Method for improving filtering performance of aluminum precipitation material in laterite-nickel ore nitric acid system
By adding sulfate additives and nanofiltration membrane treatment to the laterite nickel ore nitric acid system, the problems of difficult aluminum hydroxide filtration and high nickel and cobalt loss rate were solved, achieving efficient aluminum hydroxide filtration and nickel and cobalt recovery, thus improving production efficiency and economy.
Patent Information
- Application Number
- CN202511482136.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-16
- Publication Date
- 2026-03-06
AI Technical Summary
In the nitric acid process of laterite nickel ore, aluminum hydroxide is difficult to filter and easily forms colloids, resulting in a high loss rate of nickel and cobalt, which affects the overall yield of nickel and cobalt and the economics of the project.
Sulfate additives, such as magnesium sulfate, are added during the homogeneous aluminum precipitation process. The sulfate is then separated by nanofiltration membrane and recycled. The precipitant and reaction conditions are optimized, and the pH and temperature are controlled to generate high-purity aluminum hydroxide and reduce colloid formation.
It significantly improved the filtration speed of aluminum hydroxide from 100 mL/min to 700 mL/min, reduced the nickel and cobalt loss rate to below 2%, enhanced the processability, and reduced equipment investment and production costs.
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Figure CN121609377A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the interdisciplinary fields of chemical engineering and metallurgy, and in particular to a method for preparing aluminum hydroxide in a lateritic nickel ore nitric acid system, improving the filtration speed of aluminum hydroxide, and nickel-cobalt inclusions. Background Technology
[0002] In daily life, fields such as construction, transportation, electrical appliances, and communications mostly utilize organic polymer materials, which are often highly flammable and pose a significant fire hazard. Aluminum hydroxide granules can be incorporated into these flammable materials as a flame retardant. Aluminum hydroxide decomposes at high temperatures, releasing water of crystallization. This reaction absorbs heat, inhibiting polymer combustion, and the resulting water vapor dilutes flammable and toxic gases. After the reaction, an alumina protective layer is formed, covering the polymer surface and acting as a flame retardant by isolating it from oxygen. In the laterite nickel ore nitric acid process, a large amount of aluminum hydroxide is produced during the aluminum precipitation process. Due to system and cost considerations, magnesium-based precipitants such as magnesium oxide, magnesium hydroxide, and magnesium carbonate are typically used. During precipitation, the intrinsic physicochemical properties of the precipitant cause aluminum hydroxide in the system to easily form colloids, leading to difficulties in filtration and disrupting continuous production. Furthermore, the formation of aluminum hydroxide colloids causes nickel and cobalt to adsorb onto the colloids, resulting in nickel and cobalt loss. Additionally, the relatively weak solubility of magnesium-based precipitants can cause localized over-alkaliness during precipitation, leading to further nickel and cobalt precipitation loss. The losses of nickel and cobalt caused by these two parts are very large, which greatly reduces the overall yield of nickel and cobalt and the economics of the project. Summary of the Invention
[0003] This invention proposes a method to improve material filtration and reduce nickel-cobalt inclusions in the alumina precipitation process using a lateritic nickel ore nitric acid system. A novel additive is added during the homogeneous alumina precipitation process, successfully solving the problems of difficult filtration and easy formation of colloids in the homogeneous alumina precipitation slurry. This provides a practical solution for the technological application of aluminum hydroxide. Specifically:
[0004] A method for improving the filtration performance of aluminum-precipitating materials in a laterite nickel ore nitric acid system includes the following steps:
[0005] S1: Laterite nickel ore is subjected to pressure acid leaching with nitric acid to obtain acid leaching slurry. The acid leaching slurry is subjected to pre-neutralization and iron precipitation reaction with magnesium oxide to obtain iron concentrate and iron precipitation mother liquor.
[0006] S2: The mother liquor of iron precipitation is reacted with precipitant and additives at a certain temperature to produce aluminum hydroxide. During the reaction, precipitant is used to maintain the reaction pH at about 4.2~4.8. After the reaction is completed, the mixture is aged for a certain period of time. After aging, the solid-liquid mixture is filtered and washed to obtain aluminum hydroxide and mother liquor of aluminum precipitation.
[0007] S3: Add magnesium oxide to the aluminum precipitation mother liquor and carry out a homogeneous precipitation reaction at a certain temperature to generate nickel cobalt hydroxide (i.e., MHP). After the reaction is completed, age for a certain period of time, filter after aging, and obtain MHP and nickel cobalt precipitation mother liquor.
