ,No. 4,82—83).—Such linings in the burning zones of cement or dolomite kilns have far longer lives a t overload outputs th an can be attain ed with high-Al203 bricks. G. H. C.
D olom ite lin in g of th e sin terin g zone of cem en t k iln s. P. P. Bu d n ik o v, K. F . Mu c h in, and D. 0 . Nir e n sc h t e in (Ukrain. Chem. J ., 1938, 13, 115—
131).—Dolomite (Si02 6-64, AI203 + Fe203 6-08, Mn304 0-2, CaO 27-98, MgO 17-59%) burned a t 1560°
•did not deteriorate after exposure to atm . conditions during 2 years, and is suitable for lining the kilns.
The lining reacts with firebrick a t 1200°, so th a t its
■extent should considerably exceed the sintering zone.
J n the case of rammed linings anhyd. coal ta r should
be used as binder (8—1 0% on the wt. of dolomite), and heating conducted gradually until elimination of hydrocarbons is complete. Directions for prep, of
dolomite bricks are given. R. T.
V erification of the beat balance of a rotary [cem ent] k iln . H. Gy g i (Compt. rend. X V II Cong.
Chim. Ind., 1937,589—602).—See B., 1937, 1054.
G. H. C.
M anufacture of Portlan d cem en t from calciu m sulphate. J . Nicoletis (Compt. rend. X V II Cong.
Chim. Ind., 1937, 729—736).—An English plant is described which yields a satisfactory product. Sub
stitution of CaS04 for CaC03 leads *to presence of 8% of S 02 in th e flue gases, which can be used to produce H2S 04. The tem p, required to decompose CaS04 is diminished by addition of C and S i0 2. G. H. C.
N on -sh rin kin g and exp an din g cem en ts. H.
Lo ssier (Rev. Univ. Min., 1937, 1 3, 166— 169).—
Concrete cubes containing 300 kg./cu.m. of a special cement (composition no t stated) were either removed from the mould after 24 hr. and stored in a dam p atm . or stored under the same conditions in steel moulds capable of preventing expansion in all directions.
The compressive strengths of the cubes of both series a t 7, 28, and 45 days, and the elongation of rods of neat cement and of the concrete, are given. R. B. C.
S u lp h a te-resistin g [Portland] cem en t. S. R o r - dam (Trans. Amer. Soc. Mech. Eng., 1938, 6 0 , 233—
234).—Cements resistant to attack by sea-H20 , the compositions of which are reviewed, are recommended for uso in oil wells especially when the temp, of the corrosive H 20 encountered is < 9 3 °. R . B. C.
Influence of clinker com p osition on ch em ical sta b ility of puzzuolahic Portlan d cem en ts. I. 0 . Alex a n d r o v(Ukrain. Chem. J ., 1938,10,105— 114).—
The corrodibility of puzzuolanic cements with respect to sea-H20 , aq. 0aSO4, and MgS04 rises w ith diminish
ing saturation of the constituents with C a(0H )2.
Raising the C a(0H) 2 content with the object of in
creasing the mechanical strength of the cements
should be avoided. R. T.
M inor con stitu en ts in P ortlan d cem en t clin ker.
H. In s l e y and H. F. McMu r d ie (J. Res. N at. Bur.
Stand., 1938, 2 0 , 173—184).—The application of polished sections for exam ination with the m etal
lurgical microscope, and of a technique involving polished thin sections for examination by the m etal
lurgical and petrographical microscopes, in the investigation o f the minor components o f P ortland cement clinker is described. Free MgO m ay be determined in the unetched section and free CaO in the section after etching. Interstitial m aterial between the silicate crystals m ay be differentiated into white and grey products. The former is identified as 4Ca0,Al203,Fe203 ( I ) ; the latter is usually glass, b u t is occasionally shown in cryst. form either as prisms of a compound of CaO, Na20 , and Al20 3 or, more rarely, as rectangular crystals of 3Ca0,Al20 3. D ata are also given of the system MgO-(I), which is shown to be a simple eutectic type, the eutectic being a t 8% MgO, t = 1370°. The difficulties in tb e
determin-atlori of the compound composition of clinker are
discussed. T. W . P.
