Hydroprocessing technology of laterite nickel ore

Abstract

The present invention provides a wet treatment process for laterite nickel ore. The wet treatment process comprises step S1, high-pressure acid leaching of laterite nickel ore, solid-liquid separation and washing to obtain filtrate and filtrate residue; step S2, alkali washing the filtrate residue with alkali solution to obtain hematite; step S3, pressurized iron removal treatment of the filtrate and washing solution to obtain hematite product and iron removal liquid; step S4, neutralization and iron removal treatment of the iron removal liquid with a first neutralizer to obtain neutralized residue and neutralization and iron removal liquid; step S5, aluminum-chromium precipitation treatment of the neutralization and iron removal liquid with a second neutralizer to obtain aluminum-chromium residue and iron removal aluminum liquid; step S6, nickel-cobalt-manganese precipitation treatment of the iron removal aluminum liquid with a third neutralizer and an oxidant to obtain a crude nickel-cobalt-manganese hydroxide precipitate and a precipitated liquid; and step S7, magnesium recovery treatment of the precipitated liquid to obtain a basic magnesium carbonate product and tail liquid. The process has almost no waste residue discharge and has high economic benefits.

Description

Technical Field

[0001] The invention relates to the technical field of laterite nickel ore, and in particular to a wet treatment process of laterite nickel ore. Background Art

[0002] At present, laterite nickel ore has become the main raw material in the EV battery industry chain, among which the high-pressure leaching process is the mainstream process for producing nickel-cobalt intermediate products. The main process is: high-pressure leaching - pre-neutralization - two-stage iron and aluminum removal - two-stage nickel and cobalt precipitation - tailings neutralization. This process is mature and widely used by companies such as Ramu and Liqin.

[0003] However, the biggest problem with this process is that the iron and aluminum cannot be recycled and the slag rate is high. One ton of laterite nickel ore basically produces about 1.2 tons of slag, which cannot be recycled. If the tailings are stored, it will pose a huge threat to environmental safety. Summary of the invention

[0004] The main purpose of the present invention is to provide a wet treatment process for laterite nickel ore to solve the problem of high slag rate in the treatment process for laterite nickel ore in the prior art.

[0005] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a wet treatment process of laterite nickel ore is provided, and the wet treatment process comprises step S1, after high-pressure acid leaching of the laterite nickel ore, solid-liquid separation and washing, to obtain a filtrate and filtrate residue; step S2, using alkali solution to perform alkali washing treatment on the filtrate and filtrate residue to obtain hematite; step S3, pressurizing the filtrate and filtrate to remove iron, to obtain a hematite product and a de-ironized liquid; step S4, using a first neutralizer to perform a neutralization and de-ironization treatment on the de-ironized liquid, to obtain a neutralized residue and a neutralization and de-ironized liquid; step S5, using a second neutralizer to perform an aluminum-chromium precipitation treatment on the neutralized de-ironized liquid, to obtain an aluminum-chromium slag and a de-ironized aluminum liquid; step S6, using a third neutralizer and an oxidant to perform a nickel-cobalt-manganese precipitation treatment on the de-ironized aluminum liquid, to obtain a crude nickel-cobalt-manganese hydroxide precipitate and a precipitated liquid; and step S7, performing a magnesium recovery treatment on the precipitated liquid, to obtain a basic magnesium carbonate product and a tailings.

[0006] Furthermore, in the above step S2, the liquid-to-solid ratio of the alkali washing treatment is 3 to 8:1, the temperature of the alkali washing treatment is preferably 30 to 90°C, the time of the alkali washing treatment is preferably 0.5 to 2h, the grade of the hematite is preferably ≥51%, and the sulfur content in the hematite is preferably ≤2.8%; the alkali solution is preferably a strong alkali solution, the mass concentration of the strong alkali solution is preferably 0.5 to 10wt%, and the strong alkali solution is preferably a sodium hydroxide solution and / or a potassium hydroxide solution.

[0007] Furthermore, in the above step S1, a filter press filtering and washing mode and / or a CCD multi-stage thickener countercurrent washing mode are used for solid-liquid separation and washing; preferably, the acid-ore mass ratio in the high-pressure acid leaching step is 200-400 kg / t ore, preferably, the high-pressure acid leaching temperature is 240-260° C., and preferably, the high-pressure acid leaching time is 0.5-2 h; and preferably, the sulfur content in the filtered and washed slag is <2%.

