Method for preparing wastewater adsorbent from calcium-process vanadium extraction tailings and recovering ferrovanadium

Abstract

The invention relates to the technical field of vanadium smelting, and discloses a method for preparing a wastewater adsorbent from calcium-process vanadium extraction tailings and recovering ferrovanadium in order to solve the problems that at present, hydrolyzed and precipitated vanadium in the calcium-process vanadium extraction tailings cannot be fully extracted and recovered, and the utilization rate is low, and the method comprises the following steps that the calcium-process vanadium extraction tailings are taken, water is added, and ore pulp is prepared; adding starch into the ore pulp, and uniformly stirring; then a composite collecting agent and a foaming agent are added, flotation is conducted for multiple times, and an iron-rich material is obtained; taking the iron-rich material, adding oxalic acid and calcium fluoride, stirring, heating, carrying out acid leaching, and separating to obtain an acidic vanadium solution and acid leaching residues; adding iron powder into the acidic vanadium liquid, stirring, cooling and filtering to obtain purified vanadium liquid; washing and drying the acid-leached vanadium slag; and adding a modifier, mixing, stirring and roasting to obtain the wastewater adsorbent. Vanadium and iron in the calcium-process vanadium extraction tailings can be extracted and recycled more sufficiently, and meanwhile, residual products can be prepared into the adsorbent for wastewater treatment, which is stable in structure and remarkable in adsorption effect.

Description

Technical Field

[0001] The invention relates to the technical field of vanadium smelting, and in particular to a method for preparing a wastewater adsorbent from calcium-process vanadium extraction tailings and recovering ferrovanadium. Background Art

[0002] Calcium vanadium extraction is a method of extracting vanadium from vanadium ore. It mainly involves reacting vanadium slag with a calcium source, such as limestone, at high temperature to form a vanadium-calcium alloy, and then extracting vanadium through chemical reaction and physical separation. The tailings remaining after calcium vanadium extraction are complex, containing gypsum, iron oxide, silicates, titanium-containing minerals, etc., with a small amount of vanadium remaining, and trace amounts of heavy metals such as chromium and manganese, which have high utilization value and economic value.

[0003] In this regard, research has been conducted on how to refine or utilize the tailings after calcium vanadium extraction. For example, the patent with publication number CN114350963A provides a method for recycling calcified vanadium extraction tailings, which includes adding ammonium carbonate to the calcified vanadium extraction tailings, performing solid-liquid separation after the reaction, drying and crushing the solid phase, and then returning it to the calcification roasting process for use as calcium salt and thermal diluent.

[0004] However, the existing methods of recycling calcified vanadium-extracting tailings are difficult to be successfully carried out in large-scale industrial processing, and the vanadium hydrolyzed and precipitated in the tailings cannot be extracted and recovered, that is, the utilization rate of the calcified vanadium-extracting tailings is low and the economic efficiency is poor. Summary of the invention

[0005] The purpose of the present invention is to solve the problem that the vanadium hydrolyzed and precipitated in the calcified vanadium extraction tailings cannot be extracted and recovered, and the overall utilization rate of the calcified vanadium extraction tailings is low and the economy is poor.

[0006] The present invention is achieved through the following technical solutions:

[0007] The present invention provides a method for preparing a wastewater adsorbent and recovering ferrovanadium from tailings of vanadium extraction by calcium process, comprising the following steps:

[0008] The following steps are involved:

[0009] S1 Take calcium process vanadium extraction tailings with TFe content greater than 20wt% and S content greater than 5wt%, add water to make slurry;

[0010] S2 sends the ore pulp into the flotation tank, adds starch, and stirs it evenly; then adds a composite collector and a frother, and performs multiple flotations to obtain iron-rich material and gypsum slag;

[0011] S3: taking iron-rich material, adding oxalic acid and calcium fluoride, stirring, heating for acid leaching, and separating to obtain acidic vanadium liquid and acid leaching residue;

[0012] S4: adding iron powder to the acidic vanadium liquid, stirring, cooling, filtering, and obtaining purified vanadium liquid;

[0013] S5: taking the acid-leached vanadium slag, washing it with clean water for several times until the pH value is 6-8, and drying it; then adding a modifier, mixing and stirring, and roasting to obtain the wastewater adsorbent.

