A method for resource utilization of laterite nickel ore acid leaching residue

Abstract

The present invention provides a method for resource utilization of laterite nickel ore acid leaching residue, and relates to the technical field of high-value comprehensive utilization of laterite nickel ore. The method specifically comprises: S1: acid leaching treatment of laterite nickel ore, S2: pre-neutralization and iron precipitation, filtration, S3: aluminum removal, nickel and cobalt precipitation treatment, S4: carbonization and desulfurization treatment, S5: iron concentrate powder quality improvement treatment, S6: sulfate solution carbonization transformation treatment. Compared with other traditional methods, the method of the present invention, in particular, the iron element component in the prepared iron concentrate is effectively utilized and the sulfur element is effectively reduced, the grade of the iron concentrate is higher, the preparation process is short, the cost is low, the efficiency is high, there will be no by-products that affect the environment or have low economic value, and it is conducive to large-scale industrial production and promotion.

Description

Technical Field

[0001] The invention relates to the technical field of high-value comprehensive utilization of laterite nickel ore, and in particular to a method for resource utilization of acid leaching residues of laterite nickel ore. Background Art

[0002] The traditional pressure acid leaching process uses sulfuric acid as a leaching agent under high temperature and high pressure. By controlling the leaching conditions, most of the iron, aluminum, silicon, etc. are hydrolyzed into the slag, while nickel and cobalt enter the solution, thereby achieving selective leaching. The leachate is then neutralized and impurities (Fe, Al) are removed to obtain high-quality nickel and cobalt solutions.

[0003] The biggest advantage of the traditional pressure acid leaching process is its good leaching selectivity and high nickel and cobalt leaching rates. However, it has technical defects such as complex process technology, high equipment requirements, large investment, high operating cost, serious scarring of the pressure reactor, and the inability to achieve comprehensive utilization of the leaching slag due to low iron and high sulfur.

[0004] At present, the main way to deal with laterite nickel ore leaching residue is direct landfill, which not only causes serious waste of resources, but also brings serious burden to the environment, which is not conducive to the construction and sustainable development of a resource-saving and environmentally friendly society.

[0005] For example, Chinese patent CN116004936A discloses a method for treating laterite nickel ore acid leaching residue, which includes sending the laterite nickel ore acid leaching residue and solvent into a rotary kiln for oxidative roasting to desulfurize and remove moisture, then melting and reducing to obtain a reduced melt, and then flowing into an electrothermal sedimentation zone to further precipitate and separate the metallic iron in the slag, and then releasing the smelting slag through a slag outlet and quenching with water to obtain harmless glass slag, and releasing the molten iron through a metal outlet to cast ingots for sale; this method obviously does not make efficient use of the laterite nickel ore acid leaching residue, and smelting slag still exists in the end, and the reduction process requires the addition of reducing agents and fuels, which consumes more heat energy and has a higher cost.

[0006] Chinese patent CN110331283A discloses a method for treating laterite nickel ore acid leaching residue, which comprises pre-neutralizing the acid leaching liquid after pressurized acid leaching treatment, adjusting the pH value to perform a first-stage iron and aluminum removal to obtain a first-stage iron-aluminum slag and a first-stage iron-aluminum removal liquid; treating the mixture of the first-stage iron-aluminum slag and the iron-containing acid leaching residue by a magnetization roasting process to obtain an iron concentrate; then adjusting the pH value to perform a second-stage iron and aluminum removal to obtain a second-stage iron-aluminum slag and a second-stage iron-aluminum removal liquid; precipitating nickel and cobalt on the second-stage iron-aluminum removal liquid to obtain a nickel-cobalt precipitation barren liquid and a nickel-cobalt precipitate; precipitating manganese and magnesium on the nickel-cobalt precipitation barren liquid in steps to obtain manganese slag and magnesium slag; returning the second-stage iron-aluminum slag to the pressurized acid leaching process to improve the metal recovery rate; the process is complicated, the recycled material value is low, a large amount of coal resources are required, and the water quenching roasting consumes a high production cost, including but not limited to electricity, heat energy and water resources, and the obtained iron concentrate grade can reach up to 65%.

[0007] Chinese patent CN104291353A discloses a method for preparing 4A zeolite using laterite nickel ore acid leaching residue as raw material. Obviously, the utilization method is not precipitation recovery of iron concentrate and alloy elements, but conversion of acid leaching residue into zeolite through alkali melting and hydrothermal reaction. The added value of the utilization method is low, and the iron element component in the acid leaching residue is not effectively utilized.

