A method for processing a nickel-molybdenum ore

Abstract

The present application belongs to the field of mineral smelting, and discloses a processing method of nickel-molybdenum ore. The method comprises the following steps: mixing nickel-molybdenum ore and an additive to obtain a mixture, and then performing heat treatment on the mixture to obtain a heat-treated material; the additive is magnesium oxide or a precursor capable of being converted into magnesium oxide in the roasting stage; performing sulfuric acid leaching treatment on the heat-treated material to obtain a nickel-rich residue and a leaching solution enriched with molybdenum, magnesium and part of nickel; then performing molybdenum extraction treatment on the leaching solution by using an alkaline extractant to obtain a molybdenum-loaded organic phase and a raffinate solution enriched with magnesium and nickel; and performing magnesium-nickel separation treatment on the raffinate solution to obtain magnesium components and nickel components. The method can realize efficient recycling of sulfur, molybdenum and nickel in the nickel-molybdenum ore.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of rare metal material preparation, in particular to the field of resource utilization of nickel-molybdenum ore. BACKGROUND

[0002] Nickel-molybdenum ore is a unique non-traditional nickel-molybdenum resource in China, mainly distributed in Zunyi, Guizhou, Xiangxi, Hunan and other places, with rich reserves, rich in various valuable metals and great economic value. Especially, the enrichment degree of molybdenum and nickel is relatively high, and the general mining grade is about 4% and 3% respectively, which is usually several times, even hundreds or thousands times of the metal element grade of traditional molybdenum and nickel mineral resources. Since molybdenum and nickel mainly exist in the form of amorphous polysulfide, it is difficult to enrich by ore dressing, and enterprises usually directly smelt. Most smelting enterprises use the method of molybdenite fire smelting to process nickel-molybdenum ore, mainly including direct desulfurization roasting, etc.

[0003] For example, the Chinese patent document with publication number CN116516148A reports a method for producing molybdic acid and high-ice nickel from nickel-molybdenum ore, which includes oxidizing desulfurization roasting of the nickel-molybdenum ore; and further includes: subjecting the calcine obtained by the oxidizing desulfurization roasting to alkali leaching under an oxygen pressure of 0.5 MPa to 0.7 MPa to obtain a molybdenum-containing leach liquor for preparing molybdic acid and a nickel-containing leach residue for preparing high-ice nickel. The Chinese patent document with publication number CN109055727A discloses a method for comprehensively recovering nickel and molybdenum from nickel-molybdenum ore, which includes the following steps: 1) uniformly mixing nickel-molybdenum ore and soft manganite and then performing oxidizing roasting to obtain a roasted clinker; 2) adding the roasted clinker into an ammonia water solution for stirring reaction, and after solid-liquid separation, obtaining a leach liquor containing nickel-ammonia complex ions and molybdate ions and a leach residue containing manganese. The Chinese patent document with publication number CN105506312A discloses a method for separating molybdenum and nickel from high-carbon nickel-molybdenum ore. The process flow of the method includes crushing, mixing, ball making, roasting, acid leaching, acid-alkalinity adjustment, filtration separation, molybdenum extraction and nickel extraction. After the high-carbon nickel-molybdenum ore is crushed, it is mixed with calcium carbonate and made into a spherical shape. The spherical mixture is roasted to convert the contained molybdenum sulfide into molybdenum oxide and nickel sulfide into nickel oxide. The Chinese patent document with publication number CN104232935A discloses a process for simultaneously extracting nickel and molybdenum from nickel-molybdenum ore. The process flow includes: nickel-molybdenum ore plus calcium oxidizing roasting, low-temperature sulfuric acidizing roasting and water leaching.

[0004] The nickel-molybdenum ore is subjected to desulfurization roasting, and then subjected to smelting in an electric arc furnace to obtain an alloy primary product containing nickel and molybdenum. A large amount of sulfur dioxide is generated in the roasting process, which is difficult to treat and is forced to be shut down due to environmental protection problems. Although with the enhancement of environmental protection consciousness, some means capable of smelting and fixing sulfur dioxide have been developed in the prior art, however, most of the existing schemes can only realize efficient recycling of valuable metals such as Ni-Mo, and the sulfur therein is also abandoned in the form of hazardous solid waste which is difficult to handle, and the essence of the problem has not been solved. Not only that, but also a large amount of solid waste generated in the treatment process will increase the difficulty of the process, and inevitably interfere with the extraction and recovery of molybdenum. SUMMARY

[0005] In view of the problems existing in the prior art, the present application aims to provide a treatment method of nickel-molybdenum ore, which aims to realize comprehensive and efficient utilization of Ni-Mo-S in molybdenum-nickel ore and reduce the production of process hazardous waste in the treatment stage.

