CN1257292C - Method for recovering nickel and aluminum from waste aluminum based nickel-containing catalyst - Google Patents

Abstract

The present invention relates to a method for recovering nickel and aluminum from waste aluminum base nickel-containing catalysts. The present invention has the characteristics of novel technique, reasonable processes, simple and practical method, convenient scale production and favorable environmental protection. The method comprises the following steps: sintering sodium carbonate, and changing states; dissolving sodium aluminate by boiling water, and separating aluminum; reducing nickel residues, and making and melting matte to obtain nickel matte Ni3S2-FeS-Ni-Fe alloy or copper-nickel matte Cu2S-Ni3S2-FeS alloy; blowing to obtain high-grade nickel matte Ni3S2 or high-grade copper-nickel matte Cu2S-Ni3S2-Cu-Ni alloy; desiliconizing a crude NaAlO2 solution; making carbonating decomposition to obtain aluminium hydroxide Al2O3.3H2O; calcining to obtain anhydrous aluminum oxide alpha-Al2O3. The method is suitable for recovering nickel and aluminum from waste residues generated by the extraction of molybdenum and vanadium from waste aluminum base nickel-containing catalysts and failed catalysts containing nickel, aluminum, molybdenum and vanadium.

Description

Method for recovering nickel and aluminum from waste aluminum-based nickel-containing catalyst

The technical field is as follows:

the invention relates to the technical field of nonferrous metal refining, in particular to a method for recovering nickel and aluminum from a waste aluminum-based nickel-containing catalyst.

Background art:

according to statistics, about 50-70 ten thousand tons of waste catalysts are generated every year all over the world, and a large amount of noble metals, nonferrous metals and oxides thereof are consumed for manufacturing the catalysts. From the perspective of reasonable utilization of resources and environmental protection, the waste catalyst needs to be regenerated and recycled.

The Al-based Ni-Mo, Ni-Co-Mo and Co-Mo catalysts are prepared from Al substrate₂O₃And active components, and is widely applied to the fertilizer industry. Only the output of various chemical fertilizer catalysts in China currently keeps about 3 ten thousand tons per year. After the catalyst is used for a long time, metals such as nickel, cobalt, molybdenum, vanadium and the like serving as active components are polluted by various impurities to lose the activity, so that the catalyst becomes a waste catalyst. The waste catalyst is an important secondary resource of nonferrous metals. The method for recovering nonferrous metals from aluminum-based spent catalysts includes a carrier dissolution method, a dry volatilization method, a melting and trapping method, a plasma melting method and the like. The waste aluminum-based nickel-molybdenum, nickel-cobalt-molybdenum and cobalt-molybdenum catalysts are spherule catalysts with phi 2.5-phi 10mm or strip, cloverleaf and Raschig annular catalysts with phi 3 multiplied by phi 3-8 mm, and the appearance colors of the catalysts are gray blue, light blue, tile ash, yellow and the like. The main components are (%), Al₂O₃24-85, Ni1.1-14 (Ni content of high nickel catalyst can reach more than 20%), or Co1.1-11.8, MoO-15, K₂O+Na₂O 0.1～0.25，Fe₂O₃Trace amount of CaO (CaO content of few high-calcium catalysts can reach 15%), V₂O₅Trace of SiO₂0.2 to 2.0. After extracting molybdenum and vanadium from the spent catalyst containing nickel, aluminum, molybdenum and vanadium,the typical composition of the slag is (%) Al₂O₃62～65，Ni3.89～4.64，Na₂Trace of O, V₂O₅1.5，MoO₃0.20，Fe₂O₃Trace of SiO₂1.5. Because the catalyst is formed and then calcined at high temperature in the original manufacturing process, nickel is in NiO form, and cobalt is in CoO or Co form in the waste catalyst and the waste residue₂O₃In the form of α -Al, which is mainly insoluble₂O₃A small proportion of r-Al₂O₃The shape of the material exists, and the material belongs to a material which is difficult to treat. The effect ofthe catalyst and the waste residue thereof is not ideal when the catalyst and the waste residue thereof are treated by adopting the direct leaching process of acid and alkali. Al of the former₂O₃The leaching rate is not high, and nickel can be dispersed in the solution, so that the aim of separating nickel and aluminum can not be fulfilled; the latter nickel does not enter into the alkaline solution, but Al₂O₃The dissolution rate of (A) is also less than 50%, and SiO in the raw material₂Aluminosilicate (Na) with low solubility is easily formed₂O·Al₂O₃·2SiO₂·2H₂O) scale on the inner walls of the equipment and filtration is difficult. The raw material contains 60-80% of Al₂O₃It is not suitable for direct treatment by smelting and trapping method, and it adopts plasma smelting method to smelt the waste catalyst or waste slag at high temp. above 1500 deg.C, and can obtain ferronickel alloy, but because of low raw material grade, high energy consumption of unit product and Al matrix₂O₃Nor is it utilized.

