CN114438347B - Method for extracting and preparing high-purity vanadium oxide from high-chlorine vanadium-containing solution - Google Patents

Abstract

The invention provides a method for extracting and preparing high-purity vanadium oxide from high-chlorine vanadium-containing solution. The method comprises the following steps: adding a composite desiliconization reagent consisting of an inorganic desiliconization agent and an organic desiliconization agent into the high-chlorine vanadium-containing solution for desiliconization, extracting by using a composite extraction system comprising a neutral extraction agent, an amine extraction agent and/or a phosphorus extraction agent and isoparaffin, and then washing, back-extracting and calcining to obtain the high-purity vanadium oxide. The composite desiliconization reagent can greatly improve the desiliconization effect, the composite extraction system can avoid the influence of high-concentration chloride ions, the vanadium-chromium separation efficiency is high, and the product purity is high. The isoparaffin is used as a diluent to reduce the content of organic matters in an extraction water phase, so that the vanadium extraction process is more environment-friendly and energy-saving, and has little environmental pollution.

Description

Method for extracting and preparing high-purity vanadium oxide from high-chlorine vanadium-containing solution

Technical Field

The invention relates to the technical field of chemical metallurgy, in particular to a method for extracting and preparing high-purity vanadium oxide from high-chlorine vanadium-containing solution.

Background

With the development of the fields of vanadium-aluminum alloy, all-vanadium flow batteries, catalysts, pigments and the like, the demand of high-value high-purity vanadium products is rapidly increased, and the purity of vanadium is generally required to be more than 99.9% and the chromium content is definitely required internationally. Vanadium and chromium are adjacent in the periodic table of elements and have similar physical and chemical properties, vanadium and chromium are often associated in natural minerals, and vanadium and chromium separation is usually the main difficulty of vanadium separation and purification.

Vanadium resources are mainly added in vanadium titano-magnetite and chromite, and vanadium slag generated in the smelting process of the vanadium titano-magnetite is a main raw material for extracting vanadium. The process for extracting vanadium from vanadium slag mainly comprises (1) acid leaching process, (2) sodium salt roasting-water leaching process, (3) calcification roasting-acid leaching process and (4) sub-molten salt liquid phase oxidation process. The acid leaching process is to leach vanadium by sulfuric acid or nitric acid, add alkali for neutralization and purification, and finally precipitate vanadium by ammonium salt. In the acid leaching process, vanadium exists in the vanadium slag in a crystal form, and the vanadium leaching needs to overcome larger crystal lattice energy, so the vanadium leaching rate in the acid leaching process is lower. If the acidity is improved to increase the vanadium leaching rate, impurities in the leaching solution are increased at the same time, the alkali consumption in subsequent neutralization is increased, the product cost is high, and the purity is low. Finally, the product obtained by precipitating vanadium from ammonium salt has high impurity generally and can not reach the product standard of high-purity vanadium pentoxide. Although chromium impurities are relatively reduced in the calcification roasting-acid leaching method, the vanadium leaching rate is low due to the generation of calcium vanadate, and meanwhile, calcium impurities in the product are difficult to separate thoroughly. The sodium salt roasting-water leaching process is that vanadium slag is roasted by sodium carbonate and then is leached by water, and after the impurities of the leaching solution are removed, vanadium is precipitated by ammonium salt; also provides a process flow for hydrolyzing and purifying vanadium after the vanadium is precipitated by calcium. The sodium roasting-water leaching-ammonium salt precipitation method is a typical process for extracting vanadium at present. But the vanadium-containing product obtained by precipitation by the method still has low purity, wherein the main impurities are chromium, silicon, calcium and iron, and the leaching solution needs solvent extraction for further purification and purification of vanadium.

The method for separating vanadium and chromium mainly comprises (1) a reduction-precipitation method; (2) ion exchange method; (3) solvent extraction process. The reduction-precipitation method is to add a reducing agent into the solution after vanadium precipitation and then add alkali to neutralize the precipitation, which can cause a great amount of loss of vanadium, low vanadium-chromium separation efficiency and low product purity. Some strong base anion exchange resins can realize vanadium-chromium separation, but have low capacity, are not very suitable for extracting and separating vanadium from a vanadium-chromium solution, and have low efficiency in vanadium analysis, easy resin poisoning, long washing time and large wastewater generation amount. Solvent extraction is another method for vanadium extraction recovery, and is also a common method for further purification of vanadium. The solvent extraction method is very suitable for extracting vanadium with higher concentration due to the large extraction capacity.

Patent CN201910347376.2 describes a preparation method of vanadyl sulfate solution, which comprises reducing 5-valent vanadium at a certain acidity, re-extracting and oxidizing, using more reducing agents in the process, and additionally increasing the cost of vanadium-chromium separation, wherein the vanadium-containing stripping solution is removed by activated carbon adsorption, and the purity of vanadium pentoxide product is seriously affected by the step because the activated carbon contains more impurities. The pH value of the vanadium slag leaching solution is usually higher, and more polyacid is required to be added for tempering according to the extraction or reduction conditions (the pH value is 1.5-2.5), so that the vanadium separation and purification cost is increased invisibly. Similar patents also exist: a method for preparing vanadium oxide by low-concentration acidic vanadium liquid extraction (CN 112575207A), a method for preparing vanadyl sulfate electrolyte of an all-vanadium flow battery (CN 201210108878.8), and a method for preparing vanadium pentoxide by composite extraction (CN 201710346620.4). In these patents, the vanadium extraction organic is mainly composed of P204 or TBP and sulfonated kerosene.

