WO2025010585A1 - Method for recovering nickel and cobalt from lateritic nickel ore - Google Patents

Abstract

A method for recovering nickel and cobalt from a lateritic nickel ore. The method comprises the following steps: subjecting lateritic nickel ore to acid leaching, performing solid-liquid separation so as to obtain a leachate, and then sequentially removing iron, aluminum, calcium and magnesium in the leachate, so as to obtain a calcium-and-magnesium-removed solution; subjecting the calcium-and-magnesium-removed solution to adsorption with an ion exchange resin column for nickel adsorption, and then subjecting same to desorption and evaporative crystallization with sulfuric acid, so as to obtain nickel sulfate and adsorption raffinate; and subjecting the adsorption raffinate to adsorption with an ion exchange resin column for cobalt adsorption, and then subjecting same to desorption and evaporative crystallization with sulfuric acid, so as to obtain cobalt sulfate. The method has the advantages of simple process flow, relatively low production cost, stability and reliability.

Description

A method for recovering nickel and cobalt from laterite nickel ore Technical Field

The present invention belongs to the technical field of laterite nickel ore resource recovery, and in particular relates to a method for recovering nickel and cobalt from laterite nickel ore.

Background Art

With the rapid development of the new energy vehicle industry, major battery material manufacturers or battery recycling companies have entered the stage of capacity expansion. Nickel sulfate is mainly used in the electroplating industry and the battery industry. It is the main nickel salt for electroplating nickel and chemical nickel. In recent years, affected by the substantial increase in demand for ternary positive electrode materials for power batteries and the high nickel content of batteries, the demand for nickel sulfate has shown explosive growth. The nickel resources in nickel sulfate mainly come from nickel-containing ore resources, including nickel sulfide ore and laterite nickel ore. The reserves of nickel sulfide ore account for about 30%, and the reserves of laterite nickel ore account for 70%. With the rapid development of the new energy industry, the demand for nickel in ternary lithium batteries is increasing day by day. At present, nickel products on the market mainly come from nickel sulfide ore. Due to the relatively insufficient reserves of nickel sulfide ore, laterite nickel ore has the advantages of rich reserves and easy mining. It will become the main source of nickel in the future. It is of great practical significance to fully develop and utilize the nickel in laterite nickel ore resources.

The mainstream process for recovering nickel and cobalt from laterite nickel ore is high-pressure acid leaching. After the ferrous iron is oxidized, alkali is added to remove iron and aluminum from the leachate. After the iron and aluminum are removed, alkali is added to precipitate the liquid to obtain nickel hydroxide (MHP). After the nickel hydroxide is pulped, acid is added to dissolve it. The solution is then subjected to iron powder to remove copper and alkali to remove iron and aluminum to obtain the liquid after the iron and aluminum are removed. The liquid after the iron and aluminum are removed is first extracted with P204 to separate impurities and manganese. The manganese sulfate solution obtained after stripping is used to prepare battery-grade manganese sulfate. The raffinate is then extracted with P507 to extract cobalt. After stripping, the cobalt sulfate solution obtained is used to prepare battery-grade cobalt sulfate. The raffinate is then extracted with C272 to extract magnesium to obtain the raffinate nickel sulfate solution, which is then used to prepare battery-grade nickel sulfate. This process consumes a lot of alkali because impurities such as Mn, Cu, Mg, Zn, Si, and Al will be precipitated together when adding alkali to precipitate Ni and Co. In the subsequent solution extraction, the impurities need to be extracted and Co and Mn need to be separated, resulting in many steps and high production costs.

Summary of the invention

The present disclosure aims to solve at least one of the technical problems existing in the related art. To this end, the present disclosure proposes a method for recovering nickel and cobalt from laterite nickel ore, which has the advantages of simple process flow, low production cost, stability and reliability.

The above technical objectives of the present disclosure are achieved through the following technical solutions:

A method for recovering nickel and cobalt from laterite nickel ore comprises the following steps: acid leaching the laterite nickel ore, separating the solid from the liquid to obtain a leachate, and then removing iron, aluminum, calcium and magnesium from the leachate in sequence to obtain a calcium- and magnesium-free solution; adsorbing the calcium- and magnesium-free solution with an ion exchange resin column for adsorbing nickel, and then performing analysis and evaporation crystallization with sulfuric acid to obtain nickel sulfate and adsorption residual solution; and adsorbing the adsorption residual solution with an ion exchange resin column for adsorbing cobalt, and then performing analysis and evaporation crystallization with sulfuric acid to obtain cobalt sulfate.