[0008] In view of the defects and shortcomings in the prior art, the present invention provides a method for resource utilization of laterite nickel ore acid leaching residue. The process realizes the desulfurization resource utilization of iron-containing solid waste residue from pressure leaching of laterite nickel ore, effectively solves the problem of open-air dumping of laterite nickel ore solid waste residue treated by pressure acid leaching, and deepens and expands the economic value of the leaching residue. The entire process has no wastewater or waste residue discharge, is environmentally friendly, and has huge social and economic value. Summary of the invention

[0009] The technical problem to be solved by the present invention is that the current resource utilization level of laterite nickel ore acid leaching residue is low, especially the iron component therein has not been effectively utilized. The main purpose is to convert the acid leaching residue into zeolite or harmless metallurgical slag for utilization. Although the iron component can be converted into molten iron and iron concentrate by smelting, these existing technologies have more or less various problems, such as low utilization rate of iron element in molten iron, large loss, the grade of iron concentrate can only reach the lower limit of the market, many processes and difficult operation, which is not conducive to large-scale industrial production and promotion and other technical defects.

[0010] In order to solve the above-mentioned invention object, the technical solution provided by the present invention is as follows:

[0011] A method for resource utilization of laterite nickel ore acid leaching residue, the method for resource utilization of laterite nickel ore acid leaching residue comprising the following steps:

[0012] S1: Acid leaching of laterite nickel ore

[0013] Performing pressure acid leaching on the laterite nickel ore to obtain a leached slurry;

[0014] S2: Pre-neutralization and iron precipitation, filtration

[0015] The pH of the leaching slurry in S1 is adjusted with an alkaline substance, and an aluminum removal agent is added and filtered after sufficient reaction to obtain a main metal leaching solution and iron slag;

[0016] S3: Aluminum removal and nickel-cobalt precipitation

[0017] Adding an aluminum removal agent to the main metal leaching solution of S2, then adjusting the pH with an alkaline substance to first remove aluminum, and then adjusting the pH with an alkaline substance to precipitate nickel and cobalt to obtain a nickel-cobalt product;

[0018] S4: Carbonization desulfurization treatment

[0019] The iron slag of S2 is mixed with water to form a slurry, and the slurry is subjected to carbonization desulfurization treatment with carbonate, washed, and filtered to obtain a crude iron ore concentrate powder and a sulfate solution;

[0020] S5: Iron ore concentrate powder upgrading

[0021] The crude iron ore concentrate powder of S4 is mixed with water, nitric acid or hydrochloric acid to form a slurry, and then acid-washed to remove calcium carbonate precipitate in the solution to obtain high-grade iron ore concentrate powder;

[0022] S6: Sulfate solution carbonization transformation treatment

[0023] Calcium oxide is added to the sulfate solution of S4 to obtain calcium sulfate precipitate and alkaline solution, and then carbon dioxide is introduced into the alkaline solution to obtain a carbonate solution; wherein: the calcium sulfate precipitate is discharged from the system after washing, and the carbonate solution is circulated for the treatment of iron slag leached out by high-pressure acid leaching.

[0024] Preferably, the pressure leaching conditions in S1 are acid-ore ratio 0.2-0.25, liquid-solid ratio 2-3:1, temperature 220-230°C, and leaching time 0.5-1h.

[0025] Preferably, the calcium oxide in S2 adjusts the pH of the leaching slurry in S1, the pH is controlled at 1.8-3.5, and the reaction temperature is 40-80°C; the main components of the iron slag are: TFe is 50-56%, and the S content is 1-6%.

[0026] Preferably, the aluminum removal agent in S3 is one or more of magnesium oxide or magnesium carbonate; the pH of aluminum removal is first controlled at 4.0-5.0 by adjusting the pH with an alkaline substance, and the temperature of aluminum removal is controlled at 60-90°C; the pH of nickel and cobalt precipitation is then controlled at 7.0-8.0 by adjusting the pH with an alkaline substance, and the temperature of nickel and cobalt precipitation is controlled at 70-80°C.

[0027] Preferably, the ratio of iron slag to water in S4 is 1:2.5-8, the carbonate alkaline washing temperature is 50-100°C, and the washing time is 0.5-2h; the main components of the iron concentrate: TFe is 54-60%, and the S content is 0.05-0.3%.

[0028] Preferably, the TFe content in the main component of the iron slag in the iron concentrate in S4 is increased by at least 0.6%, and the S content is reduced by at least 70% compared with that in the iron slag in S2.

[0029] Preferably, the amount of carbonate added in S4 is 0.95-1.1 times the theoretical reaction amount of calcium sulfate and carbonate, the carbonate is one of ammonium carbonate, ammonium bicarbonate, sodium carbonate, sodium bicarbonate, and potassium carbonate, and the sulfate is determined according to the type of carbonate added, and is one of ammonium sulfate, ammonium bisulfate, sodium sulfate, and potassium sulfate. The washing method is reverse secondary washing, that is, new water is used for secondary washing, and secondary washing water is used for primary washing.

