Method for comprehensively treating tantalum-niobium production ore raffinate

Abstract

The invention discloses a tantalum-niobium production ore raffinate comprehensive treatment method, which comprises: 1, carrying out a heating reaction on an ore raffinate and a preset amount of silica fume to obtain a fluosilicic acid-containing solution; 2, sequentially adding citric acid and oxalic acid particles into the fluosilicic acid-containing solution to remove heavy metal impurities, and then filtering to obtain fluosilicic acid-containing clear liquid and filter residues 1, and 3, reacting the fluosilicic acid-containing clear liquid with a potassium salt solution, controlling the temperature at 45-55 DEG C, and filtering to obtain potassium fluosilicate crystals and crystallization mother liquor; step 4, adding the crystallization mother liquor into lime milk for neutralization and precipitation treatment, controlling the pH value of precipitation reaction to be 8-9, and filtering to obtain filtrate and filter residues 2; 5, the filtrate is subjected to adsorption treatment, and adsorption tail liquid capable of being discharged is obtained. The invention aims to improve the comprehensive treatment efficiency of the tantalum-niobium production ore raffinate.

Description

Technical Field

[0001] The present invention relates to the technical field of tantalum-niobium ore smelting, and in particular to a method for comprehensive treatment of tantalum-niobium ore extract residues in production. Background Art

[0002] Tantalum-niobium ores are usually accompanied by valuable resources such as uranium, thorium, and rare earths, and the residual liquid from the ore extraction is the filtrate obtained by solid-liquid separation of the residual phase left after the acid decomposition liquid of the tantalum-niobium ore is extracted and separated from the tantalum-niobium ore. It contains a large amount of hydrofluoric acid, sulfuric acid, fluorosilicic acid and other fluoride salts and sulfates and radioactive nuclides, and its composition is very complex. In the existing tantalum-niobium industry, lime neutralization and precipitation are generally used in the hydrometallurgical process to achieve standard emissions. However, a large amount of calcium salt slag will be generated during the neutralization and precipitation process, and the calcium salt slag is generally hazardous waste, which can only be landfilled and disposed of at present. Not only is the hydrofluoric acid and fluorosilicic acid in the residual liquid from the ore extraction not recycled, wasting a large amount of fluorine and silicon resources; the calcium salt slag in the precipitate also contains certain heavy metal elements and radioactive nuclides, forming new pollution, causing harm to the environment, and thus urgently needs to be treated.

[0003] The invention patent with the existing patent publication number CN112358104A discloses a system and method for resource treatment of wastewater and waste residue in tantalum powder smelting production. The method uses a self-unloading Gore membrane microporous filter to filter the wastewater to obtain a filter cake a rich in tantalum salt and a clear liquid. The clear liquid contains a large amount of fluorosilicic acid, fluorotitanic acid, etc. When it is returned to the tantalum niobium ore for acid decomposition production, fluorosilicic acid and fluorotitanic acid will accumulate, resulting in reduced acid decomposition efficiency, difficulty in acid decomposition operation control, difficulty in filtering the decomposition liquid, and other problems, and thus cannot be recycled. Summary of the invention

[0004] The main purpose of the present invention is to provide a method for comprehensive treatment of tantalum-niobium ore extract residues, aiming to solve the technical problem that the existing tantalum-niobium ore extract residues cannot be effectively recycled.

[0005] To achieve the above object, the present invention provides a method for comprehensive treatment of tantalum-niobium ore extract residue, the method comprising the following steps:

[0006] Step 1, heating the ore extraction residue and a preset amount of microsilica powder to react to obtain a fluorine-containing silicic acid solution, wherein the volume mass ratio of the ore extraction residue to the microsilica powder is 100L: (4.0-5.5)kg;

[0007] Step 2, adding citric acid and oxalic acid particles to the fluorine-containing silicic acid solution in sequence to remove heavy metal impurities, and then filtering to obtain a fluorine-containing silicic acid clear solution and a filter residue 1, and adding 1.05 g to 1.10 g of citric acid and 1.15 g to 1.20 g of oxalic acid to 100 mL of the fluorine-containing silicic acid solution;