[0008] Furthermore, in the above step S3, a pressurized iron removal treatment is carried out in an oxygen-containing atmosphere; the temperature of the pressurized iron removal treatment is preferably 170 to 220°C, the time of the pressurized iron removal treatment is preferably 0.5 to 2h, the oxygen partial pressure of the pressurized iron removal treatment is preferably 0.1 to 0.6MPa, the iron removal rate of the pressurized iron removal treatment is preferably 80 to 95%, the grade of the hematite product is preferably ≥58%, and the sulfur content in the hematite product is preferably ≤1.1%.

[0009] Furthermore, in the above step S4, a neutralization and iron removal process is carried out using a filter press filtration washing mode and / or a CCD multi-stage thickener countercurrent washing mode; the endpoint pH value of the neutralization and iron removal treatment is preferably controlled to be 3.5-4.5, the temperature of the neutralization and iron removal treatment is preferably 40-90°C, the time of the neutralization and iron removal treatment is preferably 1-5h, the first neutralizing agent is preferably selected from any one or more of magnesium oxide, magnesium hydroxide, and basic magnesium carbonate, the first neutralizing agent is preferably basic magnesium carbonate, and the basic magnesium carbonate is preferably the basic magnesium carbonate product obtained in step S7.

[0010] Furthermore, in the above step S5, the endpoint pH value of the aluminum-chromium precipitation treatment is controlled to be 4.0-5.2, the time of the aluminum-chromium precipitation treatment is preferably 1-5 hours, the temperature of the aluminum-chromium precipitation treatment is preferably 40-90°C, the second neutralizing agent is preferably basic magnesium carbonate, and the basic magnesium carbonate is preferably the basic magnesium carbonate product obtained in step S7.

[0011] Furthermore, in the above step S6, the oxidant is an oxygen-containing gas, and the oxygen concentration of the oxygen-containing gas is preferably 20-100%, the endpoint pH value of the nickel-cobalt-manganese precipitation treatment is preferably controlled to be 7.8-8.4, the temperature of the nickel-cobalt-manganese precipitation treatment is preferably 40-90°C, and the time of the nickel-cobalt-manganese precipitation treatment is preferably 1-5h. The third neutralizing agent is preferably selected from any one or more of magnesium oxide, magnesium hydroxide, and basic magnesium carbonate. The third neutralizing agent is preferably basic magnesium carbonate, and the basic magnesium carbonate is preferably the basic magnesium carbonate product obtained in step S7.

[0012] Furthermore, in the above step S7, an alkaline reagent is used to recover magnesium from the precipitated liquid. Preferably, the amount of the alkaline reagent is 1.0 to 1.8 times the stoichiometric ratio. Preferably, the temperature for magnesium recovery is 40 to 90° C., and the time for magnesium recovery is 1 to 5 hours. Preferably, the alkaline reagent is sodium carbonate and / or sodium bicarbonate, and the magnesium content in the tail liquid is preferably <0.1 g / L.

[0013] Furthermore, the neutralized slag is returned to the pressure iron removal treatment step.

[0014] Furthermore, the above-mentioned laterite nickel ore is limonite-type laterite nickel ore.

[0015] By applying the technical solution of the present application, the wet treatment process further enriches and recycles the waste residue (especially iron-containing residue) generated during the treatment process within the wet treatment process system, especially recycles and enriches the iron-containing residue to obtain high-quality, high-value hematite, thereby minimizing the waste residue rate, especially effectively reducing the iron-aluminum waste residue. The crude nickel-cobalt-manganese hydroxide precipitate obtained during the treatment process is used as a ternary material widely used in the battery field, and the basic magnesium carbonate product obtained can be sold or used as a neutralizer within the wet treatment process system, and the magnesium element therein can be effectively recycled, and the tail liquid can be discharged in compliance with the standards, thereby achieving the purpose of almost no waste residue discharge, thereby making the treatment process of the laterite nickel ore both green and environmentally friendly, safe and reliable, and having high economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0017] Figure 1 A schematic diagram of a wet treatment process flow of laterite nickel ore provided according to Example 1 of the present invention is shown. DETAILED DESCRIPTION

[0018] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0019] As analyzed in the background technology of the present application, the existing technology for treating laterite nickel ore has the problem of high slag rate. In order to solve this problem, the present application provides a wet treatment process for laterite nickel ore.