The invention content is as follows:

the invention aims to provide a novel alloy made of Al₂O₃The method is a method for effectively separating nickel and aluminum from waste residue and waste aluminum-based nickel-containing catalyst with any crystal form, is easy to implement, is beneficial to environmental protection, and can comprehensively recover nickel and aluminum.

The method provided by the invention comprises the steps of soda ash sintering transformation, dissolving sodium aluminate by boiling water, separating aluminum, reducing nickel slag, forming matte, and smelting to obtain nickel matte (Ni)₃S₂FeS-Ni-Fe alloy) or copper-nickel-sulfonium (Cu)₂S-Ni₃S₂-FeS alloy) -converting to nickel matte (Ni)₃S₂) Or copper-nickel high sulfonium Cu₂S-Ni₃S₂-Cu-Ni alloy) -coarse NaAlO₂Solution desilication-carbonation decomposition to obtain aluminum hydroxide (Al)₂O₃3H₂O) -calcining to obtain anhydrous alumina (α -Al₂O₃) The method comprises the following specific steps: (1) mixing waste residue obtained after molybdenum and alum are extracted from crushed waste aluminum-based nickel-containing catalyst or spent catalyst containing nickel, aluminum, molybdenum and vanadium with soda ash, namely sodium carbonate, wherein the use amount of the soda ash is 1: 0.7-1.3, preferably 1: 0.9-1.1, the temperature is 700-1250 ℃, preferably 1000-1150 ℃, the materials are subjected to interaction in a sintering furnace lined with high-alumina bricks, preferably a rotary kiln to perform a transition reaction, and the constant temperature is kept for 1-6 hours, preferably 3-4 hours. (2) The flue gas generated by the sintering furnace is sprayed and washed by water, the temperature of the gas is reduced to 30-40 ℃, and the content of smoke dust is reduced to 0.02 g/m³0.05 g/m³Preferably 0.02 to 0.03 g/m³Then used as NaAlO₂CO decomposed by carbonation of solution₂And (4) a gas source. (3) After the sinter is crushed, the sodium aluminate is dissolved by boiling water to separate aluminum, the boiling water is washing water for washing nickel slag or aluminum hydroxide crystals in a countercurrent mode, the using amount of the washing water is 1: 2-10, preferably 1: 4-6, of the weight gram of the sinter to the volume milliliter of the boiling water, the temperature is the boiling temperature of water, preferably more than 95 ℃, and the time is 0.5-2 hours, preferably 1 hour. And washing the insoluble nickel slag by hot water in the same proportion ina countercurrent mode for 2-3 times. (4) Dissolving the sinter to obtain coarse NaAlO₂Heating to 85-95 ℃, preferably more than 90 ℃, adding 5-10 g, preferably 6-8 g of lime (CaO) powder according to the volume of each liter of solution, or adding lime milk prepared in the same amount for desilication, stirring for reaction for 1-3 hours, preferably 2-3 hours, filtering, washing the filtered silica residue with hot water. The silicon slag is returned to the sintering process for retreatment to recover Al in the silicon slag₂O₃. (5) Desiliconizing Al₂O₃NaAlO with a concentration of 100 g/l to 140 g/l₂Heating the solution to 60-80 deg.C, preferably 70-75 deg.C, based on Al in the solution₂O₃Content and Al in seed crystal₂O₃Adding hydrogen in a content ratio of 1: 1 to 1.5Introducing CO into the alumina seed crystal under the stirring condition of 8-10 revolutions per minute₂The gas undergoes a carbonation decomposition reaction to CO₂The gas concentration is 8-14%, preferably more than 13%, and the decomposition time is 10-20 hours, preferably 14-16 hours. The aluminum hydroxide crystals are washed with pure water (soft water) and dried at a temperature of 80 ℃ to 160 ℃. Al content in mother liquid₂O₃5-7 g/l, concentrating with concentrated Na₂CO₃Returning the solution form to the sintering process for batching. Aluminum hydroxide (Al)₂O₃·3H₂O) is calcined at 1200 ℃ to obtain an anhydrous alumina product (α -Al)₂O₃). (6) Separating the nickel-rich slag from the aluminum, using pyrite (main component FeS)₂) Gypsum ore (CaSO as main component)₄·nH₂O, n ═ 2 or 3), copper sulfide concentrate (main component CuFeS)₂) Or copper nickel sulfide concentrate (main component CuFeS)₂Nis FeS) as vulcanizing agent, and smelting slag (FeO-SiO) of copper smelting plant or nickel smelting plant₂CaO type) or blown slag (2 FeO. SiO)₂Type) any one of the waste slag is used as a fusing agent, any one of carbon, coal or coke is used as a reducing agent to carry out reduction, matte and smelting to obtain nickel matte (Ni)₃S₂FeS-Ni-Fe alloy) or copper-nickel-sulfonium (Cu)₂S-Ni₃S₂-FeS alloy). The mixture ratio is: the weight ratio of the nickel-rich slag, the vulcanizing agent, the flux and the reducing agent is 1: 0.1-0.3: 1-3: 0.02-0.05, preferably 1: 0.1-0.15: 1.5-2: 0.03, the smelting temperature is 1250-1400 ℃, preferably 1300-1350 ℃, and the smelting time is 1-2 hours. Using quartz (SiO) in the conventional converting method of copper and nickel smelting plant₂) Blowing the mixture as a flux to obtain nickel matte (Ni)₃S₂) Or copper-nickel high sulfonium Cu₂S-Ni₃S₂-Cu-Ni alloy) and the blown slag is returned to the smelting process as a flux.