[0014] Preferably, in step S1, the calcium process vanadium extraction tailings are first crushed and ground until the slag content with a particle size of less than 0.074 mm reaches 70wt%, and then water is added to prepare a slurry with a mass concentration of 20-25wt%.

[0015] Preferably, in step S2, the pH value of the slurry is first adjusted to 7-8, and then 200-300 g / t starch is added.

[0016] Preferably, in step S2, the composite collector comprises sodium dodecylamine acetate, laurylamine dipropylene diamine and ammonium dodecyl sulfate mixed in a mass ratio of 1:1.8-2.2:0.8-1.2, and the addition amount of the composite collector is 150-400 g / t of ore pulp.

[0017] The composite collector of the present invention has a simple configuration and has extremely strong electrostatic adsorption force on calcium sulfate, and has very weak electrostatic adsorption force on iron oxide, iron oxide, and silicate phase, thereby showing stronger selectivity, and has the advantages of small foam volume and good foam mineralization effect.

[0018] In addition, the composite collector of the present invention has the advantages of good solubility, low corrosion to equipment, etc., and can withstand low temperatures. It still has a good sorting effect in a temperature environment of 5-10°C. It has a strong collecting ability and can exert a higher selectivity and collecting effect with a smaller addition amount. It can quickly separate sulfur from vanadium iron, and has broad market prospects in the field of comprehensive resource utilization of calcium-based vanadium extraction tailings.

[0019] Preferably, in step S2, turpentine is used as the foaming agent, and the amount of turpentine added is 50 g / t of slurry.

[0020] The gypsum slag obtained by flotation with the composite collector of the present invention has high purity and a gypsum recovery rate of more than 96%. In the collected gypsum slag, the impurity iron content is less than 0.2%, the vanadium content is less than 0.1%, and the gypsum calcium sulfate content is ≥97.5%. In the iron-rich material after the sulfur-containing phase is floated out, the sulfur content is less than 0.1%, and the iron content is ≥40%.

[0021] Preferably, in step S3, the amount of oxalic acid added is 3-4 mol / kg of the iron-rich material, the amount of calcium fluoride added is 4-5 wt% of the mass of the iron-rich material, and the material ratio is controlled to be 1:1-1.2:1.

[0022] Preferably, in step S3, the acid leaching temperature is 90-95° C., and the acid leaching time is 3-4 h.

[0023] During leaching treatment, the following reaction processes are mainly involved:

[0024] Fe2O3+6HF - =2FeF3+3H2O (1);

[0025] Fe2O3+2H2C2O4+2H + =2FeC2O4 + +3H2O (2);

[0026] Fe2O3+2HC2O4 - +4H+=2FeC2O4 + +3H2O (3);

[0027] Fe2O3+2C2O4 - +6H + =2FeC2O4 + +3H2O (4);

[0028] Fe2O3+6H2C2O4=2Fe(C2O4)3 3- +3H2O+6H + (5);

[0029] Fe2O3+6HC2O4 - =2Fe(C2O4)3 3- +3H2O (6);

[0030] Fe2O3+6C2O4 2- +6H + =2Fe(C2O4)3 3- +3H2O (7);

[0031] 2V2O3+4H2C2O4+O2=4VOC2O4+4H2O (8);

[0032] 2V2O3+4HC2O4 - +4H + +O2=4VOC2O4+4H2O (9);

[0033] 2V2O3+4C2O4 2- +8H + +O2=4VOC2O4+4H2O (10);

[0034] V2O5+3H2C2O4=2VOC2O4+2CO2+4H2O (11);

[0035] V2O5+3H2C2O4+3H + =2VOC2O4+2CO2+4H2O (12);

[0036] V2O5+3C2O4 2- +6H + =2VOC2O4+2CO2+4H2O (13);

[0037] 2V2O3+8H2C2O4+O2=4VO(C2O4)2 2- +8H + +4H2O (14);

[0038] 2V2O3+8HC2O4 - +O2=4VO(C2O4)2 2- +4H2O (15);

[0039] 2V2O3+8C2O4 2- +8H + +O2=4VO(C2O4)2 2- +4H2O (16);

[0040] V2O4+4H2C2O4=2VO(C2O4)2 2- +4H + +4H2O (17).