[0006] In view of the problems that the organic metal and sulfur in the molybdenum-nickel ore are difficult to be used at high value, and the separation selectivity of the valuable metals therein is not ideal, the present application provides the following scheme after in-depth research:

[0007] A treatment method of nickel-molybdenum ore, which comprises the following steps: subjecting a mixture containing nickel-molybdenum ore and an additive to heat treatment to obtain a heat-treated material, wherein the additive is magnesium oxide or a precursor capable of being converted into magnesium oxide in the roasting stage;

[0008] Subjecting the heat-treated material to sulfuric acid leaching treatment to obtain a nickel-rich residue and a leaching solution enriched with molybdenum, magnesium and part of nickel;

[0009] Subsequently, the leaching solution is subjected to molybdenum extraction treatment with an alkaline extractant to obtain a molybdenum-loaded organic phase and a raffinate solution enriched with magnesium and nickel;

[0010] The raffinate solution is subjected to magnesium-nickel separation treatment to obtain a magnesium component and a nickel component.

[0011] The present application innovatively uses magnesium oxide as an additive to assist in the heat treatment of molybdenum-nickel ore, and innovatively utilizes its special chemical reaction mechanism and physicochemical properties to realize the dual resource utilization of organic metal and sulfur in molybdenum-nickel ore, effectively avoiding the influence of sulfur slagging on leaching and recovery of nickel-rich residue. Not only that, but also it is helpful for the selective separation of nickel-molybdenum and magnesium in the subsequent process.

[0012] In the present application, the nickel-molybdenum ore is a composite sulfide ore containing nickel and molybdenum.

[0013] In the present application, the grade of the components in the nickel-molybdenum ore is not particularly required. For example, the grade of Mo in the nickel-molybdenum ore is above 1%, preferably 2-10%; the grade of Ni is above 1%, preferably 2-10%.

[0014] In the present application, the total molar ratio of Mg element in the additive and sulfur and molybdenum elements in the nickel-molybdenum ore is above 1, preferably 1.1-2.0:1, and further preferably 1.1-1.3:1. In the present application, due to the reactivity of the magnesium oxide, it has excellent reactivity, which can effectively realize the transformation and conversion of molybdenum-nickel-sulfur at a near theoretical ratio, and is conducive to forming physicochemical properties and structures that are conducive to acid leaching and subsequent selective separation of metals.

[0015] In the present application, the heat treatment process is carried out in an oxygen-containing atmosphere, for example, air;

[0016] Preferably, the temperature of the heat treatment is 400-800℃, and further 400-600℃ in consideration of the effect and economy;

[0017] Preferably, the time of the heat treatment is above 1h, and preferably 1-4h.

[0018] In the present application, due to the auxiliary heat treatment of the magnesium oxide, it can construct a suitable phase and microstructure for subsequent acid leaching, which is conducive to realizing the efficient reuse of magnesium and molybdenum in the nickel-molybdenum ore, avoiding the output of hazardous process solid waste, and further realizing the selective separation of molybdenum and nickel in the nickel-molybdenum ore.

[0019] In the present application, in the sulfuric acid leaching stage, the concentration of the initial sulfuric acid solution is 1-4M, and further preferably 1-2M;

[0020] Preferably, the liquid-solid ratio of sulfuric acid and calcined material is above 1ml / g, preferably 1-10ml / g, and preferably 1-4ml / g;

[0021] Preferably, the temperature of the sulfuric acid leaching stage is above 10℃, and preferably 50-100℃, and further preferably 50-60℃;

[0022] Preferably, the time of the sulfuric acid leaching is above 0.5h, and preferably 0.5-6h, and further preferably 1-5h;

[0023] Preferably, the leaching rate of nickel in the sulfuric acid leaching stage is less than or equal to 10%.

[0024] In the present application, the alkaline extractant includes at least one of primary amine extractants and tertiary amine extractants, and preferably at least one of N235 and N1923.

[0025] In the present application, for the system containing molybdenum-nickel-magnesium-sulfate, the alkaline extractant is used for extraction, which can unexpectedly extract molybdenum with high selectivity, and avoid the accompanying leaching of nickel and magnesium.

[0026] Preferably, the content of the basic extractant in the initial organic phase is more than 5v%, preferably 5-30v%, and more preferably 5-15v%.

[0027] In the present application, the roasting conversion assisted by the auxiliary agent and the modification advantage help to improve the leaching behavior, and further cooperate with the subsequent extraction mode, so that the advantageous extraction effect and extraction selectivity can be obtained under the condition of more moderate and lower extraction content.

[0028] In the present application, the extraction organic phase also allows the addition of a modifier, such as secondary octanol, the content of which can be adjusted according to conventional knowledge, for example, it can be 1-20v%, and further can be 5-15v%. The hydrophobic diluent can be, for example, sulfonated kerosene.

[0029] Preferably, the O / A of the molybdenum leaching treatment stage is 1-10:1, and further can be 2-5:1, and the contact time is more than 1min, preferably 1-20min, and considering the treatment efficiency, it can be further 5-10min;

[0030] Preferably, ammonia is used to strip the molybdenum-loaded organic phase to obtain a crude ammonium molybdate solution;

[0031] Preferably, the ammonia used in the stripping stage is not less than the theoretical amount of molybdenum complete reaction, and preferably is 1-5 times the theoretical amount, and the contact time is more than 1min, preferably 1-20min.