Patents CN101121962A, CN103937998, and CN101665870A describe a method for extracting vanadium under weak acid condition, in which the core extractant is LK-N21, the modifier is LK-N21X, and the diluent is sulfonated kerosene or toluene. Wherein LK-N21 does not clearly inform what kind of medicament, LK-N21X is mainly ethyl acetate, amyl acetate, methyl ethyl p-methyl acetate, tert-butyl acetate, diisopropyl succinate. And the above patent is also limited to sulfate systems only, with no or low concentrations of chloride ions in the system; is not applicable to complex systems with higher chloride ions in the water phase. In addition, in the aspect of environmental protection, the solubility of the extraction system consisting of the organic matters in a water phase is higher, particularly, the used diluent kerosene accounts for more than 60% of an organic phase, the organic matter content in the discharged raffinate waste water is higher, and the subsequent waste water treatment and the environmental influence are larger. The patent CN108298581B also has the problem of high organic content in the raffinate waste water, and in addition, the patent adopts calcium salt for desilication, and a certain amount of vanadium in the solution is lost due to the generation of calcium vanadate.

Disclosure of Invention

The invention mainly aims to provide a method for extracting and preparing high-purity vanadium oxide from a high-chlorine vanadium-containing solution, and aims to solve the problems of poor desilication effect, low separation efficiency and great environmental pollution in the prior art when vanadium is extracted from the high-chlorine vanadium-containing solution.

In order to achieve the above object, according to one aspect of the present invention, there is provided a method for preparing high purity vanadium oxide by extracting high chlorine vanadium-containing solution, comprising the following steps: step S1, adding a composite desiliconization reagent into the high-chlorine vanadium-containing solution for desiliconization to obtain a desiliconized solution; step S2, extracting the desiliconized solution by using a composite extraction system to obtain a first vanadium-loaded organic phase; step S3, washing the first vanadium-loaded organic phase to obtain a second vanadium-loaded organic phase; step S4, carrying out back extraction on the second vanadium-loaded organic phase by using a composite back extractant to obtain vanadium-containing precipitate; step S5, calcining the vanadium-containing precipitate to obtain high-purity vanadium oxide; wherein the total vanadium concentration in the high-chlorine vanadium-containing solution is 20-40 g/L, and the chloride ion concentration is 5-15 g/L; the composite desiliconization reagent comprises an inorganic desiliconization agent and an organic desiliconization agent, wherein the inorganic desiliconization agent comprises inorganic aluminum salt and/or polymeric aluminum iron, and the organic desiliconization agent is one or more of a nonionic organic desiliconization agent, a cationic organic desiliconization agent and an anionic organic desiliconization agent; the composite extraction system comprises a composite extractant and a diluent, the composite extractant comprises a first extractant and a second extractant, the first extractant is a neutral extractant, the second extractant is an amine extractant and/or a phosphorus extractant, and the diluent comprises isoparaffin.

Further, in the composite desiliconization reagent, the inorganic aluminum salt in the inorganic desiliconization reagent comprises one or more of aluminum sulfate, aluminum chloride, aluminum hydroxide, ammonium aluminate, sodium metaaluminate, potassium aluminate, potassium metaaluminate and alum; preferably, the polyaluminum ferric includes one or more of polyaluminum sulfate, polyaluminum chloride, polyferric sulfate, polyaluminum ferric sulfate chloride; in the organic desiliconization agent, the nonionic organic desiliconization agent is one or more of acrylamide, polyacrylamide, polyethylene oxide and polyvinyl pyridine; the cationic organic desiliconization agent is one or more of poly (diallyldimethylammonium chloride), poly (epichlorohydrin) amine polymer, polyetheramine D230, polyetheramine D400 and polyetheramine EC 301; the anionic organic desiliconization agent is one or more of polyacrylic acid, sodium polyacrylate and calcium polyacrylate; more preferably, the inorganic desiliconization agent is one or more of polyaluminium sulfate, polyaluminium chloride and polyferric sulfate; the organic desiliconization agent is one or more of polyacrylamide, polydiallyldimethylammonium chloride and sodium polyacrylate.

Furthermore, in the composite extraction system, the volume ratio of the composite extraction agent to the diluent is (20-45): 55-80, and the composite extraction system comprises 5-15% of the first extraction agent according to volume percentage; preferably, in the composite extractant, the neutral extractant comprises one or more of isomeric C10 alcohols, isomeric C13 alcohols, sec-octanol, isodecanol and n-octanol; the amine extractant comprises one or more of N-octylamine, dodecylamine, N-decylamine, hexadecylamine, N1519, N1923, Primene 81-R, Primene JMT, Aliquat 336, HYHAPR-OD and HYHAPR-SD; the phosphorus extractant comprises one or more of P350, TRPO and TOPO; more preferably, the first extractant is one or more of the isomeric C13 alcohols, sec-octanols and isodecanols; the second extractant is one or more of P350, TRPO, N-dodecylamine, N-decylamine, N1923, Primene 81-R, Primene JMT, Aliquat 336 and HYHAPR-OD; preferably, the diluent comprises a composition of isoparaffin and sulfonated kerosene, and the volume ratio of the isoparaffin to the sulfonated kerosene is (50-100): 0-50); more preferably, before the desiliconized solution is extracted by using the composite extraction system, the method further comprises the steps of salinizing and removing impurities by using 0.01-50 wt.% of inorganic acid aqueous solution and/or organic acid aqueous solution for the composite extraction system.

