A cobalt-nickel hydrometallurgical method

Abstract

This invention relates to the field of metallurgical technology, and more particularly to a hydrometallurgical method for cobalt and nickel. The invention involves adding ferrous sulfate to cobalt, copper, and nickel-containing sulfide ores before acid roasting in a fluidized bed furnace. This increases the sulfur trioxide content in the fluidized bed furnace, leading to a greater conversion of cobalt, copper, and nickel oxides formed during roasting into sulfates, which facilitates subsequent leaching. Furthermore, the addition of ferrous sulfate increases the iron content in the leaching slag, thereby improving its economic value. During slag leaching, an extractant primarily composed of manganese dioxide and sulfuric acid is added. This increases the leaching rates of cobalt, copper, and nickel, and oxidizes ferrous iron in the leachate to ferric iron, facilitating subsequent iron separation. Ultimately, the leaching rates of cobalt, copper, and nickel in the cobalt, copper, and nickel-containing sulfide ores are increased by 13%, copper by 15%, and nickel by 45%. This makes a significant contribution to the comprehensive utilization of medium- and low-grade cobalt, copper, and nickel sulfide ores.

Description

Technical Field

[0001] This invention relates to the field of metallurgical technology, and more particularly to a cobalt-nickel hydrometallurgical method. Background Technology

[0002] Cobalt and nickel have gained significant importance in industry as strategic resources, finding wide applications in cemented carbide, functional ceramics, catalysts, military applications, and high-energy batteries, earning them the nickname "industrial MSG." Cobalt and nickel production primarily utilizes hydrometallurgy, with the main steps being leaching, impurity removal, precursor synthesis, and reduction. Before leaching, the boiling furnace acid roasting temperature is generally between 600-650 degrees Celsius, resulting in incomplete combustion of some cobalt, copper, and nickel sulfides in the mineral raw materials. However, this incompletely burned cobalt, copper, and nickel cannot be leached by sulfuric acid, thus limiting the leaching rate. During the leaching of the acid roasting residue with water and a small amount of sulfuric acid, iron enters the solution in both ferrous and ferric forms. When reducing iron powder is added to the solution during the copper removal process, ferric iron is reduced to ferrous iron. Simultaneously, the iron powder displaces copper, producing a large amount of ferrous ions that enter the solution. Ultimately, this results in a concentration of ferrous ions in the solution far exceeding the concentration of cobalt and nickel ions, leading to a significant amount of iron entering the product. Summary of the Invention

[0003] To address the problems existing in the background technology, a cobalt-nickel hydrometallurgical method is proposed.

[0004] This invention proposes a hydrometallurgical method for cobalt and nickel, comprising the following steps: S1. Ferrous sulfate is added to sulfide ores containing cobalt, copper, and nickel and then roasted. S2. Add an extractant mainly composed of manganese dioxide and sulfuric acid to the slag to leach out cobalt, copper, and nickel; see the reaction formula below for the specific reaction process: CoS+4MnO2+4H2SO4=CoSO4+4MnSO4+4H2O; CuS+4MnO2+4H2SO4=CuSO4+4MnSO4+4H2O; NiS+4MnO2+4H2SO4=NiSO4+4MnSO4+4H2O; CoO + H₂SO₄ = CoSO₄ + H₂O; CuO + H₂SO₄ = CuSO₄ + H₂O; NiO + H₂SO₄ = NiSO₄ + H₂O; 2FeSO4+MnO2+2H2SO4=Fe2(SO4)3+MnSO4+2H2O.

[0005] Preferably, ferrous sulfate is a byproduct of titanium dioxide production, with a content of 5-10%.

[0006] Preferably, a fluidized bed furnace is used for roasting, and the roasting temperature is controlled at 650-700℃.

[0007] Preferably, the amount of extractant is 1-5% of the slag, the leaching reaction time is 4-8 hours, the reaction temperature is 80-90℃, the liquid-solid ratio is 1-3:1, and the sulfuric acid concentration is 5-10 g / L.

[0008] Preferably, lime is added to the leachate to adjust the pH of the solution to 4.5-5.0, so that the iron in the solution forms ferric hydroxide precipitate, which is then separated by filtration.

