1. A process for removing iron from a nickel sulfide concentrate leachate by a goethite method is characterized in that the nickel sulfide concentrate leachate contains iron ions, copper ions, nickel ions and cobalt ions, and the process comprises the following steps:

s10, adding reduced iron powder into the nickel sulfide concentrate leachate to reduce and replace copper ions in the leachate and reduce iron ions in the leachate into ferrous ions;

s20, oxidizing the nickel sulfide concentrate leachate after reduction treatment by adopting a microbubble oxidation method to generate goethite type precipitates;

and S30, carrying out solid-liquid separation on the leachate after the reaction in the step S20 is completed so as to remove the precipitate in the leachate.

2. The process of claim 1, wherein in the step S10, the amount of the fine reduced iron is added so that the concentration of the fine reduced iron in the nickel sulfide concentrate leachate is 3g/L to 5 g/L.

3. The process of claim 2, wherein in the step S10, the amount of the fine reduced iron is added so that the concentration of the fine reduced iron in the nickel sulfide concentrate leachate is 3.88 g/L.

4. The process according to any one of claims 1 to 3, wherein in the step S10, after the reduction reaction is completed, the precipitate containing copper ions is removed by solid-liquid separation.

5. The process according to claim 1, wherein the step S20 specifically comprises: heating the reduced leachate to a preset temperature, and introducing oxygen into the leachate to oxidize ferrous ions in the leachate into iron ions, and hydrolyzing the iron ions to generate goethite type precipitates.

6. The process according to claim 5, wherein the predetermined temperature is 70 ℃ to 100 ℃, the gas flow rate of oxygen gas introduced into the leachate is 0.8L/min to 1.2L/min, and the reaction time is 300min to 500 min.

7. The process according to claim 6, wherein the predetermined temperature is 80 ℃, the gas flow rate of oxygen gas introduced into the leachate is 1L/min, and the reaction time is 480 min.

8. The process according to any one of claims 5 to 7, wherein in step S20, the pH during the reaction is controlled to be 3 to 4.

Background

Nickel is an important strategic metal resource, and is widely applied to the fields of aerospace, military and civil industries due to good ductility, mechanical properties and chemical stability. In recent years, with the rapid development of the high-nickel ternary lithium battery industry, the market demand of nickel is rapidly increased. Among nickel mineral resources, polymetallic nickel sulfide concentrate is one of the most important nickel ore resources, and has a very important position in nickel resources in China and even in the world. At present, the nickel sulfide concentrate resource in the nickel ore resource which is globally explored accounts for about 40 percent. In recent years, an ultra-large magma copper-nickel sulfide ore deposit is found in the Ha-wood area in summer of Qinghai province in China, 106 million tons (average grade of 0.7%) of metal nickel of 332+333 grade is proved, and 21.77 million tons (average grade of 0.166%) of 333 grade copper resource and 3.81 million tons (average grade of 0.025%) of cobalt resource are associated, so that the ultra-large magma copper-nickel sulfide ore deposit becomes the second large nickel deposit in China. The discovery of the ultra-large nickel ore effectively relieves the current situation of the shortage of nickel resource markets in China. With the gradual development and utilization stage of the Hazaki copper-nickel sulfide ore, the development of a green and efficient nickel sulfide concentrate extraction technology has very important significance.

Common treatment methods for nickel ores comprise a pyrometallurgical process and a hydrometallurgical process, wherein iron elements are rich in nickel sulfide concentrate, so that the concentration of iron ions in leachate in the wet leaching process is high, and the recovery process flow and energy consumption of nickel are seriously affected, so that a process capable of effectively removing iron from the nickel sulfide concentrate leachate is urgently required to be explored.

Disclosure of Invention

In view of the defects of the prior art, the invention provides a goethite method iron removal process for nickel sulfide concentrate leachate, so as to solve the problem that high-concentration iron ions in the nickel sulfide concentrate leachate influence the recovery of nickel.

