CN115896451A - Method for combined treatment of laterite-nickel ore and ferronickel alloy and recovery of nickel and iron - Google Patents

Abstract

The invention provides a method for combined treatment of laterite-nickel ore and ferronickel alloy and recovery of nickel and iron, which comprises the following steps: (1) Carrying out acid leaching treatment after mixing the laterite-nickel ore, and carrying out solid-liquid separation to obtain a first leaching solution; (2) Mixing the nickel-iron alloy and the first leaching solution obtained in the step (1) to react, and performing solid-liquid separation to obtain a second leaching solution; (3) Mixing a phosphorus source, an oxidant and a precipitator, reacting with the second leaching solution obtained in the step (2), and carrying out solid-liquid separation to obtain an iron phosphate product anda nickel-containing solution; (4) And (4) sequentially removing impurities, concentrating and crystallizing the nickel-containing solution obtained in the step (3) to obtain the battery-grade nickel sulfate. The method utilizes the laterite-nickel ore atmospheric pressure leaching liquid to be highly acidic and rich in Fe ³⁺ The method is characterized in that the ferronickel alloy is treated, the ferronickel is utilized to neutralize residual acid in the leaching solution, and the residual acid and Fe in the leaching solution are utilized ³⁺ The strong oxidizing property of the nickel-iron composite material promotes the dissolution of nickel-iron, realizes the high-efficiency recovery of nickel and iron, and finally obtains ferric phosphate and battery-grade nickel sulfate.

Description

Method for combined treatment of laterite-nickel ore and ferronickel alloy and recovery of nickel and iron

Technical Field

The invention belongs to the technical field of hydrometallurgy, relates to a method for recovering nickel and iron, and particularly relates to a method for jointly treating laterite-nickel ore and ferronickel alloy and recovering nickel and iron.

Background

At present, the large-scale commercial new energy automobile power batteries on the market are mainly divided into two types: a ternary battery and a lithium iron phosphate battery. The difference between these two types of batteries is mainly: the anode material of the ternary battery is mainly an oxide containing three metal elements of cobalt, nickel and manganese, and the anode material of the lithium iron phosphate battery is lithium iron phosphate. In order to obtain sufficient raw materials, many power battery raw material manufacturers actively lay out upstream raw mining and waste recovery businesses, and strive to broaden raw material types.

The laterite-nickel ore is a hot tide of investment of power battery raw material enterprises in recent years, mainly aims to extract nickel therein, and iron with higher content is directly discarded as tailings, thereby undoubtedly causing a great deal of waste of resources. The process for extracting nickel from laterite-nickel ore generally adopted at present mainly comprises a wet high-pressure acid leaching process and a pyrogenic high nickel matte process. The two processes can obtain intermediate products with high nickel content, and the intermediate products are further refined to obtain battery-grade nickel sulfate. However, both of the above processes lack sufficient utilization of iron in practical applications. Although research reports also show that the atmospheric pressure acid leaching of the laterite nickel ore, because the temperature is lower and the impurity iron is involved in the co-leaching, very high acidity is needed to achieve the ideal nickel leaching effect, and the high acidity and high iron content of the solution undoubtedly bring huge cost for subsequent neutralization and impurity removal.

The method for producing nickel-iron alloy such as nickel pig iron and the like by smelting laterite-nickel ore by a pyrogenic process is generally applied to the field of alloys such as stainless steel and the like. Due to the demand of new energy industry, the nickel-iron alloy also becomes one of the raw materials considered by battery raw material manufacturers. However, since the nickel-iron alloy has high hardness and ductile properties of metal, when it is used as a leaching raw material, it is extremely difficult to break the nickel-iron alloy by pretreatment, and the leaching efficiency is low and the rate is slow.