[0041] Preferably, in step S4, the iron powder and Fe 3+ The molar ratio is 1.2:1-1.5.

[0042] After cooling to 25°C or below, FeC2O4·2H2O crystals can be precipitated, and after filtration, purified vanadium liquid containing high concentration of vanadium can be obtained. In this process, the following reaction processes are mainly involved:

[0043] Fe+2Fe(C2O4)3 3- =3Fe(C2O4)2 2- (18);

[0044] Fe+2H + =Fe 2+ +H2↑ (19);

[0045] Fe 2+ +(C2O4) 2- +2H2O=FeC2O4·2H2O↓ (20).

[0046] In the above-mentioned acid leaching process, divalent iron ions exist in the acid leaching solution in the form of FeC2O4 molecules. When reduced iron powder is used as a reducing agent, on the one hand, the trivalent iron ions in the solution can be reduced to divalent iron ions, and on the other hand, the reaction of iron powder and hydrogen ions can cause the content of divalent iron ions in the solution to increase rapidly; and divalent iron ions can combine with oxalate to form FeC2O4. When its concentration increases to supersaturation, FeC2O4 gradually precipitates, allowing the iron in the acid leaching solution to be selectively separated and recovered. Based on the direct acid leaching process under the oxalic acid leaching system, the source separation and regulation of vanadium and iron in iron-rich materials can be achieved, providing favorable conditions for the subsequent preparation of vanadium purification and enrichment processes in acid leaching solutions.

[0047] Preferably, in step S5, the drying temperature is 100-150° C. and the drying time is 5-8 hours.

[0048] Preferably, the modifier is selected from one or more of sodium hydroxide, potassium hydroxide, sodium carbonate or aluminum oxide, and the amount of the modifier added is 5-8wt% of the residue mass; after adding the modifier, the material is first stirred at a speed of 300-600rpm for 30-60min, and then roasted.

[0049] Preferably, in step S5, the calcination temperature is 400-800° C., and the calcination time is 2-6 hours.

[0050] The present invention performs a modification reaction on the residue after acid leaching, and the modifier and the residue have a deep effect at the molecular level to change the physical and chemical properties of the residue surface. After roasting under specific conditions, the crystal structure of the adsorbent is more stable and the pore structure is richer. The wastewater adsorbent has significant performance and effect in adsorbing heavy metal ions and organic pollutants in wastewater, such as lead, mercury, cadmium, etc., as well as dyes, pesticides, etc. Specifically, the adsorption capacity of the wastewater adsorbent for lead ions can reach 150mg / g, mercury ions 120mg / g, cadmium ions 100mg / g, organic dyes 100-300mg / g, and pesticides 250mg / g, and the adsorption time is short, and the applicable range of adsorption temperature can be expanded to 20-60°C. It shows excellent pollutant removal ability in a variety of different complex wastewater treatment scenarios, and builds an efficient bridge for the resource utilization of industrial waste residues and the environmental protection treatment of industrial wastewater, realizing an industrial path that realizes multiple demands at the same time.

[0051] The technical solution of the present invention has the following beneficial effects:

[0052] The present invention has found that the phases in the calcium-based vanadium tailings are mainly composed of iron oxide solid solution, iron oxide, calcium silicate, calcium sulfate, iron brookite, etc., among which the sulfur-containing phase is mainly calcium sulfate, which has very fine particles and a light specific gravity. The composite collector in the present invention has a small density, and the amino group in the collector can be electrostatically adsorbed with calcium sulfate, and can float after combining with calcium sulfate, thereby achieving the purpose of flotation. By utilizing the difference in floatability between gypsum and silicates and iron oxides, gypsum is selected by flotation separation technology, thereby reducing the sulfur content in the iron-rich material, and the extraction and recovery effect of vanadium iron in subsequent acid leaching processes can be improved; and the remaining product is chemically modified and roasted to prepare an adsorbent for wastewater impurity removal with good effect. That is, the present invention can not only effectively improve the efficient extraction and utilization of vanadium iron elements in the calcium-based vanadium tailings, but also transform and utilize the residual slag, realize the maximum recovery and reuse of resources, and the process is convenient and suitable for large-scale industrial production. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. Where specific conditions are not specified in the embodiments, they are carried out under conventional conditions or conditions recommended by the manufacturer; where the manufacturers of the instruments, equipment, reagents and raw materials used are not specified, they are all conventional products that can be purchased commercially.

