AU2019310942A1

AU2019310942A1 - Method for homogeneous precipitation separation of iron and aluminum from laterite nickel ore acid leaching solution

Info

Publication number: AU2019310942A1
Application number: AU2019310942A
Authority: AU
Inventors: Yongqiang Chen; Yong DAN; Changhao JIN; Baozhong MA; Chengyan Wang; Lin Zhao; Peng Zhao
Original assignee: Meishan Shunying Power Battery Mat Co Ltd
Current assignee: Sichuan Shunying Power Battery Material Co Ltd
Priority date: 2018-07-24
Filing date: 2019-06-24
Publication date: 2020-08-13
Anticipated expiration: 2039-06-24
Also published as: CN108950205A; CU24669B1; CU20200061A7; WO2020019919A1; CN108950205B; PH12020551379A1; AU2019310942B2

Abstract

Disclosed is a method for the homogeneous precipitation separation of iron and aluminum from a laterite nickel ore acid leaching solution, wherein the present invention belongs to the technical field of nonferrous metal wet metallurgy. The present invention comprises: finely grinding calcium carbonate or magnesium carbonate and mixing same with water in a certain ratio, and uniformly stirring same to prepare a calcium carbonate milk or a magnesium carbonate milk as a precipitating agent; transferring the precipitating agent to a homogeneous reactor via a pipe provided with a rate control device and installing a refiner at an outlet end for refining the precipitating agent; conveying a laterite nickel ore acid leaching solution to the homogeneous reactor via a pipe provided with a rate control device, and installing an atomizer at an outlet end for atomizing the acid leaching solution, wherein the controlled-rate atomized laterite nickel ore acid leaching solution and the controlled-rate refined precipitating agent are homogeneously reacted in the homogeneous reactor to obtain a post-reaction slurry; and filtering the reaction slurry to obtain a liquid remaining after iron aluminum removal and a sand-like iron-aluminum residue. The method has a simple process, a high reliability and easy industrialization, can effectively realize the separation of iron and aluminum from the red earth nickel ore acid leaching solution, and has broad application prospects.

Description

Specification

Method for homogeneous precipitation separation of iron and aluminum from a laterite-nickel ore acid leaching solution

Technical Field The present invention relates to a method for homogeneous precipitation separation of iron and aluminum from a laterite-nickel ore acid leaching solution, and relates to the technical field of non-ferrous metal hydrometallurgy.

Background Art Nickel is an important strategic material, and is mainly used in producing stainless steel, alloy steel, special alloy and the like. Nickel ore resources are divided into two types of nickel sulfide ore and nickel oxide ore, wherein the nickel oxide ore is also known as laterite-nickel ore, and the rock mass of the nickel oxide ore appears to be red because iron in the ore is oxidized due to weathering. Laterite-nickel ores are mainly divided into two types of limonitic laterite-nickel ore and serpentine-type laterite-nickel ore. Generally, the limonitic laterite-nickel ore has a relatively low nickel content and a relatively high iron content, suitable for refining by a wet process. The serpentine-type laterite-nickel ore has a relatively high nickel content and a relatively low iron content, suitable for refining by pyrometallurgy. Nowadays, since the need for nickel in the market is increasing, and nickel sulfide ore resources with high grade of nickel are gradually depleted, the extraction of nickel from the laterite-nickel ore attracts more and more attentions. At present, a wet process for refining a laterite-nickel ore mainly includes an atmospheric pressure acid leaching process and a pressurized acid leaching process. In either process, nickel finally occurs in the laterite-nickel ore acid leaching solution. However, the laterite-nickel ore acid leaching solution contains impurities such as iron and aluminum. In order to reduce their adverse effects on subsequent nickel and cobalt extraction procedure, iron and aluminum have to be separated first. The most practical and feasible method for separating iron and aluminum from the acid leaching solution is the precipitation method. However, the existed conventional methods have problems such as high nickel and cobalt contents in the precipitation residue, difficult filtration, and high water content in the precipitation residue after filtration. In addition, there is a progress on the investigation of removing iron and aluminum from a laterite-nickel ore acid leaching solution by a solvent extraction method, and the method is only suitable for a leaching solution system with a low acidity and with a low iron content. CN Patent No. CN105887136A discloses a method for separating iron and nickel from a laterite-nickel ore acid leaching solution. This method comprises: adding a complexing agent into the laterite-nickel ore acid leaching solution obtained by leaching with sulfuric acid, fully mixing them, pouring the mixture into the anode chamber of an electrolytic cell with an ion exchange membrane as separation medium after mixing, applying a direct current, and allowing nickel ions in the acid leaching solution to migrate to the cathode chamber and to deposit on the cathode under the action of electrical field by making use of the selective permeability of the ion exchange membrane with respect to anions and cations, while iron present as complexed anion remaining in the anode chamber, thereby achieving separation of iron from nickel in the laterite-nickel ore acid leaching solution. However, this method has disadvantages of complex process, high cost input, and difficulty in putting into large scale industrial production, and does not take interference of other ions in the acid leaching solution into consideration.