[0020] In one embodiment of the present application, a wet processing process for laterite nickel ore is provided, such as Figure 1As shown, the wet treatment process includes step S1, high-pressure acid leaching of laterite nickel ore, solid-liquid separation and washing to obtain filtrate and filtrate residue; step S2, alkali washing the filtrate residue with alkali solution to obtain hematite; step S3, pressurized iron removal treatment of the filtrate to obtain hematite product and iron-removed liquid; step S4, neutralizing and iron-removing the iron-removed liquid with a first neutralizer to obtain neutralized residue and neutralized iron-removed liquid; step S5, aluminum-chromium precipitation treatment of the neutralized iron-removed liquid with a second neutralizer to obtain aluminum-chromium slag and iron-removed aluminum liquid; step S6, nickel-cobalt-manganese precipitation treatment of the iron-removed aluminum liquid with a third neutralizer and an oxidant to obtain crude nickel-cobalt-manganese hydroxide precipitate and precipitated liquid; and step S7, magnesium recovery treatment of the precipitated liquid to obtain basic magnesium carbonate product and tail liquid.

[0021] The wet treatment process further enriches and recycles the waste residue (especially iron-containing residue) generated during the treatment process within the wet treatment process system, especially recovering and enriching the iron-containing residue to obtain high-quality, high-value hematite, thereby minimizing the waste residue rate, especially effectively reducing the iron-aluminum waste residue. The crude nickel-cobalt-manganese hydroxide precipitate obtained during the treatment process is used as a ternary material widely used in the battery field, and the basic magnesium carbonate product obtained can be sold or used as a neutralizer within the wet treatment process system, and the magnesium element therein can be effectively recycled, and the tail liquid can be discharged in compliance with the standards, thereby achieving the purpose of almost no waste residue discharge, thereby making the treatment process of the laterite nickel ore both green and environmentally friendly, safe and reliable, and having high economic benefits.

[0022] In one embodiment of the present application, in the above-mentioned step S2, the liquid-to-solid ratio of the alkali washing treatment is 3 to 8:1, the temperature of the alkali washing treatment is preferably 30 to 90°C, the time of the alkali washing treatment is preferably 0.5 to 2h, the grade of the hematite is preferably ≥51%, and the sulfur content in the hematite is preferably ≤2.8%; the alkali solution is preferably a strong alkali solution, the mass concentration of the strong alkali solution is preferably 0.5 to 10wt%, and the strong alkali solution is preferably a sodium hydroxide solution and / or a potassium hydroxide solution.

[0023] After high-pressure acid leaching of laterite nickel ore, about 1% of iron is leached out, and the remaining iron is converted into Fe2O3, hydrated iron alum, and hydrated aluminum alum and concentrated in the filter and washing residue. The hydrated iron vanadium and hydrated aluminum alum can be decomposed by treating the filter and washing residue with alkali solution. The liquid-solid ratio of the alkali washing treatment, the type and mass concentration of the strong alkali solution, and the temperature and time of the alkali washing treatment are within the above-mentioned preferred ranges, which helps to improve the efficiency and effect of the alkali washing treatment, thereby reducing the sulfur content in the filter and washing residue as much as possible (<2%), and further increasing the grade of the hematite to more than 51%.

[0024] In one embodiment of the present application, in the above step S1, a solid-liquid separation and washing process is performed using a filter press filtering and washing mode and / or a CCD multi-stage thickener countercurrent washing mode; preferably, the acid-ore mass ratio in the high-pressure acid leaching step is 200-400 kg / t ore, preferably, the high-pressure acid leaching temperature is 240-260° C., and preferably, the high-pressure acid leaching time is 0.5-2 h; preferably, the sulfur content in the filtered and washed slag is <2%.

[0025] The two processes of solid-liquid separation and washing can be simply and centrally carried out in the filter press filtration washing mode and / or CCD multi-stage thickener countercurrent washing mode, which helps to reduce the number of related machines and the occupied space requirements when solid-liquid separation and washing are carried out separately, and is conducive to improving the efficiency and effect of solid-liquid separation and washing. The acid-ore mass ratio helps to improve the effect of high-pressure acid leaching and minimize the waste of acid. The control of temperature and time of high-pressure acid leaching helps to fully leach the valuable metals in laterite nickel ore.

[0026] In one embodiment of the present application, in the above-mentioned step S3, a pressurized iron removal treatment is carried out in an oxygen-containing atmosphere; the temperature of the pressurized iron removal treatment is preferably 170-220°C, the time of the pressurized iron removal treatment is preferably 0.5-2h, the oxygen partial pressure of the pressurized iron removal treatment is preferably 0.1-0.6MPa, the iron removal rate of the pressurized iron removal treatment is preferably 80-95%, the grade of the hematite product is preferably ≥58%, and the sulfur content in the hematite product is preferably ≤1.1%.

[0027] The introduction of oxygen and the control of the oxygen partial pressure within the above range is conducive to converting the divalent iron in the filtrate into trivalent iron as much as possible, thereby converting all the iron ions in the filtrate to obtain hematite, and aluminum is dissolved at the same time. Controlling the temperature and time of the pressurized iron removal treatment within the above preferred range is conducive to improving the efficiency and effect of the pressurized iron removal treatment, so that the hematite product has a good grade.