[0008] S4: The above nickel-cobalt precipitate mother liquor is processed through a membrane to obtain a magnesium nitrate solution and a sulfate solution. The sulfate solution is recycled and applied to the homogeneous aluminum precipitation section.
[0009] In step S1 of the present invention, preferably, the acid-ore ratio of lateritic nickel ore to nitric acid is 0.41~0.43:1 (i.e., the mass ratio of lateritic nickel ore to pure nitric acid), the reaction temperature of the acid leaching process is 200~210℃, the acid leaching pressure is 1.4~1.8 MPa, and the acid leaching time is 1-1.5 h.
[0010] In step S1 of the present invention, preferably, the pH of the pre-neutralization reaction of aged iron is 2.5-2.8, the reaction temperature is 80-90℃, and the aging time is 0.5-1h.
[0011] In step S1 of the present invention, preferably, the composition of the iron precipitating mother liquor is Co: 0.51 g / L, Ni: 4.20 g / L, Fe: 0.01 g / L, Al: 16.50 g / L, Mn: 0.036 g / L, Ca: 1.58 g / L, and Mg: 35.98 g / L.
[0012] In step S2 of the present invention, preferably, the precipitant is one or more of magnesium oxide, magnesium carbonate, calcium oxide, and calcium carbonate.
[0013] In step S2 of the present invention, preferably, the additive is selected from one or more of magnesium sulfate, calcium sulfate, barium sulfate, sulfate, etc.
[0014] In step S2 of the present invention, preferably, the amount of the additive is 0.1 to 1 times the molar amount of aluminum in the iron precipitate mother liquor.
[0015] In step S2 of the present invention, preferably, the pH of the homogeneous alumina precipitation reaction is 4.2~4.8.
[0016] In step S2 of the present invention, preferably, the homogeneous aluminization reaction temperature is 60~70℃.
[0017] In step S3 of the present invention, preferably, the reaction pH of the nickel-cobalt hydroxide precipitation process is 6.5~7.0, the reaction temperature is 60~70℃, and the aging time is 1~2h.
[0018] In step S4 of the present invention, preferably, the membrane treatment technology used for the nickel-cobalt mother liquor is nanofiltration membrane treatment, which separates the sulfate from the nitric acid system and recycles the separated sulfate in the homogeneous aluminum precipitation section.
[0019] The beneficial effects of the technical solution provided by this invention include at least the following:
[0020] This invention provides a homogeneous aluminate precipitation sulfate additive, which increases the filtration rate of aluminum hydroxide slurry prepared in a nitric acid system from 100 mL / min to 700 mL / min, a seven-fold increase, thus enhancing the processability of aluminum hydroxide. Secondly, the addition of the additive significantly reduces the formation of colloids during homogeneous aluminate precipitation, decreasing the adsorption of nickel, cobalt, manganese, magnesium, and nitrate ions from the nitric acid system by aluminum hydroxide, thereby reducing the loss rate of valuable metals such as nickel, cobalt, and manganese. The sulfate additive added in the homogeneous aluminate precipitation stage is subsequently treated by a nanofiltration membrane to separate the sulfate from the nitric acid system and reuse it in the homogeneous aluminate precipitation stage, achieving sulfate recycling. The materials used in this invention are all common industrial products, readily available and inexpensive; the entire process is simple, low-cost, uses widely available raw materials, is environmentally friendly, and easily scalable for industrial production. Attached Figure Description
[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0022] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation
[0023] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.
[0024] The elemental analysis results of the laterite nickel ore used in the following examples are shown in Table 1.
[0025] Table 1. Elemental analysis results of laterite nickel ore
[0026]
[0027] Example 1
[0028] like Figure 1 As shown, a method for preparing aluminum hydroxide in a nitric acid system and improving the filtration rate of aluminum hydroxide specifically includes the following steps:
[0029] S1: Lateritic nickel ore and nitric acid were subjected to pressurized acid leaching at an acid-to-ore ratio of 0.41:1. The leaching temperature was 210℃, the leaching pressure was 1.6 MPa, and the leaching time was 1 hour to obtain an acid leaching slurry. A 20% magnesium oxide slurry was prepared and pre-neutralized with the acid leaching slurry for iron precipitation. The iron precipitation temperature was 90℃, the pH was adjusted to 2.5, and after aging for 0.5 hours, the mixture was filtered to obtain iron concentrate and iron precipitation mother liquor.