D eterm ination of Portlan d cem en t clinker m in erals under th e p o larisin g m icroscop e.
0 . E. Ra d c z e w s k i and H. E. Sc it w ie t e (Zement, 1938, 27, 246—257, 275t-2S0, 287—291).—The Roshval method [ibid., 1921,10, 2 2 0; 1922, 11, 442) consists in traversing a thin section across the micro
scope field and integrating tho linear traverse across each mineral component. Two commercial integrat
ing stages aro described. I t is necessary to make a to tal ru n of 50—70 mm., and the reproducibility is .± 2% on good sections o r - ± 6% on poor ones;
different clinker grains from tho same sample m ay show variations of 5% . Voids m ust be measured in the same manner as tho mineral components and the analysis afterw ards corr. for them . From a rotary kiln hourly clinker samples were, examined over a period of IT hr. and in the grains botween 7*—10 mm. the content of 3C a0,Si02 (I) varied between 51 an d 70%, 2CaO,SiOa fro m 0-5 to 10%, and pore vol. 11-5 to: 24%. High vals. of (I) and low pore vol. wero associated with hard burning. In one sample pore vol. increased with grain size. Tho val.
found for (I) was > th a t calc, by Bogue’s method.
G. H. 0.
D eterm ination of [cem ent] fin en ess w ith the tu rb id im eter. H. E. v o n Gr o n o w (Tonind.-Ztg., 1938, 62, 301—365).—Tlie instrum ent consists of a lamp, a eell containing liquid in w'hich the cement or kiln feed is dispersed, a photoelectric cell, a rheostat, a n d a ‘ microammeter. The rheostat is adjusted until the ineter indicates 1 0 0 on its Scale with the oell full of liquid bu t no cement. A known wt. of cement is dis
persed in tho liquid and the % dim inution of the fight read directly. Tho log of this is cc the sp. surface, the transmission factor of tho ccmont, and tho mass of cement dispersed. A 2 : 1 m ixture of castor oil and petrol is recommended as dispersing liquid. A table is gvyeii^ applicable to 'cells 30 mm. thick, for cortens.
near 3 nig./nil. and transmission factors between 0-37 arid 0-49^X lO"4. Most’"dements require a factor of about 0-46 X 10~ 4 arid cement kiln fekl O-40 X TO*4.
G. H. C.
DentaL cem ents. J , C- P. BESF,QRp .(Brit. D ental J . , 1938, 64, §2^-84).—Oxyphosphato derit-a} cements are n o t truly adhesive. The allege^ deleteripus action of silicate cement pn the pulp is best guarded against by a ZuO-ougonpl and not an antisoptio Cu-cement
lining. W. 0 . K.
C onstitution and bydraulicity of s la g s . L.
C iiA SSEV E N T (Compt. rend; X V II Cong. Chim. Ind., 1937, 1041—1048; cf, B., 1938, 378).—Chemical, optical, and* X -ray analytical methods do not dis
tinguish the hydraulic proportion o f slags, Hydraul- icity is best indicated by th e resistance of the slag to attac k by acid and alkali (rate of dissolution and decrease in strength J therm al reaction),' J . A. S.
T he puzzuolana reaction. G. Ba t t'a and A.
L e f e b to e (Compt. ieh d . X V II Cong. 1 Chim. Ind., 1937, 8 -2 0 ).-—Mortars containing Portland cement and trass. gaize,” or'slafr 'were attacked only slightly less strongly th an cement and sand. Tbe CaO-fixing faculty’of puzzuolaiiaS is destroyed by Mg salts; and
their protective action is purely mechanical. Trass shows a m arked base-exchanging property.
G. II. C.
Influence of fineness of cem en t on p erm ea b ility of concrete. M. M aby (Compt. rend. X V II Cong.
Chim. Ind., 1937, 264—271).—Perm eability is d eter
mined principally by the particle sizes o f tho finer p a rt of the aggregate and of the cement, th e least permeable concrete containing cement of greatest sp. surface.
