IMPROVEMENTS IN THE TREATMENT OF COPPER LIQUORS
Year: 1885

page_text: 'I, NICHOLAS GLENDINNING of St Helens in the County of Lancaster, Alkali Works,
Manager do hereby declare the nature of my said invention for IMPROVEMENTS IN
THE TREATMENT OF COPPER LIQUORS to be as follows:-
These improvements consist in blowing atmospheric air through the liquors, or
in otherwise exposing them to the action of atmospheric air or other oxygen-
bearing gases.
I prefer to heat the air or introduce steam, so as to maintain the temperature of
the liquors.
By the means described I effect :
1st. The complete or partial conversion, (as may be desired) of the cuprous
chloride to cupric chloride and thus enable a more complete separation of the silver
to be effected, and also a greater economy in the consumption of iodine.
2nd. By the operation of blowing or oxydising the liquors, I also separate arsenic
and probably bismuth and other bases from them. This separation takes place
when the proportion of free acid is not excessive; when such is excessive I employ
an alkali or alkaline earth and partially. or wholly saturate the free acid.
I carry out my process either with a view to separate both arsenic etcetera, and
silver or silver alone. In the former case the arsenical precipitate may first be
separated by subsidence or filtration, after which the silver may be precipitated,
or the silver may be precipitated without previous separation of the arsenical
precipitate, the latter being removed from the silver precipitate by hydrochloric or
other suitable acid.
When a separation of the silver alone is desired, I add hydrochloric acid before
or after oxydising the cuprous chloride,-after preferred, and then precipitate the
silver by an iodide or other suitable reagent.
I continue the blowing during the precipitation of the silver so as to maintain a
brisk agitation.

page_text: I, NICHOLAS GLENDINNING of St Helens in the County of Lancaster, Alkali Works
Manager 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:-
The treatment of copper liquors obtained by calcining ores with common salt
and subsequent lixiviation will be more readily understood from the following
considerations.
1st. When copper liquors containing cuprous chloride and hydrochloric acid in
the proportion of one molecule of cuprous chloride to two molecules of hydrochloric
acid are subjected to a current of air, cupric chloride results and hydrochloric acid
disappears from the solution which becomes neutral Ferrous chloride which is
always present in the liquors accelerates the re-action.
2nd. When neutral copper liquors containing cuprous chloride are exposed to
air without a sufficient quantity of ferrous chloride being present, a. compound
containing copper is precipitated.
:
.
This precipitation does not occur when the cuprous and ferrous chlorides are
present in the following proportions 2 Co, Cl, + 3 Fe Cl
The ferrous chloride may be in excess of this proportion, but a large excess at
the end of the blowing operation interferes with the subsequent de-silverization of
the liquors.
3rd. The hotter the calcined ore is when covered with water or tower liquor, the
richer the liquors are in cuprous chloride. The liquors are also found richer in
silver by this treatment.
According to this invention the copper liquors are treated in the following
manner.
1st. When with a view only to the de-silverization of the liquors and without
regard to the obtainment of a non-arsenical copper precipitate or copper precipitate
containing only traces of arsenic.
'
The liquors containing cuprous chloride and which may also contain an excess of
hydrochloric acid are treated in a suitable vessel with a strong current of air until
the cuprous chloride is almost entirely.converted in cupric chloride.
The liquors are then desilverized by an iodide in the usual way.
2nd. By the operation of blowing or oxydising the liquors, arsenic acid separates
chiefly in combination with ferric oxide. This separation takes place when the
proportion of free acid is not excessive, when such is excessive, I employ an alkali
or alkali earth, or I filter a portion of the liquor through a bed of cupric oxide
obtained by calcining copper precipitate in a current of air, or as a result
equivalent to the saturation of an excess of free acid may be obtained by increasing
the quantity of cuprous chloride, I effect this object when desirable by filtering a
portion of the liquor through a bed of copper precipitate.
The bed of cupric oxide or of copper precipitate may be conveniently placed over
the tank or vessel receiving the liquor.
་

page_text: I prefer that the ferrous chloride in the copper liquor should equal about
200 grains per gallon A difficiency may be made up by adding a portion of the
spent liquor from the copper precipitators. The cuprous chloride must bear such a
proportion to the hydrochloric acid and ferrous chloride present that after the
re-action between the cuprous chloride, hydrochloric acid and oxygen of the air-
producing cupric chloride and water, the remaining cuprous chloride shall not be
in greater excess of the ferrous than corresponds to two molecules of cuprous to
three of ferrous chloride. Having obtained a proper mixture the liquor is blown
with atmospheric air until the greater part of the cuprous chloride is converted
into cupric chloride. The liquor thus treated is then run into settlers, the
precipitate allowed to subside and the clear or moderately clear liquor de-silverized
by an iodide in the usual way. Any trace of the arsenical precipitate which has
not settled with the precipitate of iodide of silver is intercepted by a sand-filter
placed between the silver and copper precipitators.
As blowing fails to effect the complete separation of arsenic the liquors which
(after having been blown) are neutral or contain only traces of free acid have the
copper precipitated from them by metallic iron whilst in this condition.
The steaming of the liquors during precipitation of the copper should not be
continued longer than necessary, so as to avoid as far as possible the formation of
basic and acid compounds of iron.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is :-
1st. The application of atmospheric air to copper liquors as above described for
converting cuprous into cupric chloride.
2nd. The improvement in the treatment of copper liquors containing an excess
of free acid in order to separate the arsenic, which consists in diminishing the
relative amount of free acid, or increasing that of cuprous chloride in the manner
and to the degree, substantially as described, and then blowing in air.
3rd. The application of atmospheric air to copper liquors as above described for
the purpose of neutralizing the free acid present and for separating arsenic.