Therefore, how to provide a method for jointly treating laterite-nickel ore and ferronickel and recovering nickel and iron can improve the recovery efficiency and the product purity and reduce the recovery cost as much as possible, and the method becomes a problem which needs to be solved urgently by technical personnel in the field at present.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a method for combined treatment of laterite-nickel ore and ferronickel alloy and recovery of nickel and iron, wherein the method improves the recovery efficiency and product purity, reduces the recovery cost as much as possible and finally obtains iron phosphate and battery-grade nickel sulfate products.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides a method for combined treatment of laterite-nickel ore and ferronickel alloy and recovery of nickel and iron, which comprises the following steps:

(1) Carrying out acid leaching treatment after mixing the laterite-nickel ore, and carrying out solid-liquid separation to obtain a first leaching solution;

(2) Reacting the mixed nickel-iron alloy with the first leaching solution obtained in the step (1), and performing solid-liquid separation to obtain a second leaching solution;

(3) Reacting the mixed phosphorus source, the oxidant and the precipitator with the second leaching solution obtained in the step (2), and performing solid-liquid separation to obtain an iron phosphate product and a nickel-containing solution;

(4) And (4) sequentially removing impurities, concentrating and crystallizing the nickel-containing solution obtained in the step (3) to obtain the battery-grade nickel sulfate.

Wherein, the reaction in the step (2) mainly comprises the following chemical formulas:

2H ⁺ +Fe＝Fe ²⁺ +H ₂

2H ⁺ +Ni＝Ni ²⁺ +H ₂

2Fe ³⁺ +Fe＝3Fe ²⁺

2Fe ³⁺ +Ni＝Ni ²⁺ +2Fe ²⁺

in the above reaction, the dissolution reaction of metallic iron and nickel is itself a reduction reaction, fe ³⁺ Has strong oxidizing property, and can remarkably improve the dissolution rate of nickel and iron and accelerate the reaction when participating in the reaction.

The method provided by the invention fully considers the reaction characteristics of the laterite-nickel ore and the ferronickel alloy, and utilizes the high acid and rich Fe of the laterite-nickel ore leaching solution ³⁺ The method is characterized in that the ferronickel alloy is treated, the residual acid in the leaching solution is neutralized by the ferronickel alloy, and the residual acid and Fe in the leaching solution are utilized ³⁺ The strong oxidizing property promotes the dissolution of the nickel-iron alloy, thereby realizing the high-efficiency recovery of nickel and iron in the nickel-iron alloy and finally obtaining the iron phosphate and battery-grade nickel sulfate products.

Preferably, the liquid-solid mass ratio of the slurry prepared in step (1) is (3-5): 1, and can be, for example, 3.

In the invention, the size mixing in the step (1) is carried out by adding water, and the liquid-solid mass ratio specifically refers to the ratio of the added water amount to the mass of the laterite-nickel ore.

Preferably, the pressure of the acid leaching in step (1) is 0.8-1.2bar, for example 0.8bar, 0.85bar, 0.9bar, 0.95bar, 1bar, 1.05bar, 1.1bar, 1.15bar or 1.2bar, but is not limited to the recited values, and other values not recited in this range are equally applicable.

Preferably, the temperature of the acid leaching treatment in step (1) is 60 to 100 ℃, for example, 60 ℃, 65 ℃, 70 ℃, 75 ℃, 80 ℃, 85 ℃, 90 ℃, 95 ℃ or 100 ℃, but is not limited to the recited values, and other values not recited in the range of the values are also applicable.

Preferably, the acid leaching treatment in step (1) is carried out for 2-6h, such as 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h or 6h, but not limited to the recited values, and other values not recited in the range of the values are also applicable.

Preferably, the acid solution used in the acid leaching treatment in step (1) comprises sulfuric acid.

Preferably, the concentration of sulfuric acid is 70 to 98 wt.%, for example 70 wt.%, 72 wt.%, 74 wt.%, 76 wt.%, 78 wt.%, 80 wt.%, 82 wt.%, 84 wt.%, 86 wt.%, 88 wt.%, 90 wt.%, 92 wt.%, 94 wt.%, 96 wt.% or 98 wt.%, but is not limited to the recited values, and other non-recited values within this range are equally applicable.

Preferably, the mass ratio of the sulfuric acid to the lateritic nickel ore is (1-2): 1, and may be, for example, 1.