[0054] The present invention provides a method for preparing a wastewater adsorbent and recovering ferrovanadium from tailings of vanadium extraction by calcium process, comprising the following steps:

[0055] (1) Taking the calcium process vanadium extraction tailings, crushing and grinding until the slag with a particle size of less than 0.074 mm reaches more than 70wt%; then adding water, stirring and mixing to make slurry, and adjusting the mass concentration of the slurry to 20-25%.

[0056] Among them, in the calcium process vanadium extraction tailings, the TFe content is greater than 20wt%, and the S content is greater than 5wt%.

[0057] (2) The ore pulp is sent to the flotation tank, and the pH value of the flotation ore pulp is adjusted to 7-8 with sulfuric acid or calcium hydroxide, starch is added, and stirred for 3-10 minutes; then a composite collector and a frother are added, and reverse flotation roughing and reverse flotation concentrating are carried out in sequence to obtain concentrating iron-rich material and concentrating gypsum slag.

[0058] Among them, starch is used as an inhibitor, and its dosage is 200-300g / t;

[0059] The composite collector includes sodium dodecylamine acetate, laurylamine dipropylene diamine, and ammonium dodecyl sulfate mixed in a mass ratio of 1:1.8-2.2:0.8-1.2; the foaming agent can be turpentine oil, etc., and the dosage is 50g / t;

[0060] The specific processing process of flotation is: first add 300-400g / t composite collector and stir for 3 minutes; then add frother and stir for 2 minutes to aerate and float, and after rough selection for 4 minutes, obtain rough selection product; add 150-200g / t (based on rough selection product) composite collector to the rough selection product again, perform fine selection, and collect the selected iron-rich material.

[0061] (3) Take the selected iron-rich material obtained above, add 3-4 mol / kg oxalic acid and 4-5 wt% calcium fluoride, control the mass ratio of water to the iron-rich material to be 1-1.2:1, stir, heat to 90-95° C., acid leaching for 3-4 hours, separate and filter, and obtain acidic vanadium liquid and acid-leached vanadium slag.

[0062] (4) Add an appropriate amount of iron powder to the above acidic vanadium liquid. The iron powder reacts with the Fe in the acidic vanadium liquid. 3+ The molar ratio is 1.2:1-1.5, and the temperature is lowered to 25°C or below under stirring to precipitate crystals of FeC2O4·2H2O to obtain purified vanadium liquid.

[0063] (5) The acid leaching residue separated after acid leaching is washed with clean water several times until the pH value of the washing liquid is 6-8, and then placed in an environment of 100-150° C. and dried for 5-8 hours; a modifier is added to the dried residue, mixed, stirred at 300-600 rpm for 30-60 minutes, placed in a high temperature environment of 400-800° C., and roasted for 2-6 hours to obtain a wastewater adsorbent.

[0064] The modifier can be selected from one or more of sodium hydroxide, potassium hydroxide, sodium carbonate or aluminum oxide, and its usage is 5-8wt% of the residue mass.

[0065] Example 1

[0066] Take the calcium vanadium extraction tailings, and the chemical composition content is TFe = 27.31%, S = 5.83%, V = 1.25%. The calcium vanadium extraction tailings are treated according to the following steps:

[0067] Step 1: crush the calcium-based vanadium extraction tailings and grind for 30 minutes; add clean water to make a slurry with a mass concentration of about 20%.

