Method for deep processing of nickel-cobalt hydroxide

Abstract

The application discloses a method for deep processing of nickel-cobalt hydroxide, and belongs to the technical field of non-ferrous smelting of nickel. The method adopts a process route of 'drying + cooperative blowing', and specifically comprises the following steps: after deep dehydration, the nickel-cobalt hydroxide is transported to a melting pool of a blowing furnace by gas force; nickel-iron and flux are added into the blowing furnace from a feeding port; a sulfuration agent is added into the melting pool of the blowing furnace; oxygen is blown into the melting pool through a tuyere or a lance; and the dried nickel-cobalt hydroxide, the nickel-iron, the oxygen, the flux and the sulfuration agent are rapidly decomposed, melted, reduced and sulfurized under high temperature of the melting pool of the blowing furnace, so as to obtain high nickel matte, blowing slag and flue gas. The nickel-cobalt hydroxide is cooperatively smelted with the nickel-iron, the advantages of the two can be complemented, the overheating problem existing in the blowing of the nickel-iron is solved, the consumption of sulfur and oxygen is reduced, the consumption of a reducing agent and energy consumption existing in the separate treatment of the nickel-cobalt hydroxide are solved, and the processing cost is reduced.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of nickel non-ferrous smelting, in particular to a method for deep processing of nickel-cobalt hydroxide. BACKGROUND

[0002] Nickel sulfate is a main raw material for electroplating and batteries, and its demand is increasing with the promotion of new energy technology. Nickel-cobalt hydroxide is obtained by precipitating sodium hydroxide or calcium hydroxide after leaching and impurity removal of laterite ore. When calcium hydroxide is used for nickel-cobalt precipitation, the production cost is greatly reduced compared with sodium hydroxide precipitation, but a large amount of gypsum is contained in the product. At present, the "acid leaching-extraction-impurity removal-extraction separation" process is mainly used to treat nickel-cobalt hydroxide to prepare nickel sulfate and cobalt sulfate. This process can currently treat nickel-cobalt hydroxide produced by sodium precipitation method, but the process is complex, the cost is high, and the slag is a hazardous waste. There is no mature production case for nickel-cobalt hydroxide obtained by calcium precipitation method. How to effectively treat nickel-cobalt hydroxide produced by sodium precipitation method or calcium precipitation method is an urgent problem to be solved. SUMMARY

[0003] The purpose of the application is to overcome the defects of the prior art and provide a method for deep processing of nickel-cobalt hydroxide.

[0004] The technical problem of the application is solved by the following technical scheme.

[0005] The application provides a method for deep processing of nickel-cobalt hydroxide, which comprises: adding nickel-cobalt hydroxide, nickel-iron, flux, sulfidizing agent and oxygen-rich air into a converting furnace for converting to obtain high-ice nickel.

[0006] The application further provides high-ice nickel prepared by the above method, wherein the content of Ni in the high-ice nickel is 60-75%, and the content of Fe is ≤10%.

[0007] Optionally, the content of Fe is ≤4%.

[0008] The application has the following beneficial effects:

[0009] The application provides a method for deep processing of nickel-cobalt hydroxide, which comprises the following steps: adding nickel-cobalt hydroxide, nickel-iron, flux, sulfuration agent and oxygen-enriched air into a converter for converting to obtain high-ice nickel. BRIEF DESCRIPTION OF DRAWINGS

[0010] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be regarded as a limitation to the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0011] Figure 1 Schematic diagram of the process for deep processing of nickel-cobalt hydroxide 。 DETAILED DESCRIPTION

[0012] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described as follows. If the specific conditions are not specified in the embodiments, the conventional conditions or the conditions suggested by the manufacturers are adopted. If the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased in the market.

[0013] The method for deep processing of nickel-cobalt hydroxide provided by the embodiments of the present application will be specifically described as follows.

[0014] The embodiments of the present application provide a method for deep processing of nickel-cobalt hydroxide, which comprises the following steps: adding nickel-cobalt hydroxide, nickel-iron, flux, sulfuration agent and oxygen-enriched air into a converter for converting to obtain high-ice nickel.

