A method for desulfurization of laterite nickel ore

Abstract

The present invention provides a method for desulfurization of laterite nickel ore, comprising: step S1, mixing laterite nickel ore with water, stirring and slurrying to obtain slurry; step S2, adding alkali to the slurry to adjust pH, stirring and reacting for a period of time, filtering to obtain desulfurized and deslimed laterite nickel ore and washing water; step S3, adding nitric acid to the laterite nickel ore after desulfurization and desliming for pressure leaching, filtering to obtain leachate and iron concentrate; step S4, adding a precipitant to the leachate, reacting and aging to obtain a nickel cobalt hydroxide product and a precipitated mother liquor; step S5, evaporating, concentrating and crystallizing the precipitated mother liquor, and decomposing the crystalline product to obtain magnesium oxide and nitrogen oxides, and the nitrogen oxides are used for synthesizing nitric acid for recycling. The method of the present invention has an efficient and concise process, and has the advantages of being green, low-carbon and environmentally friendly, and has great social and economic value.

Description

Technical Field

[0001] The invention relates to the technical field of chemical metallurgy, and in particular to a method for desulfurizing laterite nickel ore. Background Art

[0002] With the continuous expansion of the demand for nickel metal, the supply demand for raw material laterite nickel ore has also gradually expanded; and most of the current laterite nickel ores contain sulfur elements, so whether it is smelting or leaching, it is necessary to consider pre-treatment of the sulfur element. The amount of slag produced by pressure leaching and acid leaching of laterite nickel ore is large. This type of iron slag is mostly used as steelmaking raw material, and the sulfur element contained in it greatly affects the smelting of iron. Therefore, the treatment of the raw material (latite nickel ore) with sulfur elements can not only reduce the processing cost of laterite nickel ore, but also reduce the sulfur element in the acid leaching slag of laterite nickel ore to make it meet the smelting feed index. The treated laterite nickel ore acid leaching slag is used for smelting to improve the utilization rate of metals, and the acid leaching slag is used as a resource, which reduces the pressure of acid leaching slag on the environment and realizes the harmless treatment of acid leaching slag. Summary of the invention

[0003] The present invention provides a method for desulfurizing laterite nickel ore, thereby obtaining laterite nickel ore raw materials with low sulfur content; the method can solve the problems of difficult smelting or leaching treatment and high treatment cost caused by sulfur element, and the price of raw and auxiliary materials is low, thereby reducing production costs; the process flow is efficient and simple, and has the advantages of being green, low-carbon and environmentally friendly, and has great social and economic value.

[0004] Specifically, the present invention provides the following technical solutions:

[0005] A method for desulfurization of laterite nickel ore, comprising:

[0006] Step S1, mixing laterite nickel ore with water, stirring and slurrying to obtain slurry.

[0007] Step S2, adding alkali to the slurry to adjust the pH, stirring and reacting for a period of time, filtering to obtain the desulfurized and desludified laterite nickel ore and washing water; during the stirring process, the fine mud on the surface of the ore particles is also washed.

[0008] Step S3, adding nitric acid to the laterite nickel ore after desulfurization and desludging for pressure leaching, and filtering to obtain the leachate and iron concentrate.

[0009] Step S4, adding a precipitant to the leaching solution to obtain a nickel cobalt hydroxide product and a precipitation mother liquor.

[0010] Step S5, evaporating and concentrating the precipitated mother liquor to crystallize, and decomposing the crystal product to obtain magnesium oxide and nitrogen oxides, which are used for synthesizing nitric acid and recycled.

[0011] Optionally, in step S1, laterite nickel ore and water are mixed at a liquid-to-solid mass ratio of 2 to 6:1.

[0012] Optionally, the main chemical components of the laterite nickel ore raw material include: Co 0.2-0.3wt%, Ni 0.5-3.0wt%, Fe 40-50wt%, Al 3.0-5.0wt%, Mn 1.0-3.0wt%, Ca 0.06-0.07wt%, Mg 1-3wt%, Cr 1-3wt%, Si 2.5-3wt%, and S 0.2%-2wt%.