[0032] In the present application, the crude ammonium molybdate solution is purified and then subjected to acid precipitation treatment to prepare ammonium tetramolybdate product;

[0033] Preferably, the purification treatment refers to the step of removing phosphorus and / or arsenic in the crude ammonium molybdate solution;

[0034] Preferably, the purification treatment is an ammonium magnesium salt precipitation method;

[0035] Preferably, the purification step is: adjusting the pH of the crude ammonium molybdate solution to 9-10 with sulfuric acid, then adding magnesium sulfate for precipitation treatment, and then subjecting to solid-liquid separation treatment to obtain the purified ammonium molybdate solution;

[0036] Preferably, the ratio of the amount of magnesium sulfate to the total molar amount of phosphorus and arsenic in the crude ammonium molybdate solution is 1-1.5:1;

[0037] Preferably, the temperature in the purification stage is more than 20℃, preferably 20-60℃, and further 20-45℃;

[0038] Preferably, the time in the purification stage is more than 0.5h, preferably 0.5-6h, and further 0.5-4h.

[0039] In the present application, the acid used in the acid precipitation stage is sulfuric acid;

[0040] Preferably, the pH of the acid precipitation stage is less than or equal to 3, preferably 1-2.

[0041] Preferably, the temperature of the acid precipitation stage is above 20℃, preferably 50-60℃.

[0042] Preferably, the time of the acid precipitation stage is above 0.5h, preferably 0.5-6h, further 0.5-4h.

[0043] In the present application, the magnesium-nickel separation process is as follows: the raffinate is subjected to magnesium crystallization treatment in advance to obtain magnesium sulfate crystals and a crystallization mother liquor; the crystallization mother liquor is subjected to magnesium extraction treatment to obtain a magnesium-loaded organic phase and a nickel component (referring to nickel sulfate and its solution or crystals in the present application); and the magnesium-loaded organic phase is subjected to stripping treatment to obtain a magnesium component (referring to magnesium sulfate and its solution or crystals in the present application).

[0044] In the present application, the magnesium crystallization method is evaporation crystallization.

[0045] Preferably, the concentration volume of the evaporation crystallization is 1 / 2-1 / 4 of the initial solution volume.

[0046] Preferably, the extractant of the magnesium extraction stage is at least one of P507 and P204.

[0047] Preferably, the concentration of the extractant in the initial organic phase of the magnesium extraction stage is 5-30v%, further 5-15v%.

[0048] Preferably, the volume ratio of O / A of the magnesium extraction stage is 1:1-3, and the contact time is above 5min, preferably 5-15min.

[0049] Preferably, sulfuric acid is used for the stripping treatment of the magnesium-loaded organic phase.

[0050] Preferably, the concentration of the sulfuric acid is 0.2-2mol / L.

[0051] In the present application, the recovered magnesium sulfate can be recycled to the purification stage.

[0052] Advantages

[0053] 1. The present application innovatively uses magnesium oxide as an auxiliary agent to assist the heat treatment of molybdenum-nickel ore, which can realize the dual resource utilization of organic metal and sulfur in molybdenum-nickel ore, effectively avoid the influence of slagging of sulfur on leaching and recovery of nickel-rich slag, and also help the subsequent selective separation of nickel-molybdenum and magnesium.

[0054] In the present application, thanks to the magnesium oxide roasting mechanism and the physical and chemical modification, the synchronous leaching and reuse of more than 98% of molybdenum, magnesium and sulfur can be realized, and the leaching rate of nickel is controlled within 10%, so that the first stage selective separation of molybdenum-magnesium and nickel is realized. Further extraction treatment of the leaching solution enriched with molybdenum-magnesium-nickel-sulfate by an alkaline extractant can unexpectedly exhibit excellent molybdenum extraction selectivity and can avoid the accompanying extraction of nickel, magnesium and the like, and can exhibit excellent selectivity.

[0055] 2、The present application has no hazardous solid waste, simple process, small equipment investment, short process, simple operation and easy industrialization. DETAILED DESCRIPTION

[0056] The following examples are further illustrated, and the following examples are intended to illustrate the present application rather than further limit the present application.

[0057] A processing method of a nickel-molybdenum ore, comprising the following steps:

[0058] S1. Roasting

[0059] The magnesium oxide is mixed with the nickel-molybdenum ore and then roasted.

[0060] S2. Acid leaching

[0061] The roasted material produced in step S1 is subjected to acid leaching, and a leaching solution containing molybdenum and magnesium sulfate and a small amount of nickel sulfate and a nickel-rich residue are obtained by filtration.

[0062] S3. Extraction and transformation of molybdenum

[0063] Molybdenum is extracted from the molybdenum and magnesium sulfate-containing leaching solution in step S2 using an alkaline extractant, and ammonium molybdate solution is obtained by ammonia transformation, and a raffinate containing magnesium sulfate and a small amount of nickel sulfate is produced.

