IMPROVE- MENTS IN THE MANUFACTURE OF EARTHY SILICATES, WITH A BYE PRODUCT OF CAUSTIC SODA, WHICH SILICATES ARE APPLICABLE IN THE MAKING OF PORCELAIN, GLASS, FIREPROOF BRICKS, ASBESTOS GOODS, AND THE LIKE
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by Edward Parry and Thomas Henry
Cobley at the Office of the Commissioners of Patents on the 1st September
1880.
EDWARD PARRY, of New Bridge Street, in the City of London, Iron Merchant,
and THOMAS HENRY COBLEY, of Dunstable, in the County of Bedford. "IMPROVE-
MENTS IN THE MANUFACTURE OF EARTHY SILICATES, WITH A BYE PRODUCT
OF CAUSTIC SODA, WHICH SILICATES ARE APPLICABLE IN THE MAKING OF
PORCELAIN, GLASS, FIREPROOF BRICKS, ASBESTOS GOODS, AND THE LIKE."
In carrying our Invention into practice, we intimately mix certain proportions of
native silica, such as sand or siliceous rocks or slags (scoria), with furnaced sulphate
of soda known as salt cake (or nitre cake furnaced with salt), and with small coal
or coal dust, such proportions being 100 parts of sand or siliceous substance, 60
parts of furnaced sulphate of soda, and 20 parts of coal dust, these proportions
however being variable according to the purity of the materials employed and the
result desired to be obtained. This mixture is burnt upon the hearth of a furnace
or in an ordinary glass maker's pot, and when the silicate is formed, it is run out
into a receptacle, and while hot a jet of steam is thrown upon it which will break
it up and render it more soluble than before; or it may be allowed to cool and then
be broken up into moderately-sized pieces, which are steeped in cold water to soften
them for grinding; they are then ground. After grinding the powder is placed
in water in a boiler, and boiled at a pressure of from sixty (60) to seventy(70) pounds
under agitation; the solution of silicate of soda obtained by this process is then
removed and treated with caustic lime (milk of lime), or the soluble sulphide of
calcium (polysulphide), or with caustic magnesia, or an admixture of caustic lime
and magnesia, such as burnt dolomite or a soluble salt of magnesia, such as the
chloride of magnesium, in order to obtain the corresponding silicate of lime or
magnesia, or the double silicate of lime and magnesia, the above-named or similar
reagents being added to the sodic silicate solution until precipitation ceases.
For removing the soda from the silicate we employ a filter press, by means of
which the whole of the soda may be removed if steam be introduced after the
pressing is finished.
Caustic soda will be produced in this process when caustic earths are employed,
and may be evaporated down for sale or used in a state of solution for treating
fibrous substances for paper making, or it may be employed for re-forming fresh

page_text: silicate of soda and so on continuously. This continuous process of reformation of
the silicate of soda also applies to the sulphide of sodium obtained when sulphide of
calcium is employed in lieu of caustic lime in the production of the silicate of lime
as above set forth,
The silicates of lime and magnesia thus produced we employ as follows, that is to
say:-
The silicate of lime we employ in a dry as well as in a gelatinous state as a
substitute for bone ash, ground flint, fel spar, and ground glass, in the manufacture
of porcelain in a dry state, and in the manufacturo of glass, and as the said silicate
is absolutely free from iron, we produce by its means a superior kind of glass. The
use of this silicate economizes also both time and fuel in the said manufactures
The silicate of magnesia we apply as a cement to the silica or sand used in the
manufacture of silica bricks and also other fire resisting goods, the mixed silicate of
lime and magnesia being also applicable to the same purpose.
We further apply the silicate of magnesia in a gelatinous state as size in the
manufacture of asbestos goods, by triturating the asbestos fibre with the gelatinous
silicate of magnesia so as to cause it to be adherent.