[0013] Optionally, in step S1, during the stirring slurrying process, the stirring time is 0.5 to 2 hours and the temperature is 20 to 50°C.

[0014] Optionally, in step S2, the base is selected from one or more of sodium carbonate, sodium hydroxide, potassium hydroxide, urea, ammonia water, and sodium bicarbonate.

[0015] Optionally, in step S2, the pH of the slurry is adjusted to 8-11, the stirring reaction temperature is 20-50° C., and the reaction time is 0.5-2 hours. In this preferred embodiment, sulfur in laterite nickel ore can be separated by this step.

[0016] Optionally, in step S3, the amount of nitric acid used for pressure leaching is 0.4-0.8 times the mass of the raw material, the reaction temperature is 160-200°C, the reaction time is 1-3h, and the liquid-solid mass ratio is 2:1-6:1. Sulfur in laterite nickel ore mainly exists in the form of sulfate or sulfide, is acidic in water, and reacts more fully under alkaline conditions. At the same time, the raw material consumes a large amount of water during the washing process. If the washing temperature is too high, the initial processing cost is greatly increased. In order to reduce production costs, the reaction is carried out under low temperature conditions. The main reason for selecting the reaction time within the range of 0.5-2h is that if the reaction time is too short, the sulfur removal effect is not good, and the washing time process increases the processing cost while reducing the processing volume, which does not meet the process requirements.

[0017] Optionally, in step S4, the precipitant is magnesium oxide, the amount of magnesium oxide is 1.1-1.5 times the molar amount of the metal element in the acid leaching solution, the precipitation reaction temperature is 50-80°C, the reaction time is 0.5-2h, and the aging time is 0.5-2h.

[0018] Optionally, in step S5, the decomposition temperature is 500-700°C.

[0019] The beneficial effects brought about by the technical solution provided by the present invention include at least:

[0020] The method of the present invention uses laterite nickel ore as raw material, and performs washing reaction under normal pressure to separate sulfur and sulfur-containing compounds, thereby obtaining laterite nickel ore raw materials with low sulfur content and mud content, which not only reduces the processing difficulty and cost of the laterite nickel ore raw materials, but also can enrich the valuable metals in the laterite nickel ore. In addition, the washing method is adopted, the price of auxiliary materials is low, the process cost is reduced, the reaction is fast, and the efficiency is high. The materials used in the present invention are all common industrial products, which are easy to purchase and cheap; the entire process is short, the cost is low, the source of raw materials is wide, it is easy to scale up, and it is easy to realize industrialization. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 The present invention is a process flow chart of a method for desulfurization and desludging of laterite nickel ore. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention more clear, the technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] The analysis results of the various components of the laterite nickel ore high iron slag raw material used in the following examples are shown in Table 1.

[0025] Table 1 Analysis results of main components of laterite nickel ore raw materials

[0026]

[0027] Example 1

[0028] like Figure 1 As shown, a method for desulfurization of laterite nickel ore specifically comprises the following steps:

[0029] S1: slurrying the laterite nickel ore with water at a liquid-to-solid mass ratio of 4:1;

[0030] S2: Add 105% of the theoretical amount (based on the sulfur content in the laterite nickel ore) of sodium carbonate to the slurry in S1, adjust the pH of the slurry in S1 to 8, carry out stirring and washing reaction for 0.5h, the reaction temperature is room temperature, filter, and obtain desulfurized laterite nickel ore and sulfur-containing washing water.

[0031] S3: adding nitric acid in an amount of 0.5 times the mass of the raw material to the above-mentioned laterite nickel ore after desulfurization and desludging, and performing pressure leaching at a reaction temperature of 180° C., a reaction time of 2 h, and a liquid-to-solid ratio of 3:1, and filtering to obtain a leachate and an iron concentrate;

[0032] S4: Add magnesium oxide in an amount of 1.25 times the molar amount of the metal element in the acid leaching solution to the above leaching solution, at a reaction temperature of 60°C, a reaction time of 1 hour, and an aging time of 0.5 hours. Precipitate the nickel and cobalt in the leaching solution to obtain a nickel-cobalt hydroxide product and a precipitated mother solution;

[0033] S5: The above-mentioned precipitation mother liquor is evaporated, concentrated and crystallized, and the crystallized product is calcined and decomposed at 500° C. for 2 hours. Magnesium oxide and nitrogen oxides are decomposed to obtain magnesium oxide, and the nitrogen oxides are synthesized into nitric acid for recycling.