[0030] Preferably, the acid washing conditions in S5 are iron concentrate: water = 1:3-5, the reaction temperature is 40-60°C, and the amount of nitric acid or hydrochloric acid added is 0.8-1.2 times the theoretical amount of calcium carbonate consumed in the iron concentrate; the main components of the high-grade iron concentrate are: TFe is 62-68%, and the S content is 0.020-0.040%.

[0031] Preferably, the reaction conditions for adding calcium oxide to the sulfate solution in S6 are: reaction temperature 25-50°C, time 1.5-2.0h, the amount of calcium oxide added is 0.8-1.2 times the theoretical amount of sulfate in the sulfate solution consumed, and the pH is controlled at 8-12; the reaction conditions for introducing carbon dioxide into the alkaline solution are: the flow rate of carbon dioxide is 0.2-1.0L / h, the temperature is 70-80°C, and the time is 1.0-2.0h.

[0032] Preferably, the product after the reaction of introducing carbon dioxide into the alkaline solution in S6 is one of ammonium sulfate, ammonium bisulfate, sodium sulfate and potassium sulfate.

[0033] Compared with the prior art, the above technical solution has at least the following beneficial effects:

[0034] The above scheme, the present invention proposes a method for resource utilization of laterite nickel ore acid leaching residue, using high-pressure acid leaching to obtain a mixed slurry for pre-neutralization to obtain a main metal leaching solution and iron slag, wherein the iron slag is used for the preparation of iron concentrate, and the total iron content of the prepared iron concentrate can reach up to 68%, and the S content can reach as low as 0.020%.

[0035] The iron content in the main metal leaching solution of the present invention is not recovered into the prepared iron concentrate, and the recovery process does not require coal blending roasting and water quenching, nor does it require weak magnetic separation. The process steps are simple and the process is short. The prepared iron concentrate has a high grade, low cost and high efficiency.

[0036] The iron concentrate prepared by the present invention has an extremely low sulfur content, has a good carbon desulfurization efficiency, does not produce byproducts such as sulfur dioxide that have an impact on the environment or have low economic value, and does not require multiple large-scale additions of calcium hydroxide. The process is simple, the flow is short, and the efficiency is high.

[0037] The carbonization desulfurization and carbonization transformation of the present invention prevent sulfate ions from being doped in the iron concentrate, fully reduce the sulfur content in the iron concentrate, and increase the carbon content in the iron concentrate. The obtained carbonate solution is circulated for the treatment of iron slag leached out by high-pressure acid leaching, which is beneficial to industrial production.

[0038] In summary, compared with other traditional methods, the method of the present invention, in particular, the iron component in the prepared iron concentrate is effectively utilized and the sulfur element is effectively reduced, the grade of the iron concentrate is higher, the preparation process is short, the cost is low, the efficiency is high, and there will be no by-products that affect the environment or have low economic value, which is conducive to large-scale industrial production and promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] 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.

[0040] Figure 1 The present invention is a flow chart of a method for resource utilization of laterite nickel ore acid leaching residue. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] Example 1

[0043] A method for resource utilization of laterite nickel ore acid leaching residue, the method for resource utilization of laterite nickel ore acid leaching residue is as follows Figure 1 As shown, the following steps are included:

[0044] S1: Acid leaching of laterite nickel ore

[0045] 500g of limonitic laterite nickel ore was mixed with 120g of 98% concentrated sulfuric acid and 880g of water to prepare slurry, and then a high pressure of 3MPa was added at a reaction temperature of 230°C for 0.5 hours to obtain a leaching slurry;

[0046] S2: Pre-neutralization and iron precipitation, filtration

[0047] The pH of the leached slurry in S1 was adjusted with 20% calcium oxide slurry, and the pH was controlled at 2.5. The reaction temperature was 70°C, and the main metal leaching solution and 415g iron slag were obtained. The main components of the iron slag were: TFe was 50%, and S content was 4%;

[0048] S3: Aluminum removal and nickel-cobalt precipitation

[0049] The main metal leaching solution of S2 is firstly dealuminized by adjusting the pH with 20% magnesium oxide slurry, the pH is controlled at 4.5, and the dealuminization temperature is controlled at 60°C; then, nickel and cobalt are precipitated by adjusting the pH with 20% magnesium oxide slurry, the pH is controlled at 7.5, and the temperature of precipitating nickel and cobalt is controlled at 70°C to obtain a nickel-cobalt product;

[0050] S4: Carbonization desulfurization treatment

[0051] The iron slag of S2 is mixed with water to form a slurry, and the slurry is subjected to carbonization desulfurization treatment, washing and filtering with carbonate, wherein: the iron slag and water are mixed in a slurrying ratio of 1:3, 99.6g of ammonium carbonate is added, the alkaline washing temperature is 70°C, and the washing time is 1h; 396.3g of crude iron ore concentrate powder and ammonium sulfate solution are obtained; wherein: the main components of the iron ore concentrate: TFe is 54.2%, and the S content is 0.082%;

