CN112176186A

CN112176186A - Method for replacing and recycling cadmium in comprehensive purification slag recycling process

Info

Publication number: CN112176186A
Application number: CN202011113911.7A
Authority: CN
Inventors: 刘延昌; 刘晓伟; 王文祥; 关旭东; 魏景文; 刘维佳
Original assignee: China Nonferrous Metals Construction Co ltd; CHIFENG ZHONGSE ZINC INDUSTRY CO LTD
Current assignee: China Nonferrous Metals Construction Co ltd; CHIFENG ZHONGSE ZINC INDUSTRY CO LTD
Priority date: 2020-10-18
Filing date: 2020-10-18
Publication date: 2021-01-05

Abstract

The invention discloses a method for replacing and recycling cadmium in a comprehensive recycling process of purification residues, which comprises three process steps of primary replacement reaction, secondary replacement reaction and acid leaching of cadmium, wherein in the primary replacement reaction, the adding amount (g) = cadmium content (g/L) × 0.8 of volume (L) of liquid in a primary replacement tank, and the reaction temperature is 60-70 ℃; adding sulfuric acid to regulate pH value to 1.5-2.0 and reaction time to 0.8-1.2 hr. The method has the characteristics of simple process, good impurity removal effect, zinc powder consumption saving and good sponge cadmium quality.

Description

Method for replacing and recycling cadmium in comprehensive purification slag recycling process

Technical Field

The invention belongs to the technical field of non-ferrous metal smelting, and particularly relates to a method for replacing and recycling cadmium in a purification slag comprehensive recycling process.

Background

In the existing zinc hydrometallurgy process technology, Chinese patent CN110195160A discloses a comprehensive recovery method of zinc hydrometallurgy liquid purification slag, the process method produces cobalt-removing leaching liquid after low acid leaching and recovering copper, removing iron and arsenic and recovering cobalt, the cadmium content of the cobalt-removing leaching liquid is about 4-10g/L, sponge cadmium and zinc-rich leaching liquid are obtained by adding zinc powder and sulfuric acid for replacement reaction, the sponge cadmium is pressed into cadmium groups to recover cadmium metal, and the zinc-rich leaching liquid is sent to a zinc hydrometallurgy system to recover zinc. The chemical equation of the principle of adding zinc powder and sulfuric acid to the cobalt-removing leaching solution to replace cadmium is as follows: cdso₄↓+Zn=ZnSO₄+Cd ↓。

The disadvantages of the prior art are as follows: when the cadmium content of the cobalt-removing leaching solution is lower than 8g/L, sponge cadmium cannot be produced in the step of recovering cadmium through the displacement reaction, or the sponge cadmium is poor in quality and cannot form cadmium clusters, so that the zinc powder is consumed twice, and auxiliary materials are seriously wasted.

Disclosure of Invention

The invention aims to overcome the problems in the prior art and provides a method for replacing and recovering cadmium in a comprehensive recovery process of purification slag, which has the characteristics of simple process, good impurity removal effect, zinc powder consumption saving and good sponge cadmium quality.

The purpose of the invention is solved by the following technical scheme: a method for replacing and recycling cadmium in a purification slag comprehensive recycling process comprises a primary replacement reaction, a secondary replacement reaction and acid leaching cadmium; the first replacement reaction is to add zinc powder and sulfuric acid into the cobalt-removing leaching solution for replacement reaction, and carry out solid-liquid separation to obtain first replacement slag and first cadmium-removing replacement solution; the secondary replacement reaction is to add zinc powder and sulfuric acid into the primary cadmium-removing replacement solution for replacement reaction, and perform solid-liquid separation to obtain secondary replacement slag and zinc-rich leachate; the acid cadmium leaching is to combine the primary replacement slag and the secondary replacement slag, add zinc powder and sulfuric acid for acid leaching reaction, and perform solid-liquid separation to obtain sponge cadmium and a cadmium leaching solution, wherein when the cadmium content of the cadmium leaching solution is less than 5g/L and the zinc content is more than 160g/L, the cadmium leaching solution returns to the secondary replacement reaction tank, and when the cadmium content of the cadmium leaching solution is more than 5g/L or the zinc content is less than 160g/L, the cadmium leaching solution returns to the acid cadmium leaching tank; the method is characterized in that: in the first replacement reaction, the adding amount (g) = cadmium content (g/L) × volume of liquid in the first replacement tank (L) × 0.8, and the reaction temperature is 60-70 ℃; adding sulfuric acid to regulate pH value to 1.5-2.0 and reaction time to 0.8-1.2 hr.

Preferably, in the first replacement reaction, the reaction temperature is 65 ℃; adding sulfuric acid to regulate pH value to 1.7-1.8 and reaction time to 0.9-1.1 hr.

Compared with the prior art, the invention has the advantages that:

(1) the method can replace and recover cadmium from the cobalt-removing leaching solution with low cadmium content, can ensure that the cadmium in the cobalt-removing leaching solution can also produce sponge cadmium at about 4g/L, and has high recovery rate and good sponge cadmium agglomeration quality;

(2) the method has the advantages of accurately controlling the usage amount of the zinc powder, having good impurity removal effect and saving a large amount of zinc powder.

Drawings

FIG. 1 is a process flow chart of the method for replacing and recovering cadmium in the comprehensive recovery process of the purification slag.

Detailed Description

The technical scheme of the invention is described in detail in the following with reference to the accompanying drawings. The following specific examples are only used to more clearly illustrate the technical solutions of the present invention, and therefore, are only used as examples, and the protection scope of the present invention is not limited thereby.

