Recycling and preparing method of battery-grade nickel sulfate and cobalt sulfate

Abstract

The invention belongs to the technical field of waste recovery, and discloses a battery-grade nickel sulfate and cobalt sulfate recovery preparation method, which comprises: 1, sequentially adding a first extraction agent to nickel-cobalt-containing wastewater to carry out extraction, and adding sulfuric acid to carry out reverse extraction treatment to obtain a first reverse extraction liquid and a raffinate; 2, a second extraction agent is sequentially added into the raffinate for extraction, sulfuric acid is added for reverse extraction treatment, second reverse extraction liquid is obtained, the second reverse extraction liquid is subjected to evaporative crystallization, and nickel sulfate is obtained; 3, the first strip liquor is sequentially subjected to deep purification treatment and evaporative crystallization, and cobaltous sulfate is obtained; the first extraction agent is a mixture of P507 and solvent oil, and the second extraction agent is a mixture of a carboxylic acid extraction agent and solvent oil; the O / A value of the reverse extraction treatment in the step 1 and the step 2 is (10-13): 1. The cobalt element is subjected to reverse extraction, deep purification treatment and evaporative crystallization to obtain cobalt sulfate, then the nickel element is subjected to reverse extraction, evaporative crystallization to obtain nickel sulfate, the production process is short, and the nickel and cobalt element recovery efficiency is high.

Description

Technical Field

[0001] The invention relates to the technical field of waste recycling, and in particular to a method for recovering and preparing battery-grade nickel sulfate and cobalt sulfate. Background Art

[0002] Nickel is a hard, ductile and magnetic metal that is highly polishable and corrosion-resistant. With the rapid development of the new energy industry, nickel compounds are produced in large quantities and are widely used in ternary batteries. However, most of the raw materials currently used to make ternary batteries are nickel cobalt hydroxide, high nickel matte, nickel sulfide and other raw materials with high nickel and cobalt content and low impurities. Nickel sulfate and cobalt sulfate required for ternary batteries made from nickel-cobalt waste, nickel-cobalt hazardous waste and other miscellaneous materials are rarely used due to their high impurity content, low nickel and cobalt content and high production cost.

[0003] Most of the nickel-cobalt waste is generally used as raw material for pyrometallurgy to be smelted into nickel iron, low-grade nickel matte and high-grade nickel matte. For example, prior art 1: Chinese patent application 200710303622.1 discloses a method for recycling nickel-cobalt alloy waste, and the recycling process is to blow the nickel-cobalt alloy waste into high-grade nickel matte, and then enter the nickel-cobalt production process to recover nickel and cobalt; this technology adopts the method of pyrometallurgy to prepare high-grade nickel matte to recover nickel and cobalt elements, but it cannot be directly used as raw material for producing battery-grade nickel sulfate and cobalt sulfate. Even if a small part of it is used as raw material for producing battery-grade nickel sulfate and cobalt sulfate, it does not have the advantage of large-scale production due to the long production process and high production cost; and this method is also difficult to be used in the treatment of nickel-cobalt-containing wastewater.

[0004] Based on this, it is necessary to find a method for recycling and treating nickel-cobalt waste and nickel-cobalt wastewater with a shorter production process and lower production cost, so as to directly generate battery-grade nickel sulfate and cobalt sulfate raw materials. Summary of the invention

[0005] One of the purposes of the present invention is to provide a method for recovering and preparing battery-grade nickel sulfate and cobalt sulfate, which can fully recover and prepare battery-grade nickel sulfate and cobalt sulfate, and has a short production process and low cost, and can be applied to large-scale production.

[0006] To achieve the above object, the present invention provides a method for recovering and preparing battery-grade nickel sulfate and cobalt sulfate, comprising the following steps:

[0007] Step 1: sequentially adding a first extractant to the nickel-cobalt-containing wastewater for extraction, and adding sulfuric acid for stripping treatment to obtain a first stripping solution and a raffinate;

[0008] Step 2: sequentially adding a second extractant to the raffinate for extraction, adding sulfuric acid for stripping to obtain a second stripping solution, and evaporating and crystallizing the second stripping solution to obtain nickel sulfate;

[0009] Step 3: subjecting the first stripping solution to deep purification, evaporation and crystallization in sequence to obtain cobalt sulfate;

[0010] The first extractant is a mixture of P507 and solvent oil, and the second extractant is a mixture of a carboxylic acid extractant and solvent oil; the O / A value of the back extraction treatment in step 1 and step 2 is both 1-10:1.

[0011] It should be noted that the nickel-cobalt-containing wastewater can be wastewater generated in the production process of ternary batteries, or it can be nickel-cobalt-containing wastewater obtained by further processing nickel-cobalt waste; the specific steps of further processing nickel-cobalt waste to form nickel-cobalt-containing wastewater are:

[0012] Step a: subjecting nickel-cobalt waste to reduction acid leaching to obtain a leaching solution;

[0013] Step b: adding an oxidant to the leaching solution to remove iron and aluminum elements to obtain nickel-cobalt-containing wastewater.