[0030] S2: The above-mentioned iron precipitation mother liquor and magnesium oxide slurry are subjected to homogeneous precipitation reaction at 65°C to generate aluminum hydroxide. During the reaction, the reaction pH is maintained at around 4.2~4.8. After the reaction is completed, the mixture is aged for 0.5h and filtered to obtain aluminum hydroxide and aluminum precipitation mother liquor. The aluminum hydroxide filter cake is washed once at a liquid-solid ratio of 6.5:1.
[0031] S3: Add magnesium oxide as a precipitant to the above aluminum precipitation mother liquor and carry out a homogeneous precipitation reaction at 65°C to generate nickel cobalt hydroxide. During the reaction, maintain the reaction pH at around 6.5~7.0. After the reaction is completed, age for 0.5h and filter to obtain nickel cobalt hydroxide and nickel cobalt precipitation mother liquor.
[0032] The experimental results of aluminum hydroxide obtained through the above steps are shown in Table 2.
[0033] Table 2 Elemental analysis results of aluminum hydroxide
[0034]
[0035] As can be seen from Table 2, the aluminum hydroxide prepared without the addition of additives in the homogeneous aluminum precipitation process has a strong adsorption capacity and will adsorb nickel, cobalt, manganese, magnesium, nitrate and other ions in the nitric acid system, resulting in the loss of valuable metals such as nickel, cobalt and manganese. Among them, the loss of nickel is as high as 30%, which reduces the purity of aluminum hydroxide itself. In addition, the aluminum hydroxide prepared without the addition of additives is easy to form a colloid, resulting in a slurry filtration speed of only 100 mL / min, which is extremely slow.
[0036] Example 2
[0037] S1: Lateritic nickel ore and nitric acid were subjected to pressurized acid leaching at an acid-to-ore ratio of 0.41:1. The leaching temperature was 210℃, the leaching pressure was 1.6 MPa, and the leaching time was 1 hour to obtain an acid leaching slurry. A 20% magnesium oxide slurry was prepared and pre-neutralized with the acid leaching slurry for iron precipitation. The iron precipitation temperature was 90℃, the pH was adjusted to 2.5, and after aging for 0.5 hours, the mixture was filtered to obtain iron concentrate and iron precipitation mother liquor.
[0038] S2: First, mix the above-mentioned iron precipitation mother liquor with magnesium sulfate. The amount of magnesium sulfate is 0.20 times the molar amount of aluminum in the iron precipitation mother liquor. Then, carry out a homogeneous precipitation reaction with magnesium oxide slurry at 65°C to generate aluminum hydroxide. During the reaction, maintain the reaction pH at around 4.2~4.8. After the reaction is completed, age for 0.5 hours and filter to obtain aluminum hydroxide and aluminum precipitation mother liquor. The aluminum hydroxide filter cake is washed once at a liquid-solid ratio of 6.5:1.
[0039] S3: Add magnesium oxide as a precipitant to the above aluminum precipitation mother liquor and carry out a homogeneous precipitation reaction at 65°C to generate nickel cobalt hydroxide. During the reaction, maintain the reaction pH at around 6.5~7.0. After the reaction is completed, age for 0.5h and filter to obtain nickel cobalt hydroxide and nickel cobalt precipitation mother liquor.
[0040] S4: The above nickel-cobalt mother liquor is treated with a nanofiltration membrane to separate the sulfate additive from the nitric acid system and reuse it in the homogeneous process.
[0041] The experimental results of aluminum hydroxide obtained through the above steps are shown in Table 3.
[0042] Table 3. Elemental analysis results of aluminum hydroxide
[0043]
[0044] As can be seen from Table 3, the aluminum hydroxide prepared by adding magnesium sulfate with a molar amount of 0.2 times that of aluminum in the mother liquor of iron precipitation during the homogeneous aluminum precipitation process has a high purity. The addition of magnesium sulfate additive reduces the generation of aluminum hydroxide colloid, thereby reducing the ability of aluminum hydroxide to adsorb nickel, cobalt, manganese, magnesium, nitrate and other ions in the nitric acid system, resulting in a lower loss rate of valuable metals. The nickel loss rate is 7.5%, and the filtration speed of aluminum hydroxide slurry is increased to 500 mL / min.
[0045] Example 3
[0046] S1: Lateritic nickel ore and nitric acid were subjected to pressurized acid leaching at an acid-to-ore ratio of 0.41:1. The leaching temperature was 210℃, the leaching pressure was 1.6 MPa, and the leaching time was 1 hour to obtain an acid leaching slurry. A 20% magnesium oxide slurry was prepared and pre-neutralized with the acid leaching slurry for iron precipitation. The iron precipitation temperature was 90℃, the pH was adjusted to 2.5, and after aging for 0.5 hours, the mixture was filtered to obtain iron concentrate and iron precipitation mother liquor.