[0008] Step 3, reacting the fluorosilicic acid-containing clear liquid with a potassium salt solution, controlling the temperature to 45° C.-55° C., and filtering to obtain potassium fluorosilicate crystals and a crystallization mother liquor;

[0009] Step 4, adding the crystallization mother liquor to lime milk for neutralization and precipitation treatment, and controlling the precipitation reaction pH value to be 8-9, filtering to obtain a filtrate and a filter residue 2, wherein the volume mass ratio of the crystallization mother liquor to the lime milk is 100L:(16.5-20.0)kg;

[0010] Step 5, subjecting the filtrate to adsorption treatment to obtain an adsorption tail liquid that can be discharged.

[0011] Optionally, in step 1, the ore extract residue is preheated to 40°C±5°C.

[0012] Optionally, in step 1, microsilica powder is added to the preheated ore extract residue and the temperature is raised to 60° C. to 65° C. for reaction for 0.5 h to 1.0 h.

[0013] Optionally, in step 2, the filtration treatment is performed by using a chamber filter press for filtration separation.

[0014] Optionally, in step 3, the potassium salt solution includes at least one of K2CO3, KCl, K2SO4, and KNO3 solutions.

[0015] Optionally, in step 3, the potassium salt solution is a KCl solution.

[0016] Optionally, in step 3, the volume mass ratio of the fluorinated silicic acid clear solution to the potassium salt is 100L:(15.5-18.5)kg.

[0017] Optionally, in step 4, the filtrate is subjected to adsorption treatment using vermiculite, wherein the adsorption contact time per volume is 45 min to 60 min.

[0018] Optionally, in step 3, the potassium fluorosilicate crystals are washed multiple times, and the washing water is used to prepare the solvent required for the potassium salt solution.

[0019] Beneficial effects:

[0020] The invention comprises the following steps: adding microsilica powder to the residual liquid of ore extraction, complexing fluorine to obtain a fluorosilicic acid solution, adding a certain amount of citric acid and oxalic acid to perform a refining treatment such as removing heavy metals and radioactive nuclides, filtering to obtain a refined fluorosilicic acid clear liquid; adding potassium salt to the fluorosilicic acid clear liquid to synthesize a potassium fluorosilicate feed liquid, filtering to obtain potassium fluorosilicate crystals, and then washing and drying to prepare a potassium fluorosilicate product; neutralizing and precipitating the crystallization mother liquor with lime milk and performing a filtrate adsorption treatment, and discharging the adsorbed tail liquid after monitoring to meet the standard, thereby achieving effective treatment of the residual liquid of ore extraction and avoiding the formation of new pollution and harm to the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic flow diagram of an embodiment of a method for comprehensive treatment of tantalum-niobium ore extract residue of the present invention;

[0022] Figure 2 for Figure 1 The flow chart shown.

[0023] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0024] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0025] See also Figure 1-2 The present invention provides a schematic flow diagram of a method for comprehensive treatment of tantalum-niobium ore extract residue, the method comprising the following steps:

[0026] Step 1, heating the ore extraction residue and a preset amount of microsilica powder to react, to obtain a fluorine-containing silicic acid solution. The tantalum-niobium ore extraction residue includes hydrofluoric acid, sulfuric acid, fluorosilicic acid and other fluoride salts and sulfates and radioactive nuclides such as U and Th. The microsilica powder is an amorphous powder, the silicon dioxide content is SiO2 ≥ 96%, and the 45μm sieve residue is ≤ 3%. And based on the fact that hydrofluoric acid can react with SiO2, the specific reaction equation is: SiO2 + 6HF = H2SiF6 + 2H2O.