[0015] The embodiment of the present application provides a method for deep processing of nickel-cobalt hydroxide, which comprises: adding nickel-cobalt hydroxide, nickel-iron, flux, sulfuration agent and oxygen-rich air into a converter for converting to obtain high nickel matte. The inventor finds that: the conversion of nickel-iron into high nickel matte is an oxidation reaction, and needs to supplement sulfur (which needs to be prepared into low nickel matte in advance or supplement sulfur during the conversion process), and it is easy to overheat when processing low-grade (Ni < 20%) raw materials, and usually needs to add a large amount of cold material to balance the heat; the nickel-cobalt hydroxide is a product obtained by using sodium hydroxide or calcium hydroxide to precipitate after leaching and impurity removal of laterite ore, and the main components are oxides and hydroxides of Ni and Co, and the reduction process is an endothermic reaction, and the nickel-cobalt hydroxide prepared by calcium precipitation contains a large amount of gypsum, and if the nickel-cobalt hydroxide and the nickel-iron are converted into high nickel matte, the advantages can be complementary, which not only solves the overheating problem of the nickel-iron conversion, reduces the consumption of sulfur and oxygen, but also solves the problems of the consumption of reducing agent and energy consumption in the processing of the nickel-cobalt hydroxide. Therefore, the inventor proposes to produce high nickel matte by cooperating the nickel-cobalt hydroxide with the nickel-iron, and the two are smelted together, which not only solves the problems of high energy consumption and high auxiliary material consumption in the processing mode of the calcium precipitation nickel-cobalt hydroxide, so as to be difficult to process, high utilization cost, complex process and easy to produce hazardous waste slag, but also solves the problems of overheating, high consumption of sulfur and oxygen in the nickel-iron conversion, and the process route has the advantages of low energy consumption, low production cost, high raw material utilization rate and the like.

[0016] In an optional embodiment, it comprises: adding dry nickel-cobalt hydroxide, nickel-iron, flux, sulfuration agent and oxygen-rich air into a converter for self-heating conversion to obtain high nickel matte.

[0017] In an optional embodiment, the method for deep processing of nickel-cobalt hydroxide comprises the following steps: adopting a "dry + cooperative conversion" process route, deeply dehydrating the nickel-cobalt hydroxide produced in a wet process and then using pneumatic conveying to the molten pool of a converter, adding nickel-iron, flux and sulfuration agent into the converter from a feeding port, and blowing oxygen-rich oxygen into the molten pool in the converter through a tuyere or a lance, so that the dry nickel-cobalt hydroxide, nickel-iron, oxygen-rich oxygen, flux and sulfuration agent are subjected to combustion, melting and reduction reaction at high temperature to obtain high nickel matte, converter slag and flue gas.

[0018] As can be seen above, the embodiment of the present application provides a method for deep processing of nickel-cobalt hydroxide, and the process route is shown in Figure 1 , which comprises: adding dry nickel-cobalt hydroxide, nickel-iron, flux, sulfuration agent and oxygen-rich air into a converter, so that the materials are rapidly decomposed, melted and reduced under the action of high temperature of the molten pool to obtain high nickel matte. The chemical reactions occurring in the whole process are as follows:

[0019] The dry nickel-cobalt hydroxide mainly undergoes the following reactions:

[0020] H2O→H2O↑ (Free water is removed, 120-200℃)

[0021] Ni(OH)₂→NiO+H₂O↑ (Water of crystallization is removed, >230℃)

[0022] Co(OH)₂→CoO+H₂O↑ (Water of crystallization is removed, >200℃)

[0023] Mn(OH)₂→MnO+H₂O↑ (Water of crystallization is removed, >140℃)

[0024] CaSO4·2H2O→CaSO4+H2O↑ (Removal of water of crystallization, >120℃)

[0025] During the blowing stage, the following reactions mainly occur inside the blowing furnace:

[0026] NiO + Fe → Ni + FeO reduction reaction

[0027] CoO + Fe → Co + FeO (reduction reaction)

[0028] CaSO4 + Fe → FeS + CaO + FeO (sulfidation reaction)

[0029] Ni + FeS + O2 → Ni3S2 + FeO oxidation reaction

[0030] Co + FeS + O2 → CoS + FeO oxidation reaction

[0031] Fe + O₂ → FeO oxidation reaction

[0032] FeO + SiO2 → 2FeO·SiO2 slag formation reaction.

[0033] As can be seen, during the entire reaction process, NiO and CoO in the dried nickel-cobalt hydroxide undergo reduction reactions with Fe to produce elemental Ni and Co, respectively. Simultaneously, CaSO4 in the calcium-precipitated nickel-cobalt hydroxide can also undergo a sulfidation reaction with Fe to produce FeS. FeS then undergoes interactive reactions with Ni and Co to generate Ni3S2 and CoS, which are the main components of high-grade nickel matte. Taking calcium-precipitated nickel-cobalt hydroxide as an example, the above reaction process not only involves the co-smelting of nickel-cobalt hydroxide with nickel-iron, but also cleverly utilizes the CaSO4 in the calcium-precipitated nickel-cobalt hydroxide. CaSO4 itself acts as a partial sulfiding agent, saving on sulfiding agent consumption and solving the problem of gypsum separation during the calcium-precipitated nickel-cobalt hydroxide treatment.