[0028] In one embodiment of the present application, in the above step S4, the neutralization and iron removal process is carried out in a filter press filtration washing mode and / or a CCD multi-stage thickener countercurrent washing mode; the endpoint pH value of the neutralization and iron removal treatment is preferably controlled to be 3.5-4.5, the temperature of the neutralization and iron removal treatment is preferably 40-90°C, the time of the neutralization and iron removal treatment is preferably 1-5h, the first neutralizing agent is preferably selected from any one or more of magnesium oxide, magnesium hydroxide, and basic magnesium carbonate, the first neutralizing agent is preferably basic magnesium carbonate, and the basic magnesium carbonate is preferably the basic magnesium carbonate product obtained in step S7.

[0029] Since the iron removal rate of the pressurized iron removal treatment is about 95%, the iron in the iron removal liquid is now trivalent iron. By neutralizing the iron removal liquid, all the iron is precipitated, and this process is accompanied by the precipitation of part of the aluminum with the iron. The process of neutralizing the iron removal treatment using a filter press filtering washing mode and / or a CCD multi-stage thickener countercurrent washing mode is helpful for the neutralization reaction of the first neutralizing agent with the iron removal liquid, and simultaneously completes the solid-liquid separation of the product system, thereby helping to improve the efficiency of the neutralization iron removal treatment. The control of the endpoint pH value of the neutralization iron removal treatment, the temperature of the neutralization iron removal treatment, and the time is helpful to improve the effect of the neutralization iron removal treatment, so that the iron is enriched in the neutralization slag as much as possible, and the basic magnesium carbonate product obtained in step S7 is preferably used as the first neutralizing agent, which helps to reduce costs.

[0030] Preferably, in the above step S5, the endpoint pH value of the aluminum-chromium precipitation treatment is controlled to be 4.0-5.2, the aluminum-chromium precipitation treatment time is preferably 1-5 hours, and the aluminum-chromium precipitation treatment temperature is preferably 40-90°C, so as to help improve the efficiency and effect of the aluminum-chromium precipitation treatment, and recover the aluminum and chromium in the neutralized and iron-removed liquid as much as possible. Preferably, the second neutralizing agent is basic magnesium carbonate, and preferably the basic magnesium carbonate is the basic magnesium carbonate product obtained in step S7, so as to help reduce costs.

[0031] In one embodiment of the present application, in the above step S6, the oxidant is an oxygen-containing gas, and the oxygen concentration of the oxygen-containing gas is preferably 20-100%, the endpoint pH value of the nickel-cobalt-manganese precipitation treatment is preferably controlled to be 7.8-8.4, the temperature of the nickel-cobalt-manganese precipitation treatment is preferably 40-90°C, and the time of the nickel-cobalt-manganese precipitation treatment is preferably 1-5h. The third neutralizer is preferably selected from any one or more of magnesium oxide, magnesium hydroxide, and basic magnesium carbonate. The third neutralizer is preferably basic magnesium carbonate, and the basic magnesium carbonate is preferably the basic magnesium carbonate product obtained in step S7.

[0032] Under the above conditions, it is helpful to precipitate nickel and manganese in one step by oxidation neutralization precipitation to obtain crude MHP, omitting the two-stage precipitation of nickel and cobalt in the traditional process, further saving energy consumption. The basic magnesium carbonate product obtained in step S7 is preferably used as the third neutralizing agent, which helps to reduce costs.

[0033] In one embodiment of the present application, in the above step S7, an alkaline reagent is used to recover magnesium from the precipitated liquid. Preferably, the amount of the alkaline reagent is 1.0 to 1.8 times the stoichiometric ratio. Preferably, the temperature for magnesium recovery is 40 to 90° C., and the time for magnesium recovery is 1 to 5 hours. Preferably, the alkaline reagent is sodium carbonate and / or sodium bicarbonate, and the magnesium content in the tail liquid is preferably <0.1 g / L.

[0034] The preferred amount of the alkaline reagent, the temperature and time of the magnesium recovery treatment are helpful to recover the magnesium in the liquid after precipitation as much as possible, wherein the basic magnesium carbonate product obtained can be sold as a product, and can also be used as a neutralizing agent in the wet treatment process system as a neutralizing agent and other reagents for reuse.

[0035] In some embodiments of the present application, the neutralized slag is preferably returned to the pressurized iron removal treatment step, thereby facilitating further recovery of iron in the neutralized slag, thereby truly achieving zero discharge of waste slag from the wet treatment process for laterite nickel ore.

