SU988892A1 - Method for leaching polymetallic zinc-bearing materials - Google Patents

Description

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This invention relates to non-ferrous metallurgy primarily to zinc and cadmium metallurgy, and may. be used for leaching oxidized zinc-containing materials, such as calcined zinc: concentrates, oxidized ores, velcokislov, slag dust, dusts, as well as materials containing non-ferrous metals in an elemental state, such as copper-cadmium cakes, alloy, zinc-based, metallic powders, shavings, etc.

A method of processing polymetallic materials is known by leaching in an acid solution of 1 J.

The disadvantage of this method is that a significant amount of equipment and a high consumption of reagents, primarily zinc dust, amounting to 80 kg per 1 ton of zinc in solution, are required to carry out the cleaning.

The closest to the proposed method is the leaching of a poly-metallic zinc-containing mate: trials in an acid solution, including electrolyzing pulp with a constant electric current of G2.

The disadvantages of this method are the complexity of instrumentation in connection with the need

To separate the anode space of the electrolyzer from the cathode; the complexity of servicing the electrolytic cell, since its cathodes constantly accumulate metallic zinc deposits and primers more electrically positive than zinc, as well as part of the solid components of the pulp mechanically "involved in the cathode precipitate, which requires regular (manual or mechanical) removal sediment from the electrodes in order to avoid a sharp disturbance of the pulp circulation, deterioration of the quality of solution cleaning, the occurrence of kopoTKoro closure of the electrodes and an increase in the power consumption. In addition, the known method is unacceptable for leaching materials in a continuous mode, since it inevitably requires interrupting the process for cleaning the electrodes from sludge. The purpose of the invention is to reduce labor costs and electric power consumption, improving the cleaning solution from impurities. The goal is achieved by the method of leaching polymetallic zinc-containing materials in an acid solution, which involves electrolyzing the pulp with a constant electric current, during the leaching process, the direction of the electric current flowing through the pulp is reversed once for 1-10 hours. electric current flowing through the pulp leads to the dissolution of the previously obtained cathode sediment. In accordance with the position of the metal components of the sediment in a series of stresses, they dissolve after reversal: first of all, zinc passes into the solution as the most electronegative metal (standard potential, 7b V), then cadmium (, CO B), cobalt (, 28 C) nickel (Е -0.23 in), etc. The main part of the cathode sludge (up to 80-85%) during the electroleaching of zinc-containing materials - zinc ogarkov, oxides, copper-cadmium cakes and others is metallic zinc. As zinc dissolves predominantly under the influence of electric current after changing its direction due to disturbance of mechanical and galvanic communication of the sediment from the electrodes, the latter is gradually exposed, and the residue from the plant grows; the composition of the initial sediment) components, more electropositive than zinc. So, without the use of special mechanical devices or. Additional labor costs remove the sediment from the electrodes according to the proposed method and, consequently, complete regeneration of the electrodes is achieved in the electro-leaching process without interrupting it and the possibility of carrying out the method in a continuous mode. In the process of electro-leaching of materials by the proposed method, up to 10 of the entire duration of the process is due to the dissolution of the previously obtained cathode sediment under the action of electric current (immediately after the reverse current). This period is characterized by a sharp decrease in voltage on the electrodes (from 3 to 0.4-0.5 V) with a constant current density. The reason for this is that the main reaction of the anodic process during the dissolution of the precipitate becomes In-2e-Zn E -0.7 V, whereas before the reverse of the current on the anode, the reaction H, 0-2e 2H + 0.5 E +1.23 6 Therefore, the periodic roaring of the current during the electro-leaching process causes a decrease in the specific power consumption. In the process of electroleaching of materials according to the proposed method, the cement deposition of impurities on dissolving zinc takes place. This occurs as a result of interaction with the solution of the residue from the dissolution of the precipitate, which still contains a significant amount of reactive zinc metal. In general, the impurities are cemented simultaneously with the cathodic process on the fresh surface of highly dispersed zinc deposited on a previously regenerated electrode. Thus, reversing the current during electroleaching improves cleaning. Example. 208 g of copper-cadmium cake with a moisture content of 2.3%, obtained as a result of cementation purification of a zinc sulphate solution with metallic zinc, having a composition,%. copper 7.08; cadmium, k zinc 1.8, leached in a 0.650 dm composition solution, zinc 11.8; sulfuric acid 48.5 at 6 (HS and mixing the pulp with a frequency of 6.67 1 / s. Simultaneously through the pulp with the help of lead-silver electrodes (1.0% silver, the size of the cathode surface is 1.46 dm) a constant electric current strength 6, OiO, 2 A.

At the end of the leaching, the mass of the cathode with precipitate is determined and the resulting zinc sulfate solution is analyzed, and the cathode with precipitate from the experiment performed is used without removing the precipitate-S for the next experiment. The effect of the reverse current on the electric leaching of the copper-cadmium gel is shown in the table.

Using the proposed cnonio method of leaching polymetallic zinc-containing materials, for example.

Zinc-rich butts, copper-cadmium cake, Velcokislov, etc., in modern zinc electrolyte plants causes a decrease in the consumption of scarce zinc dust for cleaning solutions of zinc sulphate from electropositive impurities (copper, cadmium, etc.). Therefore, the economic effect from the use of the proposed method at a zinc electrolyte plant, with a capacity of 100 thousand tons of pig zinc per year, is 37 thousand rubles.

5988892-О

Claims (2)

The claims of the invention are the electrical current board, the method of leaching polymetallic - the opposite once for zinc-containing materials in 1-10 hours. acid solution, which includes electro-s. Sources of information, pulsed LIS of a constant electric current taken into account in current examination, characterized in that 1. Lakernik MM, Pakhomova G.N., in order to reduce labor costs Zinc metallurgy and cadmium. N., and the specific consumption of electricity Metallurgy, 1968, p. 30. 55. and improve the cleaning solution from 2. USSR author's certificate, in the leaching process, to No. 7.73113, cl. From 22 to 19/22, 1980. flowing through the pulp is changed to