[0034] In an optional embodiment, when treating sodium-precipitated nickel-cobalt hydroxide, the smelting temperature in the blowing furnace is 1200-1250℃, and the mass ratio of Fe / SiO2 in the blowing slag is 1.8-2.5; when treating calcium-precipitated nickel-cobalt hydroxide, the smelting temperature in the blowing furnace is 1300-1350℃, the mass ratio of Fe / SiO2 in the blowing slag is 2.5-3.5, and the mass ratio of CaO / SiO2 is ≤1.

[0035] Optionally, the ratio of dry nickel cobalt hydroxide to ferronickel is determined based on thermal equilibrium. Since the reduction process of nickel cobalt hydroxide is an endothermic reaction, and the process of ferronickel being smelted into high-grade matte is an oxidation reaction, it is prone to overheating when processing low-grade (Ni < 20%) raw materials. Therefore, the ratio of the two during the smelting process can be adjusted according to the actual thermal equilibrium.

[0036] This invention provides a method for the deep processing of nickel-cobalt hydroxide. The smelting temperature of nickel-cobalt hydroxide in conjunction with ferronickel is around 1250℃. The smelting temperature differs slightly for calcium-precipitated nickel hydroxide and sodium-precipitated nickel hydroxide, which is determined by the slag type of the blowing slag; calcium-based slag has a relatively higher melting point. If the smelting temperature is lower than the above-mentioned temperature, difficulties in slag discharge will arise.

[0037] In an optional embodiment, the dried nickel cobalt hydroxide is obtained by deep dehydrating the nickel cobalt hydroxide produced by the wet process to a water content of ≤0.5%.

[0038] Optionally, the deep dehydration temperature is 300-350℃;

[0039] Optionally, countercurrent drying or airflow drying can be used to deeply dehydrate the nickel-cobalt hydroxide produced in the wet process.

[0040] The method for deep processing of nickel-cobalt hydroxide provided in this embodiment of the invention involves pre-dehydrating the nickel-cobalt hydroxide before use. The dehydration process reduces energy consumption during smelting, reduces flue gas emissions, and achieves partial reduction of nickel-cobalt compounds. At the same time, high-temperature deep dehydration helps to increase the processing ratio of nickel-cobalt hydroxide. When dehydration is carried out at a temperature of about 150°C, the processing ratio of nickel-cobalt hydroxide will decrease.

[0041] In an optional embodiment, the nickel content in the ferronickel is ≤25%;

[0042] Optionally, ferronickel can be completely or partially replaced with low-grade nickel matte, in which the nickel content is ≤25%;

[0043] Preferably, the ferronickel is added to the smelting furnace in a hot state, or it is made into 3-10 mm granules and added to the smelting furnace in a cold state.

[0044] The method for deep processing of nickel-cobalt hydroxide provided in this invention preferably uses low-grade ferronickel, which can increase the throughput. Simultaneously, ferronickel can be wholly or partially replaced with low-grade nickel matte. Taking the smelting of laterite nickel ore as an example, ferronickel can be produced by reduction smelting of laterite nickel ore, or low-grade nickel matte can be produced by reduction smelting of laterite nickel ore with the addition of a sulfiding agent. Therefore, both ferronickel and / or low-grade nickel matte can be used as smelting raw materials in this invention.

[0045] In an optional embodiment, the flux is quartz, and the amount of flux is determined by the Fe / SiO2 value.

[0046] In an optional implementation, the oxygen volume concentration in the oxygen-enriched air is ≥21%.

[0047] In an optional embodiment, the sulfiding agent includes at least one of sulfur, pyrite, nickel concentrate and gypsum;

[0048] Optionally, the amount of vulcanizing agent added is controlled so that the S / Ni mass ratio is 0.35-0.4.

[0049] During the blowing process, the amount of sulfur added is controlled to maintain an S / Ni mass ratio of 0.35-0.4. A too-low S / Ni mass ratio results in a high degree of metallization in the high-grade nickel matte and causes freezing during blowing. A too-high S / Ni mass ratio leads to low sulfur utilization and waste. Therefore, in actual production, the amount of sulfurizing agent used is controlled to maintain an S / Ni mass ratio of 0.35-0.4.

