Year: 1887

page_text: I 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 the manufacture of muriatic acid from calcium chloride
and has for its object to render this substance practically available as a source of
muriatic acid.
Calcium chloride is a waste product in various industrial processes, especially in
the manufacture of Soda by the ammonia process in which calcium chloride is
produced in large quantities.
In carrying this invention into practice the solution of calcium chloride is evaporated
to dryness and the dry calcium chloride is coarsely crushed and intimately mixed
with silicious material, such material, such as silica or clay. Or, if preferred, the
solution of calcium chloride may be partly evaporated and be mixed in this moist
condition with the silicious material. This mixture is molded into cakes, balls or
bricks of suitable size, preferably into cakes having the dimensions of three by two
by one and one-half inches. These cakes are dried and then placed into a converter
constructed of fire brick in order to withstand the high degree of heat which is
required in the operation. The cakes are heated in the converter to a bright red
heat by hot gases which pass through the converter and which contain steam.
At this high temperature the silica or clay decomposes the calcium chloride,
forming calcium silicate, or silico-calcium-aluminate, as the case may be, and
generating muriatic acid gas. The latter escapes from the converter and is
condensed and collected in any suitable or well known manner. The calcium-chloride
which is now a waste product, is by this method rendered valuable, thereby increasing
correspondingly the profits of the chemical industries in which the calcium chloride
is produced. The muriatic acid resulting from this conversion in the main product
while the converted solid material is a valuable by-product which may be used in the
manufacture of hydraulic lime and artificial stone.

page_text: In consequence of the comparative infusibility of this lime salt, the percentage of
calcium oxide in the converted material can be considerably increased. I have found
no difficulty in converting in the above described manner 150 parts of calcium chloride
with 100 parts of clay, which latter contained 21 per cent. of hydroscopic and
chemically bound water. These proportions produce nearly 50 per cent. of
calcium oxide in the converted material, thus showing that the silica and alumina
employed were more efficient than an equal weight of sulphuric acid. The silico-
calcium-aluminate thus obtained is a white porous material which can be decomposed
by muriatic acid. It is also decomposed by the moisture and carbon-dioxide of the
atmosphere, producing calcium carbonate and hydrated aluminum silicate in such fine
division that it combines easily with caustic lime, hence its adaptation for the
manufacture of hydraulic lime.
I prefer to use clay in this process as the use of silica alone is less desirable in a
mechanical way and requires a higher temperature in the converter.
In the accompanying drawing is a sectional elevation of an apparatus which may
be used in carrying the 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. 6 represents the pipe by which the gas
escapes from the generator. C represents 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 1 for burning the gas in the same. F
represents 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 a discharge opening and a movable bottom H.
I represents a pipe which connects with the lower portion of the converter and
through which the gases escape from the same and pass to the condenser in which the
muriatic acid gras
is condensed. When two or more converters are used in the form
of a battery, the gas exit pipe I 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 my 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 herein described method of manufacturing muriatic acid from calcium chloride
which consists in mixing the calcium chloride with the silicious material, molding the
mixture into cakes. balls or bricks beating the same in a converter by hot gases
containing steam passing through the converter, and condensing the muriatic acid
gas which is generated, substantially as set forth.
Dated this 23rd day of August 1887