The main reaction equation in the process of the invention is as follows:

1. sintering and state transition of soda ash:

oxides of Al, Si, Fe and V and Na in the material₂CO₃The following reactions are carried out:

ni in the material exists in NiO form and reacts with Al at high temperature₂O₃、SiO₂、Fe₂O₃Form NiO-Al which is difficult to dissolve in water₂O₃、NiSiO₃、NiFe₂O₄… … A compound.

2. Dissolving sodium aluminate in boiling water to separate aluminum:

3. crude NaAlO₂Solution desiliconization:

4、NaAlO₂and (3) carbonating and decomposing the solution:

in the presence of silicon;

5. smelting of nickel-rich slag through reduction and matte formation

(1) When pyrite is used as a vulcanizing agent:

when nickel silicate is contained in the material:

(2) when gypsum ore is used as a vulcanizing agent:

(3) when the copper sulfide concentrate and the copper sulfide nickel concentrate are used as vulcanizing agents:

with SiO₂Fe produced by the above formula₃O₄With FeS the following reaction takes place

6. Nickel matte or copper nickel matte converting, wherein the nickel matte converting only has oxidation slagging reaction of Fe and FeS:

the invention has the advantages that: 1. the process technology is novel, the flow structure is reasonable, and the effective separation and comprehensive recovery of nickel and aluminum can be realized. Prepared aluminum hydroxide (Al)₂O₃·3H₂O) and alumina (α -Al)₂O₃) Respectively reaches the quality requirements of national standard third-grade aluminum hydroxide and industrial third-grade aluminum oxide. The nickel-containing grade of the nickel matte obtained by the reduction and matte smelting of the nickel slag is 17.94-32.15%. The smelting recovery rate of Ni is more than or equal to 85 percent, and Al is used as Al₂O₃The content is more than or equal to 79 percent. 2. The method is simple and easy to implement, and is convenient for large-scale implementation, production and application. 3. Na (Na)₂CO₃The solution is regenerated and reused, and the waste slag of copper and nickel smelteries is used as a flux, so that the production cost of aluminum hydroxide and nickel matte is reduced. 4. Has strong adaptability to raw materials and better market prospect and popularization value. The method is not only suitable for recovering nickel and aluminum from waste residues after extracting molybdenum and vanadium from low-grade waste aluminum-based nickel-containing catalysts and spent catalysts containing nickel, aluminum, molybdenum and vanadium, but also suitable for recovering nickel, cobalt and aluminum from high-grade waste aluminum-based nickel-containing and cobalt-containing catalysts. 5. The pure alkali sintering state-changing process of the project has nosmoke harm, and the smoke of the sintering furnace is used as NaAlO after being purified₂CO decomposed by carbonation of solution₂A gas source; the process water of the wet process part can realize closed cycle operation and is not discharged outwards; the silicon slag produced by purifying the sodium aluminate solution is returned to the sintering process for retreatment so as to recover Al in the silicon slag₂O₃(ii) a The slag produced in the nickel slag smelting operation is solid smelting slag which can not change form and change after being stacked for a long time; therefore, the technology of the invention can not cause harm to the environmentAnd influence, and is beneficial to environmental protection.