In the invention, the mass ratio of the sulfuric acid to the laterite-nickel ore is required to be kept in a reasonable range. When the mass ratio is lower than 1; when the mass ratio is higher than 2.

Preferably, the mixing solid-to-liquid ratio of the ferronickel alloy in the step (2) to the first leaching solution is (0.05-0.5) kg/L, and may be, for example, 0.05kg/L, 0.1kg/L, 0.15kg/L, 0.2kg/L, 0.25kg/L, 0.3kg/L, 0.35kg/L, 0.4kg/L, 0.45kg/L, or 0.5kg/L, but not limited to the enumerated values, and other non-enumerated values in the range of the enumerated values are also applicable.

Preferably, the reaction temperature in step (2) is 60-100 ℃, for example 60 ℃, 65 ℃, 70 ℃, 75 ℃, 80 ℃, 85 ℃, 90 ℃, 95 ℃ or 100 ℃, but is not limited to the recited values, and other values not recited in the range of values are also applicable.

Preferably, the end point judgment indicator of the reaction in step (2) is a pH value, and the pH at the end point of the reaction is 1.0 to 2.0, and may be, for example, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9 or 2.0, but is not limited to the values listed, and other values not listed in the range of the values are also applicable.

Preferably, the phosphorus source in step (3) comprises any one of phosphoric acid, sodium dihydrogen phosphate or disodium hydrogen phosphate, or a combination of at least two of them, and typical, but non-limiting, combinations include a combination of phosphoric acid and sodium dihydrogen phosphate, a combination of sodium dihydrogen phosphate and disodium hydrogen phosphate, a combination of phosphoric acid and disodium hydrogen phosphate, or a combination of phosphoric acid, sodium dihydrogen phosphate and disodium hydrogen phosphate.

Preferably, the amount of the phosphorus source mixed in step (2) is based on the molar amount of Fe in the second leaching solution, and the P/Fe is 1.0 to 1.1, and may be, for example, 1.0, 1.02, 1.04, 1.06, 1.08 or 1.1, but is not limited to the recited values, and other values not recited in the numerical range are also applicable.

According to the invention, the molar quantity of Fe in the second leaching solution is used as a reference mixed phosphorus source, and the P/Fe ratio is controlled to be 1.0-1.1, so that the Fe element in the leaching solution is completely converted into an iron phosphate product, and the recovery efficiency is improved.

Preferably, the oxidant in step (3) includes any one or a combination of at least two of hydrogen peroxide, sodium hypochlorite, sodium chlorate or compressed air, and typical but non-limiting combinations include a combination of hydrogen peroxide and sodium hypochlorite, a combination of sodium hypochlorite and sodium chlorate, a combination of sodium chlorate and compressed air, hydrogen peroxide, a combination of sodium hypochlorite and sodium chlorate, a combination of sodium hypochlorite, sodium chlorate and compressed air, or a combination of hydrogen peroxide, sodium hypochlorite, sodium chlorate and compressed air.

Preferably, the mixing amount of the oxidant in the step (3) is Fe in the second leaching solution ²⁺ Is totally oxidized into Fe ³⁺ The standard is.

Preferably, the precipitant of step (3) comprises sodium hydroxide.

Preferably, the mixing amount of the precipitant in step (3) is determined based on the pH of the second leaching solution reaching 1.5-2.0, and may be, for example, 1.5, 1.55, 1.6, 1.65, 1.7, 1.75, 1.8, 1.85, 1.9, 1.95 or 2.0, but is not limited to the enumerated values, and other non-enumerated values in the range of the enumerated values are also applicable.

Preferably, the reaction temperature in step (3) is 50-100 ℃, for example 50 ℃, 55 ℃, 60 ℃, 65 ℃, 70 ℃, 75 ℃, 80 ℃, 85 ℃, 90 ℃, 95 ℃ or 100 ℃, but not limited to the recited values, and other values not recited in the range of values are also applicable.

Preferably, the reaction time in step (3) is 0.5-4h, for example 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h or 4h, but is not limited to the recited values, and other values not recited in the range of the values are also applicable.

