A NEW OR IMPROVED PROCESS FOR TREATING ZINC ÜRES, AND ALL OTHER MATTERS CONTAINING ZINC
Year: 1876

page_text: LETTERS PATENT to Henri Adrien Bonneville, of the British and Foreign
Patent Offices, 18, Rue de la Chaussée d'Antin, Paris, France, and 6, Piccadilly,
in the County of Middlesex, Patent Agent, for the Invention of "A NEW OR
IMPROVED PROCESS FOR TREATING ZINC ÜRES, AND ALL OTHER MATTERS
CONTAINING ZINC." A communication from Pierre Thomas, residing at La
Madrague de Montredon, France, Engineer.
PROVISIONAL SPECIFICATION left by the said Henri Adrien Bonneville at
the Office of the Commissioners of Patents on the 10th February 1876.
HENRI ADRIEN BONNEVILLE, of the British and Foreign Patent Offices, 18, Rue
de la Chaussée d'Antin, Paris, France, and 6, Piccadilly, in the County of Middle-
sex, Patent Agent. "A NEW OR IMPROVED PROCESS FOR TREATING ZINC ORES,
AND ALL OTHER MATTERS CONTAINING ZINC." A communication from Pierre
Thomas, residing at La Madrague de Montredon, France, Engineer.
The principle of the improved process is the direct transformation of the zinc
contained in the matters to be treated into oxyde of pure zinc capable of being
employed as zinc white.
The improved process consists in dissolving the zinc of any zinc producing
matter, whatever ore, alloy, or other, in chlorhydric acid, in precipitating it in the
state of hydrate by its equivalent of line, and in calcinating at red heat the oxyde
obtained. With pure zinc, pure acid, and pure lime, a white is thus obtained
which admits of comparison in every respect with the zinc white of the manu-
facturers.
According to the primary matters used there are certain precautions to be taken
for obtaining the dissolution of chloride of ziuc entirely free from foreign metals or
hurtful substances.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Henri Adrien Bonneville in the Great Seal Patent Office on the
3rd August 1876.
HENRI ADRIEN BONNEVILLE, of the British and Foreign Patent Offices, 18,
Rue de la Chaussée d'Antin, Paris, France, and 6, Piccadilly, in the County of
Middlesex, Patent Agent. A NEW OR IMPROVED PROCESS FOR TREATING ZINC
ORES, AND ALL OTHER MATTERS CONTAINING ZINC." A communication from
Pierre Thomas, residing at La Madrague de Montredon, France, Engineer.
The principle of the improved process is the direct transformation of the zinc
contained in the matters to be treated into oxide of pure zinc capable of being
employed as zinc white.
The improved process consists in dissolving the zine of any zinc producing
matter, whatever ore, alloy, or other, in chlorhydric acid, in precipitating it in
the state of hydrate by its equivalent of lime, and in calcinating at red heat the
oxide obtained. With pure zinc, pure acid, and pure lime a white is thus
obtained which admits of comparison in every respect with the zinc white of the
manufacturers.
According to the primary matters used there are certain precautions to be taken
for obtaining the dissolution of chloride of zine entirely free from foreign metals or
hurtful substances.
The first precaution, which concerns the chlorhydric acid, is only to use acil
gathered in the eighth vessel, at least of the condensing batteries, to get acid free
from sulphuric acid. If it is impossible thus to choose the acid, it will be found
necessary, in order to obtain a favourable result, to purify it with a little chloride
of barytes. The sulphate of lime which forms during the operation is very difficult
to remove by washing, and the quality of the white is rendered inferior.
The object of the second precaution, which concerns the matters to be treated, is
to climinate from the solution all the foreign metals, the oxides of which would
colour the product. It consists in leaving the solution while hot in contact for
some time with metallic zinc, which precipitates all foreign metals, even iron,
except mauganesc, the separation of which can only be effected by adding to the
solution a certain quantity of an ammoniacal salt which retains it in dissolution.
The precipitation of the positive metals by zine is well known, but the case is not
the same with the precipitation of iron, at least this reaction is not mentioned by
any of the best authors. Thus, by a sufficiently prolonged digestion at a
temperature of froin 80 to 100° (about 170 to 212° Fahrenheit) with zinc in plates
or granulated, all the iron of one dissolution, even were it at the minimum of
oxidation, is precipitated to the state of hydrate of sesqui-oxide.
For the elimination of iron the reaction indicated in chemistry may be used, viz.,
pass the iron at the maximum through chlorine and saturate the dissolution while
hot with carbonate of lime, or carbonate or oxide of zinc.
The third precaution, which is important for the beauty of the product and for
the facility of the washings, consists in precipitating while hot, and in letting the
precipitate of oxide of zinc boil for a few moments. The white thus obtained
is much denser, is washed better, and the layer of the white of zinc when applied
is more perfect.
When once the oxide of zinc has been precipitated and washed long enough for
the water of the washing no longer sensibly to contain either lime or chloride of
calcium, it is dried and calcined a cherry red color; it can then be delivered to the
consummation.
When very impure primary matters have to be treated, if it is not desired to
refine the white, grays more or less dark may be obtained, which are naturally of
less value, although at the same time constituting commercial products cor-
responding to the whites No. 3, to the zinc grays and the stone grays of the 5
manufactures.

page_text: The principal applications of the process to which special claim is laid by the
side of the general method are,-
1. The manufacture of the zinc white by means of metallic zinc, waste zinc, or
alloys attackable by acids.
2. The direct treatment of the ores, calamines, or blends, for making zinc white
or gray. The roasted blends casily yield all their zinc to dilated chlorhydric acid.
This application especially allows of treating economically the blend lead ores by
extracting all the zinc they contain, and leaving for residue the lead ore free from
zine and retaining all the precious metals. It is necessary for this last purpose to
use acid very strong and suitable to operate the precipitation of the metals dissolved
other than zinc, even in the operating vessel.
3. The economical treatment of the argentiferous masses resulting from the un-
silvering of the lead by the zinc.
To succeed in completely attacking the said argentiferous masses so as to
separate the zinc from the lead and the silver, it is necessary previously to burn
them, because the lead and zinc alloy, however fine a powder it may be when
mixed, remains unattackable by chlorhydric acid, even concentrated.
The burning of the said argentiferous masses can be performed either in a cast-
iron boiler or on a flat plate, and in order to have no loss of zinc, ought to be done
at a very moderate heat; dark red is quite sufficient. The masses once burnt
present the appearance of an extremely fine grayish powder, from which the diluted
chlorhydric acid separates absolutely all the zinc.
A useful precaution to take, when the mass is once completely attacked, consists
in over-saturating the liquor, as has been before stated, with metallic zinc even in
presence of the deposit of lead. The chloride of zinc which may have formed in the
deposit is thus reduced, and the little lead and silver which may have remained in
dissolution is precipitated on the deposit itself by the help of the acid chloride of zinc.
The deposit when washed can be treated directly by the refining furnace; it is
however inore suitable to re-melt it previously.
A white, No. 1, without loss of zinc, is obtained from the solution thus over-
saturated, cleared, and treated with lime.
Having thus described the nature of the Invention and the manner of carrying
it into effect, what I claim is, the direct transformation into oxide of pure zine of
the zinc contained in the ores, alloys, or other matters, by dissolving the zinc in
the chlorhydric acid, precipitating it to the state of hydrate by its equivalent
of lime, and calcinating at red heat the oxide produced, substantially as above
described.
In witness whereof I, the said Henri Adrien Bonneville, have hereunto set my
hand and seal, this Nineteenth day of July, in the year of our Lord One
H. BONNEVILLE. (L.S.)