[0036] In some embodiments of the present application, the above-mentioned laterite nickel ore is preferably a limonite-type laterite nickel ore, so as to better exert the advantages of the wet treatment process of the present application and maximize the treatment efficiency of the limonite-type laterite nickel ore.

[0037] The beneficial effects of the present application are further illustrated below in combination with embodiments and comparative examples.

[0038] Example 1

[0039] according to Figure 1 The schematic diagram of the wet treatment process shown is used to treat limonite-type laterite nickel ore:

[0040] Step S1, the nickel content of the limonite type laterite nickel ore is 1.2%, the iron content is 45%, the magnesium content is 2%, and the rest are inevitable impurities. The laterite nickel ore is subjected to high pressure acid leaching with sulfuric acid, the acid-ore ratio is controlled to be 250kg / t ore, the temperature is 255°C, and the leaching time is 1h. After leaching, filter press filtering and washing are performed to obtain filter washing liquid and filter washing residue (containing 58% iron and 1.8% sulfur).

[0041] Step S2, using 5wt% sodium hydroxide solution to perform alkaline washing treatment on the filtered and washed residue, controlling the temperature to 80°C, the treatment time to 1h, and the liquid-to-solid ratio to 4:1 to obtain hematite.

[0042] Step S3, oxygen is introduced into the autoclave, the temperature is controlled at 180°C, the treatment time is 1h, the oxygen partial pressure is 0.3MPa, the filtrate is subjected to pressurized iron removal treatment and then filtered to obtain a hematite product and an iron-removed liquid. The hematite product contains 60% iron and 0.6% sulfur, and the iron removal rate of the pressurized iron removal treatment is 85%.

[0043] Step S4, using basic magnesium carbonate to neutralize and remove iron from the deironing liquid, controlling the end point pH to 3.8, the neutralization time to 2 hours, the temperature to 80°C, and treating the neutralized and deironing system in a CCD multi-stage thickener countercurrent washing machine mode to obtain neutralized slag and neutralized and deironing liquid, and returning the neutralized slag to the pressurized deironing step.

[0044] Step S5, using basic magnesium carbonate to precipitate aluminum and chromium on the neutralized and iron-removed liquid, controlling the end point pH to 4.5, the neutralization time to 2 hours, and the temperature to 80° C. to obtain aluminum-chromium slag and iron-removed aluminum liquid.

[0045] Step S6, in an oxygen-containing atmosphere (oxygen concentration is 80%), using basic magnesium carbonate to precipitate nickel, cobalt and manganese in the liquid after iron and aluminum removal, controlling the end point pH to 8.2, the neutralization time to 4 hours, and the temperature to 70° C. to obtain a crude nickel, cobalt and manganese hydroxide precipitate and a liquid after precipitation.

[0046] Step S7, using sodium bicarbonate to recover magnesium from the precipitated liquid, controlling the neutralization time to 2 hours, the temperature to 60° C., and the amount of sodium bicarbonate to 1.2 times the stoichiometric ratio, to obtain a basic magnesium carbonate product and a tail liquid (magnesium content <0.1 g / L).

[0047] Example 2

[0048] Step S1, the nickel content of the limonite type laterite nickel ore is 1.2%, the iron content is 45%, the magnesium content is 2%, and the rest are inevitable impurities. The laterite nickel ore is subjected to high pressure acid leaching with sulfuric acid, the acid-ore ratio is controlled to be 250kg / t ore, the temperature is 255°C, and the leaching time is 1h. After leaching, filter press filtering and washing are performed to obtain filter washing liquid and filter washing residue (containing 58% iron and 2.8% sulfur).

[0049] Step S2, using 1wt% sodium hydroxide solution to perform alkaline washing treatment on the filtered and washed residue, controlling the temperature to 40°C, the treatment time to 1h, and the liquid-to-solid ratio to 4:1 to obtain hematite.

[0050] Step S3, oxygen is introduced into the autoclave, the temperature is controlled at 200°C, the treatment time is 2h, the oxygen partial pressure is 0.4MPa, the filtrate is subjected to pressurized iron removal treatment and then filtered to obtain a hematite product and an iron-removed liquid. The hematite product contains 63% iron and 0.4% sulfur, and the iron removal rate of the pressurized iron removal treatment is 93%.

[0051] Step S4, using basic magnesium carbonate to neutralize and remove iron from the deironing liquid, controlling the end point pH to 3.8, the neutralization time to 2 hours, the temperature to 80°C, and treating the neutralized and deironing system in a CCD multi-stage thickener countercurrent washing machine mode to obtain neutralized slag and neutralized and deironing liquid, and returning the neutralized slag to the pressurized deironing step.