In one embodiment, the steps include:

(1) acid leaching the laterite nickel ore, separating the solid from the liquid to obtain a leachate and a leachate residue, adding an oxidant to the leachate, and then adding an alkaline substance to adjust the pH, separating the solid from the liquid to obtain a liquid after iron and aluminum removal and an iron and aluminum residue;

(2) adding an impurity remover to the iron and aluminum-removed liquid obtained in step (1) to remove copper and zinc, performing solid-liquid separation to obtain a copper and zinc-removed liquid and copper-zinc slag, adding metal fluoride to the copper and zinc-removed liquid, reacting and aging, performing solid-liquid separation to obtain a calcium and magnesium-removed liquid and a calcium and magnesium slag;

(3) injecting the calcium- and magnesium-free solution obtained in step (2) into an ion exchange resin column for nickel adsorption, so that nickel ions in the calcium- and magnesium-free solution are adsorbed by the ion exchange resin column for nickel adsorption to obtain a primary adsorption residual solution, washing the exchange resin in the ion exchange resin column for nickel adsorption with water, and then decomposing it with sulfuric acid to obtain a nickel sulfate solution, which is then evaporated and crystallized to obtain nickel sulfate;

(4) adding an alkaline substance to the primary adsorption residual solution obtained in step (3) to adjust the pH, and then injecting it into an ion exchange resin column for adsorbing cobalt, so that the cobalt ions in the primary adsorption residual solution are adsorbed by the ion exchange resin column for adsorbing cobalt to obtain a secondary adsorption residual solution, washing the exchange resin in the ion exchange resin column for adsorbing cobalt with water, and then decomposing it with sulfuric acid to obtain a cobalt sulfate solution, and then evaporating and crystallizing it to prepare cobalt sulfate.

In one embodiment, in step (1), the oxidant is at least one of hydrogen peroxide, manganese dioxide or sodium hypochlorite.

In one embodiment, in step (1), adding an alkaline substance to adjust the pH refers to adjusting the pH value to 4-6.

In one embodiment, in step (2), the impurity remover is at least one of sodium sulfide, manganese powder, nickel sulfide, cobalt sulfide and manganese sulfide, and the amount of the impurity remover added is the theoretical amount of reaction with copper and zinc. The reaction time for removing copper and zinc is 0.5-3h.

In one embodiment, in step (2), the adding of metal fluoride means first adding calcium fluoride as seed crystals and then adding sodium fluoride, wherein the amount of calcium fluoride added is 0.01-0.1 g/L, the amount of sodium fluoride added is 1-2 times the theoretical amount for reaction with calcium and magnesium, the reaction time after adding the sodium fluoride is 1-3 h, and the aging time is 5-12 h.

In one embodiment, in step (3), the speed at which the calcium and magnesium-removed liquid is injected into the nickel-adsorbing ion exchange resin column is 5-12 BV.

In one embodiment, in step (3), the ion exchange resin column for adsorbing nickel is five columns connected in series, and the nickel concentration of the tail column outlet liquid is controlled to be less than 2 mg/L. When the nickel concentration at the tail column outlet exceeds the standard, the first column is switched out, and a new resin column is added to the tail column for adsorption.

In one embodiment, in step (3), the amount of ion exchange resin filled in each column of the nickel-adsorbing ion exchange resin column is 70%-85% of the resin volume.

In one embodiment, in step (3), the regenerated exchange ions in the ion exchange resin column that adsorbs nickel include at least one of hydrogen ions, sodium ions, calcium ions and magnesium ions.

In one embodiment, in step (3), three columns are connected in series during the analysis, wherein the amount of water is 1-3BV, the flow rate is 2-5BV, the concentration of sulfuric acid during the analysis is 1-5mol/L, the amount is 1-2.5BV, and the flow rate during the analysis is 0.5-2BV.

In one embodiment, in step (3), the resin in the ion exchange resin column for adsorbing nickel uses styrene as a raw material, and a polymer having a three-dimensional network structure is generated during the polymerization reaction, and sulfonic acid groups are introduced into the skeleton as exchange groups.

In one embodiment, in step (4), adding an alkaline substance to adjust the pH refers to adjusting the pH value to 3-5.

In one embodiment, in steps (2) and (4), the base used in adding the alkaline substance to adjust the pH is at least one of calcium carbonate, calcium hydroxide, sodium hydroxide and sodium carbonate.

In one embodiment, in step (4), the ion exchange resin column for adsorbing cobalt is four columns connected in series, and the cobalt concentration of the liquid at the tail column outlet is controlled to be less than 1 mg/L. When the cobalt concentration at the tail column outlet exceeds the standard, the first column is switched out, and a new resin column is added to the tail column for adsorption.

In one embodiment, in step (4), the amount of ion exchange resin filled in each column of the ion exchange resin column for adsorbing cobalt is 70%-85% of the resin volume.

In one embodiment, in step (4), the regenerated exchange ions in the ion exchange resin column that adsorbs cobalt include at least one of hydrogen ions, sodium ions, calcium ions and magnesium ions.

In one embodiment, in step (4), the resin in the ion exchange resin column for adsorbing cobalt uses styrene as a raw material, and a polymer having a three-dimensional network structure is generated during the polymerization reaction, and sulfonic acid groups are introduced into the skeleton as exchange groups.

In one embodiment, in step (4), two columns are connected in series during the analysis, wherein the amount of water is 1-3BV, the flow rate is 2-5BV, the concentration of sulfuric acid during the analysis is 1-5mol/L, the amount is 1-2.5BV, and the flow rate during the analysis is 0.5-2BV.