[0014] Preferably, the reducing agent used in step a is at least one of ferrous sulfate, sodium sulfite and hydrogen peroxide.

[0015] Preferably, the oxidant is at least one of oxygen and hydrogen peroxide.

[0016] Furthermore, the specific operation of step 1 is: adding a first extractant to the nickel-cobalt-containing wastewater for countercurrent extraction, countercurrent washing the organic phase after extraction, adding sulfuric acid to the washed organic phase for stripping to obtain a first stripping solution and a raffinate; wherein the O / A value of the countercurrent extraction is 1-10:1, and the O / A value of the countercurrent washing is 25-30:1.

[0017] Preferably, the mass percentage of P507 in the first extractant is 20-30%.

[0018] Further preferably, the solvent oil can be selected from sulfonated kerosene and 260# kerosene.

[0019] Furthermore, the specific operation of step 2 is: adding a second extractant to the raffinate for countercurrent extraction, countercurrent washing the organic phase after extraction, adding sulfuric acid to the washed organic phase for stripping to obtain a second stripping solution, and evaporating and crystallizing the second stripping solution to obtain nickel sulfate; wherein the O / A value of the countercurrent extraction is 1-10:1, and the O / A value of the countercurrent washing is 25-30:1.

[0020] Preferably, the mass percentage of the carboxylic acid extractant in the second extractant is 15-25%, and the carboxylic acid extractant is BC196 or DY319.

[0021] Furthermore, the specific operation of the deep purification treatment in step 3 is: the first stripping liquid is subjected to countercurrent soap transfer using P204, and the organic phase after soap transfer is subjected to countercurrent extraction using P204 to obtain the extract residue.

[0022] Beneficial Effects

[0023] Compared with the prior art, the present invention provides a method for recovering and preparing battery-grade nickel sulfate and cobalt sulfate, wherein the cobalt element is first stripped out, subjected to deep purification, and evaporated and crystallized to obtain cobalt sulfate, and then the nickel element is stripped out, evaporated and crystallized to obtain nickel sulfate, with a short production process and high recovery efficiency of nickel and cobalt elements, and finally battery-grade nickel sulfate and cobalt sulfate are obtained;

[0024] In addition, the technical solution of the present invention has the advantages of not introducing impurity ions, being simple and easy to use, having a short process, low investment, low production cost, strong raw material applicability, and being green and environmentally friendly. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with the embodiments, but it does not constitute any limitation to the present invention. Any limited number of modifications made within the scope of the claims of the present invention are still within the scope of the claims of the present invention.

[0026] In order to explain the technical content of the present invention in detail, further description is given below in conjunction with the implementation modes.

[0027] In the following examples and comparative examples, the first extractant is a mixture of P507 and sulfonated kerosene, wherein the mass percentage of P507 is 25%.

[0028] In the following examples and comparative examples, the second extractant is a mixture of DY319 and sulfonated kerosene, wherein the mass percentage of DY319 is 20%.

[0029] The following examples and comparative examples all use the same batch of nickel-cobalt-containing wastewater for recycling treatment.

[0030] Example 1

[0031] A method for recovering and preparing battery-grade nickel sulfate and cobalt sulfate comprises the following steps:

[0032] Step 1: adding a first extractant to the nickel-cobalt-containing wastewater for 8-stage countercurrent extraction, performing 14-stage countercurrent washing on the organic phase after extraction, adding 3N sulfuric acid to the washed organic phase for stripping to obtain a first stripping solution and a raffinate; wherein the O / A value of the countercurrent extraction is 10:1, the O / A value of the countercurrent washing is 30:1, and the O / A value of the countercurrent stripping is 10:1;

[0033] Step 2: adding a second extractant to the raffinate to perform 8-stage countercurrent extraction, performing 7-stage countercurrent washing on the organic phase after extraction, adding 3N sulfuric acid to the washed organic phase for stripping to obtain a second stripping solution, and evaporating and crystallizing the second stripping solution to obtain nickel sulfate; wherein the O / A value of the countercurrent extraction is 10:1, the O / A value of the countercurrent washing is 30:1, and the O / A value of the countercurrent stripping is 10:1;

[0034] Step 3: The first stripping liquid is subjected to 5-stage countercurrent soap transfer using P204, and the organic phase after soap transfer is subjected to 8-stage countercurrent extraction using P204 to obtain an extract residue; wherein the O / A value of the countercurrent soap transfer is 10:1, and the O / A value of the countercurrent extraction is 10:1.