Further, the molar ratio of the inorganic desiliconization agent to the total silicon in the high-chlorine vanadium-containing solution is (0.6-2): 1; the organic desiliconization agent is 0.01-1% of the total volume of the high-chlorine vanadium-containing solution.

Further, in step S1, before desiliconization, the pH of the high-chlorine vanadium-containing solution is adjusted to 8-10; after desiliconization treatment, adjusting the pH value of the desiliconized liquid to 7.5-8.5; preferably, the desiliconization treatment temperature is 30-80 ℃, and the desiliconization treatment time is 60-180 min.

Further, in step S2, the volume ratio of the composite extraction system to the desiliconized solution is 3:1 to 1:10, preferably, the volume ratio of the composite extraction system to the desiliconized solution is 2:1 to 1: 5; preferably, before the extraction step, the pH value of the desiliconized solution is adjusted to 2.5-8, the extraction stage number is 2-20, the single-stage extraction time is 3-20 min, and the extraction temperature is 5-60 ℃; more preferably, before the extraction step, the pH of the desiliconized solution is adjusted to 3-7, the single-stage extraction time is 4-8 min, and the extraction temperature is 10-40 ℃.

Further, in step S3, the washing solution is one or more of water, a 2-50 g/L sodium sulfate aqueous solution, a 2-50 g/L ammonium sulfate aqueous solution, and an ammonia aqueous solution with a mass concentration of less than 10 wt.%; the volume ratio of the first vanadium-loaded organic phase to the washing solution is 10: 1-1: 2; preferably, the volume ratio of the first vanadium-loaded organic phase to the washing solution is 5: 1-1: 1; preferably, the washing grade number is 1-10 grades; the single-stage washing time is 3-10 min; the washing temperature is 5-60 ℃.

Further, in step S4, the composite stripping agent includes at least two or more of ammonia water, ammonium chloride, ammonium sulfate, ammonium oxalate, ammonium carbonate and ammonium bicarbonate; preferably, the volume ratio of the second vanadium-loaded organic phase to the stripping agent is 10: 1-1: 3; the molar ratio of ammonium ions in the stripping agent to the total vanadium in the second vanadium-loaded organic phase is (1-2.5): 1; more preferably, the composite stripping agent further comprises 0-5 g/L of EDTA and/or ethylenediamine tetraacetic acid diamine.

Further, in step S4, the back-extraction time is 5-180 min, the back-extraction temperature is 0-100 ℃, and the pH of the back-extraction end-point aqueous phase is 8-13.

Further, in step S5, the calcination temperature is 200-800 ℃, the calcination time is 30-240 min, and the calcination air flow is 0-1000 mL/min.

By applying the technical scheme of the invention, the method can be suitable for extracting vanadium in the high-chloride leaching solution by reasonably setting the extraction reagent and the process. The composite desiliconization reagent comprising the inorganic desiliconization agent and the organic desiliconization agent can greatly improve the desiliconization effect of the vanadium-containing solution. The composite extraction system can also avoid the problem that the extraction efficiency is influenced by the fact that the steric hindrance of the extracting agent and the diluent is enlarged due to the fact that the number of the small-radius chloride ions is too large, and has high vanadium-chromium separation efficiency and high product purity. Meanwhile, the isoparaffin in the diluent replaces or partially replaces the sulfonated kerosene, so that the solubility of organic matters in the aqueous raffinate is greatly reduced, and the oil removal pressure of subsequent extraction wastewater treatment is reduced; correspondingly, the composite stripping agent of the invention reduces the content of organic matters in the stripping aqueous phase, reduces the loss of the vanadium-containing organic phase, and leads the vanadium extraction process to be more green and energy-saving and has little environmental pollution.

Detailed Description

It should be noted that, in the present application, the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail with reference to examples.

As in the background art, the problems of poor desilication effect, low separation efficiency and great environmental pollution exist in the prior art when vanadium is extracted from high-chlorine vanadium-containing solution. In order to solve the above problems, in an exemplary embodiment of the present invention, a method for preparing high purity vanadium oxide by extracting high chlorine vanadium-containing solution is provided, which comprises the following steps: step S1, adding a composite desiliconization reagent into the high-chlorine vanadium-containing solution for desiliconization to obtain a desiliconized solution; step S2, extracting the desiliconized solution by using a composite extraction system to obtain a first vanadium-loaded organic phase; step S3, washing the first vanadium-loaded organic phase to obtain a second vanadium-loaded organic phase; step S4, carrying out back extraction on the second vanadium-loaded organic phase by using a composite back extractant to obtain vanadium-containing precipitate; and step S5, calcining the vanadium-containing precipitate to obtain high-purity vanadium oxide.

Wherein the total vanadium concentration in the high-chlorine vanadium-containing solution is 20-40 g/L, and the chloride ion concentration is 5-15 g/L; the composite desiliconization reagent comprises an inorganic desiliconization agent and an organic desiliconization agent, wherein the inorganic desiliconization agent comprises inorganic aluminum salt and/or polymeric aluminum iron, and the organic desiliconization agent is one or more of a nonionic organic desiliconization agent, a cationic organic desiliconization agent and an anionic organic desiliconization agent; the composite extraction system comprises a composite extractant and a diluent, the composite extractant comprises a first extractant and a second extractant, the first extractant is a neutral extractant, the second extractant is an amine extractant and/or a phosphorus extractant, and the diluent comprises isoparaffin.

