Application of sodium thiosulfate as auxiliary agent for nickel-cobalt precipitation

Abstract

Disclosed in the present invention is an application of sodium thiosulfate as an auxiliary agent for nickel-cobalt precipitation. The application comprises the following steps: (1) adding sodium thiosulfate to a solution after iron and aluminum removal, and stirring at 50-65°C to obtain a nickel-cobalt precipitation stock solution; (2) adding an alkali to the nickel-cobalt precipitation stock solution, adjusting the pH of a system to 7.0-7.4, and maintaining the pH to allow for sufficient precipitation of nickel and cobalt to obtain precipitate; and (3) washing the precipitate to obtain mixed hydroxide precipitate (MHP). In the present invention, sodium thiosulfate is used as the auxiliary agent for nickel-cobalt precipitation, and the precipitation rate of nickel and cobalt from the solution after iron and aluminum removal is promoted by means of the addition of the auxiliary agent, reducing the content of manganese in MHP product. The present invention has good economic value and is easy for industrial application.

Description

Application of sodium thiosulfate as an auxiliary agent for nickel and cobalt precipitation Technical Field

[0001] The invention belongs to the field of metallurgy, and in particular relates to the application of sodium thiosulfate as an auxiliary agent for nickel and cobalt precipitation. Background Art

[0002] Laterite nickel ore resources are surface weathering crust deposits formed by the weathering, leaching, and deposition of nickel sulfide rock masses. 60% of the world's nickel ore reserves are in the form of laterite nickel ore. Although of low grade, laterite nickel ore is abundant and has high reserves. Nickel is a key industrial metal, widely used in various industries, including steel, machinery, and construction. In recent years, with the development of the new energy industry chain, nickel's application in ternary battery materials has become increasingly important. Nickel smelting methods vary depending on the grade of the ore and associated minerals, primarily including pyrometallurgy and hydrometallurgy.

[0003] In the wet extraction of nickel and cobalt from laterite nickel ore, the reuse of the barren liquor after nickel and cobalt precipitation leads to the enrichment of manganese in the system, resulting in an increasing manganese content in the finished nickel cobalt hydroxide (MHP), reducing product quality. Currently, the commonly used method is to remove manganese through an open circuit in the barren liquor after nickel and cobalt precipitation. However, this method has the disadvantages of requiring process changes, being complex, and producing a manganese slag byproduct that is difficult to handle.

[0004] Summary of the Invention

[0005] In response to the shortcomings of the prior art, the present invention aims to provide the use of sodium thiosulfate as an auxiliary agent for nickel and cobalt precipitation. The present invention uses sodium thiosulfate as an auxiliary agent for nickel and cobalt precipitation. The addition of the auxiliary agent promotes the precipitation rate of nickel and cobalt from the liquid after iron and aluminum removal, thereby reducing the manganese content in the MHP product. The method has good economic value and is easy to apply industrially.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] The application of sodium thiosulfate as an auxiliary agent for nickel and cobalt precipitation includes the following steps:

[0008] (1) adding sodium thiosulfate to the solution after iron and aluminum removal, stirring at 50-65° C. to obtain a nickel and cobalt precipitation solution;

[0009] (2) adding alkali to the nickel-cobalt precipitation solution to adjust the pH of the system to 7.0-7.4, and maintaining the pH to allow the nickel and cobalt to be fully precipitated to obtain a precipitate;

[0010] (3) After washing the precipitate, nickel cobalt hydroxide is prepared.

[0011] Preferably, the amount of sodium thiosulfate added in step (1) is 0.5 to 1 times the theoretical molar amount of manganese in the liquid after iron and aluminum removal.

[0012] Preferably, the stirring time in step (1) is 30 to 60 minutes.

[0013] Preferably, the base in step (2) is at least one of NaOH and calcium hydroxide.

[0014] Preferably, the precipitation temperature in step (2) is 50-65°C.

[0015] Preferably, the precipitation temperature in step (2) is 60°C.

[0016] Preferably, the precipitation time in step (2) is 1 to 3 hours.

[0017] Preferably, the washing method in step (3) is: washing with water at least once.

[0018] Preferably, the number of times of washing with water is 3.

[0019] Preferably, the washing time for each washing with water is 30 to 60 minutes.

[0020] The principle of using sodium thiosulfate as an auxiliary agent:

[0021] Create a reducing system for the solution to reduce the oxidation precipitation of manganese, because manganese is easily oxidized in alkaline solution to form MnO(OH)2, which will lead to a high Mn content in the precipitated MHP.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The use of sodium thiosulfate can increase the precipitation rate of nickel and cobalt, and a higher precipitation rate can be obtained in one precipitation.