CN Patent No. CN 104120259A discloses a method for removing iron from a nickel oxide ore acid leaching solution by a two-step process. This method comprises: adding a silicon-magnesium-nickel ore slurry into the nickel oxide ore acid leaching solution, performing a liquid-solid separation after complete reaction, and drying the solid to obtain a hematite product. A silicon-magnesium-nickel ore slurry is added into the liquid collected again, and a liquid-solid separation is performed after reaction. Magnesium oxide and an oxidant are added into the liquid obtained, or only an oxidant is added. The reaction mixture is stirred for 0.5-4 h. A liquid-solid separation is performed and the solid is dried to obtain a goethite product. This method achieves the separation of iron from an acid leaching solution under relatively mild conditions, and results in hematite and goethite products which can be directly sold. However, the process is complex, the amount of the nickel silicate ore added is difficult to control, the iron removal is not high, and the product purity cannot be ensured. CN Patent No. CN101392321A discloses a method for precipitating hematite at a temperature in a range of 120-200°C. However, this method requires adding a carbonaceous reductant and performing a microwave reduction roasting on the ore before the iron precipitation and leaching, and is not suitable for direct iron removal from a nickel oxide ore atmospheric pressure acid leaching solution. CN Patent No. CN102212684A uses a magnesian nickel oxide ore to neutralize residual acid in an irony nickel oxide ore acid leaching solution to increase the pH of the acid leaching solution. However, all these iron removed products obtained are difficult to recycle, and is liable to generating environment polluting sodium jarosite/jarosite. In summary, the existed technologies for separating iron and aluminum from a laterite-nickel ore acid leaching solution still have problems of incomplete removal, complex process, large capital investment, difficult liquid-solid separation, low production efficiency, and large loss of nickel and cobalt. There is an urgent need for developing a method for removing iron and aluminum from a laterite-nickel ore acid leaching solution, which is capable of solving the above problems.

Summary In order to solve the technical problems occurred in the above existed technologies, the present invention provides a method for homogeneous precipitation separation of iron and aluminum from a laterite-nickel ore acid leaching solution, and well achieves effective separation of iron and aluminum from the laterite-nickel ore acid leaching solution. The object of the present invention is achieved by the following technical solutions. A method for homogeneous precipitation separation of iron and aluminum from a laterite-nickel ore acid leaching solution, characterized by comprising: Step I: precipitant preparation: finely grinding calcium carbonate or magnesium carbonate, then mixing the calcium carbonate or magnesium carbonate with water in a ratio, stirring uniformly to produce a calcium carbonate emulsion or a magnesium carbonate emulsion as a precipitant; Step II: precipitant refining at a controlled speed: delivering the precipitant to a homogeneous reactor through a pipe having a speed control device, with a refining device mounted at an outlet end, in order to add the precipitant refined at a controlled speed into the reactor; Step III: atomization of the laterite-nickel ore acid leaching solution at a controlled speed: delivering the laterite-nickel ore acid leaching solution to the homogeneous reactor through a pipe having a speed control device, with an atomizer mounted at an outlet end, in order to add the laterite-nickel ore acid leaching solution atomized at a controlled speed into the reactor; Step IV: homogeneous reaction: homogeneously reacting the laterite-nickel ore acid leaching solution atomized at a controlled speed and the precipitant refined at a controlled speed in the homogeneous reactor to obtain a post-reaction slurry; and Step V: liquid-solid separation: filtering the post-reaction slurry for liquid-solid separation to obtain a solution with iron and aluminum removed and a sand-like iron-aluminum residue, wherein the filtration speed is increased by 10-20 times as compared to a conventional method. Further, the calcium carbonate or the magnesium carbonate in Step I has a particle size of less than 74 tm after fine grinding, and the precipitant slurry has a concentration of 20%-40%. Further, an adding speed of the precipitant in Step II is strictly controlled according to requirement for reaction, and the precipitant refining is achieved by mounting the refining device at the outlet end, wherein the refining device is a porous sprayer. Further, the laterite-nickel ore acid leaching solution of Step III comprises the following components: 0.5-10 g/L of Fe; 0.5-10 g/L of Al; 2-8 g/L of Ni; 0.3-2 g/L of Co; 1-3 g/L of Mn; 1-20 g/L of Mg; 0.1-0.5 mol/L of H', and an anion being one or more selected from NO3, Cl- or S42