The conventional vanadium-containing solution is a sulfuric acid system, and the process for extracting and preparing high-purity vanadium oxide from the high-chlorine vanadium-containing solution in the prior art is not mature. The inventor finds that in the actual extraction process, in the vanadium-containing solution with high chlorine content, chloride ions exist in a large amount as impurity ions, and influence the existing form of the vanadium ions, so that the subsequent impurity introduction risk is increased. In addition, as the radius of the chloride ions is smaller than that of the sulfate ions, the steric hindrance of an extracting agent and a diluting agent can be increased when a large amount of chloride ions exist in the solution, the performance and the selectivity of an extraction system are reduced, and the extraction and separation effects of vanadium are poor. The conventional extraction process also has the problems of difficult treatment of a large amount of organic wastewater and great environmental pollution. Aiming at the above situation, the invention firstly uses a composite desiliconization reagent to carry out desiliconization treatment on the high-chlorine vanadium-containing solution with the total vanadium concentration of 20-40 g/L and the chloride ion concentration of 5-15 g/L to obtain a desiliconized solution. And then, extracting by using a composite extraction system, and extracting vanadium in the desiliconized liquid into a first vanadium-loaded organic phase. And then washing the first vanadium-loaded organic phase to remove soluble impurities, and performing back extraction on the obtained second vanadium-loaded organic phase to ensure that vanadium enters the water phase of the composite back extractant, so that a precipitate which is not dissolved in the water phase or the organic phase is obtained, and the organic content in the back raffinate can be greatly reduced. And finally calcining the precipitate to obtain the high-purity vanadium oxide.

The method uses a composite desiliconization reagent comprising an inorganic desiliconization agent and an organic desiliconization agent, and can greatly improve the desiliconization effect of the solution containing high chlorine and vanadium. The composite extraction system can also avoid the problem that the extraction efficiency is influenced by the fact that the steric hindrance of the extracting agent and the diluent is enlarged due to the fact that too many small-radius chloride ions exist, and has high vanadium-chromium separation efficiency and high product purity. Meanwhile, the isoparaffin in the diluent replaces or partially replaces the sulfonated kerosene, so that the solubility of organic matters in the aqueous raffinate is greatly reduced, and the oil removal pressure of subsequent extraction wastewater treatment is reduced; correspondingly, the composite stripping agent of the invention reduces the content of organic matters in the stripping aqueous phase, reduces the loss of the vanadium-containing organic phase, and leads the vanadium extraction process to be more green and energy-saving and has little environmental pollution.

The desilication mechanism of the composite desilication agent is mainly related to the synergistic action of the inorganic desilication agent and the organic desilication agent. The inorganic desiliconization agent can adsorb impurity silicon and suspended particles, so that particles are formed and gradually enlarged; the organic desiliconization agent generates a net catching effect by using an active group adsorbed on an organic polymer through the self bridging effect, and further net catching impurity silicon and other impurity particles sink together. Meanwhile, the existence of the inorganic desiliconization agent neutralizes the surface charges of the impurity silicon, can synergistically promote the sedimentation effect of the organic polymer, and further improves the desiliconization effect.

In a preferred embodiment, the inorganic aluminum salt in the composite desiliconizing agent comprises one or more of aluminum sulfate, aluminum chloride, aluminum hydroxide, ammonium aluminate, sodium metaaluminate, potassium aluminate, potassium metaaluminate and alum, and the low molecular aluminum salt can lower the potential by the action of double electric layer adsorption and the charge of silicon in the solution, so as to more rapidly realize the agglomeration of silicon-containing particles. Preferably, the polyaluminum ferric includes one or more of polyaluminum sulfate, polyaluminum chloride, polyferric sulfate, polyaluminum ferric sulfate chloride, and more preferably, the inorganic desiliconizing agent is one or more of polyaluminum sulfate, polyaluminum chloride, and polyferric sulfate, and these macromolecular aluminum ferric polymers can be hydrolyzed to generate high valent ions to form hydroxyl polynuclear complexes, and further precipitate the silicon-containing particles in the solution through carbonyl bridging.

The organic desiliconization agent can carry hydrophilic groups such as-NH-, -OH and the like in macromolecules, has various structures such as chain, ring and the like, and has a plurality of active groups, high molecular weight and strong desiliconization capability. Preferably, the non-ionic organic desiliconization agent is one or more of acrylamide, polyacrylamide, polyethylene oxide and polyvinyl pyridine, and the non-ionic organic desiliconization agent, particularly the polyacrylamide, has higher molecular weight and stronger bridging capacity, and contains a certain amount of polar genes which can adsorb silicon-containing particles in a solution and accelerate the sedimentation and the detachment of the silicon-containing particles. Preferably, the cationic organic desiliconization agent is one or more of polydiallyl dimethyl ammonium chloride, a reaction product of epoxy chloropropane and amine modified polyether, can perform destabilization and desiliconization through charge neutralization and bridging, can react with a negatively charged solute to generate insoluble substances, can settle other impurities in the solution during desiliconization, and is more suitable for the wastewater with high organic content. Preferably, the anionic organic desiliconization agent is one or more of polyacrylic acid, sodium polyacrylate and calcium polyacrylate, and is cheaper and easier to obtain. More preferably, the organic desiliconization agent is one or more of polyacrylamide, polydiallyl dimethyl ammonium chloride and sodium polyacrylate, the desiliconization is quicker and more thorough, the synergistic effect with the inorganic desiliconization agent is stronger, the impurity concentration of the subsequent extraction step can be reduced, and the vanadium separation effect is further improved.