[0064] S4. Preparation of magnesium salt byproduct

[0065] Magnesium salt crystals are prepared from the raffinate containing magnesium sulfate and a small amount of nickel sulfate produced in step S3 by evaporation crystallization.

[0066] S5. Extraction and separation of magnesium from nickel-containing crystallization mother liquor

[0067] Magnesium is extracted from the crystallization mother liquor containing nickel sulfate in step S4 using extractant P507, and the raffinate is a purified nickel sulfate solution, and the back extraction process uses sulfuric acid to obtain magnesium sulfate solution which is returned to step S4.

[0068] S6. Preparation of nickel sulfate

[0069] Nickel sulfate crystals are prepared from the raffinate in step S5 by evaporation crystallization.

[0070] S7. Purification of ammonium molybdate solution

[0071] The crude ammonium molybdate solution obtained in step S3 is adjusted to pH 9.0-10.0 with sulfuric acid, and then impurities such as phosphorus and arsenic are removed by ammonium magnesium salt precipitation. The magnesium salt purifying agent used is magnesium sulfate produced in step S4.

[0072] S8. Preparation of ammonium tetramolybdate product

[0073] The ammonium molybdate solution purified in step S7 is used to prepare the ammonium tetramolybdate product by acid precipitation with sulfuric acid.

[0074] In step S1, the molar ratio of the amount of magnesium oxide added to the content of (sulfur and molybdenum) in the nickel-molybdenum ore is 1.1-2.0:1, the calcination temperature is 400-800°C, and the calcination time is 1-4 h.

[0075] In step S2, the leaching agent used is sulfuric acid, the concentration of sulfuric acid is 1-4 mol / L, the liquid-solid ratio is 1-10:1 (mL / g), the leaching temperature is 50-100°C, and the leaching time is 0.5-6 h.

[0076] In step S3, the extractant used is a primary amine or tertiary amine extractant.

[0077] In step S4, the raffinate is evaporated to 1 / 2-1 / 4 of the original volume by evaporation concentration, and then filtered to obtain magnesium sulfate crystals after cooling to room temperature.

[0078] In step S5, the extraction conditions are phase ratio O / A = 1:1-1:3, temperature 20-40°C, contact time 5-10 min, and the concentration of sulfuric acid used for back extraction is 0.2-2 mol / L.

[0079] In step S7, the ratio of the amount of magnesium sulfate purifying agent added to the total molar amount of impurities in the solution is 1.1-1.5:1, the reaction temperature is 25-60°C, and the reaction time is 0.5-6 h.

[0080] In step S8, the pH is adjusted to 1.5-2.0 by adding a sulfuric acid solution with a concentration of 15-35 wt%, the reaction temperature is 50-60°C, and the reaction time is 0.5-6 h.

[0081] In the following examples, the temperature in the extraction stage is room temperature, for example, 20-25°C, unless otherwise stated.

[0082] Example 1

[0083] S1. Calcination

[0084] Take nickel-molybdenum ore (containing Mo 4.21%, Ni 3.17%, S 23.67%, Fe 15.07%, SiO2 18.08%, P2O5 1.53%, As 0.46%) 100 g and mix with magnesium oxide uniformly, the amount of magnesium oxide is 2.0:1 of the total moles of sulfur and molybdenum in the nickel-molybdenum ore, and the roasting is carried out at 400°C for 4h, and the sulfur fixation rate is 99.1%.

[0085] S2. Acid leaching

[0086] The roasted material produced in step S1 is subjected to leaching reaction with sulfuric acid, the concentration of sulfuric acid is 2 mol / L, the liquid-solid ratio is 2:1 (ml / g), the leaching temperature is 50°C, and the leaching time is 5h. After the leaching is completed, the analysis shows that the leaching rate of molybdenum is 98.2%, and the leaching rate of nickel is 8.1%, and a nickel-rich residue is obtained by filtration, and the residue rate is 48.2%.

[0087] S3. Extraction and transformation of molybdenum

[0088] Molybdenum is extracted from the leaching solution containing molybdenum and magnesium sulfate and nickel sulfate produced in step S2 using 50ml of organic phase (10% N235 (extractant) + 10% sec-octyl alcohol + 80% sulfonated kerosene) (O / A phase ratio is 3:1, contact time is 5min), the molybdenum extraction rate is 99.1% (nickel and magnesium cations are not extracted); back extraction is carried out using 5mol / L ammonia water, the amount of ammonia water is 3 times the theoretical amount, and the single-stage back extraction rate is 94.1%, and a crude ammonium molybdate solution is obtained.

[0089] S4. Preparation of magnesium salt by-product

[0090] Magnesium sulfate is prepared from the raffinate containing magnesium sulfate and a small amount of nickel sulfate produced in step S3 by evaporation crystallization, and when the evaporation is carried out to 1 / 3 of the volume of the exchanged liquid, the crystallization rate of magnesium sulfate is 88.5% after cooling to room temperature.

