IMPROVEMENTS IN THE MANUFACTURE OF CERTAIN COAL TAR PRODUCTS
Year: 1880

page_text: LETTERS PATENT to Samuel Clift, of The Morfa, Conway, North Wales, Slate
Quarry Proprietor, for an Invention of "IMPROVEMENTS IN THE MANUFACTURE
OF CERTAIN COAL TAR PRODUCTS."
PROVISIONAL SPECIFICATION left by the said Samuel Clift at the Office of
the Commissioners of Patents on the 5th March 1880.
"6
SAMUEL CLIFT, of The Morfa, Conway, North Wales, Slate Quarry Proprietor.
IMPROVEMENTS IN THE MANUFACTURE OF CERTAIN COAL TAR PRODUCTS."
This Invention has for its object a novel, improved, and economical method of
extracting crude tar acids from their alkaline solutions, prepared in the usual well
known manner by treating the light or heavy oils obtained in the distillation of
coal tar with solutions or mixtures of potash, soda, or lime, and is carried into effect
by suitably saturating the said alkaline solutions in any convenient manner with
carbonic acid.
Suitable saturation is known to be effected when the alkaline solution treated
separates into two distinct layers, the one a dark oily layer containing the crude
tar acids, and the other a watery solution of an alkaline carbonate. The oily layer
containing the crude tar acids is separated by decantation, and after clarification by
settling or other suitable means the latter are ready for the market. I utilize the
watery solutions by preparing from them by well known processes the neutral or
acid carbonates of potash, soda, or lime, either in a crystallized or dry state, or by
regenerating the caustic bases, potash, soda, or lime, in the usual manner.
I find it convenient to super saturate the alkaline bases with carbonic acid so as
to form acid carbonates, although when the base is potash or soda this is unnecessary,
but when the alkaline base is lime super saturation is advantageous for convenient
separation of the tar acids from the residual products.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Samuel Clift in the Great Seal Patent Office on the 28th August
"
1880.
SAMUEL CLIFT, of The Morfa, Conway, North Wales, Slate Quarry Proprietor.
IMPROVEMENTS IN THE MANUFACTURE OF CERTAIN COAL TAR PRODUCTS."
This Invention has for its object a novel, improved, and economical method of
extracting crude tar acids from their alkaline solutions, prepared in the usual well
known manner by treating the light or heavy oils obtained in the distillation of
coal tar with solutions or mixtures of potash, soda, or lime, and is carried into effect
by suitably saturating the said alkaline solutions in any convenient manner with
carbonic acid. Suitable saturation is known to be effected when the alkaline
solution treated separates into two distinct layers, the one a dark oily layer con-
taining the crude tar acids, and the other a watery solution of an alkaline carbonate.
The oily layer containing the crude tar acids is separated by decantation, and after
clarification by settling or other suitable means the latter are ready for the market.
I utilize the watery solutions by preparing from them by well known processes,
the neutral or acid carbonates of potash, soda, or lime, either in a crystallized or
dry state, or by regenerating the caustic bases, potash, soda, or lime in the usual
manner.
I find it convenient to super saturate the alkaline bases with carbonic acid so as
to form acid carbonates, although when the base is potash or soda this is unnecessary,
but when the alkaline base is lime super saturation is advantageous for convenient
separation of the tar acids from the residual products.
Having thus stated the nature of my Invention, and described the manner of
performing the same, I declare that I claim,-
•
First. The use of carbonic acid for separating crude tar acids from their alkaline
solutions; and
Secondly. The production of valuable and marketable residual products, viz., the
caustic alkalies or lime or their equivalent carbonates, as described, instead of the
sulphates or chlorides of their bases, as produced by the old processes hitherto in
use.
In witness whereof, I, the said Samuel Clift, have hereunto set my hand and
seal, this Twenty sixth day of August, One thousand eight hundred and
sighty
SAMUEL CLIFT. (L.S.)