Preferably, the iron phosphate product obtained after the solid-liquid separation in the step (3) is further washed and dried.

Preferably, the impurity removal in the step (4) comprises chemical precipitation or extraction.

In the present invention, the chemical precipitation or extraction, concentration and crystallization are all conventional treatment means in the art, as long as battery-grade nickel sulfate can be obtained from the nickel-containing solution, and therefore, specific conditions of the above treatment are not particularly limited.

As a preferable technical scheme of the invention, the method comprises the following steps:

(1) Adding water into the laterite-nickel ore according to the liquid-solid mass ratio (3-5) to 1, mixing the obtained mixture, adding 70-98wt% of sulfuric acid, carrying out acid leaching treatment for 2-6h under the conditions that the pressure is 0.8-1.2bar and the temperature is 60-100 ℃, wherein the mass ratio of the sulfuric acid to the laterite-nickel ore is (1-2) to 1, and carrying out solid-liquid separation to obtain a first leaching solution;

(2) Reacting the mixed ferronickel alloy and the first leaching solution obtained in the step (1) at the temperature of 60-100 ℃ according to the solid-to-liquid ratio of (0.05-0.5) kg/L until the pH value of the solution is 1.0-2.0, and carrying out solid-liquid separation to obtain a second leaching solution;

(3) Mixing a phosphorus source, an oxidant, a precipitator and the second leaching solution obtained in the step (2), reacting for 0.5-4h at 50-100 ℃, performing solid-liquid separation to obtain an iron phosphate product and a nickel-containing solution, and washing and drying the iron phosphate product; the phosphorus source comprises any one or combination of at least two of phosphoric acid, sodium dihydrogen phosphate and disodium hydrogen phosphate, the mixing amount of the phosphorus source is based on the molar amount of Fe in the second leaching solution, and the P/Fe is 1.0-1.1; the oxidant comprises hydrogen peroxide, sodium hypochlorite, sodium chlorate or sodium chlorateAny one or combination of at least two of the compressed air and the mixing amount of the oxidant is equal to the Fe in the second leaching solution ²⁺ Is totally oxidized into Fe ³⁺ The method comprises the following steps of (1) taking; the precipitator comprises sodium hydroxide, and the mixing amount of the precipitator is based on that the pH value of the second leaching solution reaches 1.5-2.0;

(4) Sequentially removing impurities, concentrating and crystallizing the nickel-containing solution obtained in the step (3) to obtain battery-grade nickel sulfate; the impurity removal comprises chemical precipitation or extraction.

The recitation of numerical ranges herein includes not only the above-recited numerical values, but also any numerical values between non-recited numerical ranges, and is not intended to be exhaustive or to limit the invention to the precise numerical values encompassed within the range for brevity and clarity.

Compared with the prior art, the invention has the beneficial effects that:

(1) The method provided by the invention fully considers the reaction characteristics of the laterite-nickel ore and the ferronickel alloy, and utilizes the high acid and rich Fe of the leachate of the laterite-nickel ore ³⁺ The method is characterized in that the ferronickel alloy is treated, the residual acid in the leaching solution is neutralized by the ferronickel alloy, and the residual acid and Fe in the leaching solution are utilized ³⁺ The strong oxidizing property promotes the dissolution of the nickel-iron alloy, thereby realizing the high-efficiency recovery of nickel and iron in the nickel-iron alloy and finally obtaining the iron phosphate and battery-grade nickel sulfate products;

(2) Compared with the traditional method for separately treating two raw materials, the combined treatment method provided by the invention greatly saves the treatment cost, improves the treatment efficiency, and obviously improves the economic benefit, and the recycled products of ferric phosphate and nickel sulfate can be used as raw materials for synthesizing battery materials.

Detailed Description

The technical solution of the present invention is further explained by the following embodiments.