[0027] Specifically, the heating reaction of the ore extraction residue and the preset amount of microsilica powder is to preheat the ore extraction residue to 40°C ± 5°C, then add the microsilica powder and heat it to 60°C ~ 65°C for 0.5h ~ 1.0h. Among them, the volume mass ratio of the ore extraction residue to the microsilica powder is 100L: (4.0 ~ 5.5) kg. The purpose of slightly excessive microsilica powder in the actual reaction is to ensure that the hydrofluoric acid in the ore extraction residue in the complex fluorine reaction can react completely, thereby realizing the recovery of hydrofluoric acid. Preferably, the amount of microsilica powder added is 105% ~ 120% of the theoretical amount required for the complex fluorine reaction.

[0028] Step 2, adding a mixed solution of citric acid-oxalic acid to the fluorosilicic acid solution to remove heavy metals, radionuclides and other refined impurities, and then filtering to obtain a fluorosilicic acid clear solution and a filter residue 1; wherein, 1.05g to 1.10g of citric acid and 1.15g to 1.20g of oxalic acid are added to 100mL of the fluorosilicic acid solution, and the filtering treatment is performed by filtering and separating using a chamber filter press, and the obtained filter residue 1 is discarded.

[0029] Step 3, reacting the fluorinated silicic acid clear liquid with the potassium salt solution, and controlling the temperature to be 45°C-55°C, filtering to obtain potassium fluorinated silicate crystals and crystallization mother liquor; wherein the reaction time is 2.0h-4.0h; the potassium salt solution includes at least one of K2CO3, KCl, K2SO4, and KNO3 solution. wherein the above reaction formula is: H2SiF6+2K + →K2SiF6↓+2H + The amount of potassium salt added is 105% to 110% of the theoretical amount required for the reaction, and the volume mass ratio of the fluorosilicic acid clear liquid to the potassium salt is 100L: (15.5 to 18.5) kg. The potassium salt solution is slightly excessive to ensure that the fluorosilicic acid clear liquid reacts completely. A flat centrifuge is used to separate the solid and liquid of the potassium fluorosilicate liquid after the reaction. The potassium fluorosilicate crystals obtained by filtration and separation carry a certain amount of crystallization mother liquor, which needs to be removed by washing. The potassium fluorosilicate crystals are washed by adding 0.3BV to 0.5BV of deionized water. The washing method is to wash once with a pan, and the washing water is returned to prepare the potassium salt solution. The washed crystals are dried to prepare the potassium fluorosilicate product.

[0030] Preferably, the potassium salt solution is a KCl solution, and the principle is that according to the coarseness of the crystal particles of the synthetic potassium fluorosilicate, the crystals added with potassium chloride are the coarsest and the filtration time is the shortest. And the KCl solution needs to be prepared and used immediately, specifically, potassium chloride solid is added to hot water at about 40°C for dissolution, stirring is started, the dissolution reaction temperature is controlled to be 40°C to 45°C, the time is 2.0h to 3.0h, and hot potassium chloride clear liquid is immediately filtered.

[0031] Step 4, adding the crystallization mother liquor into lime milk for neutralization precipitation treatment, and controlling the pH value of the precipitation reaction to 8-9, and obtaining a filtrate and a filter residue 2 after filtering; wherein, the neutralization precipitation includes: H2SO4+Ca(OH)2=CaSO4↓+H2O, and the filter residue 2 is a calcium salt residue.

[0032] Step 5, subjecting the filtrate to adsorption treatment to obtain adsorption tail liquid that can be discharged. Specifically, the filtrate is subjected to adsorption treatment using vermiculite, wherein the adsorption contact time per volume is 45 minutes to 60 minutes, and the adsorption tail liquid is discharged to achieve discharge standards.

[0033] The invention comprises the following steps: adding microsilica powder to the residual liquid of mineral extraction, complexing fluorine to obtain a fluosilicic acid solution, adding a certain amount of citric acid and oxalic acid to perform refining treatments such as removing heavy metals and radioactive nuclides, filtering to obtain a refined fluosilicic acid clear liquid; adding potassium salt to the fluosilicic acid clear liquid to synthesize a potassium fluosilicate feed liquid, filtering to obtain potassium fluosilicate crystals, and then washing and drying to prepare a potassium fluosilicate product; and subjecting the crystallization mother liquor to neutralization and precipitation with lime milk and filtrate adsorption treatment to achieve standard discharge.