Further, an adding speed of the laterite-nickel ore acid leaching solution in Step III is strictly controlled according to requirement for reaction, and the atomization of the laterite-nickel ore acid leaching solution is achieved by mounting the atomizer at the outlet end. Further, for the homogeneous system reaction in Step IV, the pH is controlled in a range of 3.8-4.3 and maintained constant at a certain value, and a reaction temperature is 30-80°C, a reaction time is 0.5-3 h, and a stirring speed is 50-200 rpm, wherein the temperature is kept stable during the reaction. Further, the post-reaction slurry in Step V is filtered to achieve the liquid-solid separation, obtaining a solution with iron and aluminum removed and a sand-like iron-aluminum residue. It can be seen from the above technical solutions provided in the present invention that the method for homogeneous precipitation separation of iron and aluminum from a laterite-nickel ore acid leaching solution provided in the present invention uses a "precipitant preparation - precipitant refining at a controlled speed - atomization of a laterite-nickel ore acid leaching solution at a controlled speed homogeneous system reaction - separation by filtration" process route to achieve efficient separation of iron and aluminum from the laterite-nickel ore acid leaching solution. The method has advantages of simple process flow, low equipment investment, convenient operation, and capability in putting into industrial production. The merit of the present invention lies in that the precipitant and the laterite-nickel ore acid leaching solution are added through refining and atomization respectively, and the adding speeds thereof are strictly controlled, thereby achieving a homogeneous system reaction. The method for homogeneous precipitation separation of iron and aluminum from a laterite-nickel ore acid leaching solution provided in the present invention has the following advantages. (1) The iron-aluminum residue obtained by a homogeneous system precipitation method appears to be sand-like, while the nickel-cobalt residue obtained by a conventional precipitation method appears to be colloidal, such that the present technology has an ore slurry filtration speed increased by 10-20 times as compared to a conventional precipitation method, and is convenient for industrial production.

(2) The water content of the residue obtained after filtration is reduced from original about 70% to about 40%, greatly reducing the amount of nickel and cobalt entrained in the residue. (3) By using charging modes of atomization and refining, a homogeneous system reaction is achieved, which can prevent the reaction system from being partially too alkaline, thereby reducing the loss of nickel and cobalt.

Brief Description of Drawings In order to more clearly describe technical solutions of embodiments of the present invention, drawing(s) to be used in describing the embodiments will be briefly introduced below. Obviously, the drawing(s) as described below is/are only some of the embodiments of the present invention. An ordinary person skilled in the art can also obtain other drawings according to the drawing(s) without any inventive effort. Fig. 1 is a process flow diagram of a method for homogeneous precipitation separation of iron and aluminum from a laterite-nickel ore acid leaching solution according to the present invention.

Detailed Description In order to make the technical problems to be solved by the present invention, the technical solutions and the advantageous effects more clear and explicit, particular embodiments of the present invention will be further described in detail below with reference to the process flow diagram. Obviously, the embodiments as described are only a portion of, but not all of, the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by an ordinary person skilled in the art without any inventive effort fall within the protection scope of the present invention.