[0047] S2: First, mix the above-mentioned iron precipitation mother liquor with magnesium sulfate. The amount of magnesium sulfate is 0.45 times the molar amount of aluminum in the iron precipitation mother liquor. Then, carry out a homogeneous precipitation reaction with magnesium oxide slurry at 65°C to generate aluminum hydroxide. During the reaction, maintain the reaction pH at around 4.2~4.8. After the reaction is completed, age for 0.5 hours and filter to obtain aluminum hydroxide and aluminum precipitation mother liquor. The aluminum hydroxide filter cake is washed once at a liquid-solid ratio of 6.5:1.
[0048] S3: Add magnesium oxide as a precipitant to the above aluminum precipitation mother liquor and carry out a homogeneous precipitation reaction at 65°C to generate nickel cobalt hydroxide. During the reaction, maintain the reaction pH at around 6.5~7.0. After the reaction is completed, age for 0.5h and filter to obtain nickel cobalt hydroxide and nickel cobalt precipitation mother liquor.
[0049] S4: The above nickel-cobalt mother liquor is treated with a nanofiltration membrane to separate the sulfate additive from the nitric acid system and reuse it in the homogeneous process.
[0050] The experimental results of aluminum hydroxide obtained through the above steps are shown in Table 4.
[0051] Table 4. Elemental analysis results of aluminum hydroxide
[0052]
[0053] As shown in Table 4, the aluminum hydroxide prepared by adding magnesium sulfate at 0.45 times the molar amount of aluminum in the iron precipitation mother liquor during the homogeneous aluminum precipitation process has a high purity, reaching 98.05%. Furthermore, when the amount of magnesium sulfate added is increased to 0.45 times, almost no colloid is generated during the homogeneous aluminum precipitation process, and the aluminum hydroxide adsorbs fewer impurity ions from the nitric acid system, further reducing the loss rate of valuable metals. The nickel loss rate is 1.71%, and the filtration speed of the aluminum hydroxide slurry increases to 700 mL / min.
[0054] Example 4
[0055] S1: Lateritic nickel ore and nitric acid were subjected to pressurized acid leaching at an acid-to-ore ratio of 0.41:1. The leaching temperature was 210℃, the leaching pressure was 1.6 MPa, and the leaching time was 1 hour to obtain an acid leaching slurry. A 20% magnesium oxide slurry was prepared and pre-neutralized with the acid leaching slurry for iron precipitation. The iron precipitation temperature was 90℃, the pH was adjusted to 2.5, and after aging for 0.5 hours, the mixture was filtered to obtain iron concentrate and iron precipitation mother liquor.
[0056] S2: First, mix the above-mentioned iron precipitation mother liquor with magnesium sulfate. The amount of magnesium sulfate is 0.45 times the molar amount of aluminum in the iron precipitation mother liquor. Then, carry out a homogeneous precipitation reaction with magnesium carbonate slurry at 65°C to generate aluminum hydroxide. During the reaction, maintain the reaction pH at around 4.2~4.8. After the reaction is completed, age for 0.5 hours and filter to obtain aluminum hydroxide and aluminum precipitation mother liquor. The aluminum hydroxide filter cake is washed once at a liquid-solid ratio of 6.5:1.
[0057] S3: Add magnesium oxide as a precipitant to the above aluminum precipitation mother liquor and carry out a homogeneous precipitation reaction at 65°C to generate nickel cobalt hydroxide. During the reaction, maintain the reaction pH at around 6.5~7.0. After the reaction is completed, age for 0.5h and filter to obtain nickel cobalt hydroxide and nickel cobalt precipitation mother liquor.
[0058] S4: The above nickel-cobalt mother liquor is treated with a nanofiltration membrane to separate the sulfate additive from the nitric acid system and reuse it in the homogeneous process.
[0059] The experimental results of aluminum hydroxide obtained through the above steps are shown in Table 5.
[0060] Table 5. Elemental analysis results of aluminum hydroxide
[0061]
[0062] As shown in Table 5, the highest purity of aluminum hydroxide, reaching 98.51%, was obtained when the amount of magnesium sulfate added during the homogeneous aluminum precipitation process was 0.45 times the molar amount of aluminum in the iron precipitation mother liquor, and magnesium carbonate was used as the precipitant. The homogeneous aluminum precipitation process produced almost no colloids, impurity ions in the aluminum hydroxide were easily washed away, the nickel loss rate was 0.28%, and the filtration rate of the aluminum hydroxide slurry was 500 mL / min.