In order to achieve the purpose, the invention provides a goethite method iron removal process for nickel sulfide concentrate leachate, wherein the nickel sulfide concentrate leachate contains iron ions, copper ions, nickel ions and cobalt ions, and the process comprises the following steps:

s10, adding reduced iron powder into the nickel sulfide concentrate leachate to reduce and replace copper ions in the leachate and reduce iron ions in the leachate into ferrous ions;

s20, oxidizing the nickel sulfide concentrate leachate after reduction treatment by adopting a microbubble oxidation method to generate goethite type precipitates;

and S30, carrying out solid-liquid separation on the leachate after the reaction in the step S20 is completed so as to remove the precipitate in the leachate.

Preferably, in the step S10, the amount of the fine reduced iron is added so that the concentration of the fine reduced iron in the leachate of the nickel sulfide concentrate is 3g/L to 5 g/L.

Further preferably, the amount of the fine reduced iron is added so that the concentration of the fine reduced iron in the leachate of the nickel sulfide concentrate is 3.88 g/L.

Preferably, in the step S10, after the reduction reaction is completed, the precipitate containing copper ions is removed by solid-liquid separation.

Preferably, the step S20 specifically includes: heating the reduced leachate to a preset temperature, and introducing oxygen into the leachate to oxidize ferrous ions in the leachate into iron ions, and hydrolyzing the iron ions to generate goethite type precipitates.

Preferably, the preset temperature is 70-100 ℃, the gas flow of oxygen introduced into the leaching solution is 0.8-1.2L/min, and the reaction time is 300-500 min.

Further preferably, the predetermined temperature is 80 ℃, the gas flow rate of oxygen gas introduced into the leaching solution is 1L/min, and the reaction time is 480 min.

Preferably, in the step S20, the pH during the reaction is controlled to be 3-4.

According to the goethite process iron removal process for the nickel sulfide concentrate leachate, iron powder is added to reduce copper ions and iron ions in the nickel sulfide concentrate leachate, and on one hand, the iron powder can reduce and replace the copper ions in the leachate, and on the other hand, the iron ions in the leachate can be reduced into ferrous ions; then removing iron by using a microbubble oxidation method to generate goethite type precipitate. The process can efficiently remove iron ions in the nickel sulfide concentrate leachate, solves the problem that the iron ions with higher concentration influence the recovery process flow and energy consumption of nickel, and also avoids the influence on the recovery of nickel and cobalt due to the large loss of nickel and cobalt in the iron removal process. In addition, the iron slag obtained after the reaction can be directly sold as iron ore, and copper ions in the leachate are replaced in the form of sponge copper and can be directly sold, so that the utilization value of raw materials is improved.

Drawings

FIG. 1 is a flow chart of a process for removing iron from nickel sulfide concentrate leachate by goethite process according to an embodiment of the present invention;

FIG. 2 is a graph showing the relationship between the amount of iron powder added and the concentration of copper ions in a leachate during the reduction and replacement of copper ions by reduced iron powder in example 2 of the present invention;

fig. 3 is a graph showing the relationship between the pH during the reaction process of producing goethite-type precipitates by the microbubble oxidation method and the ion removal rate of metal ions in the leachate in example 3 of the present invention.

FIG. 4 is an X-ray diffraction (XRD) pattern of the iron slag in example 4 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention are described in detail below with reference to the accompanying drawings. Examples of these preferred embodiments are illustrated in the accompanying drawings. The embodiments of the invention shown in the drawings and described in accordance with the drawings are exemplary only, and the invention is not limited to these embodiments.

It should be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and/or processing steps closely related to the scheme according to the present invention are shown in the drawings, and other details not so relevant to the present invention are omitted.

The embodiment of the invention provides a goethite process iron removal process for nickel sulfide concentrate leachate, wherein the nickel sulfide concentrate leachate contains iron ions, copper ions, nickel ions and cobalt ions, and referring to figure 1, the process comprises the following steps:

step S10: and adding reduced iron powder into the nickel sulfide concentrate leachate to reduce and replace copper ions in the leachate and reduce iron ions in the leachate into ferrous ions.

Preferably, the addition amount of the reduced iron powder is such that the concentration of the reduced iron powder in the nickel sulfide concentrate leachate is 3g/L to 5 g/L.