A method for homogeneous precipitation separation of iron and aluminum from a laterite-nickel ore acid leaching solution, comprising the following steps. Step I: precipitant preparation: finely grinding calcium carbonate or magnesium carbonate, then mixing the calcium carbonate or magnesium carbonate with water in a ratio, and stirring uniformly to produce a calcium carbonate emulsion or a magnesium carbonate emulsion as a precipitant, wherein the calcium carbonate or magnesium carbonate has a particle size of less than 74 tm after fine grinding, and the precipitant slurry has a concentration of 20%-40%. Step II: precipitant refining at a controlled speed: delivering the precipitant to a homogeneous reactor through a pipe having a speed control device, with a refining device mounted at an outlet end, in order to add the precipitant refined at a controlled speed into the reactor. An adding speed of the precipitant is strictly controlled according to requirement for reaction, and the precipitant refining is achieved by mounting the refining device at the outlet end, wherein the refining device is a porous sprayer and has a pore diameter of 100-150pm. Step III: atomization of the laterite-nickel ore acid leaching solution at a controlled speed: delivering the laterite-nickel ore acid leaching solution to the homogeneous reactor through a pipe having a speed control device, with an atomizer mounted at an outlet end, in order to add the laterite-nickel ore acid leaching solution atomized at a controlled speed into the reactor. The laterite-nickel ore acid leaching solution comprises the following components: 0.5-10 g/L of Fe; 0.5-10 g/L of Al; 2-8 g/L of Ni; 0.3-2 g/L of Co; 1-3 g/L of Mn; 1-20 g/L of Mg; 0.1-0.5 mol/L of H', and an anion being one or more selected from NO3, Cl- or SO42-. The adding speed of the laterite-nickel ore acid leaching solution is strictly controlled according to requirement for reaction.

Step IV: homogeneous reaction: homogeneously reacting the laterite-nickel ore acid leaching solution atomized at a controlled speed and the precipitant refined at a controlled speed in the homogeneous reactor to obtain a post-reaction slurry, wherein for the homogeneous reaction, a pH is controlled in a range of 3.8-4.3 and maintained constant at a certain value, a reaction temperature is 30-80°C, a reaction time is 0.5-3 h, and a stirring speed is 50-200 rpm, wherein the temperature is kept stable during the reaction. Step V: liquid-solid separation: performing a liquid-solid separation on the post-reaction slurry to obtain a solution with iron and aluminum removed and a sand-like iron-aluminum residue. Example 1 As shown in Fig. 1, the method for homogeneous precipitation separation of iron and aluminum from a laterite-nickel ore acid leaching solution comprises the following steps. An emulsion slurry with a concentration of 40% was formulated as a precipitant by using calcium carbonate having a particle size of less than 74 tm after fine grinding. The precipitant was delivered through a pipe having a speed control device, and was added into a homogeneous reactor through a refining device at an outlet end. Meanwhile, the laterite-nickel ore acid leaching solution was also delivered through a pipe having a speed control device, and added into the homogeneous reactor through an atomizer at an outlet end. The laterite-nickel ore acid leaching solution atomized at a controlled speed and the precipitant refined at a controlled speed were homogeneously reacted in the homogeneous reactor. The pH of the homogeneous reaction system was maintained constant at 3.8, the reaction temperature was 30°C, the reaction time was 3 h, and the stirring speed was 100 rpm. The pH and temperature must be kept constant during the reaction. According to requirement for the reaction, the adding speeds of the laterite-nickel ore acid leaching solution and the precipitant were strictly controlled, to keep the reaction system balanced and stable. Finally, the post-reaction slurry was delivered to a filter through a pipe for filtration to obtain a solution with iron and aluminum removed and a sand-like iron-aluminum residue. The precipitation rates of iron and aluminum were 99.6% and 99.0% respectively. Example 2 The method for homogeneous precipitation separation of iron and aluminum from a laterite-nickel ore acid leaching solution comprises the following steps. An emulsion slurry with a concentration of 30% was formulated as a precipitant by using magnesium carbonate having a particle size of less than 74 tm after fine grinding. The precipitant was delivered through a pipe having a speed control device, and was added into a homogeneous reactor through a refining device at an outlet end. Meanwhile, the laterite-nickel ore acid leaching solution was also delivered through a pipe having a speed control device, and added into the homogeneous reactor through an atomizer at an outlet end. The laterite-nickel ore acid leaching solution atomized at a controlled speed and the precipitant refined at a controlled speed were homogeneously reacted in the homogeneous reactor. The pH of the homogeneous reaction system was maintained constant at 4.0, the reaction temperature was °C, the reaction time was 2 h, and the stirring speed was 200 rpm. The pH and temperature must be kept constant during the reaction. According to requirement for the reaction, the adding speeds of the laterite-nickel ore acid leaching solution and the precipitant were strictly controlled, to keep the reaction system balanced and stable. Finally, the post-reaction slurry was delivered to a filter through a pipe for filtration to obtain a solution with iron and aluminum removed and a sand-like iron-aluminum residue. The precipitation rates of iron and aluminum were 99.9% and 99.3% respectively. Example 3