[0068] Step 2: Send the ore pulp into the flotation tank, add sodium hydroxide, adjust the pH value of the ore pulp in the flotation tank to about 7, add starch at 200g / t, and stir for 5 minutes; then add 300g / t of the composite collector M1 containing sodium dodecylamine acetate, laurylamine dipropylene diamine, and ammonium dodecyl sulfate in a mass ratio of 1:2:1, and stir for 4 minutes; then add turpentine at 50g / t, stir for 2 minutes, and aerate for flotation roughing for 4 minutes; collect the flotation product, and obtain gypsum slag after filter pressing; then add 150g / t of starch and 280g / t of the composite collector M1 to the roughing product in the tank, carry out secondary flotation and concentration, and collect the flotation and concentration product, which is the iron-rich material.

[0069] Step 3: Take 500g of iron-rich material, add 260g of oxalic acid dihydrate, 20g of calcium fluoride and 6L of clean water, stir and mix, heat to 95°C, react for 4h, filter and separate, and obtain acidic vanadium liquid and acid leaching residue.

[0070] Step 4: Take the acidic vanadium liquid, add 5g of iron powder, stir, cool to below 25°C, then let it stand for 3h, precipitate crystals, filter, and obtain the purified vanadium liquid after iron removal.

[0071] Step 5: Take the acid-leached vanadium slag obtained in step 3, wash it with clean water 4 times, and place it in a constant temperature drying environment at 120°C for 6 hours; then take 300g of the dried residue, add 18g of sodium hydroxide, stir for 40 minutes, place it in a 500°C roasting furnace, and roast for 3 hours to obtain a wastewater adsorbent.

[0072] In this embodiment, the iron-rich material obtained during the treatment process has a TFe content of 41.13wt%, an iron recovery rate of 96.27%, and an S content of 0.06wt%; the calcium sulfate content in the gypsum slag is 98.3wt%, and the recovery rate is 97.7%; the iron leaching rate after acid leaching is 38.3%, and the vanadium leaching rate is 87.2%; the prepared wastewater adsorbent has an adsorption capacity of 153mg / g for lead ions, 110mg / g for mercury ions, 105mg / g for cadmium ions, 212mg / g for benzidine yellow HR (organic dye), and 238mg / g for 2,4-dichlorophenoxyacetic acid (pesticide) at an adsorption temperature of 30°C and an adsorption time of 30min.

[0073] Example 2

[0074] Take the calcium vanadium extraction tailings, and the chemical composition content is TFe = 26.68%, S = 5.93%, V = 1.32%. The calcium vanadium extraction tailings are treated according to the following steps:

[0075] Step 1: crush the calcium-based vanadium extraction tailings and grind for 30 minutes; add clean water to make a slurry with a mass concentration of about 25%.

[0076] Step 2: Send the ore pulp into the flotation tank, add sodium hydroxide, adjust the pH value of the ore pulp in the flotation tank to about 8, add starch at 250g / t, and stir for 5 minutes; then add 350g / t of the composite collector M1 containing sodium dodecylamine acetate, laurylamine dipropylene diamine, and ammonium dodecyl sulfate in a mass ratio of 1:2:1, and stir for 4 minutes; then add turpentine at 50g / t, stir for 2 minutes, and aerate for flotation roughing for 4 minutes; collect the flotation product, and obtain gypsum slag after filter pressing; then add 180g / t of starch and 280g / t of the composite collector M1 to the roughing product in the tank, carry out secondary flotation and concentration, and collect the flotation and concentration product, which is the iron-rich material.

[0077] Step 3: Take 500g of iron-rich material, add 260g of oxalic acid dihydrate, 20g of calcium fluoride and 6L of clean water, stir and mix, heat to 95°C, react for 4h, filter and separate, and obtain acidic vanadium liquid and acid leaching residue.

[0078] Step 4: Take the acidic vanadium liquid, add 5g of iron powder, stir, cool to below 25°C, then let it stand for 3h, precipitate crystals, filter, and obtain the purified vanadium liquid after iron removal.

[0079] Step 5: Take the acid-leached vanadium slag obtained in step 3, wash it with clean water 4 times, and place it in a constant temperature environment at 130°C for 5 hours; then take 300g of the dried residue, add 20g of sodium hydroxide, stir for 30 minutes, place it in a 500°C roasting furnace, and roast for 3 hours to obtain a wastewater adsorbent.