[0052] Step S5, using basic magnesium carbonate to precipitate aluminum and chromium on the neutralized and iron-removed liquid, controlling the end point pH to 4.5, the neutralization time to 2 hours, and the temperature to 80° C. to obtain aluminum-chromium slag and iron-removed aluminum liquid.

[0053] Step S6, in an oxygen-containing atmosphere (oxygen concentration is 20%), using basic magnesium carbonate to precipitate nickel, cobalt and manganese in the liquid after iron and aluminum removal, controlling the end point pH to 8.2, the neutralization time to 4 hours, and the temperature to 70° C. to obtain a crude nickel, cobalt and manganese hydroxide precipitate and a liquid after precipitation.

[0054] Step S7, using sodium bicarbonate to recover magnesium from the precipitated liquid, controlling the neutralization time to 2 hours, the temperature to 60° C., and the amount of sodium bicarbonate to 1.2 times the stoichiometric ratio, to obtain a basic magnesium carbonate product and a tail liquid (magnesium content <0.1 g / L).

[0055] Example 3

[0056] The difference from Example 1 is that the mass of the filtered and washed residue in step S2 remains unchanged, the liquid-to-solid ratio is 3:1, and finally a basic magnesium carbonate product and tail liquid are obtained.

[0057] Example 4

[0058] The difference from Example 1 is that the mass of the filtered and washed residue in step S2 remains unchanged, the liquid-to-solid ratio is 8:1, and finally a basic magnesium carbonate product and tail liquid are obtained.

[0059] Example 5

[0060] The difference from Example 1 is that the mass of the filtered and washed residue in step S2 remains unchanged, the liquid-to-solid ratio is 2:1, and finally a basic magnesium carbonate product and tail liquid are obtained.

[0061] Example 6

[0062] The difference from Example 1 is that in step S3, the oxygen partial pressure is 0.1 MPa, and finally a basic magnesium carbonate product and tail liquid are obtained.

[0063] Example 7

[0064] The difference from Example 1 is that in step S3, the oxygen partial pressure is 0.6 MPa, and basic magnesium carbonate product and tail liquid are finally obtained.

[0065] Example 8

[0066] The difference from Example 1 is that in step S3, the oxygen partial pressure is 0.08 MPa, and finally a basic magnesium carbonate product and tail liquid are obtained.

[0067] Example 9

[0068] The difference from Example 1 is that, in step S1, the nickel content of the limonite-type laterite nickel ore is 1.2%, the iron content is 45%, the magnesium content is 2%, and the rest are inevitable impurities. The laterite nickel ore is subjected to high-pressure acid leaching with sulfuric acid, the acid-ore ratio is controlled to be 400kg / t ore, the temperature is 240°C, and the leaching time is 2h. After leaching, the filter press is filtered and washed to obtain a filtrate and a filtrate residue, and finally a basic magnesium carbonate product and a tailing liquid are obtained.

[0069] Example 10

[0070] The difference from Example 1 is that, in step S2, the filtered slag is subjected to alkali washing treatment with a 10wt% sodium hydroxide solution in an oxygen-containing atmosphere, the temperature is controlled to be 30°C, the treatment time is 0.5h, the liquid-solid ratio is 4:1, hematite is obtained, and finally basic magnesium carbonate product and tailings are obtained.

[0071] Embodiment 11

[0072] The difference from Example 1 is that, in step S3, oxygen is introduced into the autoclave, the temperature is controlled to be 220° C., the treatment time is 2 h, the oxygen partial pressure is 0.6 MPa, the filtrate is pressurized to remove iron and then filtered to obtain a hematite product and a deironized liquid, and finally a basic magnesium carbonate product and a tail liquid are obtained.

[0073] Example 12

[0074] The difference from Example 1 is that, in step S4, basic magnesium carbonate is used to neutralize and remove iron from the deironing liquid, the endpoint pH is controlled to be 4.5, the neutralization time is 5 hours, the temperature is 40°C, and the CCD multi-stage thickener countercurrent washing machine mode is used to treat the neutralization and deironing system to obtain neutralized slag and neutralized deironing liquid, and the neutralized slag is returned to the pressurized deironing treatment step to finally obtain basic magnesium carbonate product and tail liquid.

[0075] Example 13

[0076] The difference from Example 1 is that, in step S5, basic magnesium carbonate is used to precipitate aluminum and chromium on the neutralized and iron-removed liquid, the end point pH is controlled to be 5.2, the neutralization time is 5 hours, the temperature is 40°C, and aluminum-chromium slag and iron-removed aluminum liquid are obtained, and finally basic magnesium carbonate product and tail liquid are obtained.