In one embodiment, in step (4), the secondary adsorption residual liquid is discharged after being subjected to qualified wastewater treatment.

The beneficial effects of the present disclosure are:

(1) The present invention utilizes the high selectivity of resin to extract nickel and cobalt, and can separate nickel and cobalt. After analysis, purified nickel sulfate and cobalt sulfate solutions are obtained respectively. Nickel sulfate and cobalt sulfate are prepared by evaporation and crystallization, without the need for complex extraction and impurity removal processes. The prepared nickel sulfate and cobalt sulfate meet battery grade standard requirements;

(2) The present invention utilizes the method of first removing the copper and zinc impurities in the solution to within the qualified range, thereby obtaining a qualified copper- and zinc-free solution, thereby avoiding the subsequent adsorption of copper and zinc ions by the ion exchange resin, and obtaining a nickel sulfate solution and a cobalt sulfate solution free of copper and zinc ions after analysis;

(3) Since the acid leaching solution in the laterite nickel ore contains calcium ions and the sulfuric acid leaching system, even after fine filtration, calcium sulfate will precipitate out of the filtrate after standing for a period of time. The present invention adds calcium fluoride as a seed crystal and then adds sodium fluoride to remove calcium and magnesium, which can not only accelerate the removal of calcium and magnesium, but also achieve deep removal of calcium and magnesium, thereby avoiding the precipitation of calcium sulfate when the filtrate passes through the resin, resulting in poor resin adsorption performance or clogging of the resin column;

(4) Compared with the traditional recovery process of adding sodium hydroxide to precipitate nickel hydroxide (MHP), since there are many impurities in the laterite nickel ore leachate, impurities such as manganese, magnesium, zinc, silicon, and calcium will also be precipitated when adding alkali for precipitation, so the consumption of alkali is very large. The process disclosed in the present invention does not require the step of adding alkali to precipitate nickel and cobalt, thus avoiding the consumption of alkali;

(5) The method for recovering nickel and cobalt from laterite nickel ore provided in the present disclosure has the advantages of simple process flow, low production cost, stability and reliability, and can selectively recover high-value metals Ni and Co in the leaching solution. And because ion exchange resin has regeneration function and can be recycled, it can greatly reduce the cost of recycling.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of a flow chart of Embodiment 1 of the present disclosure.

DETAILED DESCRIPTION

The present disclosure is further described below in conjunction with specific embodiments.

Embodiment 1:

A method for recovering nickel and cobalt from laterite nickel ore, as shown in FIG1 , comprises the following steps:

(1) taking powder of laterite nickel ore after grinding, adding water to make pulp, adding sulfuric acid, transferring to a high-pressure reactor for leaching, and after the reaction, separating the solid and the liquid to obtain a leachate and a leaching residue;

(2) taking 20 L of the above-mentioned laterite nickel ore leaching solution, adding 1.2 times the theoretical amount of hydrogen peroxide that reacts with Fe2 ⁺ at room temperature for 1 h, then adding calcium carbonate to adjust the solution pH to 5.5, and after the reaction, separating the solid and the liquid to obtain a liquid after iron and aluminum removal and iron and aluminum slag;

(3) adding 1.2 times the theoretical amount of manganese powder to react with copper and zinc to the above iron and aluminum-removed liquid, reacting at room temperature for 1 hour, and separating the solid and liquid after the reaction to obtain a copper and zinc-removed liquid and copper-zinc slag;

(4) taking the above copper and zinc removal solution, first adding 0.02 g/L calcium fluoride as a seed crystal, and then adding 1.5 times the theoretical amount of sodium fluoride that reacts with calcium and magnesium, reacting for 1 hour, stopping stirring, aging for 10 hours, and separating the solid and liquid to obtain a calcium and magnesium removal solution and a calcium and magnesium slag;

(5) The above-mentioned solution after calcium and magnesium removal is pumped into a five-column series-connected resin column at a flow rate of 8BV using a peristaltic pump. The resin column is filled with 80% of the volume of BP-327 hydrogen-type ion exchange resin. The Ni concentration at the outlet of the tail column is detected. When the Ni concentration is greater than 2mg/L, the first column is switched out, and a new resin column filled with ion exchange resin is added to the tail column for adsorption. The switched first column is analyzed. During analysis, three columns are connected in series. First, 1.5BV of pure water is added at a flow rate of 2BV for washing, and then 2BV of 3.0mol/L sulfuric acid is used at a flow rate of 1.5BV for analysis to obtain a nickel sulfate solution and an ion exchange resin column after analysis. The ion exchange resin column after analysis is returned to the adsorption end for re-adsorption, and the nickel sulfate solution is evaporated and crystallized to prepare a nickel sulfate product;

(6) The adsorption residual solution obtained in step (5) was firstly adjusted to pH 4.0 by adding sodium hydroxide, and then pumped into a resin column connected in series with four columns at a flow rate of 6 BV using a peristaltic pump. The resin column was filled with BP-625 hydrogen-type ion exchange resin with a volume of 70%. The Co concentration at the outlet of the tail column was detected. When the Co concentration When the concentration of cobalt ions is above 1mg/L, the first column is switched out, and a new resin column filled with ion exchange resin is added to the tail column for adsorption. The adsorption residual liquid is discharged to the wastewater treatment workshop for qualified treatment and then discharged. The resin column that has adsorbed cobalt ions is connected in series during analysis. It is first washed with 2BV of pure water at a flow rate of 3BV, and then analyzed with 1.5BV of 1.5mol/L sulfuric acid at a flow rate of 1BV to obtain a cobalt sulfate solution and an ion exchange resin column after analysis. The ion exchange resin column after analysis is returned to the adsorption end for re-adsorption, and the cobalt sulfate solution is evaporated and crystallized to prepare a cobalt sulfate product.