[0035] Example 2

[0036] A method for recovering and preparing battery-grade nickel sulfate and cobalt sulfate comprises the following steps:

[0037] Step 1: adding a first extractant to the nickel-cobalt-containing wastewater for 8-stage countercurrent extraction, performing 14-stage countercurrent washing on the organic phase after extraction, adding 3N sulfuric acid to the washed organic phase for stripping to obtain a first stripping solution and a raffinate; wherein the O / A value of the countercurrent extraction is 1:1, the O / A value of the countercurrent washing is 25:1, and the O / A value of the countercurrent stripping is 13:1;

[0038] Step 2: adding a second extractant to the raffinate to perform 8-stage countercurrent extraction, performing 7-stage countercurrent washing on the organic phase after extraction, adding 3N sulfuric acid to the washed organic phase for stripping to obtain a second stripping solution, and evaporating and crystallizing the second stripping solution to obtain nickel sulfate; wherein the O / A value of the countercurrent extraction is 10:1, the O / A value of the countercurrent washing is 30:1, and the O / A value of the countercurrent stripping is 13:1;

[0039] Step 3: The first stripping liquid is subjected to 5-stage countercurrent soap transfer using P204, and the organic phase after soap transfer is subjected to 8-stage countercurrent extraction using P204 to obtain an extract residue; wherein the O / A value of the countercurrent soap transfer is 10:1, and the O / A value of the countercurrent extraction is 10:1.

[0040] The nickel sulfate and cobalt sulfate obtained in Example 1-2 were tested for nickel and cobalt content, respectively. The results are shown in Table 1.

[0041] Table 1 Detection results of nickel and cobalt contents in nickel sulfate and cobalt sulfate obtained in Example 1-2

[0042] Nickel content in nickel sulfate % Cobalt content in cobalt sulfate % Example 1 22.23 21.08 Example 2 22.25 21.04

[0043] According to the results in Table 1, we can see that:

[0044] The present invention strips out the cobalt element, performs deep purification, evaporates and crystallizes to obtain cobalt sulfate, and then strips out the nickel element, evaporates and crystallizes to obtain nickel sulfate. The production process is short and the recovery efficiency of nickel and cobalt elements is high. The nickel content in the obtained nickel sulfate and the cobalt content in the obtained cobalt sulfate both reach relatively high content values, indicating that the recovery rates of nickel and cobalt elements are relatively high.

[0045] In addition, the technical solution of the present invention has the advantages of not introducing impurity ions, being simple and easy to use, having a short process, low investment, low production cost, strong raw material applicability, and being green and environmentally friendly.

[0046] The embodiments presented herein are only embodiments selected according to the combination of all possible embodiments. The appended claims should not be limited by the embodiments describing the present invention. Some numerical ranges used in the claims include sub-ranges therein, and the changes in these ranges should also be covered by the appended claims.

Claims

1. A method for recovering and preparing battery-grade nickel sulfate and cobalt sulfate, characterized in that: The steps include: Step 1: sequentially adding a first extractant to the nickel-cobalt-containing wastewater for extraction, and adding sulfuric acid for stripping treatment to obtain a first stripping solution and a raffinate; Step 2: sequentially adding a second extractant to the raffinate for extraction, adding sulfuric acid for stripping to obtain a second stripping solution, and evaporating and crystallizing the second stripping solution to obtain nickel sulfate; Step 3: subjecting the first stripping solution to deep purification treatment, evaporation and crystallization in sequence to obtain cobalt sulfate; The first extractant is a mixture of P507 and solvent oil, and the second extractant is a mixture of a carboxylic acid extractant and solvent oil; the O / A value of the stripping treatment in step 1 and step 2 is both 10-13:

1.

2. The method for recovering and preparing battery-grade nickel sulfate and cobalt sulfate according to claim 1, characterized in that: The specific operation of step 1 is: adding a first extractant to the nickel-cobalt-containing wastewater for countercurrent extraction, countercurrent washing the organic phase after extraction, adding sulfuric acid to the washed organic phase for stripping to obtain a first stripping solution and a raffinate; wherein the O / A value of the countercurrent extraction is 1-10:1, and the O / A value of the countercurrent washing is 25-30:

1.

3. The method for recovering and preparing battery-grade nickel sulfate and cobalt sulfate according to claim 2, characterized in that: The mass percentage of P507 in the first extractant is 20-30%.

4. The method for recovering and preparing battery-grade nickel sulfate and cobalt sulfate according to claim 1, characterized in that: The specific operation of step 2 is: adding a second extractant to the raffinate for countercurrent extraction, countercurrent washing the organic phase after extraction, adding sulfuric acid to the washed organic phase for stripping to obtain a second stripping solution, and evaporating and crystallizing the second stripping solution to obtain nickel sulfate; wherein the O / A value of the countercurrent extraction is 1-10:1, and the O / A value of the countercurrent washing is 25-30:

1.

5. The method for recovering and preparing battery-grade nickel sulfate and cobalt sulfate according to claim 4, characterized in that: The mass percentage of the carboxylic acid extractant in the second extractant is 15-25%, and the carboxylic acid extractant is BC196 or DY319.

6. The method for recovering and preparing battery-grade nickel sulfate and cobalt sulfate according to claim 1, characterized in that: The specific operation of the deep purification treatment in step 3 is: the first stripping liquid is subjected to countercurrent soap removal using P204, and the organic phase after soap removal is subjected to countercurrent extraction using P204 to obtain the extract residue.