Example 1

The present embodiment provides a method for combined treatment of lateritic nickel ores and ferronickel alloys and recovery of nickel and iron, said method comprising the steps of:

(1) Adding water into the laterite-nickel ore according to a liquid-solid mass ratio of 4;

(2) Mixing the ferronickel alloy and the first leaching solution obtained in the step (1) according to the solid-to-liquid ratio of 0.2kg/L, reacting at 80 ℃ until the pH value of the solution is 1.5, and carrying out solid-liquid separation to obtain a second leaching solution;

(3) Mixing phosphoric acid, hydrogen peroxide, sodium hydroxide and the second leaching solution obtained in the step (2), reacting for 2 hours at 80 ℃, carrying out solid-liquid separation to obtain an iron phosphate product and a nickel-containing solution, and washing and drying the iron phosphate product; the mixing amount of the phosphoric acid is based on the molar amount of Fe in the second leaching solution, and the P/Fe ratio is 1.05; the mixing amount of the hydrogen peroxide is Fe in the second leaching solution ²⁺ Is totally oxidized into Fe ³⁺ The method comprises the following steps of (1) taking; the mixing amount of the sodium hydroxide is based on that the pH value of the second leaching solution reaches 1.8;

(4) And (4) sequentially purifying, decontaminating, concentrating and crystallizing the nickel-containing solution obtained in the step (3) to obtain the battery-grade nickel sulfate.

Example 2

The present embodiment provides a method for combined treatment of lateritic nickel ores and ferronickel alloys and recovery of nickel and iron, said method comprising the steps of:

(1) Adding water into the laterite-nickel ore according to a liquid-solid mass ratio of 3;

(2) Mixing the ferronickel alloy and the first leaching solution obtained in the step (1) according to the solid-to-liquid ratio of 0.05kg/L, reacting at 60 ℃ until the pH value of the solution is 2.0, and carrying out solid-liquid separation to obtain a second leaching solution;

(3) Mixing sodium dihydrogen phosphate, sodium hypochlorite and sodium hydroxide with the second leaching solution obtained in the step (2), reacting for 4 hours at 50 ℃, and carrying out solid-liquid separation to obtain an iron phosphate product and a nickel-containing solution, wherein the iron phosphate product is further washed and dried; the mixing amount of the sodium dihydrogen phosphate is the mol amount of Fe in the second leaching solutionBase, and P/Fe is 1.0; the mixing amount of the sodium hypochlorite is Fe in the second leaching solution ²⁺ Is totally oxidized to Fe ³⁺ The method comprises the following steps of (1) taking; the mixing amount of the sodium hydroxide is based on that the pH value of the second leaching solution reaches 1.5;

(4) And (4) sequentially purifying, impurity removing, concentrating and crystallizing the nickel-containing solution obtained in the step (3) to obtain the battery-grade nickel sulfate.

Example 3

The present embodiment provides a method for combined processing of lateritic nickel ores and ferronickel alloys and recovering nickel and iron, said method comprising the steps of:

(1) Adding water into the laterite-nickel ore according to a liquid-solid mass ratio of 5;

(2) Mixing the ferronickel alloy and the first leaching solution obtained in the step (1) according to the solid-to-liquid ratio of 0.5kg/L, reacting at 100 ℃ until the pH value of the solution is 1.0, and carrying out solid-liquid separation to obtain a second leaching solution;

(3) Mixing disodium hydrogen phosphate, sodium chlorate, sodium hydroxide and the second leaching solution obtained in the step (2), reacting for 0.5h at 100 ℃, performing solid-liquid separation to obtain an iron phosphate product and a nickel-containing solution, and washing and drying the iron phosphate product; the mixing amount of the disodium hydrogen phosphate is based on the molar amount of Fe in the second leaching solution, and the P/Fe is 1.1; the mixing amount of the sodium chlorate is equal to the Fe in the second leaching solution ²⁺ Is totally oxidized into Fe ³⁺ The method comprises the following steps of (1) taking; the mixing amount of the sodium hydroxide is determined according to the condition that the pH value of the second leaching solution reaches 2.0;

(4) And (4) sequentially purifying, decontaminating, concentrating and crystallizing the nickel-containing solution obtained in the step (3) to obtain the battery-grade nickel sulfate.