[0091] S5. Extraction and separation of magnesium from nickel-containing crystallization mother liquor

[0092] Magnesium is extracted from the crystallization mother liquor containing nickel sulfate in step S4 using extractant P507 (the initial organic phase is a mixture of P507-sulfonated kerosene, wherein the P507 content is 10v%), the extraction conditions are phase ratio O / A=1:1, temperature 20°C, contact time 5min, the single-stage extraction rate of magnesium is 92.2%, and the extraction rate of nickel is 0.81%, and the single-stage back extraction rate is 93.3% using 2mol / L sulfuric acid, and the magnesium sulfate solution obtained by back extraction is returned to step S4.

[0093] S6. Preparation of nickel sulfate

[0094] Nickel sulfate is prepared from the raffinate in step S5 by evaporation crystallization.

[0095] S7. Purification of ammonium molybdate solution

[0096] The crude ammonium molybdate solution obtained in step S3 is first adjusted to pH 9.0 with sulfuric acid, then the magnesium sulfate crystals produced in step S4 are dissolved in water to form a 100 g / L solution, which is then added dropwise to the adjusted crude ammonium molybdate solution. The amount of magnesium sulfate added is 1.1:1 relative to the total moles of impurities phosphorus and arsenic in the solution, the reaction temperature is 25°C, and the reaction time is 4 hours. After the reaction is complete, the purified ammonium molybdate solution is obtained by filtration.

[0097] S8. Preparation of ammonium tetramolybdate product

[0098] A 15wt% sulfuric acid solution is added to the purified ammonium molybdate solution from step S5, the solution pH is adjusted to 1.5, the reaction temperature is 50°C, and after aging for 4 hours, the ammonium tetramolybdate product is obtained by filtration.

[0099] Example 2

[0100] S1. Roasting

[0101] Take 100g of nickel-molybdenum ore (containing Mo 4.21%, Ni 3.17%, S 23.67%, Fe 15.07%, SiO2 18.08%, P2O5 1.53%, As 0.46%) and mix it evenly with magnesium oxide. The amount of magnesium oxide used is 1.1:1 relative to the total moles of sulfur and molybdenum elements in the nickel-molybdenum ore, and the roasting is carried out at 800°C for 1 hour. The sulfur fixation rate is 98.3%.

[0102] S2. Acid leaching

[0103] The roasted material produced in step S1 is subjected to leaching reaction using sulfuric acid. The sulfuric acid concentration is 1 mol / L, the liquid-solid ratio is 8:1 (ml / g), the leaching temperature is 100°C, and the leaching time is 1 hour. After the leaching is complete, the molybdenum leaching rate is 98.5%, the nickel leaching rate is 8.9%, and the nickel-rich residue is obtained by filtration, with a residue rate of 48.4%.

[0104] S3. Extraction and transformation of molybdenum

[0105] Molybdenum is extracted from the leaching solution containing molybdenum and magnesium sulfate and nickel sulfate produced in step S2 using 50ml of organic phase (10% N1923 + 10% sec-octyl alcohol + 80% sulfonated kerosene) (O / A phase ratio is 4:1, contact time is 5 minutes), the molybdenum extraction rate is 98.8%; back extraction is carried out using 5 mol / L ammonia water, the amount of ammonia water used is 3 times the theoretical amount, the single-stage back extraction rate is 94.3%, and the crude ammonium molybdate solution is obtained.

[0106] S4. Preparation of magnesium salt by-product

[0107] The magnesium sulfate was prepared from the raffinate containing magnesium sulfate and a small amount of nickel sulfate produced in step S3 by evaporation crystallization. When the evaporation was to 1 / 4 of the volume of the exchanged liquid, the crystallization rate of magnesium sulfate was 90.5% after cooling to room temperature.

[0108] S5. Extraction and separation of magnesium from the nickel-containing crystallization mother liquor

[0109] The magnesium was extracted from the crystallization mother liquor containing nickel sulfate in step S4 by using the extractant P507 (the initial organic phase was a mixture of P507 and sulfonated kerosene, wherein the P507 content was 15v%), and the extraction conditions were phase ratio O / A = 1:3, temperature 40°C, and contact time 10 min. The single-stage extraction rate of magnesium was 94.3%, and the extraction rate of nickel was 0.66%. The single-stage stripping rate was 81.3% by using 0.2 mol / L sulfuric acid, and the magnesium sulfate solution obtained by stripping was returned to step S4.

[0110] S6. Preparation of nickel sulfate

[0111] The nickel sulfate crystals were prepared from the raffinate in step S5 by evaporation crystallization.