Embodiment 2:

A method for recovering nickel and cobalt from laterite nickel ore comprises the following steps:

(1) taking powder of laterite nickel ore after grinding, adding water to make pulp, adding sulfuric acid, transferring to a high-pressure reactor for leaching, and after the reaction, separating the solid and the liquid to obtain a leachate and a leaching residue;

(2) taking 25 L of the above-mentioned laterite nickel ore leaching solution, stirring, adding 1.1 times the theoretical amount of manganese dioxide that reacts with Fe2 ⁺ at room temperature for 2 h, then adding calcium hydroxide to adjust the pH of the solution to 5.0, and separating the solid and liquid after the reaction to obtain a liquid after iron and aluminum removal and iron and aluminum slag;

(3) adding 1.3 times the theoretical amount of sodium sulfide to react with copper and zinc to the above iron and aluminum-removed liquid, reacting at room temperature for 40 minutes, and separating the solid and liquid to obtain a copper and zinc-removed liquid and copper-zinc slag;

(4) taking the above copper and zinc removal solution, first adding 0.02 g/L calcium fluoride as a seed crystal, and then adding 1.3 times the theoretical amount of sodium fluoride that reacts with calcium and magnesium, reacting for 2 hours, stopping stirring, aging for 6 hours, and separating the solid and liquid to obtain a calcium and magnesium removal solution and a calcium and magnesium slag;

(5) taking the above calcium and magnesium-removed liquid, using a peristaltic pump to pump it into a five-column series-connected resin column at a flow rate of 10 BV, the resin column is filled with 85% of the volume of BP-327 hydrogen-type ion exchange resin, and the Ni concentration at the tail column outlet is detected. When the Ni concentration is greater than 2 mg/L, the first column is switched out, and a new resin column filled with ion exchange resin is added to the tail column for adsorption, and the switched first column is analyzed. During the analysis, the three columns are connected in series, and 2 BV of pure water is first added at a flow rate of 2.5 BV for washing, and then 1.5 BV of 3.5 mol/L sulfuric acid is used at a flow rate of 1 BV for analysis to obtain a nickel sulfate solution and an ion exchange resin column after analysis. The ion exchange resin column after analysis is returned to the adsorption end for re-adsorption, and the nickel sulfate solution is evaporated and crystallized to prepare a nickel sulfate product;

(6) The adsorption residual solution obtained in step (5) was first adjusted to pH 4.5 by adding sodium hydroxide, and then pumped into a four-column series resin column at a flow rate of 8 BV using a peristaltic pump. The resin column was filled with 80% BP-625 hydrogen ion exchange resin, detect the Co concentration at the tail column outlet, when the Co concentration is greater than 1 mg/L, switch out the first column, add a new resin column filled with ion exchange resin to the tail column for adsorption, and discharge the adsorbed residual liquid to the wastewater treatment workshop for qualified treatment before discharge. The resin column adsorbing cobalt ions is connected in series during analysis, first washed with 1.5BV of pure water at a flow rate of 2BV, and then analyzed with 1.0BV of 2.0mol/L sulfuric acid at a flow rate of 0.8BV to obtain a cobalt sulfate solution and an ion exchange resin column after analysis. The ion exchange resin column after analysis is returned to the adsorption end for adsorption, and the cobalt sulfate solution is evaporated and crystallized to prepare a cobalt sulfate product.

Embodiment 3:

A method for recovering nickel and cobalt from laterite nickel ore comprises the following steps:

(1) taking powder of laterite nickel ore after grinding, adding water to make pulp, adding sulfuric acid, transferring to a high-pressure reactor for leaching, and after the reaction, separating the solid and the liquid to obtain a leachate and a leaching residue;

(2) taking 35 L of the above-mentioned laterite nickel ore leaching solution, stirring was started, and sodium hypochlorite in an amount 1.1 times the theoretical amount of reaction with Fe2 ⁺ was added at room temperature for reaction for 0.5 h, and then sodium carbonate was added to adjust the pH of the solution to 5.0. After the reaction, solid-liquid separation was performed to obtain a liquid after iron and aluminum removal and iron-aluminum slag;

(3) adding 1.2 times the theoretical amount of manganese sulfide that reacts with copper and zinc to the above iron and aluminum-removed liquid, reacting at room temperature for 3 hours, and separating the solid and liquid to obtain a copper-zinc-removed liquid and copper-zinc slag;