Description of the drawings:

FIG. 1 is a process flow diagram of the present invention.

The specific implementation mode is as follows:

crushing the waste aluminum-based nickel-containing catalyst and waste residues after molybdenum and vanadium extraction by adopting an FXS-300 type winnowing crusher; the coal-fired indirect heating furnace is used as a sintering furnace, high-alumina bricks are built in the furnace, and the size length multiplied by the width multiplied by the height is 1500 multiplied by 1300 multiplied by 500 (millimeters). Each time, 80-100 kg of the materials are charged; crushing the sintered blocks by a 9FZ-23 type claw crusher; 300 liters and 1 meter³Dissolving sintered materials in an iron stirring tank and a reaction kettle, filtering by a 600X 250 (millimeter) vacuum filtration box, washing nickel slag, and driving the filtration box by an SZB-8 type water ring vacuum pump; desiliconizing and carbonating decomposing in stainless steel stirring tank of phi 500 × 600 mm; designing and building a smelting furnace with the length multiplied by the width multiplied by the height of 1500 multiplied by 250 multiplied by 800 (millimeter) to smelt the nickel-rich slag; the implementation effect of the waste aluminum-based nickel-containing catalyst and the waste residue after molybdenum and vanadium are extracted by applying the process of the invention is examined; sintering and transferring the state of the calcined soda, and dissolving and separating aluminum by boiling water; the average yield of the sintered material was 81.10%, Al₂O₃The dissolution rate is 79.93-83.79%, and nickel is enriched by 2.1-2.63 times in the nickel-rich slag; the prepared aluminum hydroxide or aluminum oxide respectively meets the three-level quality requirements of the national standard, and the nickel grade of the nickel matte obtained by the reduction, the matte and the smelting of the nickel slag is 17.94 to 32.15 percent; smelting recovery rate: ni is more than or equal to 85 percent, and Al is Al₂O₃The content is more than or equal to 79 percent.

Example 1:

1000 g of crushed pieces of phi 16 x phi 6mm tile gray Raschig annular waste catalyst with the content of α -Al₂O₃49.20％，Ni11.40％(NiO14.5％)，SiO₂2.0 percent and CaO14.80 percent; (1) at 1100-1150 deg.C, the weight ratio of waste catalyst to sodium carbonate is 1: 1, and at SX₂Sintering reaction in a 12-10 box type resistance furnace for 3 hours to obtain 1787 g of sintering material with the yield of 85.10%; (2) dissolving with boiling waterThe ratio of the weight gram of the sintering material to the volume milliliter of the boiling water is 1: 4, the temperature is the boiling temperature of water, the time is 1 hour, the nickel slag is washed by hot water for 2 times and then dried, the weight of the nickel slag is 472 grams, the grade is Ni24.12 percent, and Al is added₂O₃20.92 percent; calculated as the nickel slag component, Al₂O₃The dissolution rate is 79.93%, and the nickel is enriched by 2.1 times.