The method for homogeneous precipitation separation of iron and aluminum from a laterite-nickel ore acid leaching solution comprises the following steps. An emulsion slurry with a concentration of 20% was formulated as a precipitant by using calcium carbonate having a particle size of less than 74 tm after fine grinding. The precipitant was delivered through a pipe having a speed control device, and was added into a homogeneous reactor through a refining device at an outlet end. Meanwhile, the laterite-nickel ore acid leaching solution was also delivered through a pipe having a speed control device, and added into the homogeneous reactor through an atomizer at an outlet end. The laterite-nickel ore acid leaching solution atomized at a controlled speed and the precipitant refined at a controlled speed were homogeneously reacted in the homogeneous reactor. The pH of the homogeneous reaction system was maintained constant at 4.3, the reaction temperature was °C, the reaction time was 2.5 h, and the stirring speed was 150 rpm. The pH and temperature must be kept constant during the reaction. According to requirement for the reaction, the adding speeds of the laterite-nickel ore acid leaching solution and the precipitant were strictly controlled, to keep the reaction system balanced and stable. Finally, the post-reaction slurry was delivered to a filter through a pipe for filtration to obtain a solution with iron and aluminum removed and a sand-like iron-aluminum residue. The precipitation rates of iron and aluminum were 99.8% and 99.2% respectively. Example 4 The method for homogeneous precipitation separation of iron and aluminum from a laterite-nickel ore acid leaching solution comprises the following steps. An emulsion slurry with a concentration of 35% was formulated as a precipitant by using magnesium carbonate having a particle size of less than 74 tm after fine grinding. The precipitant was delivered through a pipe having a speed control device, and was added into a homogeneous reactor through a refining device at an outlet end. Meanwhile, the laterite-nickel ore acid leaching solution was also delivered through a pipe having a speed control device, and added into the homogeneous reactor through an atomizer at an outlet end. The laterite-nickel ore acid leaching solution atomized at a controlled speed and the precipitant refined at a controlled speed were homogeneously reacted in the homogeneous reactor. The pH of the homogeneous reaction system was maintained constant at 4.1, the reaction temperature was °C, the reaction time was 0.5 h, and the stirring speed was 50 rpm. The pH and temperature must be kept constant during the reaction. According to requirement for the reaction, the adding speeds of the laterite-nickel ore acid leaching solution and the precipitant were strictly controlled, to keep the reaction system balanced and stable. Finally, the post-reaction slurry was delivered to a filter through a pipe for filtration to obtain a solution with iron and aluminum removed and a sand-like iron-aluminum residue. The precipitation rates of iron and aluminum were 99.7% and 99.5% respectively. Example 5 The method for homogeneous precipitation separation of iron and aluminum from a laterite-nickel ore acid leaching solution comprises the following steps. An emulsion slurry with a concentration of 25% was formulated as a precipitant by using calcium carbonate having a particle size of less than 74 tm after fine grinding. The precipitant was delivered through a pipe having a speed control device, and was added into a homogeneous reactor through a refining device at an outlet end. Meanwhile, the laterite-nickel ore acid leaching solution was also delivered through a pipe having a speed control device, and added into the homogeneous reactor through an atomizer at an outlet end. The laterite-nickel ore acid leaching solution atomized at a controlled speed and the precipitant refined at a controlled speed were homogeneously reacted in the homogeneous reactor. The pH of the homogeneous reaction system was maintained constant at 4.2, the reaction temperature was °C, the reaction time was 1.5 h, and the stirring speed was 100 rpm. The pH and temperature must be kept constant during the reaction. According to requirement for the reaction, the adding speeds of the laterite-nickel ore acid leaching solution and the precipitant were strictly controlled, to keep the reaction system balanced and stable. Finally, the post-reaction slurry was delivered to a filter through a pipe for filtration to obtain a solution with iron and aluminum removed and a sand-like iron-aluminum residue. The precipitation rates of iron and aluminum were 99.9% and 99.7% respectively. In conclusion, the present invention well achieves effective separation of iron and aluminum from the laterite-nickel ore acid leaching solution. The foregoings are particular embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Variations or replacement, which can be readily envisaged by those skilled in the art within the technical scope as disclosed in the present invention, should fall within the protection scope of the present invention. Therefore, the protection scope of the present invention is defined by the protection scopes of the appended claims.