[0024] (2) Sodium thiosulfate can increase the pH of the system and effectively reduce the cost of alkali.

[0025] (3) Sodium thiosulfate can inhibit the formation of MnO(OH)2, reduce the precipitation rate of manganese, effectively reduce the manganese content in MHP, and improve the quality of MHP.

[0026] (4) Sodium thiosulfate is inexpensive, easy to add, has good economic value, and is easy to apply in industrial large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG1 is a flow chart of the application of sodium thiosulfate as an auxiliary agent for nickel and cobalt precipitation according to the present invention. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0029] The iron-deoxidized liquor used in the examples and comparative examples is the iron-deoxidized liquor of laterite nickel ore high-pressure leaching solution, and the specific composition is as follows: Ni 3.96 g / L, Co 0.448 g / L, Mn 3.13 g / L, Ca 0.611 g / L, Mg 7.29 g / L.

[0030] Example 1

[0031] The application of sodium thiosulfate as an auxiliary agent for nickel and cobalt precipitation is as follows:

[0032] (1) Add 0.5 times the theoretical molar amount of manganese in sodium thiosulfate to the solution after iron and aluminum removal, and stir at 60°C and 350 rpm for 60 minutes;

[0033] (2) After the reaction, slowly add sodium hydroxide solution to adjust the pH to 7.0, the precipitation temperature is 60 ° C, and the pH is maintained stable to carry out nickel and cobalt precipitation reaction for 1 hour;

[0034] (3) After the reaction is completed, the precipitate is filtered, and the filter cake is washed with water 3 times the weight of the wet residue for 30 minutes × 3 times, and then dried to prepare nickel cobalt hydroxide.

[0035] The prepared nickel cobalt hydroxide was analyzed. The results showed that the precipitation rates of Ni and Co were 90.68% and 84.41%, respectively. The nickel cobalt hydroxide product contained 39.59% Ni, 3.90% Co, and 6.75% Mn.

[0036] Example 2

[0037] The application of sodium thiosulfate as an auxiliary agent for nickel and cobalt precipitation is as follows:

[0038] (1) Sodium thiosulfate (0.75 times the theoretical molar amount of manganese) was added to the solution after iron and aluminum removal, and stirred at 60°C and 350 rpm for 60 minutes;

[0039] (2) After the reaction, slowly add sodium hydroxide solution to adjust the pH to 7.0, the precipitation temperature is 60 ° C, and the pH is maintained stable to carry out nickel and cobalt precipitation reaction for 1 hour;

[0040] (3) After the reaction is completed, the precipitate is filtered, and the filter cake is washed with water 3 times the weight of the wet residue for 30 minutes × 3 times, and then dried to prepare nickel cobalt hydroxide.

[0041] The prepared nickel cobalt hydroxide was analyzed. The results showed that the precipitation rates of Ni and Co were 95.19% and 92.83%, respectively. The nickel cobalt hydroxide product contained 40.19% Ni, 4.39% Co, and 5.39% Mn.

[0042] Example 3

[0043] The application of sodium thiosulfate as an auxiliary agent for nickel and cobalt precipitation is as follows:

[0044] (1) Sodium thiosulfate (1 times the theoretical molar amount of manganese) was added to the solution after iron and aluminum removal, and stirred at 60°C and 350 rpm for 60 minutes;

[0045] (2) After the reaction, slowly add sodium hydroxide solution to adjust the pH to 7.0, the precipitation temperature is 60 ° C, and the pH is maintained stable to carry out nickel and cobalt precipitation reaction for 1 hour;

[0046] (3) After the reaction is completed, the precipitate is filtered, and the filter cake is washed with water 3 times the weight of the wet residue for 30 minutes × 3 times, and then dried to prepare nickel cobalt hydroxide.

[0047] The prepared nickel cobalt hydroxide was analyzed. The results showed that the precipitation rates of Ni and Co were 94.85% and 94.36%, respectively. The nickel cobalt hydroxide product contained 40.02% Ni, 4.22% Co, and 5.12% Mn.

[0048] Comparative Example 1

[0049] The de-ironized and de-aluminized solution was stirred at 60°C and 350 rpm for 60 minutes. Sodium hydroxide solution was slowly added to adjust the pH to 7.0. The precipitation temperature was set at 60°C, and the pH was maintained stable for 1 hour. After the reaction, the precipitate was filtered, and the filter cake was washed three times with water (3 times the weight of the wet residue) for 30 minutes. Finally, the filter residue was dried and sent for analysis.

[0050] The analysis results showed that the precipitation rates of Ni and Co were 85.33% and 75.75% respectively; the MHP product contained 38.54% Ni, 3.56% Co and 7.07% Mn.