: G. H. C.
Coloured and decorative concrete in road s and b u ild in gs. H . A. Holt (Chem. and Ind., 1938,
467—468), ;
E xam in ation of se t con crete. A ; Ste o t o e
(Tonind.-Ztg., 1938, 62, 305—367).-—When inert aggregate has been used, th e proportioning of th e mix may be found by dissolving in 3-5%: HCI, and treating th e insol. residue with 5% ‘NaOH, to romovo gelatinous S i02 remaining from the cement. Alternatively, the maSs m ay be broken up by dissolving in conc. HCI, or by heatnig arid quenohing, and th e cement removed by washing. Determ ination of “ sol. S i02 ” gives high results. The grading o f the aggregate is found from the insol. residue. The “ sol. S i02 ” content of the sand appears to have an influence on th e properties, of
the concrete. G. H. C.
P la stic m ortar cu b es. H. W- Le a v it t (Proo.
Amer. Soc. T est, Mat., 1937, 37, I, 321—332).—
Three different methods of preparing 2-in, cubes, for use in testing the compresSiye strength of" coricfeto were investigated h y ' ten* co-operating laboratories.
No one m ethod was better th an another. R. B. C.
Crushed stone research . -A. T. Go l d b e c k
(Rock Products, J 933, 41, No.^3, 44—7-JO),-- TcsJjs of three gradings of crushed limestone (I in. . down, witli, respec^jyely, $, a n d ,2 0%v <2 0 0-niesh) .and one gradiug;with added ,elaytwej;e made w ith a loaded, pneumaticaily-tyrod wheel on a; circular, traok.
Although the toqack was quite stable when dry, ruts weije, rapidly forin.qd' wrhcn HaO was present.., j The fine m atter kpcps HjO out, bu t clay c c ^ e rs plasticity apd .is ■ deleterious. Asphalt Avhijsh. retains tpo much volatile m atter j has th,e. same effeot; in genera^, its effect is prim arily exclusion, o f H2 0 . I t is in effective if no. dust, b e , present. Tho ; proportion of voids ,selves, as a,.,good measqre o f .angularity of crushed stone or sand. Concrete'm^da,>yith splintery
or flaky sand needs more H20 - . ; G. H - C>
W ater-penetoability of .clay and-shale b uild in g brick- J- W- M c B u rn e y and A. R . E r e r l e (J.
Amer. Ceram. Soe., 1938,17, 210—216).—Tho results of H20-adsorption tests on 1600 brick samples are considered with respect to a . specification demanding a H aO-adsorption. range per. brick (after' 3 min.
partial immersion) of 1—4 oz. J. A. S.
A queous sa lt solu tion s for layin g road d u st.
H. WiESENTHAL (Teer u. Bitumen, 1937, 35, 294—
295).—The advantages and disadvantage^ of aq.
CaCLj aud MgCla are discussed. R. B. C., W eathering te s ts on filled [and unfilled] coating asp h a lts. O0 :G. S tb i e tk r : (J ; -Res. N at.: Bur.
Stand., 1938, 20, 159—171)i—The durability of th e asphalts was determined both in outdoor and in
,Cl. IX .—BUILDING MATERIALS. 789 accelerated exposures; The filled, were the more
durable; the increase . in durability depending, on character j proportion,, and particle size of the filler.
Ca(OH) 2 as a filler was an exception and did not increase durability. The data dem onstrate th e sim ilarity between outdoor and accelerated weather
ing. T. W. P.
A ction of cem en t on w ood . W . Do m in ik .and Mr Ha u s (Przcmysl Chem., 1938,. 2 2 , 74—82).—The harmful action of. cements on tim ber is due exclusively to Ca(OH)2, which causes dissolution of lipins, and decomp. chiefly of pentosans, to a smaller ex ten t of lignin, and least of all of cellulose. The destructive action of clay cements is < th a t of P ortland cement.
■ ■ R .T .
M odern m eth od s of tim b er preservation . C.