Example 4

The embodiment provides a method for combined treatment of laterite-nickel ore and ferronickel alloy and recovery of nickel and iron, except that the temperature of acid leaching in step (1) is changed to 50 ℃, and the other steps and conditions are the same as those in embodiment 1, and thus the details are not repeated herein.

Compared with the example 1, because the temperature of the acid leaching treatment in the example is too low, the nickel and the iron in the laterite-nickel ore can not be sufficiently leached, so that the yield of the finally obtained iron phosphate product and the battery-grade nickel sulfate is obviously lower than that in the example 1.

Example 5

The embodiment provides a method for combined treatment of laterite-nickel ore and ferronickel alloy and recovery of nickel and iron, except that the mass ratio of sulfuric acid to laterite-nickel ore in step (1) is changed to 0.8.

Compared with the example 1, because the sulfuric acid in the acid leaching treatment in the example is too little, the nickel and iron in the laterite-nickel ore can not be leached sufficiently, so that the final yield of the obtained iron phosphate product and the battery-grade nickel sulfate is obviously inferior to that in the example 1.

Example 6

The embodiment provides a method for combined treatment of laterite-nickel ore and ferronickel alloy and recovery of nickel and iron, which is the same as embodiment 1 except that the mass ratio of sulfuric acid to laterite-nickel ore in step (1) is changed to 2.2.

Compared with example 1, the yield of the final iron phosphate product and the battery grade nickel sulfate is not significantly increased due to the excessive sulfuric acid in the acid leaching treatment in the present example, so that the recovery cost is unnecessarily increased, and the economic benefit is not as good as that in example 1.

Example 7

This embodiment provides a method for combined treatment of laterite-nickel ore and ferronickel and recovery of nickel and iron, except that the reaction temperature in step (2) is changed to 50 ℃, and the remaining steps and conditions are the same as those in embodiment 1, and therefore, detailed description thereof is omitted.

Compared with example 1, since the reaction temperature of the ferronickel alloy and the first leaching solution is too low and the reaction rate is slow in this embodiment, nickel and iron in the ferronickel alloy cannot be sufficiently dissolved, so that the final yields of the obtained iron phosphate product and battery-grade nickel sulfate are obviously inferior to those of example 1.

Example 8

This embodiment provides a method for combined treatment of laterite-nickel ore and ferronickel and recovery of nickel and iron, except that the reaction temperature in step (3) is changed to 40 ℃, and the remaining steps and conditions are the same as those in embodiment 1, and thus are not described herein again.

Compared with example 1, because the reaction temperature of the phosphorus source, the oxidant, the precipitating agent and the second leaching solution is too low in this example, iron elements in the leaching solution cannot be sufficiently separated out to form iron phosphate precipitates, so that the yield and quality of the finally obtained iron phosphate product are obviously inferior to those of example 1.

Comparative example 1

The present comparative example provides a process for the treatment of lateritic nickel ores for the recovery of nickel and iron, said process comprising the steps of:

(1) Adding water into the laterite-nickel ore according to a liquid-solid mass ratio of 4;

(2) Mixing phosphoric acid, hydrogen peroxide, sodium hydroxide and the leachate obtained in the step (1), reacting for 2 hours at 80 ℃, carrying out solid-liquid separation to obtain an iron phosphate product and a nickel-containing solution, and washing and drying the iron phosphate product; the mixing amount of the phosphoric acid is based on the molar weight of Fe in the leaching solution, and the P/Fe is 1.05; the mixing amount of the hydrogen peroxide is Fe in the leaching solution ²⁺ Is totally oxidized into Fe ³⁺ The method comprises the following steps of (1) taking; the mixing amount of the sodium hydroxide is based on that the pH value of the leaching solution reaches 1.8;

(3) And (3) sequentially purifying, impurity removing, concentrating and crystallizing the nickel-containing solution obtained in the step (2) to obtain the battery-grade nickel sulfate.

Compared with the embodiment 1, the comparative example can only treat the laterite-nickel ore to recover nickel and iron, and has huge consumption of auxiliary materials for neutralizing residual acid in subsequent procedures and higher cost; meanwhile, the recovery treatment of the nickel-iron alloy cannot be realized, and the application scene is single.

