Method for directly separating and recycling ferronickel in acid solution and preparing nickel hydroxide through one-step method

Abstract

The invention belongs to the technical field of ferronickel separation, and particularly relates to a method for directly separating and recycling ferronickel in an acid solution and preparing nickel hydroxide through a one-step method. The method comprises the following steps that a reducing agent is added into an acid leaching solution containing iron and nickel for partial reduction of iron, the reduction time is 30-60 min, a coprecipitation method is further adopted for nickel-iron precipitation separation, the pH control range is 9-11, the reaction time is 10-60 min, separation of nickel-containing alkali liquor and magnet slag is achieved through a magnetic separation method, and the iron-containing alkali liquor is obtained. Furthermore, nickel hydroxide is prepared from the nickel-containing alkali liquor in a manner of raising the temperature to adjust the pH value, the iron precipitation rate reaches 99% or above, and the nickel recovery rate reaches 99% or above.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgical separation, and relates to the technical field of a method for directly separating and recovering nickel iron in an acidic solution and preparing nickel hydroxide in one step. Background Art

[0002] Iron is an element that is widely present in nature, and is often present as a co-element in various minerals or secondary resources. Acid leaching recovery is often used to achieve nickel leaching. Iron and nickel coexist in the acid leaching solution. Conventional methods of separating and removing iron from acidic solutions, such as pH precipitation, hematite method, goethite method, and sodium iron alum method, can achieve the removal of iron, but they have strict requirements on the concentration of iron in the solution and the reaction temperature or are limited by the filtering effect, resulting in poor separation of nickel and iron in the solution, long process, and low purity. Therefore, it is necessary to develop a method for directly and effectively separating nickel and iron from nickel-iron acid solution. Summary of the invention

[0003] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a one-step method for directly separating and recovering nickel iron in an acidic solution and preparing nickel hydroxide.

[0004] To achieve the above object, the present invention is implemented by the following technical solutions:

[0005] The present invention provides a one-step method for directly separating and recovering nickel iron in an acidic solution and preparing nickel hydroxide, the method comprising the following steps:

[0006] A reducing agent is added to an acid leaching solution containing iron and nickel to partially reduce the iron, the reduction time is 30 to 60 minutes, and the nickel-iron precipitation separation is further carried out by a co-precipitation method, the reaction time is 10 to 60 minutes, and the separation of the nickel-containing alkali solution and the magnetite slag is achieved by a magnetic separation method. The nickel-containing alkali solution is further used to prepare nickel hydroxide by adjusting the pH value by increasing the temperature, wherein the iron precipitation rate is more than 99%, and the nickel recovery is more than 99%.

[0007] The present invention adopts a partial reduction method to make the iron in the solution coexist in the form of trivalent iron and ferrous iron, uses ammonia water as a precipitant, adopts a coprecipitation method to prepare magnetic ferroferric oxide, and controls the pH value at 9-11. Nickel and ammonia exist in the alkaline solution in the form of nickel-ammonia complex ions, and effectively separate the nickel-containing solution from the magnetic iron slag by magnetic separation. The one-step method directly realizes the separation and purification of nickel and iron, solves the problems of easy entrainment, low purity, long process and difficult filtration brought by the conventional precipitation iron removal method, improves the separation effect of nickel and iron, simplifies the process flow, reduces the difficulty of operation, and is suitable for large-scale industrial production.

[0008] Furthermore, the reducing agent is one or a combination of two of sodium sulfite, sodium pyrosulfite, sodium dithionite, and hydrazine hydrate;

[0009] Further, the reducing agent is used in an amount such that the molar ratio of the reducing agent to iron is 0.2 to 1:1;

[0010] Furthermore, the precipitant in the coprecipitation method is ammonia water;

[0011] Furthermore, the pH control range of the iso-pH precipitation method is 9 to 11;

[0012] Furthermore, the nickel-containing alkali solution is used to prepare nickel hydroxide by increasing the temperature and adjusting the pH value;

[0013] Furthermore, the iron precipitation rate obtained through the above steps is more than 99%, and the nickel recovery is more than 99%.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The one-step method realizes direct separation of iron and nickel in the acid leaching solution, improves the efficiency of nickel-iron separation, improves product purity, simplifies the process flow, reduces the difficulty of operation, and is suitable for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the coprecipitation slurry before and after solid-liquid separation under magnetic field conditions of the present invention;

[0017] Figure 2 It is a comparative schematic diagram of the co-precipitation slurry before and after solid-liquid separation under magnetic field conditions in the comparative example of the present invention. DETAILED DESCRIPTION