The extraction step is a key step for separating vanadium from other impurities, particularly chromium, and a proper extracting agent needs to be selected to realize high-efficiency extraction. In a preferred embodiment, the composite extraction system comprises 5-15% of the first extractant by volume percentage, so as to further exert the synergistic extraction effect of the neutral extractant and the amine extractant or the phosphorus extractant. Preferably, the neutral extractant comprises one or more of isomeric C10 alcohol, isomeric C13 alcohol, sec-octanol, isodecanol and n-octanol, the extractant molecules all contain-OH, can generate hydrogen bond association with water molecules, has certain solubility in an aqueous phase, can be combined with vanadium-containing anions or can generate a complex with vanadium to enter an organic phase to be extracted. In addition, the neutral extracting agents can also perform quenching and tempering modification on an organic system, inhibit intermolecular polymerization of extraction compounds, inhibit formation of reverse micelles, and simultaneously facilitate phase separation, thereby further improving the separation efficiency of vanadium. More preferably, the first extractant is one or more of isomeric C13 alcohol, sec-octanol and isodecanol, and the second extractant is one or more of P350, TRPO, N-dodecylamine, N-decylamine, N1923, Primene 81-R, Primene JMT, Aliquat 336 and HYHAPR-OD, so that the synergistic extraction and the synergistic steric hindrance reduction effect in the vanadium extraction process can be better exerted, and the extraction effect is further improved.

Preferably, the amine extractant comprises one or more of N-octylamine, dodecylamine, N-decylamine, hexadecylamine, N1519, N1923, Primene 81-R, Primene JMT, Aliquat 336, HYHAPR-OD and HYHAPR-SD, and the amine extractant takes a nitrogen atom as an extraction functional group, utilizes the more excellent structure and performance of the amine extractant, or forms an association by a nitrogen-containing group and a hydrogen bond, so as to selectively and preferentially extract vanadium; or exchanging vanadium-containing anions with anions in the vanadium-containing anions so as to enable the vanadium to enter an organic phase, so that the vanadium is more thoroughly separated from other impurities, particularly chromium-containing ions, and the separation efficiency of the vanadium is further improved. Preferably, the acidic extractant comprises one or more of P350, TRPO and TOPO, and the extractant has fewer C-P bonds in molecules, more alkoxy groups and stronger electron-withdrawing effect, and is more favorable for synergistically reducing steric hindrance and improving vanadium extraction performance with amine extractants.

The volume ratio of the composite extracting agent to the diluent is preferably (20-45): (55-80), and preferably, the diluent comprises a composition of isoparaffin and sulfonated kerosene, and the volume ratio of the isoparaffin to the sulfonated kerosene is (50-100): 0-50. In the composite extraction system, the proportion of the diluent is low, and meanwhile, the isoparaffin is used for replacing or partially replacing the sulfonated kerosene, so that the solubility of organic matters in the aqueous raffinate is greatly reduced, the oil removal pressure of subsequent extraction wastewater treatment is reduced, and the extraction effect is not influenced by too low dosage. More preferably, before the desiliconized solution is extracted by using the composite extraction system, the method further comprises the step of salinizing and removing impurities by using 0.01-50 wt% of inorganic or organic acid aqueous solution for the composite extraction system, so that the extraction efficiency of the organic extractant can be further enhanced, the influence of high-concentration chloride ions on the extraction system is smaller, the vanadium-chromium separation efficiency is higher, and the product purity is higher.

In a preferred embodiment, in step S1, the inorganic desiliconization agent and the organic desiliconization agent are added to the high-chlorine vanadium-containing solution in sequence, and the desiliconization solution is obtained by filtration. In order to reduce the waste of the desiliconization agent while ensuring that the impurity silicon in the high-chlorine vanadium-containing solution is removed as much as possible, the molar ratio of the inorganic desiliconization agent to the silicon ions in the high-chlorine vanadium-containing solution is preferably (0.6-2): 1; the organic desiliconization agent is 0.01-1% of the total volume of the high-chlorine vanadium-containing solution, and the inorganic desiliconization agent and the organic desiliconization agent are beneficial to better exerting a synergistic effect of the inorganic desiliconization agent and the organic desiliconization agent in the range, so that the desiliconization effect is further improved.

When the solution is in an alkaline environment during the use of the inorganic desiliconization agent, amphoteric elements such as zinc, manganese, aluminum, silicon and the like can precipitate and are easy to remove, but when the alkalinity is too high, vanadium can precipitate to increase the vanadium loss, and simultaneously, the organic aluminum polymer can also cause the stability to be reduced due to the too high alkalinity, so that the desiliconization effect is reduced. Therefore, in a preferred embodiment, in step S1, before the desiliconization treatment, the pH of the high-chlorine vanadium-containing solution is adjusted to 8-10; after desiliconization treatment, the pH value of the liquid after desiliconization treatment is adjusted to 7.5-8.5, and the desiliconization efficiency and the precipitation performance are high in a proper pH environment. In order to further accelerate the desiliconization speed while ensuring the desiliconization effect, the desiliconization reaction temperature is preferably 30-80 ℃, and the desiliconization reaction time is preferably 60-180 min. In the desiliconization step, impurities such as iron, aluminum, and zinc are also substantially removed, and the desiliconization step is herein collectively referred to as a desiliconization step.