Example 2:

200 kg of light blue waste residue containing Al and after molybdenum and vanadium are extracted from the spent catalyst containing nickel, aluminum, molybdenum and vanadium₂O₃64.96％，Ni4.64％(NiO5.89％)，V₂O₅1.50％，MoO₃0.20％，SiO₂1.5％，Na₂O and Fe₂O₃Trace; (1) the waste residue is dried and crushed powder, and is sintered in 5 batches in the coal-fired heating furnace, 40 kg of the material is fed each time, the temperature is 1000-1050 ℃, the weight ratio of the waste residue to sodium carbonate is 1: 1-1.25, the sintering reaction is carried out for 4-6 hours, 336.4 kg of the sintering material is obtained, and the yield is 82.05%; (2) after the sintering material is crushed, the nickel slag is dissolved by washing water which is heated to boiling and used for washing the nickel slag, 40 kg of sintering material powder is added each time, the weight kg of the sintering material and the volume rise of boiling water are 1: 4-6, the temperature is the boiling temperature of water, the time is 1 hour, and the nickel slag is washed by hot water in the same proportion in a counter-current mode for 2 times. The obtained nickel slag is 72.7 kg, and the component Al is₂O₃28.96%, average Ni grade 11.44%, Al₂O₃The dissolution rate is 83.79%, and the nickel in the nickel slag is enriched by 2.63 times. (3) Transferring the mixed solution (crude solution) 40 of the sintering material into a stainless steel stirring tank, wherein the components are as follows: al (Al)₂O₃124.4 g/l, Ni0.005 g/l, SiO₂0.71 g/l, heating to 95 ℃, adding lime powder for desiliconization under the condition of stirring, adding 280 g of charcoal powder according to the amount of 7 g of CaO added into each volume of the solution, keeping the temperature at 95 +/-5 ℃ for 2 hours, washing the silicon slag with hot water, drying, merging the washing liquid into desiliconization liquid, and adjusting the volume of the solution to 40 l. The weight of the silicon slag is 620 g, and the components are as follows: al (Al)₂O₃31.94％，SiO₂2.88 percent and CaO47.13 percent; desiliconizing solution (refined NaAlO)₂Solution) composition: al (Al)₂O₃120 g/l, SiO₂0.32 g/l, solution silicon ratio 375. Silicon removal rate of 66.62%, Al₂O₃The recovery rate was 96%. (4) The refined NaAlO after desiliconization₂Transferring 40L of the solution into a carbonation decomposer made of stainless steel, heating to 75 ℃, adding aluminum hydroxide crystal seeds, and adding the aluminum hydroxide crystal seeds according to the amount of Al in the solution₂O₃With Al in the seed crystal₂o₃Adding 7.5 kg of aluminum hydroxide according to the weight ratio of 1: 1, and introducing industrial-grade steel bottled CO under the stirring condition of 8-10 r/min₂The gas is subjected to carbonation decomposition reaction, and the process temperature is controlled by CO₂The reaction heat released by the neutralization reaction with NaOH in the solution is maintained at 70-50 ℃ (the ambient temperature is 30 ℃), the decomposition reaction time is 16 hours, the aluminum hydroxide crystal is washed to be neutral by hot tap water, dried to constant weight at the temperature of 150 +/-10 ℃, the washing liquid is combined with the mother solution and adjusted to the original volume of 40 liters and contains Al₂O₃5.32 g/l, Al₂O₃The decomposition rate is 95.5 percent. 14.54 kg of aluminum hydroxide is obtained, and 7.5 kg of seed crystal and 7.04 kg of solid weight are deducted, and the aluminum hydroxide contains Al₂O₃65.03 percent, the quality of the catalyst meets the requirements of national standard GB4294-84 third-grade aluminum hydroxide, and Al is used from the waste catalyst to the aluminum hydroxide product₂O₃The actual yield is 76.88 percent, and the method is calculated in the Al recovered by returning the silicon slag to sintering and retreating₂O₃Then Al₂O₃The recovery rate of (A) was 79.92%; 1000 g of aluminium hydroxide is calcined for 2 hours at 1200 ℃ to obtain 642 g of anhydrous alumina of grade Al₂O₃99.22 percent, and the quality of the aluminum oxide meets the requirements of the colored industry standard YS/T274-1888 third-grade aluminum oxide. (5) 1kg of nickel-rich slag containing 14.07 percent of Nix; pyrite is used as a vulcanizing agent; the smelting slag of smeltery is used as flux, and its composition is FeO 18.96%, SiO₂41.04%, CaO14.23%; carbon powder is used as a reducing agent; in the above-mentioned 500X 250X 800 mm smelting furnace, coke is used as fuel and 40 is used^#And smelting in a graphite clay crucible. The mixture ratio is: the nickel-rich slag, the pyrite, the smelting slag and the carbon powder of a certain plant are 1: 0.2: 2.2: 0.03, the temperature is 1300-1350 ℃, the time is 1.5 hours, 0.417 kg of nickel matte is obtained, and the grade is as follows: ni32.15 percent and 2.8 kg of slag containing Ni0.14%, the recovery rate of nickel smelting is 95.28%, and the recovery rate from waste catalyst to nickel matte is 85.37%.