[0052] S5: Iron ore concentrate powder upgrading

[0053] 396.3g of S4 iron concentrate was added to 1600g of water for slurrying, and then 97.97g of 60% nitric acid was added. The reaction temperature was 50°C and the reaction time was 2h. The calcium carbonate precipitate in the solution was removed to obtain high-grade iron concentrate powder. The main components of the high-grade iron concentrate were: TFe was 63% and S content was 0.040%;

[0054] S6: Carbonization transformation treatment of ammonium sulfate solution

[0055] Calcium oxide is added to the ammonium sulfate solution of S4 to obtain calcium sulfate precipitate and alkaline solution, and then carbon dioxide is introduced into the alkaline solution to obtain ammonium carbonate solution; wherein: the reaction temperature for adding 30g of calcium oxide is 40°C, the time is 2.0h, and the pH is controlled at 9; the reaction conditions for introducing carbon dioxide into the alkaline solution are: the flow rate of carbon dioxide is 1.0L / h, the temperature is 80°C, and the time is 1.0h; and the calcium sulfate precipitate is discharged from the system after washing, and the ammonium carbonate solution is circulated for the treatment of iron slag leached out by high-pressure acid leaching.

[0056] Example 2

[0057] A method for resource utilization of laterite nickel ore acid leaching residue, the method for resource utilization of laterite nickel ore acid leaching residue is as follows Figure 1 As shown, the following steps are included:

[0058] S1: Acid leaching of laterite nickel ore

[0059] 500 g of limonitic laterite nickel ore was mixed with 150 g of 98% concentrated sulfuric acid and 1350 g of water to prepare slurry, and then a high pressure of 3 MPa was added at a reaction temperature of 230° C. for 1.0 hour to obtain a leaching slurry;

[0060] S2: Pre-neutralization and iron precipitation, filtration

[0061] The pH of the leached slurry in S1 was adjusted with 30% calcium oxide slurry, and the pH was controlled at 2.5. The reaction temperature was 80°C, and the main metal leaching solution and 405g iron slag were obtained. The main components of the iron slag were: TFe was 52%, and S content was 4.94%;

[0062] S3: Aluminum removal and nickel-cobalt precipitation

[0063] The main metal leaching solution of S2 is firstly dealuminized by adjusting the pH with 20% magnesium oxide slurry, the pH is controlled at 4.5, and the dealuminization temperature is controlled at 60°C; then, the pH is adjusted with 20% magnesium oxide slurry to precipitate nickel and cobalt, the pH is controlled at 7.5, and the temperature of precipitating nickel and cobalt is controlled at 60°C to obtain a nickel-cobalt product;

[0064] S4: Carbonization desulfurization treatment

[0065] The iron slag of S2 is mixed with water to form a slurry, and the slurry is subjected to carbonization desulfurization treatment, washing and filtering with carbonate, wherein: the ratio of the iron slag to water is 1:3, 114.34g of ammonium carbonate is added for alkaline washing at a temperature of 70°C and a washing time of 1h; 382.46g of crude iron ore concentrate powder and ammonium sulfate solution are obtained; wherein: the main components of the iron ore concentrate: TFe is 56%, and the S content is 0.032%;

[0066] S5: Iron ore concentrate powder upgrading

[0067] 396.3g of S4 iron concentrate was added to 1600g of water for slurrying, and then 97.97g of 60% nitric acid was added. The reaction temperature was 50°C and the reaction time was 2h. The calcium carbonate precipitate in the solution was removed to obtain high-grade iron concentrate powder. The main components of the high-grade iron concentrate were: TFe was 66.28% and S content was 0.025%;

[0068] S6: Carbonization transformation treatment of ammonium sulfate solution

[0069] Calcium oxide is added to the ammonium sulfate solution of S4 to obtain a calcium sulfate precipitate and an alkaline solution, and then carbon dioxide is introduced into the alkaline solution to obtain an ammonium carbonate solution; wherein: the reaction temperature for adding 35g of calcium oxide is 40°C, the time is 1.5h, and the pH is controlled at 10; the reaction conditions for introducing carbon dioxide into the alkaline solution are: the flow rate of the introduced carbon dioxide is 2.0L / h, the temperature is 70°C, and the time is 1.5h; and the calcium sulfate precipitate is discharged from the system after washing, and the ammonium carbonate solution is circulated for the treatment of iron slag leached out by high-pressure acid leaching.