(4) taking the above copper and zinc removal solution, first adding 0.05 g/L calcium fluoride as a seed crystal, and then adding 1.2 times the theoretical amount of sodium fluoride that reacts with calcium and magnesium, reacting for 1 hour, stopping stirring, aging for 5 hours, and separating the solid and liquid to obtain a calcium and magnesium removal solution and a calcium and magnesium slag;

(5) Take the above calcium and magnesium-removed liquid and pump it into a five-column series-connected resin column with a peristaltic pump at a flow rate of 10 BV. The resin column is filled with 85% of the volume of BP-327 hydrogen-type ion exchange resin. The Ni concentration at the tail column outlet is detected. When the Ni concentration is greater than 2 mg/L, the first column is switched out, and a new resin column filled with ion exchange resin is added to the tail column for adsorption. The switched first column is analyzed. During the analysis, the three columns are connected in series. First, 2 BV of pure water is added at a flow rate of 2.5 BV for washing, and then 1.2 BV of 4.0 mol/L sulfuric acid is used at a flow rate of 1 BV for analysis to obtain a nickel sulfate solution and an ion exchange resin column after analysis. The ion exchange resin column after analysis is returned to the adsorption end for re-adsorption, and the nickel sulfate solution is evaporated and crystallized to prepare a nickel sulfate product;

(6) The adsorption residual solution obtained in step (5) was first adjusted to pH 4.0 by adding sodium carbonate, and then pumped into a four-column series resin column at a flow rate of 8 BV using a peristaltic pump. The resin column was filled with 80% of the volume BP-625 hydrogen-type ion exchange resin is used to detect the Co concentration at the tail column outlet. When the Co concentration is greater than 1 mg/L, the first column is switched out, and a new resin column filled with ion exchange resin is added to the tail column for adsorption. The adsorption residual liquid is discharged to the wastewater treatment workshop for qualified treatment and then discharged. The resin column that adsorbs cobalt ions is connected in series during analysis. First, it is washed with 2.5BV of pure water at a flow rate of 2BV, and then analyzed with 1.5BV of 2.0mol/L sulfuric acid at a flow rate of 0.8BV to obtain a cobalt sulfate solution and an ion exchange resin column after analysis. The ion exchange resin column after analysis is returned to the adsorption end for adsorption, and the cobalt sulfate solution is evaporated and crystallized to prepare a cobalt sulfate product.

Comparative Example 1: (Compared with Example 1, the only difference is that copper and zinc are not removed)

A method for recovering nickel and cobalt from laterite nickel ore comprises the following steps:

(1) taking powder of laterite nickel ore after grinding, adding water to make pulp, adding sulfuric acid, transferring to a high-pressure reactor for leaching, and after the reaction, separating the solid and the liquid to obtain a leachate and a leaching residue;

(2) taking 20 L of the above-mentioned laterite nickel ore leaching solution, adding 1.2 times the theoretical amount of hydrogen peroxide that reacts with Fe2 ⁺ at room temperature for 1 h, then adding calcium carbonate to adjust the solution pH to 5.5, and after the reaction, separating the solid and the liquid to obtain a liquid after iron and aluminum removal and iron and aluminum slag;

(3) taking the above iron and aluminum-removed liquid, first adding 0.02 g/L calcium fluoride as a seed crystal, and then adding 1.5 times the theoretical amount of sodium fluoride that reacts with calcium and magnesium, reacting for 1 hour, stopping stirring, aging for 10 hours, and separating the solid and liquid to obtain a calcium and magnesium-removed liquid and a calcium and magnesium slag;

(4) The above-mentioned solution after calcium and magnesium removal is pumped into a five-column series-connected resin column at a flow rate of 8BV using a peristaltic pump. The resin column is filled with 80% of the volume of BP-327 hydrogen-type ion exchange resin. The Ni concentration at the outlet of the tail column is detected. When the Ni concentration is greater than 2mg/L, the first column is switched out, and a new resin column filled with ion exchange resin is added to the tail column for adsorption. The switched first column is analyzed. During analysis, three columns are connected in series. First, 1.5BV of pure water is added at a flow rate of 2BV for washing, and then 2BV of 3.0mol/L sulfuric acid is used at a flow rate of 1.5BV for analysis to obtain a nickel sulfate solution and an ion exchange resin column after analysis. The ion exchange resin column after analysis is returned to the adsorption end for re-adsorption, and the nickel sulfate solution is evaporated and crystallized to prepare a nickel sulfate product;

(5) The adsorption residual solution obtained in step (5) was first adjusted to pH 4.0 by adding sodium hydroxide, and then pumped into a resin column connected in series with four columns at a flow rate of 6 BV using a peristaltic pump. The resin column was filled with BP-625 hydrogen-type ion exchange resin with a volume of 70%. The Co concentration at the outlet of the tail column was detected. When the Co concentration was greater than 1 mg/L, the first column was switched out, and a new column filled with ion exchange resin was added to the tail column. The resin column is subjected to adsorption again, and the adsorption residual liquid is discharged to the wastewater treatment workshop for qualified treatment and then discharged. The resin column that has adsorbed the cobalt ions is connected in series during analysis. It is first washed with 2BV of pure water at a flow rate of 3BV, and then analyzed with 1.5BV of 1.5mol/L sulfuric acid at a flow rate of 1BV to obtain a cobalt sulfate solution and an ion exchange resin column after analysis. The ion exchange resin column after analysis is returned to the adsorption end for re-adsorption, and the cobalt sulfate solution is evaporated and crystallized to prepare a cobalt sulfate product.