[0034] Furthermore, in order to better illustrate the process and effect of a method for comprehensive treatment of tantalum-niobium ore extract residue, the following is a detailed description through specific examples, the details are as follows:

[0035] Example 1

[0036] The residual liquid of tantalum-niobium ore extraction contains HF: 80.10 g / L, H2SO4: 300.50 g / L, Si: 10.03 g / L, U: 0.32 g / L, and Th: 1.58 g / L.

[0037] Add a certain amount of tantalum-niobium ore extract residue to the complex fluorine reactor, heat to 40°C, start stirring, and add microsilica powder, first fast and then slowly. The amount of microsilica powder added is 105% of the theoretical amount required for the complex fluorine reaction. Control the reaction temperature to 63°C ± 2°C, the time to 1.0h, and the liquid in the complex fluorine reactor does not bubble up to obtain a fluorine-containing silicic acid solution.

[0038] 1.05 g of citric acid and 1.20 g of oxalic acid granules were added to every 100 mL of the fluorosilicic acid solution to perform purification treatment such as removing heavy metals and radionuclides, and the refined fluorosilicic acid solution was filtered and separated using a chamber filter press to obtain a fluorosilicic acid clear solution;

[0039] Add a certain amount of water to the potassium chloride dissolving tank, heat it to 40°C, start stirring, add potassium chloride solid to the dissolving tank to dissolve, continue heating, control the dissolving reaction temperature to 43°C±2°C and the time to 3.0h, and filter immediately after the dissolution is completed to obtain the hot potassium chloride clear liquid, which is ready for use.

[0040] The hot potassium chloride clear liquid is transferred to the potassium fluorosilicate synthesis tank, stirring is started, and then the fluorosilicic acid clear liquid is added to the synthesis tank, and the double decomposition reaction temperature is controlled to be 48°C ± 2°C and the time is 4.0h to obtain a potassium fluorosilicate feed liquid. The potassium fluorosilicate feed liquid is separated into solid and liquid using a plate centrifuge, the filter cake is potassium fluorosilicate crystals, and the filtrate is the crystallization mother liquor, which needs to be comprehensively treated.

[0041] 0.3 BV of deionized water was added to the potassium fluorosilicate crystals in the filter press, and the crystals were washed once. The washing water was returned for the preparation of potassium chloride. The crystals were dried to obtain a potassium fluorosilicate product, which met the first-class quality requirements of HG / T4693-2014 standard, K2S i F4: 98.30%, free acid (calculated as HCl): 0.26%, drying loss: 0.42%, and water-insoluble matter: 0.36%.

[0042] The crystallization mother liquor is added to the lime milk for neutralization and precipitation treatment, and the precipitation reaction pH value is controlled to be 9.0 and the time is 6.0h; the filtrate is filtered and needs to be treated in the wastewater treatment system. The filter cake is calcium salt residue and is discarded.

[0043] The filtrate is treated by vermiculite adsorption, with the adsorption contact time for each volume being 60 minutes, and the adsorption tail liquid is discharged to achieve standard discharge.

[0044] Example 2

[0045] The residual liquid of tantalum-niobium ore extraction contains HF: 76.45 g / L, H2SO4: 310.12 g / L, Si: 8.46 g / L, U: 0.31 g / L, and Th: 1.62 g / L.

[0046] Add a certain amount of tantalum-niobium ore extract residue to the complex fluorine reactor, heat to 43°C, start stirring, and add microsilica powder, first fast and then slowly. The amount of microsilica powder added is 135% of the theoretical amount required for the complex fluorine reaction. Control the reaction temperature to 62°C ± 2°C, the time to 0.75h, and the liquid in the complex fluorine reactor does not bubble up to obtain a fluorine-containing silicic acid solution.