[0070] Example 3

[0071] A method for resource utilization of laterite nickel ore acid leaching residue, the method for resource utilization of laterite nickel ore acid leaching residue is as follows Figure 1 As shown, the following steps are included:

[0072] S1: Acid leaching of laterite nickel ore

[0073] 500g of limonitic laterite nickel ore was mixed with 100g of 98% concentrated sulfuric acid and 1150g of water to prepare pulp, and then a high pressure of 2.8MPa was added at a reaction temperature of 220°C for 1.0 hour to obtain a leaching slurry;

[0074] S2: Pre-neutralization and iron precipitation, filtration

[0075] The pH of the leached slurry in S1 was adjusted with 10% calcium oxide slurry, and the pH was controlled at 3.0. The reaction temperature was 80°C, and the main metal leaching solution and 410g iron slag were obtained. The main components of the iron slag were: TFe was 51.7%, and S content was 3.76%;

[0076] S3: Aluminum removal and nickel-cobalt precipitation

[0077] The main metal leaching solution of S2 is firstly dealuminized by adjusting the pH with 20% magnesium oxide slurry, the pH is controlled at 5.0, and the dealuminization temperature is controlled at 60°C; then, nickel and cobalt are precipitated by adjusting the pH with 20% magnesium oxide slurry, the pH is controlled at 7.5, and the temperature of precipitating nickel and cobalt is controlled at 60°C to obtain a nickel-cobalt product;

[0078] S4: Carbonization desulfurization treatment

[0079] The iron slag of S2 is mixed with water to form a slurry, and the slurry is subjected to carbonization desulfurization treatment, washing and filtering with sodium carbonate, wherein: the ratio of iron slag to water is 1:2.5, 51.1g of sodium carbonate is added for alkaline washing at a temperature of 70°C, and the washing time is 1h; 395.3g of crude iron ore concentrate powder and sodium sulfate solution are obtained; wherein: the main components of the iron ore concentrate: TFe is 56.7%, and the S content is 0.060%;

[0080] S5: Iron ore concentrate powder upgrading

[0081] 395.3g of S4 iron concentrate was added to 1900g of water for slurrying, and then 106.35g of 60% nitric acid was added. The reaction temperature was 60°C and the reaction time was 3h. The calcium carbonate precipitate in the solution was removed to obtain high-grade iron concentrate powder. The main components of the high-grade iron concentrate were: TFe was 67% and S content was 0.022%;

[0082] S6: Sodium sulfate solution carbonization transformation treatment

[0083] Calcium oxide is added to the sodium sulfate solution of S4 to obtain calcium sulfate precipitate and alkaline solution, and then carbon dioxide is introduced into the alkaline solution to obtain ammonium carbonate solution; wherein: the reaction temperature for adding 27g of calcium oxide is 30°C, the time is 1.5h, and the pH is controlled at 10; the reaction conditions for introducing carbon dioxide into the alkaline solution are: the flow rate of carbon dioxide is 1.5L / h, the temperature is 80°C, and the time is 1.0h; and the calcium sulfate precipitate is discharged from the system after washing, and the ammonium carbonate solution is circulated for the treatment of iron slag leached out by high-pressure acid leaching.

[0084] Example 4

[0085] A method for resource utilization of laterite nickel ore acid leaching residue, the method for resource utilization of laterite nickel ore acid leaching residue is as follows Figure 1 As shown, the following steps are included:

[0086] S1: Acid leaching of laterite nickel ore

[0087] 1000g of limonitic laterite nickel ore was mixed with 225g of 98% concentrated sulfuric acid and 1780g of water to prepare slurry, and then a high pressure of 2.9MPa was added at a reaction temperature of 225°C for 1 hour to obtain a leaching slurry;

[0088] S2: Pre-neutralization and iron precipitation, filtration

[0089] The pH of the leached slurry in S1 was adjusted with 30% calcium oxide slurry, and the pH was controlled at 2.5. The reaction temperature was 60°C, and the main metal leaching solution and 800g iron slag were obtained. The main components of the iron slag were: TFe was 54% and S content was 3%;

[0090] S3: Aluminum removal and nickel-cobalt precipitation

[0091] The main metal leaching solution of S2 is firstly dealuminized by adjusting the pH with 30% magnesium carbonate slurry, the pH is controlled at 4.7, and the dealuminization temperature is controlled at 70°C; then, nickel and cobalt are precipitated by adjusting the pH with 30% magnesium oxide slurry, the pH is controlled at 7, and the temperature of precipitating nickel and cobalt is controlled at 80°C to obtain a nickel-cobalt product;

[0092] S4: Carbonization desulfurization treatment

[0093] The iron slag of S2 is mixed with water to form a slurry, and the slurry is subjected to carbonization desulfurization treatment, washing and filtering with sodium carbonate, wherein: the ratio of the iron slag to water is 1:6, 51g of sodium carbonate is added for alkaline washing at a temperature of 100°C and a washing time of 2h; 773g of crude iron ore concentrate powder and sodium sulfate solution are obtained; wherein: the main components of the iron ore concentrate: TFe is 56%, and the S content is 0.08%;