Further preferably, the amount of the fine reduced iron is added so that the concentration of the fine reduced iron in the leachate of the nickel sulfide concentrate is 3.88 g/L.

Preferably, after the reduction reaction is completed, the precipitate containing copper ions is removed by solid-liquid separation.

The reduced iron powder reduces copper ions in the leachate, so that the copper ions are replaced in a form of sponge copper, and then the sponge copper precipitate is filtered to achieve the purpose of removing the copper ions in the leachate; in addition, the reduced iron powder also plays a role in reducing iron ions in the leachate into ferrous ions.

And step S20, oxidizing the nickel sulfide concentrate leaching solution subjected to reduction treatment by adopting a microbubble oxidation method to generate goethite type precipitates.

Specifically, the step S20 includes: heating the reduced leachate to a preset temperature, and introducing oxygen into the leachate to oxidize ferrous ions in the leachate into iron ions, and hydrolyzing the iron ions to generate goethite type precipitates.

Goethite is one of the main minerals containing hydrous oxides, generally called alpha-form monohydrated iron oxide, and its composition is alpha-Fe₂O₃·H₂The iron content of the precipitate of O or alpha-FeOOH is high, and the precipitate has little adsorption to other metal ions in the solution, so the goethite method can ensure that the recovery rate of the metallic iron is higher.

The specific reaction process of goethite method iron removal comprises oxidation reaction and hydrolysis reaction:

and (3) oxidation reaction:

4Fe²⁺+O₂+4H⁺→4Fe³⁺+2H₂O

and (3) hydrolysis reaction:

Fe³⁺+H₂O→FeOH²⁺+H⁺

FeOH²⁺+H₂O→FeOOH+2H⁺

oxygen first Fe²⁺Oxidation to Fe³⁺，Fe³⁺Forming simple hydrolysate FeOH through hydrolysis²⁺The hydrolysate is further hydrolyzed to generate FeOOH microcrystals, the FeOOH microcrystals are aggregated and grown to form goethite type solid precipitate alpha-FeOOH, wherein Fe²⁺Oxidation and Fe³⁺The hydrolysis reactions occur sequentially in a compositional series.

The oxidation reaction is carried out by oxygen, the oxidation process relates to physical processes such as gas-liquid diffusion, mass transfer and the like, the speed is low, and Fe³⁺Are extremely unstable in solution and therefore Fe³⁺FeOH is generated by hydrolysis reaction²⁺Is very fast. But if Fe is in solution³⁺Content is too high (>1g/L), Fe is easily caused³⁺Formation of Fe (OH)₃Colloidal precipitation, and therefore, in the process of removing iron by the goethite process, the key is to control Fe²⁺The oxidation rate of (2).

Preferably, the preset temperature is 70-100 ℃, the gas flow of oxygen introduced into the leaching solution is 0.8-1.2L/min, and the reaction time is 300-500 min.

Further preferably, the predetermined temperature is 80 ℃, the gas flow rate of oxygen gas introduced into the leaching solution is 1L/min, and the reaction time is 480 min.

Removing iron by goethite method, and adding Fe in the leaching solution³⁺The concentration of (B) has a large influence on iron removal, and therefore, Fe is controlled²⁺The oxidation speed is the key of removing iron by the goethite method, and the invention adopts the microbubble oxidation method to oxidize Fe²⁺Controlling the flow of oxygen to control Fe²⁺The oxidation process of (2) to solve the problem of difficult iron removal control by goethite method.

Preferably, the pH value in the reaction process is controlled to be 3-4.

In the process of removing iron by goethite method, Fe²⁺Oxidation rate of ion and [ H ]⁺]^0.25Inversely proportional, Fe in solution with increasing pH²⁺Has an increased oxidation rate of Fe³⁺The quantity of the ion hydrolysis precipitate is increased, and the iron removal efficiency is obviously improved; however, if the pH is too high, Fe is formed by oxidation³⁺Ion concentrationThe degree is more than 1g/L, which is easy to cause Fe³⁺Rapidly precipitate and form Fe (OH)₃Colloid, so that a large amount of nickel and cobalt are adsorbed, and the loss rate of the nickel and the cobalt is increased sharply.