[0112] S7. Purification of ammonium molybdate solution

[0113] First, the crude ammonium molybdate solution obtained in step S3 was adjusted to pH 9.0 by using sulfuric acid, and then the magnesium sulfate crystals produced in step S4 were dissolved in water to form a 100 g / L solution, which was then added dropwise into the adjusted crude ammonium molybdate solution. The ratio of the amount of magnesium sulfate added to the total molar amount of impurities phosphorus and arsenic in the solution was 1.5:1, the reaction temperature was 50°C, and the reaction time was 0.5 h. After the reaction, the purified ammonium molybdate solution was obtained by filtration.

[0114] S8. Preparation of tetramolybdate product

[0115] A 35wt% sulfuric acid solution was added to the purified ammonium molybdate solution from step S5, the pH of the solution was adjusted to 2.0, the reaction temperature was 60°C, and the solution was aged for 0.5 h before being filtered to obtain the tetramolybdate product.

[0116] Example 3

[0117] S1. Roasting

[0118] 100 g of nickel-molybdenum ore (containing Mo 4.21%, Ni 3.17%, S 23.67%, Fe 15.07%, SiO2 18.08%, P2O5 1.53%, and As 0.46%) was mixed with magnesium oxide, and the amount of magnesium oxide used was 1.5:1 of the total molar amount of sulfur and molybdenum in the nickel-molybdenum ore. The mixture was roasted at 600°C for 2 h, and the sulfur fixation rate was 98.8%.

[0119] S2. Acid leaching

[0120] The roasted material from step S1 was leached with sulfuric acid, the sulfuric acid concentration was 2 mol / L, the liquid-solid ratio was 5:1 (ml / g), the leaching temperature was 80°C, and the leaching time was 4 h. After the leaching was completed, the molybdenum leaching rate was 97.8%, the nickel leaching rate was 7.6%, and a nickel-rich residue was obtained by filtration, with a residue rate of 49.8%.

[0121] S3. Extraction and transformation of molybdenum

[0122] Molybdenum was extracted from the leaching solution containing molybdenum and magnesium sulfate and nickel sulfate produced in step S2 using 50 ml of organic phase (10% N235 + 10% sec-octyl alcohol + 80% sulfonated kerosene) (O / A phase ratio was 3:1, contact time was 5 min), molybdenum extraction rate was 99.5%; Stripping with 5 mol / L ammonia water, the amount of ammonia water was 3 times the theoretical amount, the single-stage stripping rate was 92.8%, and a crude ammonium molybdate solution was obtained.

[0123] S4. Preparation of magnesium salt by-product

[0124] Magnesium sulfate was prepared from the raffinate containing magnesium sulfate and a small amount of nickel sulfate produced in step S3 by evaporation crystallization. When the evaporation was stopped at 1 / 2 of the volume of the exchanged solution, the crystallization rate of magnesium sulfate was measured to be 78.1% after cooling to room temperature.

[0125] S5. Extraction and separation of magnesium from nickel-containing crystallization mother liquor

[0126] Magnesium was extracted from the crystallization mother liquor containing nickel sulfate in step S4 using extractant P507 (the initial organic phase was a mixture of P507-sulfonated kerosene, wherein the P507 content was 10v%), the extraction conditions were phase ratio O / A = 1:2, temperature 30°C, contact time 5 min, the single-stage extraction rate of magnesium was 93.5%, and the extraction rate of nickel was 0.71%. Stripping with 1 mol / L sulfuric acid, the single-stage stripping rate was 92.6%, and a magnesium sulfate solution was obtained by stripping and returned to step S4.

[0127] S6. Preparation of nickel sulfate

[0128] Nickel sulfate crystals were prepared from the raffinate in step S5 by evaporation crystallization.

[0129] S7. Purification of ammonium molybdate solution

[0130] First, the crude ammonium molybdate solution obtained in step S3 was adjusted to pH 9.0 with sulfuric acid, then the magnesium sulfate crystals produced in step S4 were dissolved in water to prepare a 100 g / L solution, and then added dropwise into the adjusted crude ammonium molybdate solution, the ratio of magnesium sulfate addition amount to total molar amount of impurities phosphorus and arsenic in the solution was 1.2:1, the reaction temperature was 40°C, and the reaction time was 2 h. After the reaction was completed, the purified ammonium molybdate solution was obtained by filtration.

[0131] S8. Preparation of ammonium tetramolybdate product

[0132] A 20wt% sulfuric acid solution was added to the ammonium molybdate solution purified from step S5, the solution pH was adjusted to 1.5, the reaction temperature was 60°C, and after aging for 2h, filtration was performed to obtain the ammonium tetramolybdate product.

[0133] Example 4

[0134] S1. Roasting

[0135] 100g of a nickel-molybdenum ore (containing Mo 4.21%, Ni 3.17%, S 23.67%, Fe 15.07%, SiO2 18.08%, P2O5 1.53%, As 0.46%) was mixed with magnesium oxide, the amount of magnesium oxide was 1.2:1 relative to the total moles of sulfur and molybdenum in the nickel-molybdenum ore, and roasting was performed at 700°C for 2h, with a sulfur fixation rate of 98.6%.