Claims

1. A method for homogeneous precipitation separation of iron and aluminum from a laterite-nickel ore acid leaching solution, characterized by comprising: Step I: precipitant preparation: finely grinding calcium carbonate or magnesium carbonate, then mixing the calcium carbonate or magnesium carbonate with water in a ratio, stirring uniformly to produce a calcium carbonate emulsion or a magnesium carbonate emulsion as a precipitant; Step II: precipitant refining at a controlled speed: delivering the precipitant to a homogeneous reactor through a pipe having a speed control device, with a refining device mounted at an outlet end, in order to add the precipitant refined at a controlled speed into the reactor; Step III: atomization of the laterite-nickel ore acid leaching solution at a controlled speed: delivering the laterite-nickel ore acid leaching solution to the homogeneous reactor through a pipe having a speed control device, with an atomizer mounted at an outlet end, in order to add the laterite-nickel ore acid leaching solution atomized at a controlled speed into the reactor; Step IV: homogeneous reaction: homogeneously reacting the laterite-nickel ore acid leaching solution atomized at a controlled speed and the precipitant refined at a controlled speed in the homogeneous reactor to obtain a post-reaction slurry; and Step V: liquid-solid separation: filtering the post-reaction slurry to achieve liquid-solid separation, to obtain a solution with iron and aluminum removed and a sand-like iron-aluminum residue.

2. The method for homogeneous precipitation separation of iron and aluminum from a laterite-nickel ore acid leaching solution according to claim 1, characterized in that, the calcium carbonate or the magnesium carbonate has a particle size of less than 74 tm after fine grinding, and the precipitant slurry has a concentration of 20%-40%.

3. The method for homogeneous precipitation separation of iron and aluminum from a laterite-nickel ore acid leaching solution according to claim 1, characterized in that, an adding speed of the precipitant in Step II is strictly controlled according to requirement for reaction, and the precipitant refining is achieved by mounting the refining device at the outlet end, wherein the refining device is a porous sprayer and has a pore diameter of 100-150 pm.

4. The method for homogeneous precipitation separation of iron and aluminum from a laterite-nickel ore acid leaching solution according to claim 1, characterized in that, the laterite-nickel ore acid leaching solution of Step III comprises the following components: 0.5-10 g/L of Fe; 0.5-10 g/L of Al; 2-8 g/L of Ni; 0.3-2 g/L of Co; 1-3 g/L of Mn; 1-20 g/L of Mg; 0.1-0.5 mol/L of H', and an anion being one or more selected from NO3, Cl- or SO4

5. The method for homogeneous precipitation separation of iron and aluminum from a laterite-nickel ore acid leaching solution according to claim 1, characterized in that, an adding speed of the laterite-nickel ore acid leaching solution in Step III is strictly controlled according to requirement for reaction, and the atomization of the laterite-nickel ore acid leaching solution is achieved by mounting the atomizer at the outlet end to ensure that the acid leaching solution can be uniformly sprayed into the reactor.

6. The method for homogeneous precipitation separation of iron and aluminum from a laterite-nickel ore acid leaching solution according to claim 1, characterized in that, for the homogeneous system reaction in Step IV, a pH is controlled in a range of 3.8-4.3 and maintained constant at a certain value, and a reaction temperature is 30-80°C, a reaction time is 0.5-3 h, and a stirring speed is 50-200 rpm, wherein the temperature is kept stable during the reaction.