And step S30, carrying out solid-liquid separation on the leachate after the reaction in the step S20 is completed so as to remove the precipitate in the leachate.

Specifically, the leachate after the reaction in step S20 is filtered to remove the precipitate in the leachate.

The above process for removing iron from a nickel sulfide concentrate leachate by goethite process will be described with reference to specific examples, which are not intended to limit the entirety of the process for removing iron from a nickel sulfide concentrate leachate by goethite process according to the present invention, as will be understood by those skilled in the art.

Example 1: preparation of nickel sulfide concentrate leachate

The nickel sulfide concentrate according to the embodiment of the present invention is provided by Qinghai yellow river mining company, and the main components and the phase analysis of the nickel sulfide concentrate are shown in tables 1 and 2.

Table 1: main metal component of nickel sulfide concentrate

Table 2: full element semi-quantitative analysis (XRF) of nickel sulfide concentrate

Treating the nickel sulfide concentrate by adopting an ultra-fine grinding-oxygen pressure leaching process to obtain a nickel sulfide concentrate leaching solution:

step one, size mixing: and mixing the nickel sulfide concentrate with water for size mixing to form nickel sulfide concentrate slurry with the concentration of 25%.

Step two, fine grinding: placing the nickel sulfide concentrate slurry into a ball mill for ball milling to form ultra-fine milled nickel sulfide concentrate; wherein, the ball milling time is 6min, and the mass ratio of the ore material with the granularity of below 400 meshes of the superfine grinding nickel sulfide concentrate is more than 90 percent.

Step three, leaching: placing the superfine grinding nickel sulfide concentrate into a reaction furnace, adding a sulfuric acid solution with the concentration of 50g/L as a leaching solution, and introducing oxygen with the pressure of 1.4Mpa into the sulfuric acid solution to leach metal elements in the superfine grinding nickel sulfide concentrate; wherein the solid-to-liquid ratio of the superfine grinding nickel sulfide concentrate to the sulfuric acid solution is 200g/L, the leaching temperature is 110 ℃, and the leaching time is 300 min.

And after the leaching reaction of the superfine grinding nickel sulfide concentrate is finished, filtering the superfine grinding nickel sulfide concentrate to obtain a nickel sulfide concentrate leaching solution, wherein the concentrations of iron, nickel, cobalt and copper in the nickel sulfide concentrate leaching solution are 31.5g/L (0.563mol/L), 17.2g/L (0.29mol/L), 0.61g/L (0.01mol/L) and 2.94g/L (0.0459mol/L), respectively.

Example 2: influence of addition amount of reduced iron powder on iron removal process

Step one, adding reduced iron powder to the nickel sulfide concentrate leachate obtained in example 1 to reduce copper ions in the leachate, so that the copper ions are replaced in the form of copper sponge, reducing the iron ions in the leachate to ferrous ions, and after the reduction reaction is completed, filtering to remove the copper sponge precipitate.

Step two, oxidizing the nickel sulfide concentrate leaching solution subjected to reduction treatment by adopting a microbubble oxidation method to generate goethite type precipitates: heating the reduced leachate to 80 ℃, and introducing oxygen into the leachate to oxidize ferrous ions in the leachate into iron ions, and further hydrolyzing the iron ions to generate goethite type precipitates, wherein the gas flow rate of introducing the oxygen into the leachate is 1L/min, and the reaction time is 480 min.

And step three, filtering the leachate after the reaction in the step two is finished so as to remove the precipitate in the leachate.

And under the conditions, the influence of the addition of the reduced iron powder on the goethite process iron removal process of the nickel sulfide concentrate leachate is examined. Fig. 2 is a graph showing the relationship between the amount of iron powder added and the concentration of copper ions in the process of reducing and replacing copper ions by reduced iron powder in the leachate of nickel sulfide concentrate, and the experimental results obtained under the above conditions are shown in fig. 2.