[0009] Compared with existing technologies, this invention has the following beneficial technical effects: By adding ferrous sulfate to cobalt, copper, and nickel sulfide ores before acid roasting in a fluidized bed furnace, the sulfur trioxide content in the fluidized bed furnace is increased, leading to a greater conversion of cobalt, copper, and nickel oxides formed during roasting into sulfates, which is beneficial for subsequent leaching. Furthermore, the addition of ferrous sulfate increases the iron content in the leaching residue, thereby improving its economic value. During leaching of the residue, an extractant mainly composed of manganese dioxide and sulfuric acid is added. This increases the leaching rate of cobalt, copper, and nickel and oxidizes ferrous iron in the leachate to ferric iron, thus adding an iron removal step to the process. Simply adding lime to the leachate and adjusting the pH of the solution allows the iron in the solution to precipitate as ferric hydroxide. Ultimately, the leaching rate of cobalt in cobalt, copper, and nickel sulfide ores is increased by 13%, the leaching rate of copper by 15%, and the leaching rate of nickel by 45%. This makes a significant contribution to the comprehensive utilization of medium- and low-grade cobalt, copper, and nickel sulfide ores. Detailed Implementation

[0010] Example 1: This invention proposes a hydrometallurgical method for cobalt and nickel, the specific operation of which is as follows: 1000g of raw ore containing 0.5% cobalt, 0.8% copper, 1.1% nickel, and 30% sulfur is weighed. 100g of ferrous sulfate is added, mixed evenly, and then placed in a fluidized bed furnace. The mixture is heated to 650℃ and reacted for 6 hours. After cooling, 900g of the ore is weighed, and the cobalt content is found to be 0.56%, copper 0.89%, and nickel 1.22%. The slag is placed in a 2000ml beaker, and 1500ml of water, 10ml of concentrated sulfuric acid, and 27g of manganese dioxide are added. The mixture is kept at a constant temperature of 90℃ in a water bath and stirred for 6 hours. After vacuum filtration, 1200ml of filtrate is obtained. The cobalt content in the filtrate is found to be 2.96g / L, copper 4.54g / L, and nickel 7.32g / L. The filter residue was washed with 1200 ml of water using vacuum filtration. The washings were combined to obtain 2400 ml of filtrate. The filtrate contained 1.85 g / L cobalt, 2.84 g / L copper, 3.89 g / L nickel, and 4.52 g / L iron. The washed filter residue was then dried in an oven at 105°C to constant weight, yielding 840 g of filter residue. The residue contained 0.072% cobalt, 0.143% copper, and 0.196% nickel. The leaching rates were calculated based on the residual metal content: 88% for cobalt, 85% for copper, and 85% for nickel.

[0011] Example 2: This invention proposes a hydrometallurgical method for cobalt and nickel, the specific operation of which is as follows: 1000g of raw ore containing 2.3% cobalt, 3.2% copper, 4.5% nickel, and 25% sulfur is weighed. 100g of ferrous sulfate is added, and the mixture is thoroughly mixed. The mixture is then placed in a fluidized bed furnace, heated to 700℃, and reacted for 6 hours. After cooling, the ore is weighed to 935g, and the cobalt content is measured to be 2.46%, copper 3.42%, and nickel 4.81%. The slag is placed in a 2000ml beaker, and 1500ml of water, 20ml of concentrated sulfuric acid, and 54g of manganese dioxide are added. The mixture is kept at a constant temperature of 90℃ in a water bath and stirred for 6 hours. After vacuum filtration, 1200ml of filtrate is obtained. The cobalt content in the filtrate is measured to be 13.81g / L, copper 18.76g / L, and nickel 27.58g / L. The filter residue is washed with 1200ml of water, and the washings are combined to obtain 2400ml of filtrate. The filtrate contained 8.51 g / L cobalt, 11.23 g / L copper, 16.87 g / L nickel, and 6.76 g / L iron. The washed filter residue was dried in an oven at 105°C to constant weight, yielding 815 g of residue. The residue contained 0.28% cobalt, 0.47% copper, and 0.44% nickel. Based on the residual metal content, the leaching rates were 90% for cobalt, 88% for copper, and 92% for nickel. Due to the high cobalt, copper, and nickel content, this leaching solution can be directly used in copper electrolysis and cobalt / nickel extraction systems to recover cobalt, nickel, and copper.

[0012] Example 3: This invention proposes a hydrometallurgical method for cobalt and nickel, the specific operation of which is as follows: Weigh 1000g of raw ore, containing 0.5% cobalt, 0.8% copper, 1.1% nickel, and 30% sulfur. Add 100g of ferrous sulfate, mix evenly, and place in a fluidized bed furnace. Heat to 650℃ and react for 6 hours. Remove and cool. Weigh 900g, and the cobalt content is found to be 0.56%, copper 0.89%, and nickel 1.22%. Place the slag in a 2000ml beaker, add 1500ml of water and 10ml of concentrated sulfuric acid, and maintain the temperature at 90℃ in a water bath. Stir and react for 6 hours, then vacuum filter to obtain 1200ml of filtrate. The cobalt content in the filtrate is found to be 2.42g / L, copper 4.06g / L, and nickel 2.71g / L. Wash the filter residue with 1200ml of water, combine the washings, and obtain 2400ml of filtrate. The filtrate contained 1.49 g / L cobalt, 2.45 g / L copper, 1.61 g / L nickel, and 3.67 g / L iron. The washed filter residue was dried in an oven at 105°C to constant weight, yielding 849 g of residue. The residue contained 0.166% cobalt, 0.226% copper, and 0.827% nickel. Based on the residual metal content, the leaching rates were 72% for cobalt, 76% for copper, and 36% for nickel.