Comparative Example 2: (Compared with Example 1, the only difference is that calcium and magnesium are not removed)

A method for recovering nickel and cobalt from laterite nickel ore comprises the following steps:

(1) taking powder of laterite nickel ore after grinding, adding water to make pulp, adding sulfuric acid, transferring to a high-pressure reactor for leaching, and after the reaction, separating the solid and the liquid to obtain a leachate and a leaching residue;

(2) taking 20 L of the above-mentioned laterite nickel ore leaching solution, adding 1.2 times the theoretical amount of hydrogen peroxide that reacts with Fe2 ⁺ at room temperature for 1 h, then adding calcium carbonate to adjust the solution pH to 5.5, and after the reaction, separating the solid and the liquid to obtain a liquid after iron and aluminum removal and iron and aluminum slag;

(3) adding 1.2 times the theoretical amount of manganese powder to react with copper and zinc to the above iron and aluminum-removed liquid, reacting at room temperature for 1 hour, and separating the solid and liquid after the reaction to obtain a copper and zinc-removed liquid and copper-zinc slag;

(4) The above copper and zinc removal solution is pumped into a five-column series-connected resin column at a flow rate of 8 BV using a peristaltic pump. The resin column is filled with 80% of the volume of BP-327 hydrogen-type ion exchange resin. The Ni concentration at the tail column outlet is detected. When the Ni concentration is greater than 2 mg/L, the first column is switched out, and a new resin column filled with ion exchange resin is added to the tail column for adsorption. The switched first column is analyzed. During analysis, the three columns are connected in series. First, 1.5 BV of pure water is added at a flow rate of 2 BV for washing, and then 2 BV of 3.0 mol/L sulfuric acid is used at a flow rate of 1.5 BV for analysis to obtain a nickel sulfate solution and an ion exchange resin column after analysis. The ion exchange resin column after analysis is returned to the adsorption end for re-adsorption, and the nickel sulfate solution is evaporated and crystallized to prepare a nickel sulfate product;

(5) The adsorption residual liquid obtained in step (5) is firstly added with sodium hydroxide to adjust the pH to 4.0, and then pumped into four resin columns in series at a flow rate of 6 BV using a peristaltic pump. The resin columns are filled with BP-625 hydrogen-type ion exchange resin with a volume of 70%. The Co concentration at the outlet of the tail column is detected. When the Co concentration is greater than 1 mg/L, the first column is switched out, and a new resin column filled with ion exchange resin is added to the tail column for adsorption. The adsorption residual liquid is discharged to the wastewater treatment workshop after being treated and discharged after passing the treatment. The resin column that adsorbs cobalt ions is connected in series with two columns during analysis. First, 2 BV of pure water is used at a flow rate of 3 BV. The mixture is washed and then analyzed with 1.5 BV of 1.5 mol/L sulfuric acid at a flow rate of 1 BV to obtain a cobalt sulfate solution and an ion exchange resin column after analysis. The ion exchange resin column after analysis is returned to the adsorption end for re-adsorption, and the cobalt sulfate solution is evaporated and crystallized to prepare a cobalt sulfate product.

Comparative Example 3:

A method for recovering nickel and cobalt from laterite nickel ore comprises the following steps:

The powder of laterite nickel ore after grinding is taken, water is added to make pulp, sulfuric acid is added, and it is transferred to a high-pressure reactor for leaching. After the reaction, the solid-liquid is separated to obtain a leachate and a leachate residue. 25L of the leachate is taken, hydrogen peroxide is first added to oxidize the ferrous ions, and then alkali is added to adjust the value to remove iron and aluminum. After solid-liquid separation, sodium hydroxide is added to the obtained iron-aluminum-removed liquid to precipitate nickel and cobalt. After solid-liquid separation, MHP and a nickel-cobalt-precipitated liquid are obtained. After pure water is added to the MHP to make pulp, acid is added to dissolve it, and then sodium carbonate is added to remove iron and aluminum. After solid-liquid separation, a iron-aluminum-removed liquid and iron-aluminum slag are obtained. After iron and aluminum are removed, the liquid is first extracted with manganese, calcium, zinc and copper using P204, and then acid is added for stripping to obtain an impure manganese sulfate solution. The raffinate containing nickel, cobalt and magnesium is then subjected to P507 to extract cobalt, and a cobalt sulfate solution is obtained after stripping. The raffinate containing nickel and magnesium is then extracted with C272 to extract magnesium, and a nickel sulfate raffinate is obtained after stripping. The impure manganese sulfate solution is extracted with C272 to obtain a manganese sulfate solution. The manganese sulfate solution, cobalt sulfate solution and nickel sulfate solution are deoiled and then evaporated and crystallized to prepare manganese sulfate, cobalt sulfate and nickel sulfate products.