Comparative example 2

The present comparative example provides a process for the treatment of nickel-iron alloys for the recovery of nickel and iron, comprising the following steps:

(1) Mixing nickel-iron alloy and 20wt% sulfuric acid according to a solid-to-liquid ratio of 0.2kg/L, reacting at 80 ℃ until the pH value of the solution is 1.5, and performing solid-liquid separation to obtain a leaching solution;

(2) Mixing phosphoric acid, hydrogen peroxide, sodium hydroxide and the leachate obtained in the step (1), reacting for 2 hours at 80 ℃, carrying out solid-liquid separation to obtain an iron phosphate product and a nickel-containing solution, and washing and drying the iron phosphate product; the mixing amount of the phosphoric acid is based on the molar weight of Fe in the leaching solution, and the P/Fe ratio is 1.05; the mixing amount of the hydrogen peroxide is Fe in the leaching solution ²⁺ Is totally oxidized into Fe ³⁺ The method comprises the following steps of (1) taking; the mixing amount of the sodium hydroxide is based on that the pH value of the leaching solution reaches 1.8;

(3) And (3) sequentially purifying, decontaminating, concentrating and crystallizing the nickel-containing solution obtained in the step (2) to obtain the battery-grade nickel sulfate.

Compared with the embodiment 1, the comparative example can only process the nickel-iron alloy to recover nickel and iron, and the nickel-iron alloy is slowly dissolved, so that the processing efficiency is low; meanwhile, the element extraction of the laterite-nickel ore cannot be realized, and the application scene is single.

Therefore, the method provided by the invention fully considers the reaction characteristics of the laterite-nickel ore and the ferronickel alloy, and utilizes the high acid and rich Fe of the laterite-nickel ore leaching solution ³⁺ The method is characterized in that the ferronickel alloy is treated, the residual acid in the leaching solution is neutralized by the ferronickel alloy, and the residual acid and Fe in the leaching solution are utilized ³⁺ The strong oxidizing property promotes the dissolution of the nickel-iron alloy, thereby realizing the high-efficiency recovery of nickel and iron in the nickel-iron alloy and finally obtaining the iron phosphate and battery-grade nickel sulfate products.

In addition, compared with the traditional method for separately treating two raw materials, the combined treatment method provided by the invention greatly saves the treatment cost, improves the treatment efficiency, and obviously improves the economic benefit because the recovered products of ferric phosphate and nickel sulfate can be used as raw materials for synthesizing battery materials.

The above-mentioned embodiments, objects, technical solutions and advantages of the present invention are further described in detail, it should be understood that the above-mentioned embodiments are only examples of the present invention, and should not be construed as limiting the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A method for the combined treatment of lateritic nickel ores with ferronickel alloys and the recovery of nickel and iron, characterized in that it comprises the following steps:

(1) Mixing laterite nickel ore into slurry, carrying out acid leaching treatment, and carrying out solid-liquid separation to obtain a first leaching solution;

(2) Reacting the mixed nickel-iron alloy with the first leaching solution obtained in the step (1), and performing solid-liquid separation to obtain a second leaching solution;

(3) Reacting the mixed phosphorus source, the oxidant and the precipitator with the second leaching solution obtained in the step (2), and performing solid-liquid separation to obtain an iron phosphate product and a nickel-containing solution;

(4) And (4) sequentially removing impurities, concentrating and crystallizing the nickel-containing solution obtained in the step (3) to obtain the battery-grade nickel sulfate.

2. The method according to claim 1, wherein the liquid-solid mass ratio of the size mixing in the step (1) is (3-5): 1;

preferably, the pressure of the acid leaching treatment in the step (1) is 0.8-1.2bar;

preferably, the temperature of the acid leaching treatment in the step (1) is 60-100 ℃;

preferably, the time of the acid leaching treatment in the step (1) is 2-6h.