[0051] Comparative Example 2

[0052] Sodium thiosulfate containing 1.25 times the theoretical molar amount of manganese is added to the liquid after iron and aluminum removal, and the mixture is stirred at 60°C and 350 rpm for 60 minutes. After the reaction, sodium hydroxide solution is slowly added to adjust the pH to 7.0, the precipitation temperature is 60°C, and the pH is maintained stable to carry out nickel and cobalt precipitation reaction for 1 hour. After the reaction is completed, the precipitate is filtered, and the filter cake is washed with water 3 times the weight of the wet residue for 30 minutes × 3 times, and then dried to prepare nickel cobalt hydroxide.

[0053] The prepared nickel cobalt hydroxide was analyzed. The results showed that the precipitation rates of Ni and Co were 92.32% and 93.87%, respectively. The nickel cobalt hydroxide product contained 39.52% Ni, 4.03% Co, and 5.63% Mn.

[0054] Comparative Example 3

[0055] Sodium thiosulfate with 0.25 times the theoretical molar amount of manganese is added to the liquid after iron and aluminum removal, and stirred at a temperature of 60°C and a rotation speed of 350 rpm for 60 minutes; after the reaction, sodium hydroxide solution is slowly added to adjust the pH to 7.0, the precipitation temperature is 60°C, and the pH is maintained stable to carry out nickel and cobalt precipitation reaction for 1 hour; after the reaction is completed, the precipitate is filtered, and the filter cake is washed with water 3 times the weight of the wet residue for 30 minutes × 3 times, and then dried to prepare nickel cobalt hydroxide.

[0056] The prepared nickel cobalt hydroxide was analyzed. The results showed that the precipitation rates of Ni and Co were 89.86% and 80.23%, respectively. The nickel cobalt hydroxide product contained 38.54% Ni, 3.74% Co, and 7.03% Mn.

[0057] Comparing Examples 1 to 3 with Comparative Example 1, we can see that the addition of the auxiliary agent sodium thiosulfate significantly increases the precipitation rates of Ni and Co, and also effectively reduces the manganese content in MHP.

[0058] By comparing Examples 1 to 3 and Comparative Examples 2 to 3, we can see that adding too much sodium thiosulfate does not significantly improve the nickel-cobalt precipitation rate, but instead increases the cost; adding too little sodium thiosulfate results in poor nickel-cobalt precipitation. It can be seen that only when the amount of sodium thiosulfate added is within an appropriate range can both cost savings and a higher nickel-cobalt precipitation rate be achieved.

[0059] The specific embodiments of the present invention described above do not limit the scope of protection of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. Application of sodium thiosulfate as a nickel and cobalt precipitation aid, characterized in that, it includes the following steps: (1) Add sodium thiosulfate to the solution after iron and aluminum removal, and stir at 50 - 65 °C to obtain the stock solution for nickel and cobalt precipitation; (2) Add alkali to the stock solution for nickel and cobalt precipitation, adjust the pH of the system to 7.0 - 7.4, and maintain this pH to fully precipitate nickel and cobalt to obtain a precipitate; (3) After washing the precipitate, nickel cobalt hydroxide is prepared.

2. The application of sodium thiosulfate as a nickel and cobalt precipitation aid according to claim 1, characterized in that, the addition amount of sodium thiosulfate in step (1) is 0.5 - 1 times the theoretical molar amount of manganese in the solution after iron and aluminum removal.

3. The application of sodium thiosulfate as a nickel and cobalt precipitation aid according to claim 1 or 2, characterized in that, the stirring time in step (1) is 30 - 60 min.

4. The application of sodium thiosulfate as a nickel and cobalt precipitation aid according to claim 3, characterized in that, The base described in step (2) is at least one of NaOH and Ca(OH) 2 2 5. The application of sodium thiosulfate as a nickel and cobalt precipitation aid according to claim 1 or 2, characterized in that, the precipitation temperature in step (2) is 50 - 65 °C.

6. The application of sodium thiosulfate as a nickel and cobalt precipitation aid according to claim 5, characterized in that, the precipitation temperature in step (2) is 60 °C.

7. The application of sodium thiosulfate as a nickel and cobalt precipitation aid according to claim 6, characterized in that, the precipitation time in step (2) is 1 - 3 h.

8. The application of sodium thiosulfate as a nickel and cobalt precipitation aid according to claim 1 or 2, characterized in that, the washing method in step (3) is: wash with water at least once.

9. The application of sodium thiosulfate as a nickel and cobalt precipitation aid according to claim 8, characterized in that, the number of times of washing with water is 3.

10. The application of sodium thiosulfate as a nickel and cobalt precipitation aid according to claim 9, characterized in that, the washing time for each time of washing with water is 30 - 60 min.

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