[0047] 1.10 g of citric acid and 1.15 g of oxalic acid granules were added to every 100 mL of fluorosilicic acid solution to perform purification treatment such as removing heavy metals and radionuclides, and the refined fluorosilicic acid solution was filtered and separated using a chamber filter press to obtain a fluorosilicic acid filtered clear liquid;

[0048] Add a certain amount of water to the potassium chloride dissolving tank, heat it to 42°C, start stirring, add potassium chloride solid to the dissolving tank to dissolve, continue heating, control the dissolving reaction temperature to 42°C±2°C and the time to 2.5h. After the dissolution is completed, filter immediately to obtain the hot potassium chloride clear liquid, which is ready for use.

[0049] The hot potassium chloride clear liquid is transferred to the potassium fluorosilicate synthesis tank, stirring is started, and then the fluorosilicic acid clear liquid is added to the synthesis tank, and the double decomposition reaction temperature is controlled to be 51°C ± 2°C and the time is 3.5 hours to obtain a feed liquid containing potassium fluorosilicate. The potassium fluorosilicate feed liquid is filtered and separated by a plate centrifuge, and the filter cake is potassium fluorosilicate crystals, and the filtrate is the crystallization mother liquor, which needs further comprehensive treatment.

[0050] 0.4 BV of deionized water was added to the potassium fluorosilicate crystals in the filter press, and the crystals were washed once. The washing water was returned for preparing potassium chloride. The crystals were dried to obtain a potassium fluorosilicate product, which met the first-class quality requirements of HG / T4693-2014 standard, K2S iF4: 99.12%, free acid (calculated as HCl): 0.22%, drying loss: 0.36%, and water-insoluble matter: 0.30%.

[0051] The crystallization mother liquor is added to the lime milk for neutralization and precipitation treatment, and the precipitation reaction pH value is controlled to be 8.7 and the time is 5.5 hours; the filtrate is obtained by filtration and needs to be treated in the wastewater treatment system. The filter cake is calcium salt residue and is discarded.

[0052] The wastewater is treated by vermiculite adsorption, with the adsorption contact time for each volume being 55 minutes, and the adsorption tail liquid is discharged to achieve standard discharge.

[0053] Example 3

[0054] The residual liquid of tantalum-niobium ore extraction contains HF: 83.24 g / L, H2SO4: 294.56 g / L, Si: 9.18 g / L, U: 0.29 g / L, and Th: 1.57 g / L.

[0055] Add a certain amount of tantalum-niobium ore extract residue to the complex fluorine reactor, heat to 45°C, start stirring and add microsilica powder, first fast and then slowly. The amount of microsilica powder added is 140% of the theoretical amount required for complex fluorine. Control the reaction temperature to 63°C ± 2°C and the time to 0.9h until the liquid in the complex fluorine reactor stops bubbling, and obtain a fluorine-containing silicic acid solution.

[0056] 1.10 g of citric acid and 1.15 g of oxalic acid were added to every 100 mL of the fluorosilicic acid solution to perform purification treatment such as removing heavy metals and radionuclides, and the refined fluorosilicic acid solution was filtered and separated using a chamber filter press to obtain a filtered clear liquid;

[0057] Add a certain amount of water to the potassium chloride dissolving tank, heat it to 40°C, start stirring, add potassium chloride solid to the dissolving tank to dissolve, continue heating, control the dissolving reaction temperature to 42°C±2°C and the time to 2.8h, and filter immediately after the dissolution is completed to obtain the hot potassium chloride clear liquid, which is ready for use.

[0058] The hot potassium chloride clear liquid is transferred to the potassium fluorosilicate synthesis tank, stirring is started, and then the fluorosilicic acid clear liquid is added to the synthesis tank, and the double decomposition reaction temperature is controlled to be 50°C ± 2°C and the time is 3.5 hours to obtain a feed liquid containing potassium fluorosilicate. The potassium fluorosilicate feed liquid is filtered and separated by a plate centrifuge, and the filter cake is potassium fluorosilicate crystals, and the filtrate is the crystallization mother liquor, which needs further comprehensive treatment.