S i s l e y (Oil and Col. Tr. J ., 1938, 9 3 , 750—755).—Tho life history of and damage caused by different species of fungi and beetles are described and the use of wood preservatives is briefly reviewed. 13. R,. I).
E xam in ation and p reservation of w ood p o les, and p rolongation of th eir life, by th e oxy-acetyl
ene scou rin g and charring p ro cess. H . C.
Morgan (Proc. X II Intern at. Congr. Acetylene:
1936, 5, 113S—1155).—A general, description of the process (now of commercial im portance in Australia) and treatm ent plant is given and the m onetary savings effected and advantages over the older preservative methods are discussed. P. G. McC.
Fire-protective treatm en t of w ood . IC. Pe s-
c h e k (Osterr. Chem.-Ztg., 1938, 41, 179—182).—
Thermal decomp. of W ood begins a t 105° and becomes rapid a t >200°. I t becomes exothermic a t 260—
290°, according to its physical properties. Methods of testing wood im pregnated w ith fire-resistant materials are described, and impregnation and coating methods of treatm ent are compared. The protective materials used 'are generally aq. solutions, 75% of them being based on water-glass, w ith various ad mixtures. Wood previously freed from H20 , reSin, etc. by heating, and im pregnated with low-m.p.
metals (Pb, Sn, and alloys), develops no combustiblo gas and shows good fire-resistance. Plates made from sawdust and scrap wood, bound with water- glass and cem ent,: are very fire-resistant. Another process involves im pregnation w ith materials which on heating evolvo H2 0 vapour, which dilutes the combustible gases. The wood m ay also be im pregnated with a, non-volatile liquid, .which gives mechanical;protection from .the atm . J . W. S.
Fire te sts of treated and u ntreated w ood p artition s. C. R . B r o w n (J. Res. N at. Bur. S tand., 1938, 2 0 , 217— 239).—-Tests are described' on 4-ft.
square partitions of untreated longleaf pine and of the latter treated with varying am ounts of N H4H2P 0 4.
Three different thioknesses were tested. F urther teste on partitions (10 ft. X 16 ft.) :of treated birch are also described. Results from the former indicated th a t the fire-resistance varied with; the thickness and design of the specimens, but th a t the concn. of solution had little effect. The size of the specimen was not im portant. Fire-tube and flam e-penetration test d a ta are given. Fire-resistance as given by the
first :tests does not bear any relation; to the fire-tube tests, but compares with the flame-penetration test on partitions of the same type of construction.
: T. W. P. . Collapse [of tim b er] and its r e m o v a l: recen t in v estiga tion s w ith E u c a ly p tu s regtin tis. W. L.
Gr e e n h il l (Counc. Sci. Ind. Res. Australia, 1938, Div. Forest Prod., Tech. Paper 24, 29 pp.).—Collapse in tim ber, rosulting in excessive shrinkage, m ay be perm anently. removed by reconditioning in steam (70—100°) for periods u p to 24 hr. E. A . R.
E xtraction of w ood b y g ly co l m on oeth yl ether.
W. D o m in ik and M. H a u s (Przemysl Chem., 1938, 2 2 , 97—107).—Tho residue (55%) from extraction of pine sawdust with 0H-fCH2]2-0 E t (I) containing 0'2% of II2S 04 (12 hr. a t the b.p.) consists of a- collulose (II) 72 and lignin 17% ; the yield of (II) falls when th e [H2S 0 4] is altered, or when otner acids (H N 03, H2C2 0 4) are taken. The corresponding residues from ash or willow contain more (II) and less lignin th an from pine. The extracts are diluted
1 0-fold, when resins and lignin separate, leaving carbohydrates in solution (8% yield). Alternatively, tho extracts are distillod, when a brittle, black residue of resins + lignin, m .p. 105°, is obtained.
(I) is determined in the extracts by distillation from H2S 0 4-H B r and measuring the vol. of E tB r collecting
in the receiver. R. T.