[0080] In this embodiment, the iron-rich material obtained during the treatment process has a TFe content of 40.67wt%, an iron recovery rate of 96.75%, and an S content of 0.07wt%; the calcium sulfate content in the gypsum slag is 98.4wt%, and the recovery rate is 98.1%; the iron leaching rate after acid leaching is 38.7%, and the vanadium leaching rate is 87.1%; the prepared wastewater adsorbent has an adsorption capacity of 157mg / g for lead ions, 113mg / g for mercury ions, 103mg / g for cadmium ions, 217mg / g for benzidine yellow HR (organic dye), and 227mg / g for 2,4-dichlorophenoxyacetic acid (pesticide) at an adsorption temperature of 30°C and an adsorption time of 30min.

[0081] Example 3

[0082] Take the calcium vanadium extraction tailings, and the chemical composition content is TFe = 26.37%, S = 5.79%, V = 1.27%. The calcium vanadium extraction tailings are treated according to the following steps:

[0083] Step 1: crush the calcium vanadium extraction tailings and grind for 30 minutes; add clean water to make a slurry with a mass concentration of about 25%.

[0084] Step 2: Send the ore pulp into the flotation tank, add sodium hydroxide, adjust the pH value of the ore pulp in the flotation tank to about 8, add starch at 230g / t, and stir for 5 minutes; then add 350g / t of the composite collector M1 containing sodium dodecylamine acetate, laurylamine dipropylene diamine, and ammonium dodecyl sulfate in a mass ratio of 1:2:1, and stir for 4 minutes; then add turpentine at 50g / t, stir for 2 minutes, and aerate for flotation roughing for 4 minutes; collect the flotation product, and obtain gypsum slag after filter pressing; then add 180g / t of starch and 280g / t of the composite collector M1 to the roughing product in the tank, carry out secondary flotation and concentration, and collect the flotation and concentration product, which is the iron-rich material.

[0085] Step 3: Take 500g of iron-rich material, add 260g of oxalic acid dihydrate, 20g of calcium fluoride and 6L of clean water, stir and mix, heat to 95°C, react for 4h, filter and separate, and obtain acidic vanadium liquid and acid leaching residue.

[0086] Step 4: Take the acidic vanadium liquid, add 5g of iron powder, stir, cool to below 25°C, then let it stand for 3h, precipitate crystals, filter, and obtain the purified vanadium liquid after iron removal.

[0087] Step 5: Take the acid-leached vanadium slag obtained in step 3, wash it with clean water 4 times, and place it in a constant temperature environment of 130°C for 5 hours; then take 300g of the dried residue, add 10g of potassium hydroxide and 10g of aluminum oxide, stir for 30 minutes, place it in a 500°C roasting furnace, and roast for 3 hours to obtain a wastewater adsorbent.

[0088] In this embodiment, the iron-rich material obtained during the treatment process has a TFe content of 40.62wt%, an iron recovery rate of 96.8%, and an S content of 0.05wt%; the calcium sulfate content in the gypsum slag is 98.5wt%, and the recovery rate is 97.8%; the iron leaching rate after acid leaching is 37.9%, and the vanadium leaching rate is 86.6%; the prepared wastewater adsorbent has an adsorption capacity of 161mg / g for lead ions, 118mg / g for mercury ions, 127mg / g for cadmium ions, 216mg / g for benzidine yellow HR (organic dye), and 231mg / g for 2,4-dichlorophenoxyacetic acid (pesticide) at an adsorption temperature of 30°C and an adsorption time of 30min.

[0089] Comparative Example 1

[0090] Take the calcium vanadium extraction tailings, and the chemical composition content is TFe = 27.31%, S = 5.83%, V = 1.25%. The calcium vanadium extraction tailings are treated according to the following steps:

[0091] Step 1: crush the calcium vanadium extraction tailings and grind for 30 minutes; add clean water to make a slurry with a mass concentration of about 20%.