[0063] In summary, the addition of sulfate (preferably magnesium sulfate) to this system increases the filtration rate of the aluminum precipitation process from 100 ml / min to 500-700 ml / min. In addition, the nickel loss rate is reduced from 30% to below 2% (as low as 0.28%). The added sulfate is separated from the nitric acid system through membrane separation technology, and the sulfate can be reused in the previous aluminum precipitation process.
[0064] The process technology involved in this invention makes the aluminum precipitation process in the nitric acid system more continuous and reduces the nickel and cobalt loss rate. The increased filtration speed significantly increases the processing capacity of the filtration equipment, reducing the number of processing units and investment. The reduced nickel and cobalt inclusion rate significantly increases the project's economics. Based on a project processing 1.2 million tons of laterite nickel ore annually, theoretically producing 10,000 tons of nickel, a 1% reduction in nickel inclusions (120,000 RMB / ton, 83% discount) is equivalent to an annual increase in economic benefits of nearly 10 million RMB.
[0065] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.
Claims
1. A method for improving the filtration performance of an aluminum precipitation material in a laterite nickel ore nitric acid system, characterized by, The application relates to a method for preparing nickel hydroxide and cobalt hydroxide from laterite nickel ore. The method comprises the following steps: S1: pressure acid leaching of laterite nickel ore with nitric acid to obtain an acid leaching slurry, pre-neutralization and iron precipitation of the acid leaching slurry with magnesium oxide to obtain iron concentrate and iron precipitation mother liquor; S2: homogeneous aluminum precipitation of the iron precipitation mother liquor with a precipitant and an additive at a certain temperature to generate aluminum hydroxide, use of the precipitant to maintain the reaction pH at 4.2-4.8 during the reaction, aging for a certain time after the reaction, and filtration and washing of the obtained solid-liquid mixture after the aging to obtain aluminum hydroxide and aluminum precipitation mother liquor; S3: homogeneous precipitation of the aluminum precipitation mother liquor with magnesium oxide at a certain temperature to generate nickel-cobalt hydroxide, aging for a certain time after the reaction, and filtration after the aging to obtain nickel-cobalt hydroxide and nickel-cobalt precipitation mother liquor; 2. The method of claim 1, wherein, S4: membrane treatment of the nickel-cobalt precipitation mother liquor to obtain a monovalent salt magnesium nitrate solution and a sulfate solution, and recycling of the sulfate to the homogeneous aluminum precipitation section.
3. The method of claim 1, wherein, In step S1, the acid-ore ratio of the laterite nickel ore to nitric acid is 0.41-0.43:1, the acid leaching process reaction temperature is 200-210 DEG C, the acid leaching pressure is 1.4-1.8 MPa, and the acid leaching time is 1-1.5 h.
4. The method of claim 1, wherein, In step S1, the pre-neutralization and iron precipitation reaction pH is 2.5-2.8, the reaction temperature is 80-90 DEG C, and the aging time is 0.5-1 h.
5. The method of claim 1, wherein, In step S1, the composition of the iron precipitation mother liquor is Co: 0.51 g / L, Ni: 4.20 g / L, Fe: 0.01 g / L, Al: 16.50 g / L, Mn: 0.036 g / L, Ca: 1.58 g / L and Mg: 35.98 g / L.
6. The method of claim 1, wherein, In step S2, the precipitant is one or more of magnesium oxide, magnesium carbonate, calcium oxide and calcium carbonate.
7. The method of claim 1, wherein, In step S2, the additive is one or more of magnesium sulfate, calcium sulfate, barium sulfate and sulfates.
8. The method of claim 1, wherein, In step S2, the additive is used in an amount of 0.1-1 times the molar amount of aluminum in the iron precipitation mother liquor.
9. The method of claim 1, wherein, In step S2, the homogeneous aluminum precipitation reaction pH is 4.2-4.8, and the reaction temperature is 60-70 DEG C.
10. The method of claim 1, wherein, In step S3, the MHP precipitation process reaction pH is 6.5-7.0, the reaction temperature is 60-70 DEG C, and the aging time is 1-2 h. In step S4, the membrane treatment technology used for the nickel-cobalt precipitation mother liquor is nanofiltration membrane treatment, the sulfate is separated from the nitric acid system, and the separated sulfate is recycled to the homogeneous aluminum precipitation in step S2.