P h en ol-form ald eh yd e resin as a plyw ood adhesive. L. E. St o u tand B . Br e w (Mod. Plastics, 1938, 15, No, 7, 39- -10, -11, 6 8, 70).—From tosts carried ou t on maple, red gum, cottonwood, and birch it is cpnchidcd th a t PhO H -C H 2Q resin gives a satisfactory m oisture-resistant bond for plywood under properly controlled conditions. Optimum bonding temp, range from 190° to 2 0 0°, and suitable pressures are 100 and 250: lb./sq. in. for soft and
hard woods, respectively. F. McK.
G luing togeth er of plyw ood. E. M 6 r a t i i (Chem.- Ztg., 1938', 6 2 , 293—294).—The supply of gluo can be increased by a more caroful utilisation of tanned leather scrap, bones, and fish refuse. Blood-albumih and by-product protein glues , obtained from pressed soya-bean arid castor : oil .seed are used to replace im ported casein. Wood joints m ade by using PhO H -C H aQ resin glues, or urea or CS(NHa)a resins, and hot-pressed, are very resistant to the action of damp and mould. Very flexible joints are produced by polyvinyl and polyacrylic acid resin
glues. D. P.
W ood, w a ste for stea m gen eration .—See I.
R oadm aking m ix tu re s.—See II. CaO. H ydrated CaO. P eroxid ation .—See YU. P a in t adhesion on concrete.—See X III.
Pa t e n t s.
Cooling of cem en t. C. E. Ev e r y-Cl a y t o n. From N. Ah l m a n n (B:P, 482,831, 5.10.36),—The H20 vapour is removed from ground cement, prior to th e final cooling in heat-conductive apparatus, either by specially injected air or b y conveying the cement
pneumatically. B. M. V.
Colouring of ston e ch ipp in gs and th e like.
G . H . Ho d g s o n, and Pe n m a e n m a w r & We l s h
Gr a n it e Co., Lt d. (B .P . 483,016, 9.10.36 and 3.9.37).—The colouring m atter is bound by pptd. S i0 2.
Preferably N a silicate, colouring m atter, and acid or salt are applied, in th a t order (possibly the last two together), and sotting is effected by heat. B . M. V.
C onstruction of road s, floorin gs, tenn is cou rts, etc. D. K om los (B.P. 481,868,18.6.36).—Binders of drying oils and oil- or spirit-sol. resins for aggregates free from powder are claimed. [S tat. ref.]
B. M. V.
W allhoards. F. B . De h n. From Pl a s t e r g o n
Wa l l Bo a r d Co. (B.P. 482,640, 24.5.37).—The margins (and, if desired, other parts) of the board are stiffened with a suitable agent (urea-aldehyde resin), but considerable interior areas are left un stiffened to take up expansion strains. B . M. V .
S p u n -g lass in su lation .—See I. T reatin g b itu- m in a .—See II .
X . - M E T A L S ; M ET ALLU R G Y , INCLUDING ELECTROMETALLURGY.
Flotation treatm en t of sp ecu lar iron ore.
G. Ge r t h, A. Ba u m g a r t e n, and W. Pr u f e r (Metall u.
E rz, 1937, 34, 616—619)—Tho ore can be satis
factorily floated in a slightly acid pulp (pH 4-7—4-9) in presence of K benzylxanthate or Cl0H7'N H2 as collector, H2SiFe as a depressant for pyrite, and
“ Texapon ” or oleic acid as a frother. The ore m ust be ground to a max. particle size of 150 (i. to obtain
> 9 0 % yield of a concentrate containing 90—95%
of Fe203 free from pyrite. Grinding finer than 50 j*.
renders it difficult to prevent entanglement of much quartz in the flocculated F e20 3. A. R . P .
G eology and m in in g of th e chrom e-iron ore d ep osits of th e B alkan m ou n tain s. G. Hi e s s-
l e i t n e r (Berg- u. H iittenm ann. Jah rb ., 1937 , 85,
338—344). R. B. C.
U tilisa tio n of low -grad e G erm an iron ores.