[0092] Step 2: Send the ore pulp into the flotation tank, add sodium hydroxide, adjust the pH value of the ore pulp in the flotation tank to about 9, add starch at 200g / t, and stir for 5 minutes; then add 300g / t of a composite collector M2 containing sodium hexametaphosphate, ammonium sulfate, and dodecyl ammonium chloride in a mass ratio of 1:2:1, and stir for 4 minutes; then add 50g / t of turpentine, stir for 2 minutes, and aerate for flotation roughing for 4 minutes; collect the flotation product, and obtain gypsum slag after filter pressing; then add 150g / t of starch and 280g / t of the above-mentioned composite collector M2 to the roughing product in the tank, carry out secondary flotation and concentration, and collect the flotation and concentration product, which is the iron-rich material.

[0093] Step 3: Take 500g of iron-rich material, add 260g of sulfuric acid, 20g of calcium fluoride and 6L of clean water, stir and mix, heat to 95°C, react for 4h, filter and separate, and obtain acidic vanadium liquid.

[0094] In this comparative example, the iron-rich material obtained during the treatment process has a TFe content of 36.13wt%, an iron recovery rate of 93.56%, and an S content of 0.13wt%; the calcium sulfate content in the gypsum slag is 97.8wt%, and the recovery rate is 93.3%; the iron leaching rate after acid leaching is 32.4%, and the vanadium leaching rate is 85.2%. Compared with Example 1, it can be clearly found that the vanadium-iron extraction degree of this comparative example is significantly lower.

[0095] Comparative Example 2

[0096] Take the calcium vanadium extraction tailings, and the chemical composition content is TFe = 26.68%, S = 5.93%, V = 1.32%. The calcium vanadium extraction tailings are treated according to the following steps:

[0097] Step 1: crush the calcium vanadium extraction tailings and grind for 30 minutes; add clean water to make a slurry with a mass concentration of about 25%.

[0098] Step 2: Send the ore pulp into the flotation tank, add sodium hydroxide, adjust the pH value of the ore pulp in the flotation tank to about 9, add starch at 200g / t, and stir for 5 minutes; then add 350g / t of the composite collector M2 containing sodium hexametaphosphate, ammonium sulfate, and dodecyl ammonium chloride in a mass ratio of 1:2:1, and stir for 4 minutes; then add turpentine at 50g / t, stir for 2 minutes, and aerate for flotation roughing for 4 minutes; collect the flotation product, and obtain gypsum slag after filter pressing; then add 180g / t of starch and 280g / t of the composite collector M2 to the roughing product in the tank, carry out secondary flotation and concentration, and collect the flotation and concentration product, which is the iron-rich material.

[0099] Step 3: Take 500g of iron-rich material, add 260g of sulfuric acid, 20g of calcium fluoride and 6L of clean water, stir and mix, heat to 95°C, react for 4h, filter and separate, and obtain acidic vanadium liquid.

[0100] In this comparative example, the iron-rich material obtained during the treatment process has a TFe content of 35.52wt%, an iron recovery rate of 92.83%, and an S content of 0.16wt%; the calcium sulfate content in the gypsum slag is 97.6wt%, and the recovery rate is 91.7%; the iron leaching rate after acid leaching is 32.3%, and the vanadium leaching rate is 85.2%. Compared with Example 2, it can be clearly found that the vanadium-iron extraction degree of this comparative example is significantly lower.

[0101] Comparative Example 3

[0102] Take the calcium vanadium extraction tailings, and the chemical composition content is TFe = 26.37%, S = 5.79%, V = 1.27%. The calcium vanadium extraction tailings are treated according to the following steps:

[0103] Step 1: crush the calcium vanadium extraction tailings and grind for 30 minutes; add clean water to make a slurry with a mass concentration of about 25%.

[0104] Step 2: send the ore pulp into the flotation tank, add sodium hydroxide, adjust the pH value of the ore pulp in the flotation tank to about 9, add starch at 230g / t, and stir for 5 minutes; then add 350g / t of the composite collector M2 containing sodium hexametaphosphate, ammonium sulfate, and dodecyl ammonium chloride in a mass ratio of 1:2:1, and stir for 4 minutes; then add turpentine at 50g / t, stir for 2 minutes, and aerate for flotation roughing for 4 minutes; collect the flotation product, and obtain gypsum slag after filter pressing; then add 180g / t of starch and 280g / t of the composite collector M2 to the roughing product in the tank, carry out secondary flotation and concentration, and collect the flotation and concentration product, which is the iron-rich material.