[0050] In an optional embodiment, the sulfurizing agent is selected from sulfur. The sulfur is ground into powder and then pneumatically conveyed into the blowing furnace, or it is made into liquid sulfur at 140-150°C and sprayed into the blowing furnace.

[0051] In an optional embodiment, dry nickel cobalt hydroxide and sulfur are sprayed into the molten pool to a depth of 150 mm or less. If the spraying depth is too shallow, severe sulfur splashing will occur, causing some sulfur to enter the flue gas, increasing the dust concentration and reducing sulfur utilization. It is preferable to spray a layer of nickel matte, which is beneficial to improving the reduction effect of nickel cobalt hydroxide and the utilization rate of the sulfiding agent.

[0052] In an optional embodiment, the sulfiding agent is selected from one or more of pyrite, nickel concentrate and gypsum, and the sulfiding agent is added from the top of the blowing furnace.

[0053] In optional embodiments, the blowing furnace is selected from any one of a PS converter, a side-blown furnace, and a bottom-blown furnace. When using continuous blowing equipment, it is preferable to use a slag depletion treatment facility to improve the recovery rate of nickel and cobalt.

[0054] This invention also provides a high-grade nickel matte prepared by the above method, wherein the nickel matte has a Ni content of 60-75% and an Fe content of ≤10%;

[0055] Optionally, the Fe content in high-grade nickel matte is ≤4%.

[0056] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0057] Example 1

[0058] S1 Drying: Take 2t of sodium-precipitated nickel-cobalt hydroxide (wet basis water content 40%, dry basis main components Ni: 39%, Co: 3%, Mn: 7.5%, S: 4%), dehydrate at 300℃ for 2h to obtain 1t of nickel-cobalt oxide mixture, main components Ni: 44.1%, Co: 3.4%, Mn: 8.5%, S: 7.4%.

[0059] S2 smelting: Take 1.95t of ferronickel (ferronickel temperature 1450℃, main components Ni: 25%, Co: 0.5%, C: 0.5%, Fe: 73.9%), and use 200Nm 3 Compressed air was used to transport 1 ton of nickel-cobalt oxide mixture obtained from S1 into the nickel matte layer. Simultaneously, 302 kg of liquid sulfur (150°C) was injected, 750 kg of quartz was added, and 790 Nm of air was blown in. 3 1278 kg of high-grade nickel matte (Ni: 69.3%, Fe: 4.05%, S: 23.9%, Co: 2.8%) was obtained by blowing in oxygen-enriched air (22% oxygen concentration) at 1250℃. The Fe / SiO2 mass ratio in the blowing slag was 2.0. The direct recovery rate of nickel was 92.67%, and the direct recovery rate of Co was 78.67%.

[0060] Example 2

[0061] S1 Drying: Take 3t of calcium-precipitated nickel-cobalt hydroxide (wet basis water content 40%, dry basis main components Ni: 17.5%, Co: 1.3%, Mn: 3.4%, S: 13.2%, Ca: 14%), dehydrate at 350℃ for 2h to obtain 1.5t of nickel-cobalt oxide mixture, with main components Ni: 21%, Co: 1.6%, Mn: 4.0%, S: 15.9%, Ca: 16.9%.

[0062] S2 blowing: Take 210 kg / h of nickel-iron (3-10 mm particles, composition the same as in Example 1), and blow it into a 360 Nm drum. 3 The smelting process is carried out with oxygen-enriched air (70% oxygen concentration) at a rate of / h, while simultaneously using 20Nm 3 A compressed air supply of 100 kg / h is used to deliver the nickel-cobalt oxide mixture of S1, using 50 Nm 3Nitrogen gas is supplied at a rate of 8 kg / h, sulfur powder is blown into the matte layer through a spray gun, and 60 kg / h of quartz is added. Continuous blowing at 1350℃ yields 75 kg / h of high-grade matte (Ni: 64%, Fe: 8%, S: 25.2%, Co: 2.4%). The Fe / SiO2 mass ratio in the blowing slag is 3.0, and the CaO / SiO2 mass ratio is 0.5. The direct nickel recovery rate is 91.5%, and the direct Co recovery rate is 68%.