[0013] In Example 4, 1500 mL of the filtrate from Example 1 was taken, stirred and heated to 85°C, and lime was added to adjust the pH of the solution to 4.5. The mixture was stirred and reacted for 30 minutes, filtered, and washed three times with water. The washings were combined to obtain 1600 mL of solution. The cobalt content in the solution was 1.69 g / L, copper 2.59 g / L, nickel 3.42 g / L, and iron 0.021 g / L. After removing the iron, the solution was stirred and heated to 60°C, and 15% sodium sulfide solution was slowly added until the cobalt content in the solution decreased to 0.01 g / L. The solution was then filtered, and the filter residue was dried in an oven at 105°C to constant weight, yielding 22.64 g of product. The product content was found to be 11.89% cobalt, 18.12% copper, 23.95% nickel, and 0.086% iron.

[0014] The working principle of this invention is as follows: By adding ferrous sulfate to sulfide ores containing cobalt, copper, and nickel before acid roasting in a fluidized bed furnace, the sulfur trioxide content in the fluidized bed furnace is increased, leading to a greater conversion of cobalt, copper, and nickel oxides formed during roasting into sulfates, which facilitates subsequent leaching. Furthermore, the addition of ferrous sulfate increases the iron content in the leaching residue, thereby improving its economic value. During leaching, an extractant mainly composed of manganese dioxide and sulfuric acid is added. This increases the leaching rates of cobalt, copper, and nickel (cobalt leaching rate increased by 13%, copper by 15%, and nickel by 45%). Additionally, it oxidizes ferrous iron in the leachate to ferric iron, thus adding an iron removal step to the process. Simply adding lime to the leachate and adjusting the pH of the solution allows the iron in the solution to precipitate as ferric hydroxide. The filtered solution after iron removal directly enters the finished product process, reducing the iron content in the product to below 0.1%.

[0015] Through the above method, this invention increases the leaching rate of cobalt by 13%, copper by 15%, and nickel by 45% in cobalt-, copper-, and nickel-containing sulfide ores. This makes a significant contribution to the comprehensive utilization of medium- and low-grade cobalt-, copper-, and nickel sulfide ores. Taking a domestic plant processing 50,000 tons of sulfide ore annually containing 0.5% cobalt, 0.8% copper, 1.1% nickel, and 10% moisture content as an example, the economic benefit analysis is shown in the table below: .

[0016] The embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A cobalt-nickel hydrometallurgical method, characterized in that, The steps are as follows: S1. Ferrous sulfate is added to sulfide ores containing cobalt, copper, and nickel and then roasted. S2. Add an extractant mainly composed of manganese dioxide and sulfuric acid to the slag to leach out cobalt, copper, and nickel; see the reaction formula below for the specific reaction process: CoS+4MnO2+4H2SO4=CoSO4+4MnSO4+4H2O; CuS+4MnO2+4H2SO4=CuSO4+4MnSO4+4H2O; NiS+4MnO2+4H2SO4=NiSO4+4MnSO4+4H2O; CoO + H₂SO₄ = CoSO₄ + H₂O; CuO + H₂SO₄ = CuSO₄ + H₂O; NiO + H₂SO₄ = NiSO₄ + H₂O; 2FeSO4+MnO2+2H2SO4=Fe2(SO4)3+MnSO4+2H2O.

2. The cobalt-nickel hydrometallurgical method according to claim 1, characterized in that, Ferrous sulfate is a byproduct of titanium dioxide plants, with a content of 5-10%.

3. The cobalt-nickel hydrometallurgical method according to claim 1, characterized in that, The calcination is carried out in a fluidized bed furnace, with the calcination temperature controlled at 650-700℃.

4. The cobalt-nickel hydrometallurgical method according to claim 1, characterized in that, The amount of leaching agent used is 1-5% of the slag, the leaching reaction time is 4-8 hours, the reaction temperature is 80-90℃, the liquid-solid ratio is 1-3:1, and the sulfuric acid concentration is 5-10 g / L.

5. The cobalt-nickel hydrometallurgical method according to claim 1, characterized in that, Lime is added to the leachate to adjust the pH of the solution to 4.5-5.0, causing the iron in the solution to form ferric hydroxide precipitate, which is then separated by filtration.