[0094] S5: Iron ore concentrate powder upgrading

[0095] 773g of S4 iron concentrate was added to 3865g of water for slurrying, and then 210g of 60% nitric acid was added. The reaction temperature was 60°C and the reaction time was 5h. The calcium carbonate precipitate in the solution was removed to obtain high-grade iron concentrate powder. The main components of the high-grade iron concentrate were: TFe was 66% and S content was 0.02%;

[0096] S6: Sodium sulfate solution carbonization transformation treatment

[0097] Calcium oxide is added to the sodium sulfate solution of S4 to obtain calcium sulfate precipitate and alkaline solution, and then carbon dioxide is introduced into the alkaline solution to obtain ammonium carbonate solution; wherein: the reaction temperature for adding 52g of calcium oxide is 50°C, the time is 2h, and the pH is controlled at 10; the reaction conditions for introducing carbon dioxide into the alkaline solution are: the flow rate of carbon dioxide is 1L / h, the temperature is 75°C, and the time is 2h; and the calcium sulfate precipitate is discharged from the system after washing, and the ammonium carbonate solution is circulated for the treatment of iron slag leached out by high-pressure acid leaching.

[0098] Example 5

[0099] A method for resource utilization of laterite nickel ore acid leaching residue, the method for resource utilization of laterite nickel ore acid leaching residue is as follows Figure 1 As shown, the following steps are included:

[0100] S1: Acid leaching of laterite nickel ore

[0101] 1000g of limonitic laterite nickel ore was mixed with 210g of 98% concentrated sulfuric acid and 1700g of water to prepare pulp, and then a high pressure of 3.0MPa was added at a reaction temperature of 228°C for 0.8 hours to obtain a leaching slurry;

[0102] S2: Pre-neutralization and iron precipitation, filtration

[0103] The pH of the leached slurry in S1 was adjusted with 30% calcium oxide slurry, and the pH was controlled at 2.8. The reaction temperature was 70°C, and the main metal leaching solution and 806g of iron slag were obtained. The main components of the iron slag were: TFe was 54% and S content was 2%;

[0104] S3: Aluminum removal and nickel-cobalt precipitation

[0105] The main metal leaching solution of S2 is firstly dealuminized by adjusting the pH with 30% magnesium oxide slurry, the pH is controlled at 4.9, and the dealuminization temperature is controlled at 73°C; then, nickel and cobalt are precipitated by adjusting the pH with 30% magnesium carbonate slurry, the pH is controlled at 7.2, and the temperature of precipitated nickel and cobalt is controlled at 76°C to obtain a nickel-cobalt product;

[0106] S4: Carbonization desulfurization treatment

[0107] The iron slag of S2 is mixed with water to form a slurry, and the slurry is subjected to carbonization desulfurization treatment, washing and filtering with sodium carbonate, wherein: the ratio of the iron slag to water is 1:7, 53g of sodium carbonate is added for alkaline washing at a temperature of 87°C, and the washing time is 2h; 775g of crude iron ore concentrate powder and sodium sulfate solution are obtained; wherein: the main components of the iron ore concentrate: TFe is 57%, and the S content is 0.075%;

[0108] S5: Iron ore concentrate powder upgrading

[0109] 775g of S4 iron concentrate was added to 3800g of water for slurrying, and then 220g of 60% nitric acid was added. The reaction temperature was 58°C and the reaction time was 5h. The calcium carbonate precipitate in the solution was removed to obtain high-grade iron concentrate powder. The main components of the high-grade iron concentrate were: TFe was 65.8% and S content was 0.023%;

[0110] S6: Sodium sulfate solution carbonization transformation treatment

[0111] Calcium oxide is added to the sodium sulfate solution of S4 to obtain calcium sulfate precipitate and alkaline solution, and then carbon dioxide is introduced into the alkaline solution to obtain ammonium carbonate solution; wherein: the reaction temperature for adding 55g calcium oxide is 48°C, the time is 1.7h, and the pH is controlled at 11; the reaction conditions for introducing carbon dioxide into the alkaline solution are: the flow rate of carbon dioxide is 0.8L / h, the temperature is 78°C, and the time is 1.7h; and the calcium sulfate precipitate is discharged from the system after washing, and the ammonium carbonate solution is circulated for the treatment of iron slag leached out by high-pressure acid leaching.