[0136] S2. Acid leaching

[0137] The roasted material from step S1 was subjected to a leaching reaction using sulfuric acid, the sulfuric acid concentration was 3mol / L, the liquid-solid ratio was 6:1 (ml / g), the leaching temperature was 90°C, and the leaching time was 5h. After the leaching was completed, the molybdenum leaching rate was 98.3%, the nickel leaching rate was 9.4%, and a nickel-rich residue was obtained by filtration, with a residue rate of 48.0%.

[0138] S3. Extraction and transformation of molybdenum

[0139] Molybdenum was extracted from the leaching solution containing molybdenum and magnesium sulfate and nickel sulfate produced in step S2 using 50ml of an organic phase (10% N1923 + 10% sec-octyl alcohol + 80% sulfonated kerosene) (O / A phase ratio was 2:1, contact time was 10min), the molybdenum extraction rate was 99.2%; back extraction was performed using 5mol / L ammonia water, the amount of ammonia water was 3 times the theoretical amount, the single-stage back extraction rate was 92.8%, and a crude ammonium molybdate solution was obtained.

[0140] S4. Preparation of magnesium salt byproduct

[0141] Magnesium sulfate was prepared from the raffinate containing magnesium sulfate and a small amount of nickel sulfate produced in step S3 by evaporation crystallization, and when the evaporation was stopped at 1 / 3 of the volume of the exchanged solution, the crystallization rate of magnesium sulfate was measured to be 88.7% after cooling to room temperature.

[0142] S5. Extraction and separation of magnesium from nickel-containing crystallization mother liquor

[0143] The magnesium is extracted from the crystallization mother liquor containing nickel sulfate in step S4 by using extractant P204 (the initial organic phase is a mixture of P204-sulfonated kerosene, wherein the P507 content is 10v%), the extraction conditions are phase ratio O / A = 1:1, temperature 40℃, and contact time 5min, the single-stage extraction rate of magnesium is 92.0%, and the extraction rate of nickel is 0.63%, and the single-stage stripping rate is 94.1% by using 2mol / L sulfuric acid, and the magnesium sulfate solution obtained by stripping is returned to step S4.

[0144] S6. Preparation of nickel sulfate

[0145] The nickel sulfate crystals are prepared from the raffinate in step S5 by using evaporation crystallization.

[0146] S7. Purification of ammonium molybdate solution

[0147] First, the crude ammonium molybdate solution obtained in step S3 is adjusted to pH 9.0 by using sulfuric acid, then the magnesium sulfate crystals produced in step S4 are dissolved in water to form a 100g / L solution, and the solution is added dropwise into the crude ammonium molybdate solution which has been adjusted, the ratio of the amount of magnesium sulfate added to the total molar amount of impurities phosphorus and arsenic in the solution is 1.3:1, the reaction temperature is 25℃, and the reaction time is 2h. After the reaction is completed, the purified ammonium molybdate solution is obtained by filtration.

[0148] S8. Preparation of ammonium tetramolybdate product

[0149] A 25wt% sulfuric acid solution is added to the purified ammonium molybdate solution obtained in step S5, the solution pH is adjusted to 1.5, the reaction temperature is 50℃, and the ammonium tetramolybdate product is obtained by filtration after aging for 4h.

[0150] Comparative Example 1

[0151] Compared with Example 1, the only difference is that in S1, equal molar calcium hydroxide is used to replace the magnesium oxide, and other operations and parameters are the same as those in Example 1.

[0152] After testing, it is found that in S2, after the leaching is completed, the molybdenum leaching rate is 74.3%, the nickel leaching rate is 8.6%, and the low-grade nickel residue containing calcium sulfate is obtained by filtration, and the residue rate is 152.7%.

[0153] In addition, based on Comparative Example 1, the acid in S2 is further changed to hydrochloric acid, and the leaching rate and residue rate are not improved.

[0154] Comparative Example 2

[0155] Compared with Example 1, the only difference is that in S3, the extractant is equal amount of P507, and other operations and parameters are the same as those in Example 1.

[0156] The test results show that in S3, the extraction rates of Mo, Mg and Ni are 62.0%, 45.8% and 1.3%, respectively.

Claims

1. A process for the treatment of a nickel-molybdenum ore, characterized in that, The mixture containing nickel-molybdenum ore and additives is subjected to heat treatment to obtain a heat-treated material, the additives being magnesium oxide or a precursor capable of being converted into magnesium oxide in the roasting stage; the nickel-molybdenum ore being a composite sulfide ore of nickel and molybdenum; the total molar ratio of Mg element in the additives and sulfur and molybdenum elements in the nickel-molybdenum ore being above 1; the temperature of heat treatment being 400-800℃; the heat treatment process being carried out in an oxygen-containing atmosphere; The heat-treated material is subjected to sulfuric acid leaching treatment to obtain a nickel-rich residue and a leachate rich in molybdenum, magnesium and part of nickel; The leachate is subjected to molybdenum extraction treatment using an alkaline extractant to obtain a molybdenum-loaded organic phase and a raffinate rich in magnesium and nickel; The alkaline extractant is at least one of N235 and N1923; The raffinate is subjected to magnesium-nickel separation treatment to obtain magnesium component and nickel component.