In the actual extraction process, the volume ratio of the composite extraction system to the desiliconized solution is preferably 3: 1-1: 10, and more preferably 2: 1-1: 5, so that the vanadium extraction separation effect is ensured, the use amount of an organic extractant is reduced, the treatment difficulty of raffinate wastewater is further reduced, and the environmental pollution is less. The acidity of the solution to be extracted has a certain influence on the extraction effect of the extractant, for example, the amine extractant is generally firstly mixed with H in the aqueous phase ⁺ In combination, the extraction performance is better in a lower pH environment, but the element selectivity is poor. In order to balance the extraction performance and the element selectivity, in a preferred embodiment, in step S2, before the extraction step, the pH of the desiliconized solution is adjusted to 2.5 to 8 again, and then countercurrent extraction is performed, wherein the number of extraction stages is 2 to 20, the single-stage extraction time is 3 to 20min, and the extraction temperature is 5 to 60 ℃. In order to further improve the extraction separation efficiency, more preferably, before the extraction step, the pH of the desiliconized solution is adjusted to 3-7 again, and then countercurrent extraction is carried out, wherein the single-stage extraction time is 4-8 min, and the reaction temperature is 10-40 ℃.

In a preferred embodiment, in step S3, the washing solution is one or more of water, 2 to 50g/L sodium sulfate aqueous solution, 2 to 50g/L ammonium sulfate aqueous solution, and aqueous ammonia solution with a mass concentration of less than 10wt%, and the aqueous ammonia is added for washing during washing, so as to adjust the pH of the solution within a suitable range, reduce the amount of the subsequent complex stripping agent, and facilitate the precipitation process of the stripping operation. In order to further improve the washing effect and remove soluble impurity ions, especially high-concentration chloride ions, sodium ions and residual chromium ions, in the vanadium-containing organic phase, the volume ratio of the first vanadium-loaded organic phase to the washing liquid is preferably 10: 1-1: 2, and more preferably 5: 1-1: 1. Specifically, the number of washing stages is 1-10; the single-stage washing time is 3-10 min; the washing temperature is 5-60 ℃, preferably 10-40 ℃.

In a preferred embodiment, in step S4, the composite stripping agent includes at least two or more of ammonia water, ammonium chloride, ammonium sulfate, ammonium oxalate, ammonium carbonate and ammonium bicarbonate, and the stripping agent can completely strip vanadium in the second vanadium-loaded organic phase into the aqueous phase, and precipitate the vanadium under the alkaline condition, and finally separate the vanadium-containing precipitate with high purity by simple solid-liquid separation. In order to further improve the stripping separation efficiency, preferably, the volume ratio of the second vanadium-loaded organic phase to the composite stripping agent is 10: 1-1: 3, and the molar ratio of ammonium ions in the composite stripping agent to the total vanadium in the second vanadium-loaded organic phase is (1-2.5): 1; more preferably, the composite stripping agent also comprises 0-5 g/L of EDTA and/or ethylenediamine tetraacetic acid diamine, so that the generation rate of vanadium-containing precipitates is further accelerated.

Correspondingly, in the step S4, the back-extraction time is 5-180 min, preferably 20-180 min, the back-extraction temperature is 0-100 ℃, the pH value of the back-extraction end-point aqueous phase is 8-13, vanadium in the system basically enters the precipitate, in the practical application process, whether the end point of the precipitate is reached can be conveniently judged by measuring the pH value of the back-extraction end-point aqueous phase, the pH value and other properties of the back-extraction solution can be timely adjusted, and the back-extraction efficiency is further improved. In addition, compared with the traditional organic extraction system, the organic phase used in the extraction process of the invention uses isoparaffin to partially or completely replace sulfonated kerosene, so that the organic phase has lower solubility in the strip liquor, and can further reduce environmental pollution in the strip process, thereby ensuring that the whole extraction process is more green.

In a preferred embodiment, in step S5, the calcination temperature is 200 to 800 ℃, the calcination time is 30 to 240min, the calcination air flow is 0 to 1000mL/min, preferably the calcination air flow is greater than 0mL/min and less than or equal to 200mL/min, and thus the purity of the obtained vanadium oxide is higher.

The present application is described in further detail below with reference to specific examples, which should not be construed as limiting the scope of the invention as claimed.

Example 1

The total vanadium concentration of the high-chlorine vanadium-containing leaching solution is 30.21g/L, the chloride ion concentration is 10.32g/L, and the silicon ion concentration is 1819.1 ppm.

Adjusting the pH value of the high-chlorine vanadium-containing leaching solution to 9.5 by using concentrated sulfuric acid, and sequentially adding an inorganic desiliconization agent polyaluminium chloride and an organic desiliconization agent polyacrylamide, wherein the addition amount of the inorganic desiliconization agent is 0.8 times of the total mole amount of silicon in the solution, and the addition amount of the organic desiliconization agent polyacrylamide is 0.1 percent of the total volume of the high-chlorine vanadium-containing leaching solution. Controlling the desiliconization temperature at 60 ℃, adding a desiliconization reagent for reaction for 60min, and stirring at the rotating speed of 400 rpm; after the reaction is finished, when the temperature of the system is reduced to be below 40 ℃ (> 15 ℃), the pH is slowly adjusted to be 8.2 by adopting concentrated sulfuric acid or concentrated NaOH, then the mixture is kept stand for 20min, then solid-liquid separation is carried out, desiliconized liquid is obtained, and the solid-liquid separation is rapid. Sampling analysis shows that the concentration of silicon ions in the vanadium-containing leaching solution is reduced from 1819.1ppm to 1.4ppm, the desiliconization rate is 99.9 percent, and the vanadium loss rate is lower than 1.5 percent, which is shown in Table 1.