Example 3:

1kg of nickel-rich slag is taken, and the grade of nickel is 10.83%; using gypsum ore as vulcanizing agent and containing CaSO₄·2H₂O87.51%; the blowing slag of smeltery is usedas flux, and its composition is FeO66.23%, SiO₂23.05 percent; coal powder is used as a reducing agent; the mixture ratio: nickel-rich slag, gypsum ore, converting slag and coal powder in the weight ratio of 1kg to 0.3 kg2 kg to 0.03 kg, and smelting for 1.5 hours at 1300-1350 ℃ by using the smelting and crucible to obtain 0.367 kg of nickel matte, the grade, the Ni27.80 percent, 2.8 kg of slag, the Ni0.18 percent and the recovery rate of nickel smelting is 94.21 percent.

Example 4:

1kg of nickel-rich slag is taken, and the grade of nickel is 10.83%; copper-nickel sulfide ore is used as a vulcanizing agent, and the vulcanizing agent contains 1.8 percent of Cu1 and 2.21 percent of Nis; the smelting slag is used as a flux, and Cu1.81 percent of carbon powder is used as a reducing agent; the mixture ratio: the nickel-rich slag, the copper-nickel sulfide ore, the limestone, the blown slag and the carbon powder are 1kg, 0.2 kg, 2 kg and 0.03 kg, and the smelting furnace and the crucible are used for smelting at 1300 ℃ to 1350 ℃ for 1.5 hours to obtain 0.371 kg of copper-nickel matte, the grade of which is Cu9.4 percent, Ni28.10 percent, 3.2 kg of slag, which contains 0.12 percent of Cu0.16 percent of Ni0.16 percent, the smelting recovery rate of which is Cu87.62 percent and Ni94.55 percent.

Claims (1)

1. A process for recovering Ni and Al from waste Al-base Ni-contained catalyst includes such steps as calcining sodium carbonate, dissolving sodium aluminate in boiling water, separating Al, reducing the dregs to obtain Ni matte Ni₃S₂-FeS-Ni-Fe alloy or copper-nickel-matte Cu₂S-Ni₃S₂-FeS alloy-converting to obtain nickel high-matte Ni₃S₂Or copper-nickel high sulfonium Cu₂S-Ni₃S₂-Cu-Ni alloy-coarse NaAlO₂Solution desilication-carbonation decomposition to obtain aluminum hydroxide Al₂O₃·3H₂Calcining to obtain anhydrous alumina α -Al₂O₃Several steps, characterized by:

a. the calcined soda sintering transition condition is as follows: mixing waste residues obtained after molybdenum and vanadium are extracted from the crushed waste catalyst or the spent catalyst containing nickel, aluminum, molybdenum and vanadium with soda ash, namely sodium carbonate, wherein the use amount of the soda ash is 1: 0.7-1.3 of the weight ratio of the waste catalyst or the waste residues to the sodium carbonate, the temperature is 700-1250 ℃, materials interact in a sintering furnace lined with a high-alumina brick to perform a transition reaction, and the constant temperature time is 1-6 hours;

b. spraying and washing the sintering furnace flue gas generated in the step a by using water, reducing the temperature of the gas to 30-40 ℃, and reducing the content of smoke dust to 0.02 g/m³0.05 g/m³Then used as NaAlO₂CO decomposed by carbonation of solution₂A source of gas;