The BP-327 hydrogen-type ion exchange resin and the BP-625 hydrogen-type ion exchange resin used in Examples 1-3 and Comparative Examples 1-2 are both produced by Xi'an Lanxiao Technology New Materials Co., Ltd.

Test example:

The element contents in nickel sulfate and cobalt sulfate in Examples 1-3 and Comparative Examples 1-3 were measured. Table 1 shows the element content data in the nickel sulfate products prepared by Examples 1-3 and Comparative Examples 1-3, and Table 2 shows the element content data in the cobalt sulfate products prepared by Examples 1-3 and Comparative Examples 1-3. The specific data were measured by ICP-AES equipment.

Table 1: Element content in nickel sulfate products (unit: g/L)

It can be seen from Table 1 that the nickel sulfate products obtained in Examples 1-3 all meet the battery grade standard (HG/T5919-2021 nickel sulfate for batteries). In Comparative Example 1, the copper content in nickel sulfate is as high as 40ppm, and the Zn content is as high as 10ppm, which exceeds the impurity content requirement of battery-grade nickel sulfate. In Comparative Example 2, the Ca content in nickel sulfate is as high as 60ppm, which also exceeds the impurity content requirement of battery-grade nickel sulfate. Although the impurities in Comparative Example 3 are within the qualified range, compared with the embodiment, the content of impurities Co, Mn, and Na in the product is significantly higher.

Table 2: Element content in cobalt sulfate products (unit: g/L)

It can be seen from Table 2 that the cobalt sulfate products obtained in Examples 1-3 all meet the battery grade standard (HG/T5918-2021 cobalt sulfate for batteries). In Comparative Example 1, the Zn content in cobalt sulfate is as high as 20 ppm, which exceeds the impurity content requirement of battery-grade cobalt sulfate. In Comparative Example 2, the Ca content in cobalt sulfate is as high as 50 ppm, which exceeds the impurity content requirement of battery-grade cobalt sulfate. Although the impurities in Comparative Example 3 are within the qualified range, the content of impurities Ni, Mn, and Na in the product is significantly higher than that in the embodiment.

Claims (20)