[0077] Embodiment 14

[0078] The difference from Example 1 is that, in step S6, in an oxygen-containing atmosphere (oxygen concentration is 100%), basic magnesium carbonate is used to precipitate nickel, cobalt and manganese in the liquid after iron and aluminum removal, the endpoint pH is controlled to be 7.8, the neutralization time is 1 hour, and the temperature is 40°C to obtain a crude nickel, cobalt and manganese hydroxide precipitate and a post-precipitation liquid, and finally a basic magnesium carbonate product and a tail liquid are obtained.

[0079] Embodiment 15

[0080] The difference from Example 1 is that, in step S7, the precipitated liquid is subjected to magnesium recovery treatment with sodium bicarbonate, the neutralization time is controlled to be 5 h, the temperature is 90° C., the amount of sodium bicarbonate is 1.8 times the stoichiometric ratio, and a basic magnesium carbonate product and a tail liquid (magnesium content <0.1 g / L) are obtained, and finally a basic magnesium carbonate product and a tail liquid are obtained.

[0081] The iron content and sulfur content of the hematite obtained by alkali washing in the above Examples 1 to 15, the iron removal rate of the pressure iron removal treatment, the iron content and sulfur content of the hematite product, and the magnesium content in the tail liquid were measured respectively. The results are shown in Table 1 below.

[0082] Table 1

[0083]

[0084] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0085] The wet treatment process further enriches and recycles the waste residue (especially iron-containing residue) generated during the treatment process within the wet treatment process system, especially recovering and enriching the iron-containing residue to obtain high-quality, high-value hematite, thereby minimizing the waste residue rate, especially effectively reducing the iron-aluminum waste residue. The crude nickel-cobalt-manganese hydroxide precipitate obtained during the treatment process is used as a ternary material widely used in the battery field, and the basic magnesium carbonate product obtained can be sold or used as a neutralizer within the wet treatment process system, and the magnesium element therein can be effectively recycled, and the tail liquid can be discharged in compliance with the standards, thereby achieving the purpose of almost no waste residue discharge, thereby making the treatment process of the laterite nickel ore both green and environmentally friendly, safe and reliable, and having high economic benefits.

[0086] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A wet treatment process for laterite nickel ore, characterized in that: The wet treatment process comprises: Step S1, high pressure acid leaching of the laterite nickel ore, solid-liquid separation and washing to obtain a filtrate and a filtrate residue; Step S2, using alkaline solution to perform alkaline washing treatment on the filtration and washing residue to obtain hematite; Step S3, performing pressurized iron removal treatment on the filtrate and washing liquid to obtain a hematite product and an iron-removed liquid; Step S4, using a first neutralizing agent to neutralize and remove iron from the deironing liquid to obtain neutralized slag and neutralized deironing liquid; Step S5, using a second neutralizer to perform aluminum-chromium precipitation on the neutralized iron-removed liquid to obtain aluminum-chromium slag and iron-removed aluminum liquid; Step S6, using a third neutralizer and an oxidant to precipitate nickel, cobalt and manganese on the liquid after iron and aluminum removal to obtain a crude nickel, cobalt and manganese hydroxide precipitate and a liquid after precipitation; and Step S7, performing magnesium recovery treatment on the liquid after precipitation to obtain a basic magnesium carbonate product and a tail liquid; The liquid-to-solid ratio of the alkali washing treatment is 3-8:1; The oxidant is an oxygen-containing gas, and the oxygen concentration of the oxygen-containing gas is 20-100%; The high pressure acid leaching is carried out using sulfuric acid; The alkali solution is a strong alkali solution, and the mass concentration of the strong alkali solution is 0.5-10wt%; The acid-ore mass ratio in the high-pressure acid leaching step is 200-400 kg / t ore, the temperature of the high-pressure acid leaching is 240-260° C., and the sulfur content in the filtered slag is <2%; The temperature of the pressurized iron removal treatment is 170-220°C, the oxygen partial pressure of the pressurized iron removal treatment is 0.1-0.6MPa, and the iron removal rate of the pressurized iron removal treatment is 80-95%; The endpoint pH value of the neutralization and iron removal treatment is 3.5-4.5; The endpoint pH value of the aluminum-chromium precipitation treatment is 4.0-5.2, and the second neutralizing agent is basic magnesium carbonate; The endpoint pH value of the nickel-cobalt-manganese precipitation treatment is controlled to be 7.8-8.4, and the third neutralizing agent is selected from any one or more of magnesium oxide, magnesium hydroxide, and basic magnesium carbonate.

