SU1395588A1 - Method of recovering nickel - Google Patents

Abstract

The invention relates to the field of purification of aqueous solutions from nickel and allows the process to be monitored while maintaining a high degree of purification. The method for extracting nickel from sulfuric acid solutions containing 0.001-1.0 g / l nickel consists in electrochemical treatment in a membrane electrolyzer with a cation-exchange membrane while circulating the initial solution through the cathode chamber at a speed of 1–20 M VMh, and the anode chamber is filled with a solution of sulfuric acid and an alkali metal sulfate salt in a molar ratio (1.5-6.0): 1 at a current density of 500-2500 A / m1 1 tab.

Description

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The invention relates to the purification of aqueous solutions of various industries from nickel. The purpose of the invention is to simplify the process while maintaining a high degree of purification. Example. Wash water formed after washing the workpieces from the electrolyte nickel plating of the following composition, g / l: NiSO 7NHO 300; 60; butyndiol 0.1, 40; Formalin 0.3, pH 4.5–5.5 and containing, 260 mg / l nickel, is continuously fed into the electrolyzer with cathode and anodic spaces separated by a cation-exchange membrane. Electrodeposition of nickel is produced; water is applied to cathodes of carbon-graphite fibrous materials. The process of nickel extraction is organized in such a way that all nickel introduced into the rinsing bath with: nickel plating electrolyte with the surface of the workpieces is extracted in the electrolyzer between the flushing of two consecutive batches of parts and thus the rinsing bath at a constant nickel concentration of 250 ml / l At the same time, the degree of nickel recovery, carried away from the nickel plating bath to the wash bath, is 99.6%. With the help of an anolyte consisting of serial acid and sodium sulphate in a 4: 1 molar ratio, the pH of the processed wash water is maintained at 5.5. The electrolysis is carried out at a current density of 750 A / m and the speed of the flow of wash water through the electrolyzer 6. h. Cathode material - mtilon. Anode — 1Latinated titanium. MK-40 cation-exchange membrane is used to separate the cathode and anode spaces. The electricity consumption for extracting 1 kg of nickel is 24.1 kW. h. Other process examples are presented in the table.

Simplification of the method is achieved by eliminating the multistage, since nickel is extracted by the proposed method in one stage. In addition, the proposed method practically does not require the use of reagents, whereas by a known method it is characteristic to use a large amount of reagents {ion exchange resin, acid and water). The electrolysis of nickel-containing wash water is carried out at current densities of 500 to 2500 A / m. At a current density of less than 500 A / m, nickel is not recovered, and at a current density of more than 2500 A / m, the process becomes economically unprofitable due to the high power consumption.

Wash water is pumped through the electrolyzer at a rate of 1-20 hours. At a flow rate of less than 1 hour, nickel is removed at a low speed.

and accumulates in the wash water. The increase in flow rate is greater than 20 .h. is unprofitable, since it does not lead to a decrease in the nickel concentration in the wash water, but leads to an increase in the power consumption for pumping (circulating) the wash water.

In the process, the required pH is maintained with an anolyte consisting of a solution of sulfuric acid and an alkali metal sulphate taken in a molar ratio of (1.5 + 6.0): at a sulfuric acid concentration of 1 mol / l. Sulfuric acid and alkali metal sulphate salts are not buffer substances.

In the proposed method, nickel is extracted directly from the wash water directed to the electrolytic cell, i.e. the process is carried out in one stage and continuously. This also simplifies

process. Nickel is obtained in a compact form suitable for reuse, for example, as soluble anodes in a nickel plating bath, which does not require additional costs. Reagents are used in minor amounts.

for anolyte preparation only. The proposed method is characterized by the compactness of the equipment and the reduction of the produced space required for its placement. In addition, this method reduces the damage to the environment.

environment wastewater containing nickel ions.

Claims (1)

Invention Formula A method for extracting nickel from sulphate solutions containing x 0.001 - 1.0 g / l nickel, including electrochemical treatment, characterized in that, in order to simplify the process while maintaining a high degree of purification, electrochemical treatment is carried out at a current density of 500-2500 electrolyzer with a cation-exchange membrane during the circulation of the initial solution through the cathode chamber at a rate of 1-20. h, and the anode chamber is filled with a solution rum of sulfuric acid and sulfate salt of the otelochny metal in a molar ratio (1.5-6.0): 1.