As can be seen from fig. 2, when the amount of iron powder added is such that the concentration of reduced iron powder in the leachate of nickel sulfide concentrate reaches 3.0g/L or more, the concentration of copper ions in the solution is greatly reduced, so the amount of iron powder added in the solution of the present invention is such that the concentration of reduced iron powder in the leachate of nickel sulfide concentrate is preferably 3.0g/L to 5.0 g/L; when the addition amount of the iron powder is such that the concentration of the reduced iron powder in the nickel sulfide concentrate leachate is 3.88g/L, the concentration of copper ions in the solution is reduced from 2940mg/L to 3ppm, at this time, the copper ions in the leachate can be removed completely theoretically, the addition amount of the iron powder is increased continuously, and the concentration of the copper ions is basically unchanged, so the addition amount of the reduced iron powder is selected to be the optimum concentration of the reduced iron powder in the nickel sulfide concentrate leachate of 3.88 g/L.

Example 3: influence of pH during the reaction on the iron removal process

Step one, adding reduced iron powder into the nickel sulfide concentrate leachate obtained in example 1 to reduce copper ions in the leachate, so that the copper ions are replaced in the form of copper sponge, reducing the iron ions in the leachate into ferrous ions, and after the reduction reaction is finished, filtering to remove the copper sponge precipitate; wherein the addition amount of the reduced iron powder is such that the concentration of the reduced iron powder in the nickel sulfide concentrate leachate is 3.88 g/L.

Step two, oxidizing the nickel sulfide concentrate leaching solution subjected to reduction treatment by adopting a microbubble oxidation method to generate goethite type precipitates: heating the reduced leachate to 80 ℃, and introducing oxygen into the leachate to oxidize ferrous ions in the leachate into iron ions, and hydrolyzing the iron ions to generate goethite type precipitates; wherein the gas flow of oxygen introduced into the leaching solution is 1L/min, and the reaction time is 480 min.

And step three, filtering the leachate after the reaction in the step two is finished so as to remove the precipitate in the leachate.

And under the conditions, the influence of the pH value in the reaction process on the goethite deironing process of the nickel sulfide concentrate leaching solution is examined. Fig. 3 is a graph showing the relationship between the pH and the ion removal rate of each metal ion in the leachate during the reaction process of producing the goethite-type precipitate by the microbubble oxidation method, and the experimental results obtained under the above conditions are shown in fig. 3.

As can be seen from fig. 3, as the pH of the reaction increases from 1.5 to 3, the removal efficiency of iron ions in the nickel sulfide concentrate leachate increases from 36.5% to 92%, and the concentration of nickel ions and cobalt ions in the leachate is basically unchanged, and the ion removal rate is close to 0 and remains unchanged. When the pH of the reaction is further increased to 5, the removal efficiency of iron ions is substantially maintained, but the ion removal rate of nickel ions and cobalt ions is sharply increased, and the ion loss rate thereof is sharply increased. This is due to Fe²⁺Oxidation rate of [ H ]⁺]^0.25Inversely proportional, Fe in solution with increasing pH²⁺Accelerated oxidation of ions, Fe³⁺The number of the hydrolyzed precipitates of the ions is increased, and the iron removal efficiency is obviously improved; however, when the pH is 5, Fe is generated by oxidation because the pH is too high³⁺The ion concentration is more than 1g/L, resulting in Fe³⁺Rapidly precipitate and form Fe (OH)₃The colloid adsorbs a large amount of nickel ions and cobalt ions, resulting in a sharp increase in the loss rate of nickel ions and cobalt ions. Therefore, when the goethite method is adopted for removing iron, the pH value in the reaction process of controlling the microbubble oxidation method to generate goethite type precipitates is optimally controlled to be 3-4.

Example 4: optimized technological condition of goethite method iron removal technology of nickel sulfide concentrate leachate

Step one, adding reduced iron powder into the nickel sulfide concentrate leachate obtained in example 1 to reduce copper ions in the leachate, so that the copper ions are replaced in the form of copper sponge, reducing the iron ions in the leachate into ferrous ions, and after the reduction reaction is finished, filtering to remove the copper sponge precipitate; wherein the addition amount of the reduced iron powder is such that the concentration of the reduced iron powder in the nickel sulfide concentrate leachate is 3.88 g/L.