Filtering the desiliconized solution by using activated carbon, adjusting the pH value to 5.5 by using sulfuric acid, then performing countercurrent extraction by using 25% of JMT + 5% of P350 + 5% of isomeric C10 alcohol + 65% of isoparaffin according to volume percentage, acidifying the composite extraction system by using 10% of sulfuric acid aqueous solution for 10min before use, wherein the volume ratio of the composite extraction system to the desiliconized solution is 1:3, the extraction stages are 8 stages, the single-stage extraction time is 10min, and the extraction temperature is 20 ℃, thereby obtaining a first vanadium-loaded organic phase. And then carrying out countercurrent washing by adopting 30g/L sodium sulfate solution, wherein the washing stage number is 4, and then carrying out countercurrent washing by adopting pure water, the washing stage number is 2, and the single-stage washing time is 10min, so as to obtain a second vanadium-loaded organic phase. The composite stripping agent adopts 14wt% of ammonia water and 0.4mol/L of ammonium sulfate aqueous solution, the volume ratio of the second vanadium-loaded organic phase to the composite stripping agent is 2:1, the stripping is carried out for 1h at 40 ℃, the pH value of the aqueous phase is 10 at the moment, the temperature of the aqueous phase is controlled to be less than 10 ℃ after the stripping, the standing is carried out for 1h, then the solid-liquid separation is carried out, the ammonium metavanadate solid is obtained, and the oil content in the supernatant of the precipitate is only 71 ppm. Calcining the ammonium metavanadate solid for 4 hours at the temperature of 600 ℃ and under the condition of air flow rate of 100mL/min to obtain a high-purity vanadium pentoxide product with the purity of more than 99.95%.

Example 2

Example 2 differs from example 1 in that the following operations are carried out after the desilication treatment is completed: filtering the desiliconized solution by using activated carbon, adjusting the pH value to 4.75 by using sulfuric acid, and extracting by using a composite extraction system in the table 1, wherein the composite extraction system is acidified by using a 10% sulfuric acid aqueous solution for 10min before use, the extraction time is 20min, the volume ratio of the composite extraction system to the desiliconized solution is 1.5:1, the extraction temperature is 20 ℃, and the vanadium extraction rate, the chromium extraction rate and the organic content in a raffinate water phase are shown in the table 1.

Example 3

Example 3 differs from example 1 in that the following operations are carried out after the desilication operation has been completed: after the desiliconized solution is filtered by active carbon, the pH value is adjusted to 5.5 by sulfuric acid, and a composite extraction system in the table 1 is adopted for extraction. Before use, the composite extraction system is acidified for 10min by using 2% sulfuric acid aqueous solution with the same volume, the extraction time is 10min, the volume ratio of the composite extraction system to the desiliconized solution is 1:1, the extraction temperature is 25 ℃, and the vanadium extraction rate, the chromium extraction rate and the organic content in the raffinate water phase are shown in table 1.

Example 4

The difference between the embodiment 4 and the embodiment 1 is that the composite desiliconization reagent is polymeric aluminum sulfate and poly diallyl dimethyl ammonium chloride, the addition amount of the polymeric aluminum sulfate is 0.6 times of the total mole amount of silicon in the solution, and the poly diallyl dimethyl ammonium chloride is 0.2 percent of the total volume of the high-chlorine vanadium-containing leachate. According to volume percentage, the composite extraction system is 10 percent of secondary octanol and 15 percent of Primene 81-R and 5 percent of TRPO and 70 percent of diluent (the volume ratio of isoparaffin to sulfonated kerosene is 50: 50), and the volume ratio of the composite extraction system to the desiliconized solution is 2: 1. The washing solution is 50g/L sodium sulfate aqueous solution, and the volume ratio of the first vanadium-loaded organic phase to the washing solution is 5: 1. The composite stripping agent is 18wt% of ammonia water and 0.4mol/L of ammonium chloride, the volume ratio of the second vanadium-loaded organic phase to the composite stripping agent is 10:1, and the pH value of the stripping endpoint aqueous phase is 8. The vanadium extraction rate, chromium extraction rate, organic content in raffinate aqueous phase, and desilication rate are shown in table 2.

Example 5

Example 5 differs from example 1 in that the composite desiliconization agent is polyferric sulfate added in an amount of 2 times the total mole amount of silicon in the solution and sodium polyacrylate in an amount of 0.02% of the total volume of the high-chlorine vanadium-containing leachate. According to volume percentage, the composite extraction system is 10 percent of isodecyl alcohol, 10 percent of Aliquat 336 and 80 percent of diluent (the volume ratio of isoparaffin to sulfonated kerosene is 50: 50), and the volume ratio of the composite extraction system to the desiliconized liquid is 1: 6. The washing solution is 50g/L ammonium sulfate aqueous solution, and the volume ratio of the first vanadium-loaded organic phase to the washing solution is 1: 1. The composite stripping agent is 14wt% of ammonia water and 0.4mol/L of ammonium carbonate, the volume ratio of the second vanadium-loaded organic phase to the composite stripping agent is 1:2, and the pH value of the stripping end-point aqueous phase is 13. The vanadium extraction rate, chromium extraction rate, organic content in raffinate aqueous phase, and desilication rate are shown in table 2.