2. The wet treatment process according to claim 1, characterized in that: In step S2, the temperature of the alkali washing treatment is 30-90°C.

3. The wet treatment process according to claim 1, characterized in that: The alkali washing treatment time is 0.5~2h.

4. The wet treatment process according to claim 1, characterized in that: The grade of the hematite is ≥51%.

5. The wet treatment process according to claim 1, characterized in that: The sulfur content in the hematite is ≤2.8%.

6. The wet treatment process according to claim 1, characterized in that: The strong alkali solution is sodium hydroxide solution and / or potassium hydroxide solution.

7. The wet treatment process according to any one of claims 1 to 6, characterized in that: In the step S1, the solid-liquid separation and washing process is performed using a filter press filtering and washing mode and / or a CCD multi-stage thickener countercurrent washing mode.

8. The wet treatment process according to any one of claims 1 to 6, characterized in that: The high pressure acid leaching time is 0.5 to 2 hours.

9. The wet treatment process according to any one of claims 1 to 6, characterized in that: The time of the pressurized iron removal treatment is 0.5 to 2 hours.

10. The wet treatment process according to any one of claims 1 to 6, characterized in that: The grade of the hematite product is ≥58%.

11. The wet treatment process according to any one of claims 1 to 6, characterized in that: The sulfur content in the hematite product is ≤1.1%.

12. The wet treatment process according to any one of claims 1 to 6, characterized in that: In the step S4, the neutralization and iron removal process is performed using a filter press filtration washing mode and / or a CCD multi-stage thickener countercurrent washing mode.

13. The wet treatment process according to any one of claims 1 to 6, characterized in that: The temperature of the neutralization and iron removal treatment is 40-90°C.

14. The wet treatment process according to any one of claims 1 to 6, characterized in that: The neutralization and iron removal treatment time is 1 to 5 hours.

15. The wet treatment process according to any one of claims 1 to 4, characterized in that: The first neutralizing agent is selected from any one or more of magnesium oxide, magnesium hydroxide, and basic magnesium carbonate.

16. The wet treatment process according to claim 15, characterized in that: The first neutralizing agent is basic magnesium carbonate.

17. The wet treatment process according to claim 16, characterized in that: The basic magnesium carbonate is the basic magnesium carbonate product obtained in step S7.

18. The wet treatment process according to any one of claims 1 to 6, characterized in that: In the step S5, the aluminum-chromium precipitation treatment time is 1 to 5 hours.

19. The wet treatment process according to any one of claims 1 to 6, characterized in that: The temperature of the aluminum chromium precipitation treatment is 40-90°C.

20. The wet treatment process according to any one of claims 1 to 6, characterized in that: In the step S5, the basic magnesium carbonate is the basic magnesium carbonate product obtained in the step S7.

21. The wet treatment process according to any one of claims 1 to 6, characterized in that: In the step S6, the temperature of the nickel-cobalt-manganese precipitation treatment is 40-90°C.

22. The wet treatment process according to any one of claims 1 to 6, characterized in that: The nickel-cobalt-manganese precipitation treatment time is 1 to 5 hours.

23. The wet treatment process according to any one of claims 1 to 6, characterized in that: The third neutralizing agent is basic magnesium carbonate.

24. The wet treatment process according to claim 23, characterized in that: The basic magnesium carbonate is the basic magnesium carbonate product obtained in step S7.

25. The wet treatment process according to any one of claims 1 to 6, characterized in that: In the step S7, an alkaline reagent is used to perform the magnesium recovery treatment on the post-precipitation liquid.

26. The wet treatment process according to claim 25, characterized in that The amount of the alkaline agent used is 1.0 to 1.8 times the stoichiometric ratio.

27. The wet treatment process according to any one of claims 1 to 6, characterized in that: The temperature of the magnesium recovery treatment is 40-90°C.

28. The wet treatment process according to any one of claims 1 to 6, characterized in that: The magnesium recovery treatment time is 1 to 5 hours.

29. The wet treatment process according to claim 25, characterized in that: The alkaline agent is sodium carbonate and / or sodium bicarbonate.

30. The wet treatment process according to any one of claims 1 to 6, characterized in that: The magnesium content in the tail liquid is less than 0.1 g / L.

31. The wet treatment process according to any one of claims 1 to 6, characterized in that: The neutralized slag is returned to the pressure iron removal treatment step.

32. The wet treatment process according to any one of claims 1 to 6, characterized in that: The laterite nickel ore is a limonite-type laterite nickel ore.

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