[0059] 0.4 BV of deionized water was added to the potassium fluorosilicate crystals in the filter press, and the crystals were washed once. The washing water was returned for the preparation of potassium chloride. The crystals were dried to obtain a potassium fluorosilicate product, which met the first-class quality requirements of HG / T4693-2014 standard, K2S i F4: 98.84%, free acid (calculated as HCl): 0.30%, drying loss: 0.32%, and water-insoluble matter: 0.28%.

[0060] The crystallization mother liquor is added to the lime milk for neutralization and precipitation treatment, and the precipitation reaction pH value is controlled to be 8.0 and the time is 6.0h; the filtrate is obtained by filtration and needs to be treated in the wastewater treatment system. The filter cake is calcium salt residue and is discarded.

[0061] The wastewater is treated by vermiculite adsorption, with the adsorption contact time for each volume being 50 minutes, and the adsorption tail liquid is discharged to achieve standard discharge.

[0062] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or system. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or system including the element.

[0063] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0064] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for comprehensive treatment of tantalum-niobium ore extract residue, characterized in that: The method comprises the following steps: Step 1, heating the ore extraction residue and microsilica powder to react, to obtain a fluorine-containing silicic acid solution, wherein the volume mass ratio of the ore extraction residue to the microsilica powder is 100L: (4.0-5.5)kg; Step 2, adding citric acid and oxalic acid particles to the fluorine-containing silicic acid solution in sequence to remove heavy metal impurities, and then filtering to obtain a fluorine-containing silicic acid clear solution and a filter residue 1, wherein 1.05 g to 1.10 g of citric acid and 1.15 g to 1.20 g of oxalic acid are added to 100 mL of the fluorine-containing silicic acid solution; Step 3, reacting the fluorosilicic acid-containing clear liquid with a potassium salt solution, controlling the temperature to 45° C.-55° C., and filtering to obtain potassium fluorosilicate crystals and a crystallization mother liquor; Step 4, adding the crystallization mother liquor to lime milk for neutralization and precipitation treatment, and controlling the precipitation reaction pH value to be 8-9, filtering to obtain a filtrate and a filter residue 2, wherein the volume mass ratio of the crystallization mother liquor to the lime milk is 100L:(16.5-20.0)kg; Step 5, subjecting the filtrate to adsorption treatment to obtain an adsorption tail liquid that can be discharged.

2. The method for comprehensive treatment of tantalum-niobium ore extract residue according to claim 1, characterized in that: In step 1, the ore extract residue is preheated to 40°C ± 5°C.

3. The method for comprehensive treatment of tantalum-niobium ore extract residue according to claim 2, characterized in that: In step 1, add microsilica powder into the preheated ore extract residue and heat to 60°C to 65°C for reaction for 0.5h to 1.0h.

4. The method for comprehensive treatment of tantalum-niobium ore extract residue according to claim 1, characterized in that: In step 2, the filtration treatment is performed by using a chamber filter press for filtration separation.

5. The method for comprehensive treatment of tantalum-niobium ore extract residue according to claim 1, characterized in that: In step 3, the potassium salt solution includes at least one of K2CO3, KCl, K2SO4, and KNO3 solutions.

6. The method for comprehensive treatment of tantalum-niobium ore extract residue according to claim 5, characterized in that: In step 3, the potassium salt solution is a KCl solution.

7. The method for comprehensive treatment of tantalum-niobium ore extract residue according to claim 1, characterized in that: In step 3, the volume mass ratio of the fluorinated silicic acid clear solution to the potassium salt is 100L:(15.5-18.5)kg.

8. The method for comprehensive treatment of tantalum-niobium ore extract residue according to claim 1, characterized in that: In step 4, the filtrate is subjected to adsorption treatment by using vermiculite, wherein the adsorption contact time per volume is 45 min to 60 min.

9. The method for comprehensive treatment of tantalum-niobium production raffinate according to any one of claims 1 to 8, characterized in that: In step 3, the potassium fluorosilicate crystals are washed multiple times, and the washing water is used to prepare the solvent required for the potassium salt solution.

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