[0112] Example 6

[0113] A method for resource utilization of laterite nickel ore acid leaching residue, the method for resource utilization of laterite nickel ore acid leaching residue is as follows Figure 1 As shown, the following steps are included:

[0114] S1: Acid leaching of laterite nickel ore

[0115] 700g of limonitic laterite nickel ore was mixed with 165g of 98% concentrated sulfuric acid and 1530g of water to prepare slurry, and then a high pressure of 2.9MPa was added at a reaction temperature of 227°C for 0.9 hours to obtain a leaching slurry;

[0116] S2: Pre-neutralization and iron precipitation, filtration

[0117] The pH of the leached slurry in S1 was adjusted with 30% calcium oxide slurry, and the pH was controlled at 2.5. The reaction temperature was 68°C, and the main metal leaching solution and 563g of iron slag were obtained. The main components of the iron slag were: TFe was 53% and S content was 4%;

[0118] S3: Aluminum removal and nickel-cobalt precipitation

[0119] The main metal leaching solution of S2 is firstly dealuminized by adjusting the pH with 30% magnesium oxide slurry, the pH is controlled at 4.5, and the dealuminization temperature is controlled at 70°C; then, nickel and cobalt are precipitated by adjusting the pH with 30% magnesium oxide slurry, the pH is controlled at 7.5, and the temperature of precipitating nickel and cobalt is controlled at 76°C to obtain a nickel-cobalt product;

[0120] S4: Carbonization desulfurization treatment

[0121] The iron slag of S2 is mixed with water to form a slurry, and the slurry is subjected to carbonization desulfurization treatment, washing and filtering with sodium carbonate, wherein: the ratio of the iron slag to water is 1:7, 51g of sodium carbonate is added for alkaline washing at a temperature of 98°C, and the washing time is 2h; 542g of crude iron ore concentrate powder and sodium sulfate solution are obtained; wherein: the main components of the iron ore concentrate: TFe is 56.5%, and the S content is 0.07%;

[0122] S5: Iron ore concentrate powder upgrading

[0123] 542g of S4 iron concentrate was added to 2512g of water for slurrying, and then 153g of 60% nitric acid was added. The reaction temperature was 55°C and the reaction time was 6h. The calcium carbonate precipitate in the solution was removed to obtain high-grade iron concentrate powder. The main components of the high-grade iron concentrate were: TFe was 67% and S content was 0.022%;

[0124] S6: Sodium sulfate solution carbonization transformation treatment

[0125] Calcium oxide is added to the sodium sulfate solution of S4 to obtain calcium sulfate precipitate and alkaline solution, and then carbon dioxide is introduced into the alkaline solution to obtain ammonium carbonate solution; wherein: the reaction temperature for adding 38.5g calcium oxide is 47°C, the time is 2h, and the pH is controlled at 9; the reaction conditions for introducing carbon dioxide into the alkaline solution are: the flow rate of carbon dioxide is 0.9L / h, the temperature is 77°C, and the time is 2h; and the calcium sulfate precipitate is discharged from the system after washing, and the ammonium carbonate solution is circulated for the treatment of iron slag leached out by high-pressure acid leaching.

[0126] The above scheme, the present invention proposes a method for resource utilization of laterite nickel ore acid leaching residue, using high-pressure acid leaching to obtain a mixed slurry for pre-neutralization to obtain a main metal leaching solution and iron slag, wherein the iron slag is used for the preparation of iron concentrate, and the total iron content of the prepared iron concentrate can reach up to 68%, and the S content can reach as low as 0.020%.

[0127] The iron content in the main metal leaching solution of the present invention is not recovered into the prepared iron concentrate, and the recovery process does not require coal blending roasting and water quenching, nor does it require weak magnetic separation. The process steps are simple and the process is short. The prepared iron concentrate has a high grade, low cost and high efficiency.

[0128] The iron concentrate prepared by the present invention has an extremely low sulfur content, has a good carbon desulfurization efficiency, does not produce byproducts such as sulfur dioxide that have an impact on the environment or have low economic value, and does not require multiple large-scale additions of calcium hydroxide. The process is simple, the flow is short, and the efficiency is high.

[0129] The carbonization desulfurization and carbonization transformation of the present invention prevent sulfate ions from being doped in the iron concentrate, fully reduce the sulfur content in the iron concentrate, and increase the carbon content in the iron concentrate. The obtained carbonate solution is circulated for the treatment of iron slag leached out by high-pressure acid leaching, which is beneficial to industrial production.

[0130] In summary, compared with other traditional methods, the method of the present invention, in particular, the iron component in the prepared iron concentrate is effectively utilized and the sulfur element is effectively reduced, the grade of the iron concentrate is higher, the preparation process is short, the cost is low, the efficiency is high, and there will be no by-products that affect the environment or have low economic value, which is conducive to large-scale industrial production and promotion.