A method for recovering nickel and cobalt from laterite nickel ore, characterized in that it comprises the following steps: acid leaching the laterite nickel ore, separating the solid from the liquid to obtain a leachate, and then removing iron, aluminum, calcium and magnesium from the leachate in sequence to obtain a solution after calcium and magnesium are removed; the solution after calcium and magnesium are adsorbed by an ion exchange resin column for adsorbing nickel, and then analyzed and evaporated and crystallized by sulfuric acid to obtain nickel sulfate and adsorption residual solution; the adsorption residual solution is adsorbed by an ion exchange resin column for adsorbing cobalt, and then analyzed and evaporated and crystallized by sulfuric acid to obtain cobalt sulfate. The method for recovering nickel and cobalt from laterite nickel ore according to claim 1, characterized in that it comprises the following steps: (1) acid leaching the laterite nickel ore, separating the solid from the liquid to obtain a leachate and a leachate residue, adding an oxidant to the leachate, and then adding an alkaline substance to adjust the pH, separating the solid from the liquid to obtain a liquid after iron and aluminum removal and an iron and aluminum residue; (2) adding an impurity remover to the iron and aluminum-removed liquid obtained in step (1) to remove copper and zinc, performing solid-liquid separation to obtain a copper and zinc-removed liquid and copper-zinc slag, adding metal fluoride to the copper and zinc-removed liquid, reacting and aging, performing solid-liquid separation to obtain a calcium and magnesium-removed liquid and a calcium and magnesium slag; (3) injecting the calcium- and magnesium-free solution obtained in step (2) into an ion exchange resin column for nickel adsorption, so that nickel ions in the calcium- and magnesium-free solution are adsorbed by the ion exchange resin column for nickel adsorption to obtain a primary adsorption residual solution, washing the exchange resin in the ion exchange resin column for nickel adsorption with water, and then decomposing it with sulfuric acid to obtain a nickel sulfate solution, which is then evaporated and crystallized to obtain nickel sulfate; (4) adding an alkaline substance to the primary adsorption residual solution obtained in step (3) to adjust the pH, and then injecting it into an ion exchange resin column for adsorbing cobalt, so that the cobalt ions in the primary adsorption residual solution are adsorbed by the ion exchange resin column for adsorbing cobalt to obtain a secondary adsorption residual solution, washing the exchange resin in the ion exchange resin column for adsorbing cobalt with water, and then decomposing it with sulfuric acid to obtain a cobalt sulfate solution, and then evaporating and crystallizing it to prepare cobalt sulfate. The method for recovering nickel and cobalt from laterite nickel ore according to claim 2, characterized in that: in step (1), the oxidant is at least one of hydrogen peroxide, manganese dioxide or sodium hypochlorite. The method for recovering nickel and cobalt from laterite nickel ore according to claim 2, characterized in that: in step (1), adding an alkaline substance to adjust the pH refers to adjusting the pH value to 4-6. The method for recovering nickel and cobalt from laterite nickel ore according to claim 2, characterized in that: in step (2), the impurity remover is at least one of sodium sulfide, manganese powder, nickel sulfide, cobalt sulfide and manganese sulfide, the amount of the impurity remover added is 1-1.5 times the theoretical amount of reaction with copper and zinc, and the reaction time for removing copper and zinc is 0.5-3h. The method for recovering nickel and cobalt from laterite nickel ore according to claim 2, characterized in that: in step (2), the adding of metal fluoride means first adding calcium fluoride as a seed crystal and then adding sodium fluoride, wherein the amount of calcium fluoride added is 0.01-0.1 g/L, the amount of sodium fluoride added is 1-2 times the theoretical amount of reaction with calcium and magnesium, the reaction time after adding the sodium fluoride is 1-3 h, and the aging time is 5-12 h. The method for recovering nickel and cobalt from laterite nickel ore according to claim 2, characterized in that: in step (3), the speed at which the calcium and magnesium-removed liquid is injected into the ion exchange resin column for adsorbing nickel is 5-12 BV. The method for recovering nickel and cobalt from laterite nickel ore according to claim 2 is characterized in that: in step (3), the ion exchange resin column for adsorbing nickel is five columns connected in series, and the nickel concentration of the tail column outlet liquid is controlled to be less than 2 mg/L. When the nickel concentration at the tail column outlet exceeds the standard, the first column is switched out, and a new resin column is added to the tail column for adsorption. The method for recovering nickel and cobalt from laterite nickel ore according to claim 2, characterized in that: in step (3), the amount of ion exchange resin filled in each column of the ion exchange resin column for adsorbing nickel is 70%-85% of the resin volume. A method for recovering nickel and cobalt from laterite nickel ore according to any one of claims 2 to 9, characterized in that: in step (3), the regenerated exchange ions in the ion exchange resin column that adsorbs nickel include at least one of hydrogen ions, sodium ions, calcium ions and magnesium ions. A method for recovering nickel and cobalt from laterite nickel ore according to claim 2, characterized in that: in step (3), three columns are connected in series during analysis, wherein the amount of water is 1-3BV, the flow rate is 2-5BV, the concentration of sulfuric acid during analysis is 1-5mol/L, the amount is 1-2.5BV, and the flow rate during analysis is 0.5-2BV. The method for recovering nickel and cobalt from laterite nickel ore according to claim 2 is characterized in that: in step (3), the resin in the ion exchange resin column for adsorbing nickel is made of styrene as a raw material, and a polymer having a three-dimensional network structure is generated during the polymerization reaction, and the skeleton is further Sulfonic acid groups were introduced as exchange groups. The method for recovering nickel and cobalt from laterite nickel ore according to claim 2, characterized in that: in step (4), adding an alkaline substance to adjust the pH refers to adjusting the pH value to 3-5. The method for recovering nickel and cobalt from laterite nickel ore according to claim 2, characterized in that: in steps (2) and (4), the alkaline substance used to adjust the pH by adding an alkaline substance is at least one of calcium carbonate, calcium hydroxide, sodium hydroxide and sodium carbonate. The method for recovering nickel and cobalt from laterite nickel ore according to claim 2 is characterized in that: in step (4), the ion exchange resin column for adsorbing cobalt is four columns connected in series, and the cobalt concentration of the liquid at the tail column outlet is controlled to be less than 1 mg/L. When the cobalt concentration at the tail column outlet exceeds the standard, the first column is switched out, and a new resin column is added to the tail column for adsorption. The method for recovering nickel and cobalt from laterite nickel ore according to claim 2, characterized in that: in step (4), the amount of ion exchange resin filled in each column of the ion exchange resin column for adsorbing cobalt is 70%-85% of the resin volume. The method for recovering nickel and cobalt from laterite nickel ore according to claim 2, characterized in that: in step (4), the regenerated exchange ions in the ion exchange resin column that adsorbs cobalt include at least one of hydrogen ions, sodium ions, calcium ions and magnesium ions. The method for recovering nickel and cobalt from laterite nickel ore according to claim 2 is characterized in that: in step (4), the resin in the ion exchange resin column for adsorbing cobalt uses styrene as a raw material, and a polymer having a three-dimensional network structure is generated during the polymerization reaction, and sulfonic acid groups are introduced into the skeleton as exchange groups. A method for recovering nickel and cobalt from laterite nickel ore according to claim 2, characterized in that: in step (4), two columns are connected in series during the analysis, wherein the amount of water is 1-3BV, the flow rate is 2-5BV, the concentration of sulfuric acid during the analysis is 1-5mol/L, the amount is 1-2.5BV, and the flow rate during the analysis is 0.5-2BV. The method for recovering nickel and cobalt from laterite nickel ore according to claim 2 is characterized in that: in step (4), the secondary adsorption residual liquid is discharged after being subjected to qualified wastewater treatment.