c. the conditions for dissolving sodium aluminate in boiling water and separating aluminum are as follows: b, crushing the sintered blocks obtained in the step a, and dissolving sodium aluminate by using hot water in a boiling state, wherein the hot water is washing water for washing nickel slag or aluminum hydroxide crystals in a counter-current manner, the using amount of the washing water is 1: 2-10 of the weight gram of the sintered materials and the volume milliliter of the hot water, the temperature is the boiling temperature of the water, the time is 0.5-2 hours, and the insoluble nickel slag is washed by using the hot water in the same proportion in a counter-current manner for 2-3 times;

d. the smelting conditions for nickel slag reduction and matte formation are as follows: enriching nickel in the nickel slag obtained in the step c by 2-3 times, namely, the nickel-rich slag is obtained by using FeS as a main component₂The pyrite is mainly CaSO₄·nH₂Gypsum ore of O, wherein n is 2 or 3, main component CuFeS₂Copper sulfide concentrate or main component CuFeS₂Any sulfur-containing mineral in the copper-nickel sulfide concentrate of NiS-FeS is used as a vulcanizing agent, and smelting slag of a copper smelting plant or a nickel smelting plant, namely FeO-SiO₂CaO type, or converting slag 2 FeO. SiO₂Any one of the waste slag is used as a flux, any one of carbon, coal or coke is used as a reducing agent for matte smelting, and the mixture ratio is as follows: nickel-rich slag and vulcanizing agent; the weight ratio of the flux to the reducing agent is 1: 0.1-0.3: 1-3: 0.02-0.05, the smelting temperature is 1250-1400 ℃, and the smelting time is 1-2 hours;

e. ni of nickel matte obtained in the step d₃S₂-FeS-Ni-Fe alloy or copper-nickel-matte Cu₂S-Ni₃S₂FeS alloys, by SiO, according to the conventional converting method of copper, nickel smelters₂As solventsBlowing to obtain nickel matte Ni₃S₂Or copper-nickel high sulfonium Cu₂S-Ni₃S₂-Cu-Ni alloy, blowing slag to return to the step d for use as a flux;

f. crude NaAlO₂The solution desiliconization method comprises the following steps: at the temperature of 85-95 ℃, adding lime powder to the solution obtained in the step c for desilicication, adding 5-10 g of CaO to each liter of solution according to the lime amount or adding prepared lime milk according to the proportion, stirring and reacting for 1-3 hours, and washing the silica residue with hot water after filtering;

g. returning the silicon slag obtained in the step f to the step a, and adding 10-30% of limestone CaCO in excess respectively₃And sodium carbonate are sintered again to recover Al contained in the silicon slag₂O₃；

h、NaAlO₂The solution carbonation decomposition method comprises the following steps: fine NaAlO obtained in the step f₂Solution Al₂O₃Adjusting the concentration to 100 g/L-140 g/L, heating to 60-80 ℃ in a carbonating tank, controlling the rotating speed of a chain type stirrer to 8-10 r/min, adding aluminum hydroxide crystal seeds, wherein the addition amount is Al in the solution₂O₃Content and Al in seed crystal₂O₃C, the content ratio is 1: 1-1.5, and the CO obtained in the step b is blown by a centrifugal blower₂The clean gas with the content of 8-14 percent is pressed into the tank through a bubbling hole at the bottom of the carbonating tank to ensure that CO is generated₂Gas in bubblesThe form is contacted with the solution to perform carbonation reaction at the temperature of CO₂The reaction heat released by the neutralization reaction with NaOH is maintained at 70-50 ℃, the decomposition time is 10-20 hours, the aluminum hydroxide crystals are washed by soft water or tap water in a counter-current manner until the washing liquid is neutral, the drying is carried out at the temperature of 80-160 ℃, and the decomposed mother liquor contains Al₂O₃5 g/L-7 g/L, evaporating and concentrating, adding concentrated Na₂CO₃Returning the solution form to the step a for sintering and burdening;

i. the aluminum hydroxide Al obtained in the step h is₂O₃·3H₂Calcining O at 1200 deg.C according to conventional calcining method in alumina industry to obtain anhydrous alumina α -Al₂O₃。

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