[0034] Table 1.1 Analysis results of main components of laterite nickel ore after washing

[0035]

[0036] Table 1.2 Analysis results of main components of iron ore concentrate

[0037]

[0038] The sulfur content in the desulfurized laterite nickel ore obtained in this embodiment is 0.012%, and the sulfur removal rate is 97.6%. The calculation formula is as follows:

[0039]

[0040] (1) Where S 0 is: the sulfur content in the laterite nickel ore raw material; S 1 =Sulfur content of laterite nickel ore after washing

[0041] Example 2

[0042] like Figure 1 As shown, a method for desulfurization of laterite nickel ore specifically comprises the following steps:

[0043] S1: slurrying the laterite nickel ore with water at a liquid-to-solid mass ratio of 5:1;

[0044] S2: Add 125% of the theoretical amount (based on the sulfur content in the laterite nickel ore) of sodium carbonate to the slurry in S1, adjust the pH of the slurry in S1 to 9, carry out stirring and washing reaction for 1 hour at a reaction temperature of 30°C, filter, and obtain desulfurized laterite nickel ore and sulfur-containing washing water.

[0045] S3: adding nitric acid in an amount of 0.5 times the mass of the raw material to the above-mentioned laterite nickel ore after desulfurization and desludging, and performing pressure leaching at a reaction temperature of 180° C., a reaction time of 2 h, and a liquid-to-solid ratio of 3:1, and filtering to obtain a leachate and an iron concentrate;

[0046] S4: Add magnesium oxide in an amount of 1.25 times the molar amount of the metal element in the acid leaching solution to the above leaching solution, at a reaction temperature of 60°C, a reaction time of 1 hour, and an aging time of 0.5 hours. Precipitate the nickel and cobalt in the leaching solution to obtain a nickel-cobalt hydroxide product and a precipitated mother solution;

[0047] S5: The above-mentioned precipitation mother liquor is evaporated, concentrated and crystallized, and the crystallized product is calcined and decomposed at 500° C. for 2 hours. Magnesium oxide and nitrogen oxides are decomposed to obtain magnesium oxide, and the nitrogen oxides are synthesized into nitric acid for recycling.

[0048] Table 2.1 Analysis results of main components of laterite nickel ore after washing

[0049]

[0050] Table 2.2 Analysis results of main components of iron ore concentrate

[0051]

[0052] The sulfur content in the desulfurized laterite nickel ore obtained in this example is 0.0015%, and the sulfur removal rate is 99.7%. It can be seen that the amount of sodium carbonate participating in the reaction increases after the pH rises, and after the reaction time is extended to 1 hour, the reaction is more complete and the desulfurization is more thorough.

[0053] Comparative Example 1

[0054] like Figure 1 As shown, a method for desulfurization of laterite nickel ore specifically comprises the following steps:

[0055] S1: slurrying the laterite nickel ore with water at a liquid-to-solid mass ratio of 4:1;

[0056] S2: Add 95% of the theoretical amount (based on the sulfur content in the laterite nickel ore) of sodium carbonate to the slurry in S1, adjust the pH of the slurry in S1 to 7, carry out stirring and washing reaction for 0.5h, the reaction temperature is room temperature, filter, and obtain desulfurized laterite nickel ore and sulfur-containing washing water.