Example 1: as shown in figure 1, the method for replacing and recycling cadmium in the comprehensive recycling process of the purification residue comprises a primary replacement reaction, a secondary replacement reaction and acid leaching of cadmium; the first replacement reaction is to add zinc powder and sulfuric acid into the cobalt-removing leaching solution for replacement reaction, and carry out solid-liquid separation to obtain first replacement slag and first cadmium-removing replacement solution; the secondary replacement reaction is to add zinc powder and sulfuric acid into the primary cadmium-removing replacement solution for replacement reaction, and perform solid-liquid separation to obtain secondary replacement slag and zinc-rich leachate; the acid cadmium leaching is to combine the primary replacement slag and the secondary replacement slag, add zinc powder and sulfuric acid for acid leaching reaction, and perform solid-liquid separation to obtain sponge cadmium and a cadmium leaching solution, wherein when the cadmium content of the cadmium leaching solution is less than 5g/L and the zinc content is more than 160g/L, the cadmium leaching solution returns to the secondary replacement reaction tank, and when the cadmium content of the cadmium leaching solution is more than 5g/L or the zinc content is less than 160g/L, the cadmium leaching solution returns to the acid cadmium leaching tank; 1000L of cobalt-removing leaching solution with the cadmium content of 5g/L is added into a primary replacement reaction tank, sulfuric acid is added to adjust the pH value to be 1.8, the volume of the cobalt-removing leaching solution and the added sulfuric acid liquid is 1010L, and the adding amount of zinc powder is as follows: the cadmium content is 5g/L multiplied by the volume of the liquid in the primary replacement tank is 1010L multiplied by 0.8=4040 g; the reaction temperature is 65 ℃; the reaction time was 1 hour. Finally, sponge cadmium with better agglomeration effect is prepared, the cadmium content in the zinc-rich leaching solution is 2g/L, and the cadmium recovery rate is 60%.

Example 2: the process flow is the same as in example 1, except as follows: 1000L of cobalt-removing leaching solution with the cadmium content of 6g/L is added into a primary replacement reaction tank, sulfuric acid is added to adjust the pH value to be 1.7, the volume of the cobalt-removing leaching solution and the added sulfuric acid liquid is 1008L, and the adding amount of zinc powder is as follows: the cadmium content is 6g/L multiplied by the volume 1008L multiplied by 0.8=4838.4g of the liquid in the primary replacement tank; the reaction temperature is 60 ℃; the reaction time was 1.2 hours. Finally, sponge cadmium with better agglomeration effect is prepared, the cadmium content in the zinc-rich leaching solution is 2.2g/L, and the cadmium recovery rate is 63%.

Example 2: the process flow is the same as in example 1, except as follows: 1000L of cobalt-removing leaching solution with the cadmium content of 8g/L is added into a primary replacement reaction tank, sulfuric acid is added to adjust the pH value to be 1.9, the volumes of the cobalt-removing leaching solution and the added sulfuric acid liquid are 1020L, and the adding amount of zinc powder is as follows: the cadmium content is 8g/L multiplied by the volume of the liquid in the primary replacement tank is 1020L multiplied by 0.8=6528 g; the reaction temperature is 70 ℃; the reaction time was 0.8 hours. Finally, sponge cadmium with better agglomeration effect is prepared, the cadmium content in the zinc-rich leaching solution is 2.3g/L, and the cadmium recovery rate is 71%.

Finally, it should be noted that the above specific embodiments are only used for illustrating the technical solutions of the present invention, and do not limit the protection scope of the present invention, and those skilled in the art can make simple modifications or equivalent substitutions on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for replacing and recycling cadmium in a purification slag comprehensive recycling process comprises a primary replacement reaction, a secondary replacement reaction and acid leaching cadmium; the first replacement reaction is to add zinc powder and sulfuric acid into the cobalt-removing leaching solution for replacement reaction, and carry out solid-liquid separation to obtain first replacement slag and first cadmium-removing replacement solution; the secondary replacement reaction is to add zinc powder and sulfuric acid into the primary cadmium-removing replacement solution for replacement reaction, and perform solid-liquid separation to obtain secondary replacement slag and zinc-rich leachate; the acid cadmium leaching is to combine the primary replacement slag and the secondary replacement slag, add zinc powder and sulfuric acid for acid leaching reaction, and perform solid-liquid separation to obtain sponge cadmium and a cadmium leaching solution, wherein when the cadmium content of the cadmium leaching solution is less than 5g/L and the zinc content is more than 160g/L, the cadmium leaching solution returns to the secondary replacement reaction tank, and when the cadmium content of the cadmium leaching solution is more than 5g/L or the zinc content is less than 160g/L, the cadmium leaching solution returns to the acid cadmium leaching tank; the method is characterized in that: in the first replacement reaction, the adding amount (g) = cadmium content (g/L) × volume of liquid in the first replacement tank (L) × 0.8, and the reaction temperature is 60-70 ℃; adding sulfuric acid to regulate pH value to 1.5-2.0 and reaction time to 0.8-1.2 hr.

2. The method for replacing and recycling cadmium in the comprehensive purification slag recycling process according to claim 1 is characterized in that: in the primary replacement reaction, the reaction temperature is 65 ℃; adding sulfuric acid to regulate pH value to 1.7-1.8 and reaction time to 0.9-1.1 hr.