[0105] Step 3: Take 500g of iron-rich material, add 260g of sulfuric acid, 20g of calcium fluoride and 6L of clean water, stir and mix, heat to 95°C, react for 4h, filter and separate, and obtain acidic vanadium liquid.

[0106] In this comparative example, the iron-rich material obtained during the treatment process has a TFe content of 35.83wt%, an iron recovery rate of 91.57%, and an S content of 0.21wt%; the calcium sulfate content in the gypsum slag is 97.3wt%, and the recovery rate is 90.6%; the iron leaching rate after acid leaching is 32.2%, and the vanadium leaching rate is 84.8%. Compared with Example 3, it can be clearly found that the vanadium-iron extraction degree of this comparative example is significantly lower.

[0107] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing wastewater adsorbent and recovering ferrovanadium from calcium-process vanadium extraction tailings, characterized in that: The following steps are involved: S1 takes the calcium process vanadium extraction tailings, adds water, and makes a slurry; S2 adds starch to the ore pulp and stirs it evenly; then adds a composite collector and a frother, and performs multiple flotation to obtain iron-rich material; S3: taking iron-rich material, adding oxalic acid and calcium fluoride, stirring, heating for acid leaching, and separating to obtain acidic vanadium liquid and acid leaching residue; S4: adding iron powder to the acidic vanadium liquid, stirring, cooling, filtering, and obtaining purified vanadium liquid; S5: taking the acid-leached vanadium slag, washing it, and drying it; then adding a modifier, mixing and stirring it, and roasting it to obtain the wastewater adsorbent.

2. The method for preparing wastewater adsorbent and recovering ferrovanadium from calcium vanadium tailings according to claim 1, characterized in that: In step S1, the calcium process vanadium extraction tailings are first crushed and ground until the slag content with a particle size of less than 0.074 mm reaches 70wt%, and then water is added to prepare a slurry with a mass concentration of 20-25wt%.

3. The method for preparing wastewater adsorbent and recovering ferrovanadium from calcium vanadium tailings according to claim 1, characterized in that: In step S2, the pH value of the slurry is first adjusted to 7-8, and then 200-300 g / t starch is added.

4. The method for preparing wastewater adsorbent and recovering ferrovanadium from calcium-process vanadium tailings according to claim 1, characterized in that: In step S2, the composite collector includes sodium dodecylamine acetate, laurylamine dipropylene diamine, and ammonium dodecyl sulfate mixed in a mass ratio of 1:1.8-2.2:0.8-1.2, and the addition amount of the composite collector is 150-400 g / t of ore pulp.

5. The method for preparing wastewater adsorbent and recovering ferrovanadium from calcium vanadium tailings according to claim 1, characterized in that: In step S3, the amount of oxalic acid added is 3-4 mol / kg of the iron-rich material, and the amount of calcium fluoride added is 4-5 wt% of the mass of the iron-rich material.

6. The method for preparing wastewater adsorbent and recovering ferrovanadium from calcium-process vanadium tailings according to claim 5, characterized in that: In step S3, the acid leaching temperature is 90-95° C., and the acid leaching time is 3-4 hours.

7. The method for preparing wastewater adsorbent and recovering ferrovanadium from calcium-process vanadium tailings according to claim 1, characterized in that: In step S4, the iron powder and the Fe 3+ The molar ratio is 1.2:1-1.

5.

8. The method for preparing wastewater adsorbent and recovering ferrovanadium from calcium-process vanadium tailings according to claim 1, characterized in that: In step S5, the drying temperature is 100-150° C. and the drying time is 5-8 hours.

9. The method for preparing wastewater adsorbent and recovering ferrovanadium from calcium-process vanadium tailings according to claim 1, characterized in that: The modifier is selected from one or more of sodium hydroxide, potassium hydroxide, sodium carbonate or aluminum oxide, and the added amount of the modifier is 5-8wt% of the residue mass.

10. The method for preparing wastewater adsorbent and recovering ferrovanadium from calcium-process vanadium tailings according to claim 1, characterized in that: In step S5, the calcination temperature is 400-800° C. and the calcination time is 2-6 hours.