Step two, oxidizing the nickel sulfide concentrate leaching solution subjected to reduction treatment by adopting a microbubble oxidation method to generate goethite type precipitates: heating the reduced leachate to 80 ℃, and introducing oxygen into the leachate to oxidize ferrous ions in the leachate into ferric ions, and hydrolyzing the ferric ions to generate goethite type precipitates, wherein the gas flow of introducing the oxygen into the leachate is 1L/min, the reaction time is 480min, and the pH value in the reaction process is 3.

And step three, filtering the leachate after the reaction in the step two is finished so as to remove the precipitate in the leachate.

And filtering the leachate to obtain iron slag precipitate and nickel sulfide concentrate leachate, wherein the content of iron in the nickel sulfide concentrate leachate is 0.012 g/L.

The iron slag obtained after filtering the nickel sulfide concentrate leaching solution is subjected to XRF full-element semi-quantitative analysis, and the XRF full-element semi-quantitative analysis result of the iron slag is shown in Table 3.

Table 3: full element semi-quantitative analysis of iron slag (XRF)

As is clear from Table 3, the main elements in the iron slag were Fe (65.7%), O (31.3%) and S (1.90%), and the other elements were Ni, Co, Si, Al, Cl, Ca, etc.

Further, an ICP-OES inductively coupled plasma emission spectrometer was used to perform quantitative analysis on the iron slag, and the results of quantitative analysis of the main metal elements in the iron slag and analysis of the leachate components are shown in table 4.

Table 4: quantitative analysis (ICP-OES) of main metal elements in iron slag and analysis of leachate components

As can be seen from table 4, the Fe content in the iron slag can reach 55.9%, the iron slag can be sold as iron ore directly, and the Ni and Co contents are only 0.23% and 0.03%. The concentrations of Fe, Ni and Co in the nickel sulfide concentrate leachate without iron removal by the goethite method are respectively 31.5g/L, 17.2g/L and 0.61g/L, and after iron removal is carried out on the nickel sulfide concentrate leachate by the goethite method, the concentrations of Fe, Ni and Co in the nickel sulfide concentrate leachate are respectively 0.012g/L, 16.38g/L and 0.607g/L, at the moment, the iron removal rate in the nickel sulfide concentrate leachate reaches more than 99%, the loss of nickel is less than 3%, and the cobalt is almost free of loss.

FIG. 4 is an X-ray diffraction (XRD) pattern of the iron slag, and it can be seen from FIG. 4 that the iron slag obtained by the above process is a single-phase α -FeOOH.

According to the goethite process iron removal process for the nickel sulfide concentrate leachate, iron powder is added to reduce copper ions and iron ions in the nickel sulfide concentrate leachate, and on one hand, the iron powder can reduce and replace the copper ions in the leachate, and on the other hand, the iron ions in the leachate can be reduced into ferrous ions; the removal rate of iron in the nickel sulfide concentrate leachate can reach more than 99 percent by adopting a microbubble oxidation method to generate goethite type precipitate for iron removal, the loss of nickel is less than 3 percent, and the loss of cobalt is almost zero. Therefore, the process can efficiently remove the iron ions in the nickel sulfide concentrate leachate, solves the problem that the iron ions with higher concentration influence the recovery process flow and energy consumption of nickel, and also avoids the influence on the recovery of nickel and cobalt due to the large loss of nickel and cobalt in the iron removal process. In addition, the iron content in the iron slag obtained after the reaction is finished reaches more than 55 percent, the iron slag can be directly sold as iron ore, and copper ions in the leachate are replaced in the form of sponge copper and can be directly sold, so that the utilization value of raw materials is favorably improved.

The foregoing is directed to embodiments of the present application and it is noted that numerous modifications and adaptations may be made by those skilled in the art without departing from the principles of the present application and are intended to be within the scope of the present application.