2. The processing method of pentlandite according to claim 1, characterized in that In the nickel-molybdenum ore, the grade of Mo is above 1%, and the grade of Ni is above 1%.

3. The processing method of pentlandite according to claim 2, characterized in that In the nickel-molybdenum ore, the grade of Mo is 2-10%, and the grade of Ni is 2-10%.

4. The processing method of pentlandite according to claim 1, characterized by, The total molar ratio of Mg element in the additives and sulfur and molybdenum elements in the nickel-molybdenum ore is 1.1-2.0:

1.

5. The processing method of pentlandite according to claim 4, characterized in that, The total molar ratio of Mg element in the additives and sulfur and molybdenum elements in the nickel-molybdenum ore is 1.1-1.3:

1.

6. The treatment method of nickel-molybdenum ore according to claim 1, characterized in that, The time of heat treatment is above 1h.

7. The process for treating a nickel-molybdenum ore according to claim 6, characterized in that, The time of heat treatment is 1-4h.

8. The processing method of pentlandite according to claim 1, characterized by, In the sulfuric acid leaching stage, the concentration of the initial sulfuric acid solution is 1-4M; The liquid-solid ratio of sulfuric acid to the roasted material is above 1mL / g; The temperature in the sulfuric acid leaching stage is above 10℃; The time of sulfuric acid leaching is above 0.5h; The leaching rate of nickel in the sulfuric acid leaching stage is less than or equal to 10%.

9. The processing method of pentlandite according to claim 8, characterized in that, The liquid-solid ratio of sulfuric acid to the roasted material is 1-10mL / g; The temperature in the sulfuric acid leaching stage is 50-100℃; The time of sulfuric acid leaching is 0.5-6h.

10. The processing method of pentlandite according to claim 1, characterized by, In the initial organic phase, the content of the alkaline extractant is above 5v%; In the molybdenum extraction stage, O / A is 1-10:1, and the contact time is above 1min; The molybdenum-loaded organic phase is subjected to back extraction using ammonia water to obtain ammonium molybdate crude solution; The contact time in the back extraction stage is above 1min.

11. The processing method of pentlandite according to claim 10, characterized in that, In the initial organic phase, the content of the alkaline extractant is 5-30v%; The contact time in the molybdenum extraction stage is 1-20min; The contact time in the back extraction stage is 1-20min.

12. The processing method of pentlandite according to claim 10, characterized in that, The ammonium molybdate crude solution is subjected to purification and acid precipitation treatment to obtain ammonium tetramolybdate product; The purification treatment refers to a step of removing phosphorus and / or arsenic from the ammonium molybdate crude solution; The purification treatment is ammonium-magnesium salt precipitation method; The purification step is: the pH of the ammonium molybdate crude solution is adjusted to 9-10 using sulfuric acid, then magnesium sulfate is added for precipitation treatment, and then solid-liquid separation treatment is carried out to obtain purified ammonium molybdate solution; The ratio of the amount of magnesium sulfate to the total molar amount of phosphorus and arsenic in the ammonium molybdate crude solution is 1-1.5:1; The temperature in the purification stage is above 20℃; The time in the purification stage is above 0.5h.

13. The processing method of pentlandite according to claim 12, characterized in that, The acid used in the acid precipitation stage is sulfuric acid; The pH in the acid precipitation stage is less than or equal to 3; The temperature in the acid precipitation stage is above 20℃; The time in the acid precipitation stage is above 0.5h.

14. The processing method of pentlandite according to claim 13, characterized in that, The pH of the acid precipitation stage is 1-2; The temperature of the acid precipitation stage is 50-60℃; The time of the acid precipitation stage is 0.5-6h.

15. The process for treating a nickel-molybdenum ore according to claim 1, characterized in that, The process of magnesium-nickel separation treatment is as follows: magnesium crystallization treatment is performed on the raffinate in advance to obtain magnesium sulfate crystals and a crystallization mother liquor; magnesium extraction treatment is performed on the crystallization mother liquor to obtain a magnesium-loaded organic phase and a nickel component; and the magnesium-loaded organic phase is subjected to back extraction treatment to obtain a magnesium component.

16. The processing method of pentlandite according to claim 15, characterized in that, The magnesium crystallization mode is evaporation crystallization; The concentration volume of the evaporation crystallization is 1 / 2-1 / 4 of the initial solution volume; The extractant of the magnesium extraction stage is at least one of P507 and P204; The concentration of the extractant in the initial organic phase of the magnesium extraction stage is 5-30v%; The volume ratio of O / A of the magnesium extraction stage is 1:1-3, and the contact time is more than 5min; The magnesium-loaded organic phase is subjected to back extraction treatment using sulfuric acid; The concentration of the sulfuric acid is 0.2-2mol / L.