[0131] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for resource utilization of laterite nickel ore acid leaching residue, characterized in that: The method for resource utilization of laterite nickel ore acid leaching residues comprises the following steps: S1: Acid leaching of laterite nickel ore Performing pressure acid leaching on the laterite nickel ore to obtain a leached slurry; S2: Pre-neutralization and iron precipitation, filtration The pH of the leached slurry in S1 is adjusted with an alkaline substance, and filtered to obtain a main metal leaching solution and iron slag; S3: Aluminum removal and nickel-cobalt precipitation Add aluminum removal agent to the main metal leaching solution of S2, then use alkaline substances to adjust the pH to remove aluminum first, and then use alkaline substances to adjust the pH to precipitate nickel and cobalt to obtain nickel and cobalt products; calcium oxide is used to adjust the pH of the leaching slurry in S1, the pH is controlled at 1.8-3.5, and the reaction temperature is 40-80°C; the main components of the iron slag are: TFe is 50-56%, and the S content is 1-6%; S4: Carbonization desulfurization treatment The iron slag of S2 is mixed with water to form a slurry, and the slurry is subjected to carbonization desulfurization treatment with carbonate, washed, and filtered to obtain a crude iron ore concentrate powder and a sulfate solution; wherein the aluminum removal agent is one or more of magnesium oxide or magnesium carbonate; the pH of aluminum removal is first controlled at 4.0-5.0 by adjusting the pH with an alkaline substance, and the temperature of aluminum removal is controlled at 60-90°C; and then the pH of nickel and cobalt precipitation is controlled at 7.0-8.0 by adjusting the pH with an alkaline substance, and the temperature of nickel and cobalt precipitation is controlled at 70-80°C; S5: Iron ore concentrate powder upgrading The crude iron ore concentrate powder of S4 is mixed with water, nitric acid or hydrochloric acid to form a slurry, and then acid washing is performed to remove calcium carbonate precipitation in the solution to obtain high-grade iron ore concentrate powder; the main components of the high-grade iron ore concentrate are: TFe is 62-68%, and S content is 0.020-0.040%; S6: Sulfate solution carbonization transformation treatment Calcium oxide is added to the sulfate solution of S4 to obtain calcium sulfate precipitate and alkaline solution, and then carbon dioxide is introduced into the alkaline solution to obtain a carbonate solution; wherein: the calcium sulfate precipitate is discharged from the system after washing, and the carbonate solution is circulated for the treatment of iron slag leached out by high-pressure acid leaching.

2. The method for resource utilization of laterite nickel ore acid leaching residue according to claim 1, characterized in that: The pressure leaching conditions in S1 are acid-ore ratio 0.2-0.25, liquid-solid ratio 2-3:1, temperature 220-230°C, and leaching time 0.5-1h.

3. The method for resource utilization of laterite nickel ore acid leaching residue according to claim 1, characterized in that: The ratio of iron slag to water in S4 is 1:2.5-8, carbonate alkaline washing temperature is 50-100℃, and washing time is 0.5-2h; the main components of iron concentrate are: TFe is 54-60%, and S content is 0.05-0.3%.

4. The method for resource utilization of laterite nickel ore acid leaching residue according to claim 1, characterized in that: Compared with S2, the TFe content of the main components of iron slag in S4 iron concentrate increased by at least 0.6%, and the S content decreased by at least 70%.

5. The method for resource utilization of laterite nickel ore acid leaching residue according to claim 1, characterized in that: The amount of carbonate added in S4 is 0.95-1.1 times the theoretical reaction amount of calcium sulfate and carbonate, the carbonate is one of ammonium carbonate, ammonium bicarbonate, sodium carbonate, sodium bicarbonate, and potassium carbonate, and the sulfate is determined according to the type of carbonate added, and is one of ammonium sulfate, ammonium bisulfate, sodium sulfate, and potassium sulfate. The washing method is reverse secondary washing, that is, new water is used for secondary washing, and secondary washing water is used for primary washing.

6. The method for resource utilization of laterite nickel ore acid leaching residue according to claim 1, characterized in that: The acid washing conditions in S5 are iron concentrate: water = 1:3-5, the reaction temperature is 40-60°C, and the amount of nitric acid or hydrochloric acid added is 0.8-1.2 times the theoretical amount of calcium carbonate consumed in the iron concentrate; the main components of high-grade iron concentrate are: TFe is 62-68%, and S content is 0.020-0.040%.

7. The method for resource utilization of laterite nickel ore acid leaching residue according to claim 1, characterized in that: The reaction conditions for adding calcium oxide to the sulfate solution in S6 are: reaction temperature 25-50°C, time 1.5-2.0h, the amount of calcium oxide added is 0.8-1.2 times the theoretical amount of sulfate ions consumed in the sulfate solution, and the pH is controlled at 8-12; the reaction conditions for introducing carbon dioxide into the alkaline solution are: the flow rate of carbon dioxide is 0.2-1.0L / h, the temperature is 70-80°C, and the time is 1.0-2.0h.

8. The method for resource utilization of laterite nickel ore acid leaching residue according to claim 1, characterized in that: The product of the reaction after carbon dioxide is introduced into the alkaline solution in S6 is one of ammonium sulfate, ammonium hydrogen sulfate, sodium sulfate and potassium sulfate.

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