Year: 1887

page_text: Date of Application, 23rd Aug., 1887.
Specification Accepted, 23rd Sept., 1887.
[Communicated from abroad by ADOLF KAYSER, Chemist, HORACE WILLIAMS and
ALBERT BARNES YOUNG, Gentlemen, all of the City of Buffalo, New York,
United States of America.]
1, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co., Patent Agents,
Southampton Buildings, in the County of Middlesex, do hereby declare the nature of
this invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
This invention relates to a pneumatic process of manufacturing the silicate of
sodium or of potassium and has for its object to produce these substances in a simple
and economical manner.
It is well known that silica and sodium chloride, heated to red heat in a current of
steam produce muriatic acid gas and sodium oxide which latter combines with the
silicic acid, forming sodium silicate.
When this conversion is carried on in an externally heated tube or vessel, through
which a current of steam is passed, as heretofore proposed, only a limited amount of
sodium chloride is converted. This is principally due to the insufficiency of tempera-
ture in the inner portions of the mass which latter does not become sufficiently heated
to excite the acid properties of the silica in all of its parts to the point at which the
silica decomposes the sodium chloride, which reaction as is well known, takes place
only at a high temperature. The present invention is designed to obviate this
difficulty and to effect a thorough and practically complete conversion of the sodium
chloride into its silicate.
In carrying the said invention into practice I mix finely divided silica with common
salt (sodium chloride) and sufficient water to render the mixture plastic. The
quantity of sodium chloride should be so calculated that the resulting sodium silicate
does not contain more than about 15 per cent. of sodium oxide. If sodium chloride
is used in excess of this proportion such excess will be evaporated and escape with the

page_text: muriatic acid and the waste gases. When the silica absorbs sodium oxide in excess
of about 15 per cent, the substance becomes soft, and the outer portions of the cakes
become glassy whereby the porosity of the cakes is destroyed and the further action of
the gases upon the interior portions of the cakes rendered impossible. The silica
should be employed in a finely divided condition in order to give the best results.
Infusorial earth answers the purpose very well. If coarse sand is used, the interstices
between the grains allow the escape of a large proportion of the evaporated sodium
chloride. This can be avoided in a measure by mixing sufficient quantity of fine sand
with the coarse sand to fill the interstices between the coarse particles. It has been
found very advantageous to mould the cakes under pressure, whereby the solidity of
the cakes is considerably increased and the evaporation of the chloride correspondingly
prevented.
The granular condition and the quality of the sodium chloride does not materially
affect the process. Coarse salt, such as is produced by evaporating brine, or crushed
rock-salt is practically as effective as finely ground salt.
This mixture of silica and sodium chloride is moulded into cakes, balls or bricks of
convenient size and dried. Cakes having the dimensions of three by two by one and
one-half inches will' answer the purpose very well. The dry cakes are then placed
into a converter constructed of fire brick, in order to withstand the high degree of
heat which is required for the conversion. This converter is heated by highly heated
gasses which pass through the converter and come in direct contact with the cakes
placed in the same.
I prefer to employ generator gases and admit below the grate of the generator as
much steam as can be used without impairing the operation of the generator. This
generator being charged with coal, produces carbon monoxide and hydrogen
which gases pass from the generator to a combustion chamber located near the gas
inlet opening of the converter. In this combustion chamber the gases are burned by
a forced air blast forming carbon dioxide and steam under development of a high
degree of heat.
In order to avoid any reducing action by carbon monoxide a slight
excess of air is admited to the combustion chamber. These hot gases pass through
the converter and come in intimate contact with the cakes contained therein and
penetrate the latter thoroughly, carrying the heat and stean into the innermost
portions of the cakes, and heating the latter to a bright red heat. The active
substance contained in this current of gases is the steam, and these gases act not only
as the heating agent in the converter but facilitate by diffusion the formation of
muriatic acid, acting even more energetically than superheated steam alone. The
muriatic acid gas which is generated during the process of conversion can be
condensed or collected in any suitable manner. These generator gases may contain
sulphurous products from the coal used in the generator, which products being
transformed into sulphurous acid will at a low temperature produce sodium sulphate.
This salt is decomposed at a higher temperature and converted into silicate, the
sulphurous acid being driven off.
When the conversion is complete, which usually occurs in from 18 to 24 hours after
the working temperature has been reached, the silicate containing about 85 per cent.
of silica and 15 per cent. of sodium oxide is removed from the converter and crushed
in a suitable reducing machine. This silicate is an excellent material for the manu-
facture of glass, in which manufacture it takes the place of a part of the soda and sand
ordinarily employed. By its use in the manufacture of glass the time required for
fusing the material is greatly reduced. Upon smelting the silicate together with a
suitable quantity of soda on a hearth, water glass is produced.
Potassium chloride is substituted for the sodium chloride when it is desired, to
produce potassium silicate.
The accompanying drawing is a sectional elevation of an apparatus which may be
employed in carrying the said invention into practice.
A represents the gas generator which may be of any suitable construction and
which is charged with coal, coke or other suitable fuel. a represents the pipe by
which steam is supplied to the generator. b represents the pipe by which the gas

page_text: escapes from the generator. Crepresents a fan blower or other apparatus connected
with the gas pipe b. d represents the discharge pipe of the fan C, and D represents
the combustion chamber into which the gas is delivered by the pipe d. e represents a
pipe by which a blast of air is delivered from a fan blower E or other suitable
apparatus into the combustion chamber D for burning the gas in the same.
F repre-
sents the converter connected near its top with the combustion chamber D by a
pipe through which the hot gases pass from the combustion chamber to the
converter. The latter is provided in its top with a feed opening g having a removable
cover G and at its lower end with discharge openings and a movable bottom H.
The latter is preferably of the same diameter as the converter in order to permit the
free discharge of the converted cakes which are liable to cake together, I represents
a pipe which connects with the lower portion of the converter and through which the
waste gases escape from the same and pass to the condenser in which the muriatic acid
gas is condensed.
When two or more converters are used in a battery, the gas exit
pipe of one converter is connected with the gas inlet of the next following
converter.
While I recommend the employment of this apparatus I do not wish to confine
myself to the same, as it may be modified without departing from my invention.
Having now particularly described and ascertained the nature of the said invention,
and in what manner the same is to be performed, as communicated to me by my
foreign Correspondents I declare that what I claim is :-
The heroin described method of producing the silicate of sodium or potassium from
the chlorides thereof, which consists in mixing the chloride with silica, moulding the
mixture into cakes or bricks, and heating the same in a converter by means of highly
heated gases containing steam passed through the converter, substantially as set
forth.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London,
Agents for the Applicant.