US1055157A - Electrolytic recovery of zinc and manganese. - Google Patents

Description

ITED STATES PATENT OFFICE.

ANDREW GORDON FRENCH, OI NELSON, BRITISH COLUMBIA, CANADA.

ELECTROLYTIC RECOVERY OF ZINC AND KANGANEQE.

No Drawing.

Specification of Letters Patent.

Application filed September 4, 1912. Serial No. 718,506.

Patented Mar. 4, 1913.

To all whom it may concern:

Be it known that. I, ANDREW GORDON FRENCH, a citizen of the Dominion of Canada, residing at Nelson, in the Province of British Columbia, Canada, have invented a new and useful Electrolytic Recovery of Zinc and Manganese, of which the following is a specification.-

This invention relates to a process for the recove of metallic zinc and manganese dioxid y electrolysis, the object being to recover these materials in a dense, pure form in the case of zinc, and in a pure marketable condition in the case of the manganese dioxid. It forms part of a treatment for the recovery of these materials from refrac- "tory complex zinc-lead ores containing manganese. The preparatory treatment of these ores is set forth in an application for a patent, now pending, whic was filed on the 30th of September, 1911, under Serial No. 652,047, patented October 15, 1912, #1,o41,0e0.

In the process set forth in that application the final result was a strong, aqueous solution of sulfate of zinc with neutral sulfate of sodium and containing more or less sulfate of manganese, which is usually present in the complex ores which this process is designed to treat. These three salts, when in solution to ether, are easily split up by a low voltage direct electric current and yields on the cathode a dense deposit of very pure, metallic zinc and on the anode pure manganese dioxid. 'It is on the favorable combination of these three salts that the success of this process depends and where the manganese is not in sufiicient quantity to form that favorable combination, this element should be added-in order to obtain the mostsatisfactory results.

The following specification fully describes the process as. conducted.

' as a dense deposit on the cathodes and a pure manganese dioxid at the anodes.

The purity of the zinc, particularly in its absolute freedom from oxid of zinc and sulfur compounds, the presence of which in previous attempts at electrolytic recovery have caused sponginess and deterioration of 50 the deposit, is attributable chiefly to the ass'oclation with the zinc in the electrolyte, of the manganese and sodium sulfates. These three salts in solution to ether, when crystallized out do so as a trip e salt. A further advantageous feature of this treatment lies in the fact that the sulfuric acid which is liberated from the zinc and man anese sulfates combines in its nascent con ition with the neutral sulfate of sodium to form bisulfate and persulfate of sodium in the electrolyte, and as these reactions are exothermic' the current is correspondingly reinforced. A second reinforcement in a similar manner is obtained from the formation of the manganese dioxid at the anode.

In the practice of the process, the solution, which forms the electrolyte, is made to flow continuously from the ore leaching tanks into the electrolytic tank, in a nearly saturated condition and free from acidity, and a return flow of the electrolyte, after having been partially acted upon by the current, is returned from the electrolytic tank to the ore leaching tank. A proportion of the zinc and the manganese having been abstracted from the solution and deposited respectively on the cathodes and at the anodes, the return flow of the solution to the leaching tank is in an acid condition, having from one and a half to two and a half per cent. of acidity as bisulfate and persulfate of sodium. This acidity enables it to dissolve out a fresh supply of zinc and manganese in the leaching tank, and this process is continued until the ore. in the leaching tank is depleted of its zinc and manganese.

As described above, when treating solutions from ores which'are poor in manganese, it is necessary to mix it with others richer in that. element so as to give one unit of manganese to from four to six units of zinc, which I find to be a good working proportion although if a greater proportion of manganese be employed the operation may still be successfully performed.

In circumstances where ores sufiiciently rich in manganese are not obtainable, I obtain the required sulfate of manganese by treating a proportion of the manganese dioxid mud, as deposited at the anodes, with sulfurous acid gas, either free or in solution, while the dioxid is carried in 'as small a quantit of water as will hold it in suspen- S1011. 'l his immediately takes oxygen from the dioxid forming the soluble manganese sulfate which is required to add to the electrolyte.

The sulfurous acid may be obtained from the flues of the furnace used for calciningthe sulfid ores in the earlier treatment re ferred to, as being the subject of the application filed September 30, 1911 and hereinbefore referred to. I

The process here described is advantageous in that it produces a particularly dense and pure form of. metallic zinc, and

similarly the dioxid of manganese is comof the required sulfate of manganese by treating-dioxid of manganese in suspension in water by sulfurous acid gas or a sulfurousacid solution, is employed, since that form of the invention constitutes the subject-matter of my divisional application filed on February 4, 1913, Serial No. 746121.

Having now particularly described my invention I hereby declare that what I claim as new and desire-to be protected in by Letters Patent, is:

3. A process for the recovery of pure I metallic zinc and manganese 'dioxid, said process comprising the passage of an elec-' tric current of from two and a half to four and a half volts from. a lead anodeto a zinc cathode immersed in a solution containing sulfate of zinc, sulfate of manganese-and neutral sulfate of sodium.

4. A process for the recovery of pure metallic zinc and manganese dioxid, said process comprising the electrolytic decomposition of a solution containing sulfate of zinc, sulfate of, manganese and neutral sulfate of sodium the electrolyte after being acted uponbeing continuousl delivered to the leaching tank from which the original supply was obtained and continually replaced in the electrolytic tank by a supply drawn from the same leaching tank.

In testimony whereof I have signed my name to thisspecification in the presence of two subscribing witnesses.

ANDREW GORDON FRENCH.

Witnesses:

WM. .0. MCCLELLAND, W. F. TEETZEL.