[0057] S3: adding nitric acid in an amount of 0.5 times the mass of the raw material to the above-mentioned laterite nickel ore after desulfurization and desludging, and performing pressure leaching at a reaction temperature of 180° C., a reaction time of 2 h, and a liquid-to-solid ratio of 3:1, and filtering to obtain a leachate and an iron concentrate;

[0058] S4: Add magnesium oxide in an amount of 1.25 times the molar amount of the metal element in the acid leaching solution to the above leaching solution, at a reaction temperature of 60°C, a reaction time of 1 hour, and an aging time of 0.5 hours. Precipitate the nickel and cobalt in the leaching solution to obtain a nickel-cobalt hydroxide product and a precipitated mother solution;

[0059] S5: The above-mentioned precipitation mother liquor is evaporated, concentrated and crystallized, and the crystallized product is calcined and decomposed at 500° C. for 2 hours. Magnesium oxide and nitrogen oxides are decomposed to obtain magnesium oxide, and the nitrogen oxides are synthesized into nitric acid for recycling.

[0060] Table 3.1 Analysis results of main components of laterite nickel ore after washing

[0061]

[0062] Table 3.2 Analysis results of main components of iron ore concentrate

[0063]

[0064] The sulfur content in the desulfurized laterite nickel ore obtained in this embodiment is 0.1%, and the sulfur removal rate is 80%.

[0065] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for desulfurization of laterite nickel ore, characterized in that: include: Step S1, mixing laterite nickel ore with water, stirring and slurrying to obtain slurry; Step S2, adding alkali to the slurry to adjust the pH, stirring the reaction for a period of time, and filtering to obtain the desulfurized and desludified laterite nickel ore and wash water; Step S3, adding nitric acid to the desulfurized and desludified laterite nickel ore for pressure leaching, and filtering to obtain a leachate and an iron concentrate; Step S4, adding a precipitant to the leaching solution, reacting and aging to obtain a nickel cobalt hydroxide product and a precipitated mother solution; Step S5, evaporating and concentrating the precipitated mother liquor to obtain crystals, and decomposing the crystal products to obtain magnesium oxide and nitrogen oxides, wherein the nitrogen oxides are used for synthesizing nitric acid and recycled; The main chemical components of laterite nickel ore raw materials include: Co 0.2-0.5wt%, Ni 0.5-3.0wt%, Fe40-50wt%, Al 3.0-5.0wt%, Mn 1.0-3.0wt%, Ca 0.06-0.07wt%, Mg 1-3wt%, Cr 1-3wt%, Si 2.5-3wt%, S 0.2%-2wt%; In step S2, the alkali is selected from one or more of sodium carbonate, sodium hydroxide, potassium hydroxide, urea, ammonia water, and sodium bicarbonate; the pH of the slurry is adjusted to 8-11, the stirring reaction temperature is room temperature, and the reaction time is 0.5-2h; sulfur in laterite nickel ore mainly exists in the form of sulfate or sulfide and is acidic in water.

2. The method according to claim 1, characterized in that In step S1, laterite nickel ore and water are mixed in a liquid-to-solid mass ratio of 2 to 6:

1.

3. The method according to claim 1, characterized in that In step S1, during the stirring slurrying process, the stirring time is 0.5 to 2 hours and the temperature is 20 to 50°C.

4. The method according to claim 1, characterized in that: In step S3, the reaction temperature of the pressure leaching is 160-200° C., the reaction time is 1-3 hours, and the liquid-to-solid ratio is 2:1-6:

1.

5. The method according to claim 4, characterized in that The reaction temperature is 180°C, the reaction time is 2h, and the liquid-to-solid ratio is 3:

1.

6. The method according to claim 1, characterized in that In step S4, the precipitant is magnesium oxide, the amount of magnesium oxide is 1.1-1.5 times the molar amount of the metal element in the acid leaching solution, the precipitation reaction temperature is 50-80°C, the reaction time is 0.5-2h, and the aging time is 0.5-2h.

7. The method according to claim 6, characterized in that The precipitation reaction temperature was 65°C and the reaction time was 1.5 h.

8. The method according to claim 1, characterized in that: In step S5, the decomposition temperature is 500-700°C.

9. The method according to claim 8, characterized in that The decomposition temperature is 600℃.

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