[0018] The present invention is further described in detail below in conjunction with specific embodiments so that those skilled in the art can implement the invention with reference to the description. However, the following embodiments are only simple examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0019] Example 1

[0020] A one-step method for directly separating and recovering nickel iron in an acidic solution and preparing nickel hydroxide comprises the following steps:

[0021] 0.8 times of sodium metabisulfite was added to the acid leaching solution containing iron and nickel to partially reduce the iron, and the reduction time was 60 minutes. Ammonia water was further used as a precipitant, and a continuous equal pH precipitation method was adopted to precipitate and separate nickel and iron. The pH was controlled at 10 and the reaction time was 60 minutes. The nickel-containing alkali solution was separated from the magnetite slag by a magnetic separation method. The nickel-containing alkali solution was further heated to 80°C and the pH was adjusted to 13 to prepare nickel hydroxide, wherein the iron precipitation rate reached 99.5% and the nickel recovery reached 99.2%.

[0022] Example 2

[0023] A one-step method for directly separating and recovering nickel iron in an acidic solution and preparing nickel hydroxide comprises the following steps:

[0024] 0.5 times of sodium dithionite was added to the acid leaching solution containing iron and nickel to partially reduce the iron, and the reduction time was 60 minutes. Ammonia water was further used as a precipitant, and a continuous equal pH precipitation method was adopted to precipitate and separate nickel and iron. The pH was controlled at 9.5 and the reaction time was 60 minutes. The nickel-containing alkali solution was separated from the magnetite slag by a magnetic separation method. The nickel-containing alkali solution was further heated to 80°C and the pH was adjusted to 13 to prepare nickel hydroxide, wherein the iron precipitation rate reached 99.2% and the nickel recovery reached 99.5%.

[0025] Example 3

[0026] A one-step method for directly separating and recovering nickel iron in an acidic solution and preparing nickel hydroxide comprises the following steps:

[0027] 0.5 times of sodium dithionite was added to the acid leaching solution containing iron and nickel to partially reduce the iron. The reduction time was 60 minutes. Ammonia water was further used as a precipitant and a continuous equal pH precipitation method was adopted to precipitate and separate nickel and iron. The pH was controlled at 10.5 and the reaction time was 90 minutes. The nickel-containing alkali solution was separated from the magnetite slag by magnetic separation. The nickel-containing alkali solution was further heated to 80°C and the pH was adjusted to 13 to prepare nickel hydroxide. The iron precipitation rate reached 99.2% and the nickel recovery reached 99.5%.

[0028] Comparative Example 1

[0029] Compared with Example 1, the difference is that no reduction treatment is performed, and the remaining steps and parameters are the same. The magnetic separation method cannot achieve solid-liquid separation of the alkali-soluble slurry, the atmospheric pressure filtration speed is slow, and it is difficult to wash. The iron precipitation rate is 99.8%, and the nickel recovery rate is 17.6%.

[0030] The applicant declares that the present invention illustrates the detailed method of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed method, that is, it does not mean that the present invention must rely on the above-mentioned detailed method to be implemented. Those skilled in the art should understand that the equivalent replacement of the raw materials of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A one-step method for directly separating and recovering nickel iron in an acidic solution and preparing nickel hydroxide, characterized in that it comprises the following steps: A reducing agent is added to an acid leaching solution containing iron and nickel to partially reduce the iron, the reduction time is 30 to 60 minutes, and the nickel-iron precipitation separation is further carried out by a co-precipitation method, the reaction time is 10 to 60 minutes, and the separation of the nickel-containing alkali solution and the magnetite slag is achieved by a magnetic separation method. The nickel-containing alkali solution is further used to prepare nickel hydroxide by adjusting the pH value by increasing the temperature, wherein the iron precipitation rate is more than 99%, and the nickel recovery is more than 99%.

2. The method for directly separating and recovering nickel iron in an acidic solution and preparing nickel hydroxide by a one-step method according to claim 1, characterized in that: The reducing agent is one or a combination of two of sodium sulfite, sodium pyrosulfite, sodium dithionite and hydrazine hydrate.

3. The method for directly separating and recovering nickel iron in an acidic solution and preparing nickel hydroxide by a one-step method according to claim 1, characterized in that: The amount of the reducing agent is such that the molar ratio of the reducing agent to iron is 0.2 to 1:

1.

4. The method for directly separating and recovering nickel iron in an acidic solution and preparing nickel hydroxide by a one-step method according to claim 1, characterized in that: The precipitant in the coprecipitation method is ammonia water.

5. The method for directly separating and recovering nickel iron in an acidic solution and preparing nickel hydroxide by a one-step method according to claim 1, characterized in that: The pH control range of the iso-pH precipitation method is 9-11.

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