W. Lu y k e n (Metall u. Erz, 1937, 34, 611—616).—
The relative economic vals. of th e direct acid-slag smelting process, dry and wet magnotic-separation processes, magnetising roasting, and the K rupp pelletising-reduction process for tho treatm ent of low-grade Fe ores are discussed w ith reference to the
4-year plan. A. R. P.
C om parison of the re su lts given by the Z im m er- m an -R einh ard t and Knop m eth od s for deter
m in ation of iron in ores. J . I . Sc h t s c h e r b a k o v
(Zavod. Lab., 1938, 7, 97—98).—The two methods give identical results when org. m atter in the ores is eliminated by ignition or by oxidation w ith KC103.
R. T.
P ressu re operation of the p ig iron b la st fur
nace and tbe p rob lem of solu tion lo s s . J . M.
Av e r y (Amer. Inst. Min. Met. Eng., 1938, Tech.
Publ. 921, 10 p p .; Met. Tech., 1938, 5, No. 3).—
A crit. review. R. B. C.
T em perature readin gs in a blast-furnace stock colum n. H . W. Jo h n s o n (Blast F um . Steel Plant, 1938, 26, 165—168).—The technique is described.
R. B. C.
B la st furnace and raw m a terials developm ent.
T. L. Jo s e p h (Blast Furn. Steel P lant, 1938, 26, 47—52).—Recent developments in American blast
furnace practice are reviewed. R. B. C.
B last-furnace dust, a G erm an in su la tin g m a teria l from iron w ork s. H . A. Wa h l s (Brenn- stoff u. W armewirts., 1938, 20, 45—51).—Develop
m ents in the production and application of insulating m aterials prepared from the finely-ground dust are reviewed. A paste consisting of tho dust mixed with asbestos can be painted on to pipes etc. R. B. C.
N atu ral g a s in the open-hearth [furnace]., R. Va il l (Iron Age, 1938, 141, No. 9, 34— 36).—
Various types of furnace are discussed in relation to th e efficient use of natural gas. The m aintenance of the full heat input a t certain parts of the heat cycle is more difficult with a non-luminous th an w ith a
luminous flame. R . B. C.
B ritish open-hearth data and th eir co rrel
ation. Op e n- He a r t h Co m m e e. o f t h e Ir o n a n d
St e e l In d u s t r ia l Re s. Co u n c. (Iron & Steel In st., Symp. on Steelmaking, 1938, May 4—6, Advance copy, 33 pp.).—British production and practice are surveyed. A basis of measurement for determining the operating efficiency of an open- hearth furnace, “ the performance figure,” is estab
lished. Normal practice produces 2-0 and 1-6 lb.
of steel/hr./therm , respectively, for fixed and tilting furnaces; th e latter show a lower refractory consump
tion. The area of the air port should be < 6 times th a t of th e gas port. A charge with a high % of hot m etal and a high metalloid content is worked in a deeper bath. The basic, hot-m etal, fixed furnace gives the highest production per u n it capacity.
S. J . K.
A pplication of p h y sical ch em istry to steel- m ak ing. A. McCa n c e (Iron & Steel In st., Symp.
on Steelmaking, 1938, May 4—6, Advance copy, 43 pp.).—A survey of published work on th e reac
tions : MeO + C = Me + CO ; FeO + Mn = MnO + F e ; 2FeO + Si = SiO, + 2 F e ; 2MnO + Si = S i02 + 2M n; and the S and P reactions. Conclu
sions having direct bearing on open-hearth steel
making practice are drawn. S. J . K.
S tu d ies of regen erative and recuperative furnaces. W. A. Mo r t o n (Iron Steel Eng., 1938, 15, 24—40, 45).—Recent types of furna.ce, e.g., a producer gas-fired, regenerative blast furnace, and an Armco non-reversing p it furnace for ingot heating
S tu d ies of regen erative and recuperative furnaces. W. A. Mo r t o n (Iron Steel Eng., 1938, 15, 24—40, 45).—Recent types of furna.ce, e.g., a producer gas-fired, regenerative blast furnace, and an Armco non-reversing p it furnace for ingot heating