IMPROVEMENTS IN THE MANUFACTURE OF PHOSPHATES OF SODA AND OTHER ALKALINE BASES
Year: 1871

page_text: PROVISIONAL SPECIFICATION left by Benjamin Tanner at the Office
of the Commissioners of Patents, with his Petition, on the 5th
June 1871.
I, BENJAMIN TANNER, of New Brighton, in the County of Chester,
Manufacturing Chemist, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE MANUFACTURE OF PHOSPHATES OF SODA
AND OTHER ALKALINE BASES," to be as follows:—
For the production of phosphates of soda in accordance with this
Invention it is found advantageous and economical to take phosphates
of lime (other than the acid phosphate of lime so far as the same is
now employed for this manufacture) or phosphate of alumina or
phosphates of iron or phosphoric acid or mixtures thereof either in a
ground, pulverised, precipitated, or liquid condition, and to intermix the
same with chloride of sodium, caustic soda, or any soda salt, having an
acid or element capable of being displaced by phosphoric acid, or
mixtures of any of the said sodium or soda compounds. When
necessary (as will be well understood by persons conversant with such
operations) the mixture thus formed is exposed to heat, either with or
without the addition of water. A process of decomposition takes place
under which the acid or element is separated or evolved, and then

page_text: condensed or utilised by well known arrangements, whilst the residue
consists of a phosphate or phosphates of soda intermixed with lime,
alumina, iron, or such other impurity as may have been derived from
the substances employed. From such residue any phosphate of soda
contained therein is dissolved out and evaporated, and, if necessary, i
purified by arrangements such as are commonly employed for similar
purposes. It is sometimes found convenient in carrying out this
process to separate the phosphoric acid from the lime, alumina, and
iron with which it may be combined before treating the said sodium or
soda compounds therewith. This may be accomplished by dissolving ]
these phosphates in hydrochloric acid and then adding sulphuric acid or
oxalic acid, or mixtures thereof, or the sulphuric acid may be added
direct to the phosphates of alumina and iron. In each case the
phosphoric acid is separated from its combinations ready to be employed
for the production of phosphates of soda as already described. The 1
proportions in which the phosphoric acid or its compounds are intermixed
with the sodium or soda compounds for the production of phosphate
of soda are regulated by the condition or form in which it is desired
to obtain the phosphate of soda, as will be well understood, but for
economical working it is preferred to use the phosphoric acid either 2
free or in combination in the proportion of one equivalent of phosphoric
acid to one, two, or three equivalents of sodium or soda, and by also
exercising a control over the temperature employed during the process,
mono-basic, bi-basic, or tri-basic phosphates of soda can be obtained.
The same general processes are employed in the production of 2
phosphates of other alkaline bases by the employment of any of the
said bases in a caustic condition, or in combination with any acid or
element capable of being displaced by phosphoric acid or mixtures
thereof.
In like manner and on the same principle phosphates having more a
than one alkaline base may be produced by using, in the manner herein-
before described a mixture of the said bases or of the before mentioned
compounds thereof, instead of using a single base or any of the before
mentioned compounds thereof.