3. The method according to claim 1 or 2, wherein the acid solution used in the acid leaching treatment in step (1) comprises sulfuric acid;

preferably, the concentration of the sulfuric acid is 70-98wt%;

preferably, the mass ratio of the sulfuric acid to the laterite-nickel ore is (1-2): 1.

4. The method according to any one of claims 1 to 3, wherein the mixing solid-to-liquid ratio of the ferronickel alloy to the first leaching solution in step (2) is (0.05-0.5) kg/L;

preferably, the temperature of the reaction of the step (2) is 60-100 ℃;

preferably, the end point judgment indicator of the reaction in the step (2) is a pH value, and the pH value of the end point of the reaction is 1.0-2.0.

5. The method of any one of claims 1 to 4, wherein the phosphorus source of step (3) comprises any one of phosphoric acid, sodium dihydrogen phosphate, or disodium hydrogen phosphate, or a combination of at least two thereof;

preferably, the mixing amount of the phosphorus source in the step (2) is based on the molar amount of Fe in the second leaching solution, and the P/Fe is 1.0-1.1.

6. The method according to any one of claims 1 to 5, wherein the oxidant in step (3) comprises any one or a combination of at least two of hydrogen peroxide, sodium hypochlorite, sodium chlorate or compressed air;

preferably, the mixing amount of the oxidant in the step (3) is Fe in the second leaching solution ²⁺ Is totally oxidized into Fe ³⁺ The standard is.

7. The method according to any one of claims 1 to 6, wherein the precipitating agent of step (3) comprises sodium hydroxide;

preferably, the mixing amount of the precipitant in step (3) is determined based on that the pH of the second leaching solution reaches 1.5-2.0.

8. The process according to any one of claims 1 to 7, wherein the temperature of the reaction of step (3) is 50 to 100 ℃;

preferably, the reaction time of the step (3) is 0.5-4h;

preferably, the iron phosphate product obtained after the solid-liquid separation in the step (3) is further washed and dried.

9. The method of any one of claims 1-8, wherein the removing of impurities in step (4) comprises chemical precipitation or extraction.

10. Method according to any of claims 1-9, characterized in that the method comprises the steps of:

(1) Adding water into the laterite-nickel ore according to the liquid-solid mass ratio (3-5) to 1, mixing the obtained mixture, adding 70-98wt% of sulfuric acid, carrying out acid leaching treatment for 2-6h under the conditions that the pressure is 0.8-1.2bar and the temperature is 60-100 ℃, wherein the mass ratio of the sulfuric acid to the laterite-nickel ore is (1-2) to 1, and carrying out solid-liquid separation to obtain a first leaching solution;

(2) Reacting the mixed ferronickel alloy and the first leaching solution obtained in the step (1) at the temperature of 60-100 ℃ according to the solid-to-liquid ratio of (0.05-0.5) kg/L until the pH value of the solution is 1.0-2.0, and carrying out solid-liquid separation to obtain a second leaching solution;

(3) Mixing a phosphorus source, an oxidant, a precipitator and the second leaching solution obtained in the step (2), reacting for 0.5-4h at 50-100 ℃, performing solid-liquid separation to obtain an iron phosphate product and a nickel-containing solution, and washing and drying the iron phosphate product; the phosphorus source comprises any one or combination of at least two of phosphoric acid, sodium dihydrogen phosphate and disodium hydrogen phosphate, the mixing amount of the phosphorus source is based on the molar amount of Fe in the second leaching solution, and the P/Fe is 1.0-1.1; the oxidant comprises any one or combination of at least two of hydrogen peroxide, sodium hypochlorite, sodium chlorate or compressed air, and the mixing amount of the oxidant is equal to the Fe in the second leaching solution ²⁺ Is totally oxidized into Fe ³⁺ The method comprises the following steps of (1) taking; the precipitant comprises sodium hydroxide, and the mixing amount of the precipitant is based on that the pH value of the second leaching solution reaches 1.5-2.0;

(4) Sequentially removing impurities, concentrating and crystallizing the nickel-containing solution obtained in the step (3) to obtain battery-grade nickel sulfate; the impurity removal comprises chemical precipitation or extraction.