[0063] As can be seen from the above, the embodiments of the present invention provide a method for deep processing of nickel-cobalt hydroxide, employing a "drying + co-smelting" process to process nickel-cobalt hydroxide and ferronickel to obtain high-grade nickel matte. Specifically, nickel-cobalt hydroxide is deeply dehydrated to a moisture content of <0.5% and then pneumatically conveyed to the molten pool of a smelting furnace. Ferrronickel and / or low-grade nickel matte, flux, and sulfiding agent are added to the smelting furnace through the charging port. Oxygen-enriched air is blown into the molten pool through tuyeres or spray guns. The dried nickel-cobalt hydroxide, ferronickel and / or low-grade nickel matte, oxygen-enriched air, flux, and sulfiding agent undergo rapid decomposition, melting, and reduction reactions at high temperatures to obtain high-grade nickel matte, smelting slag, and flue gas. The solution provided by the embodiments of the present invention, by co-processing nickel-cobalt hydroxide and ferronickel to produce high-grade nickel matte, complements each other's advantages, solving the overheating problem in ferronickel smelting and reducing sulfur and oxygen consumption, as well as solving the reducing agent and energy consumption problems associated with processing nickel-cobalt hydroxide alone.

[0064] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for deep processing of nickel-cobalt hydroxide, characterized in that, Includes the following steps: After deep dehydration, the nickel-cobalt hydroxide produced in the wet process is pneumatically conveyed to the molten pool of the blowing furnace. Nickel-iron, flux, and sulfiding agent are added to the blowing furnace through the charging port. Oxygen-enriched air is blown into the molten pool of the blowing furnace through tuyeres or spray guns, causing the dried nickel-cobalt hydroxide, nickel-iron, oxygen-enriched air, flux, and sulfiding agent to undergo decomposition, melting, and reduction reactions at high temperatures, yielding high-grade nickel matte, blowing slag, and flue gas. When processing sodium-precipitated nickel-cobalt hydroxide, the smelting temperature in the blowing furnace is 1200-1250℃, and the mass ratio of Fe / SiO2 in the blowing slag is 1.8-2.5; when processing calcium-precipitated nickel-cobalt hydroxide, the smelting temperature in the blowing furnace is 1300-1350℃, the mass ratio of Fe / SiO2 in the blowing slag is 2.5-3.5, and the mass ratio of CaO / SiO2 is ≤1. The amount of the vulcanizing agent is controlled so that the S / Ni mass ratio is 0.35-0.4; The flux is quartz, and the amount of flux is determined by the Fe / SiO2 value. The oxygen volume concentration in the oxygen-enriched air is ≥21%.

2. The method according to claim 1, characterized in that, The ratio of the dried nickel cobalt hydroxide to the nickel iron is determined based on thermal equilibrium.

3. The method according to claim 1, characterized in that, The blowing furnace is selected from any one of PS converter, side-blown furnace, and bottom-blown furnace.

4. The method according to claim 1, characterized in that, The dried nickel cobalt hydroxide is obtained by deep dehydrating the nickel cobalt hydroxide produced by the wet process to a water content of ≤0.5%, wherein the deep dehydration temperature is 300-350℃.

5. The method according to claim 4, characterized in that, The nickel-cobalt hydroxide produced by the wet process is deeply dehydrated by countercurrent drying or airflow drying.

6. The method according to claim 1, characterized in that, The nickel content in the nickel-iron is ≤25%.

7. The method according to claim 1, characterized in that, The ferronickel can be completely or partially replaced with low-grade nickel matte, wherein the nickel content in the low-grade nickel matte is ≤25%.

8. The method according to claim 7, characterized in that, The ferronickel is added to the smelting furnace in a hot state, or it is made into 3-10mm particles and added to the smelting furnace in a cold state.

9. The method according to claim 1, characterized in that, The sulfiding agent includes one or more of sulfur, pyrite, nickel concentrate, and gypsum.

10. The method according to claim 9, characterized in that, The sulfurizing agent is selected from sulfur. The sulfur is ground into powder and then pneumatically conveyed into the blowing furnace, or it is made into liquid sulfur at 140-150°C and sprayed into the blowing furnace.

11. The method according to claim 10, characterized in that, The dried nickel-cobalt hydroxide and the sulfur are sprayed into the molten pool to a depth of 150 mm or less.

12. The method according to claim 10, characterized in that, The dried nickel-cobalt hydroxide and the sulfur are sprayed into the nickel ice layer.

13. The method according to claim 10, characterized in that, The sulfiding agent is selected from one or more of pyrite, nickel concentrate and gypsum, and the sulfiding agent is added from the top of the blowing furnace.

14. The method according to claim 1, characterized in that, The high-grade nickel matte contains 60-75% Ni and ≤10% Fe.

15. The method according to claim 14, characterized in that, The Fe content in the high-grade nickel matte is ≤4%.

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