552 ,
(1)
Calcium Silicates Part 1. Synthesis
By Seiji Kondo and Toshiyoshi Yamauchi
Abstract
A thorough study was made of the effect of temperature on the
chemical combination
of lime and silica in their mixtures.
Chemically pure calcium carbonate and silica were proportioned
in the molecular ratios
of 3:1, 2:1, 3:2 and 1:1, and the mixtures were heated at
temperatures ranging from 600to
1800 for 30 to 120 min. The products were analyzed for calcium
carbonate, free lime and free
silica, and the amounts and molecular ratios of combined lime
and silica were calculated; also
their true specific gravities were determined.
Some difficulties were encountered in the determination of free
silica in those samples
which had been heated at comparatively low temperatures, since
it was more or less soluble in
5% aqueous soalution of sodium carbonate. Therefore the silica
ignited at 1350 was used for
their these samples.
Rathke's method of determining free lime was improved and the
vessels containing the
samples and grycerine were heated on a mechanical shaker in an
electric oven of a constant
temperature; the requisite temperature and time were also
determined.
The authors succeeded in obtaining 100.00% pure 3 CaOESiO2,
100.00% pure 2 CaOESiO2, 99.80%
pure 3 CaOE2SiO2 and 99.72% pure CaOESiO2 by heating
corresponding raw mixturea at 1300
(2hr.), 1700 (1hr.), 1475 (0.5hr.) and 1540 (0.5hr.) resp.
The reaction between CaCO3 and SiO2 began already at 600, the
velocity rising suddenly
at 800to 900and being retarded at about 1200and up.
The processes in the molecular ratios of combined lime and
silica with the rise of tem
perature are discussed for the four mixtures.
(Department of Ceramic Engineering, Tokio University of
Engineering)
1.
SiO2-CaO A. L. Day, E.T. Allen, E. S. Shepherd, W. P.White &
F. E.Wright (1906)
, E. S. Shepherd & G. A. Rankzn (1911, 1915) , B. Ferguson
& H. E. Merwin
(1919) J. W. Greig (1927)
4 3 CaOSiO2, 2 CaOSiO2, 3 CaO2 SiO2CaOSiO2
3 CaOSiO21900 CaO 2CaOSiO2 2065 CaO
2 CaOSiO2 ,, 3 , 21301420,142675,675
Rankin 1425
3 CaO2 SiO21475 2 CaOSiO2 CaOSiO2 2 ,
15401200,1200
, Le Chatelier (1887), Newberry (1897) W. C.
(1) 553
Hansen (1928),(1932)
Ferguson & Merwin ,
,
,, , , X
, (1400)(, , 38, 711,511)
3CaCO3+SiO2, 2CaCO+SiO2, 3CaCO3+2SiO,CaCO3+SiO2100014000.51
6001800 4
, X
, 13( 34,
12261231, 6, 35, 1015, 161166,7) CaCO3SiO21:1, 2:13:1
900155016001
, ,
1:194.88%, 2:199.22%, 3:1 79.18%
X 100%
2.
1.
60O1800
1350 6001000
6001000 1100
4900,1104
10 30
,
1cm,1.5cm,0.4cm ,
70
13501 4900110
4 2 5
20 ,9003 ,5
SiO2 30g 5g
,