Example 6

Example 6 differs from example 1 in that the composite desiliconization agent is aluminum hydroxide added in an amount of 2 times the total mole amount of silicon in the solution and polyethylene oxide in an amount of 0.01% of the total volume of the high-chlorine vanadium-containing leachate. According to volume percentage, the composite extraction system is 15 percent of n-octanol, 25 percent of hexadecylamine and 60 percent of diluent (the volume ratio of isoparaffin to sulfonated kerosene is 50: 50), and the volume ratio of the composite extraction system to the desiliconized solution is 1: 3. The washing solution is 50g/L ammonium sulfate aqueous solution, and the volume ratio of the first vanadium-loaded organic phase to the washing solution is 10: 1. The composite stripping agent is 25wt% of ammonia water and 0.4mol/L of ammonium carbonate, and the volume ratio of the second vanadium-loaded organic phase to the composite stripping agent is 5: 1. The vanadium extraction rate, chromium extraction rate, organic content in raffinate aqueous phase, and desilication rate are shown in table 2.

Example 7

Example 7 differs from example 1 in that the composite desiliconization agent is aluminum hydroxide added in an amount of 2 times the total mole amount of silicon in the solution and polyethylene oxide in an amount of 0.01% of the total volume of the high-chlorine vanadium-containing leachate. According to volume percentage, the composite extraction system is 15 percent of n-octanol, 25 percent of hexadecylamine and 60 percent of diluent (the volume ratio of isoparaffin to sulfonated kerosene is 50: 50), and the volume ratio of the composite extraction system to the desiliconized solution is 1: 5. The washing solution is 50g/L ammonium sulfate aqueous solution, and the volume ratio of the first vanadium-loaded organic phase to the washing solution is 1: 2. The composite stripping agent is 14wt% of ammonia water and 0.4mol/L of ammonium carbonate, and the volume ratio of the second vanadium-loaded organic phase to the composite stripping agent is 1: 3. The vanadium extraction rate, chromium extraction rate, organic content in raffinate aqueous phase, and desilication rate are shown in table 2.

Comparative example 1

Comparative example 1 differs from example 1 in that the following operations are carried out after the desilication operation has been completed: after the desiliconized solution is filtered by active carbon, the pH is adjusted to 5.0 by sulfuric acid, and the compound extraction system in the table 1 is adopted for extraction. The composite extraction system is acidified for 10min by using 2% sulfuric acid aqueous solution with the same volume before use, the extraction time is 10min, the volume ratio of the composite extraction system to the desiliconized solution is 1:1, the extraction temperature is 25 ℃, and the vanadium extraction rate, the chromium extraction rate and the organic content in a raffinate water phase are shown in table 1.

Comparative example 2

Comparative example 2 differs from example 1 in that the following operations are carried out after the desilication operation has been completed: after the desiliconized solution is filtered by active carbon, the pH value is adjusted to 5.5 by sulfuric acid, and a composite extraction system in the table 1 is adopted for extraction. Before use, the composite extraction system is acidified for 10min by using 2% sulfuric acid aqueous solution with the same volume, the extraction time is 10min, the volume ratio of the composite extraction system to the desiliconized solution is 1:1, the extraction temperature is 25 ℃, and the vanadium extraction rate, the chromium extraction rate and the organic content in the raffinate water phase are shown in table 1.

As can be seen from Table 1, for vanadium extraction in a high-chlorine aqueous phase, the vanadium extraction rate is low, vanadium and chromium separation is poor, organic solubility in raffinate is high, a small amount of impurities are formed after phase separation, and the subsequent treatment cost is high by directly using an N1923-octanol-sulfonated kerosene system for extraction. The extraction result of the system has better indexes, and particularly, the oil content of the water phase is greatly reduced, so that the vanadium extraction process is more environment-friendly.

As is clear from Table 2, the desiliconization effect and the extraction effect are better when the inorganic desiliconization agent, the organic desiliconization agent, the composite extractant and the diluent in the preferable range of the present invention and the ratio thereof are used.

Comparative examples 3 to 7

Only inorganic desiliconization agent polyaluminum chloride is added into vanadium-containing leachate (the total vanadium concentration is 30.21g/L, the chloride ion concentration is 10.32g/L, and the silicon ion concentration is 1819.1 ppm), and the addition amount is the multiple of the total silicon molar weight in the solution and is shown in table 3. Adjusting the pH value of the vanadium-containing leaching solution to 9.5 by using concentrated sulfuric acid, controlling the desiliconization temperature to be 60 ℃, adding a desiliconization reagent for reacting for 60min, and stirring at the rotating speed of 400 rpm; after the reaction is finished, when the temperature is reduced to below 40 ℃ (> 15 ℃), the pH is slowly adjusted to 8.2 by concentrated sulfuric acid or concentrated NaOH, then the mixture is kept stand for 12 hours, and then solid-liquid separation is carried out to obtain desiliconized solution. Sampling analysis shows that the concentration of silicon ions in the vanadium-containing leaching solution, the desiliconization rate, the content of impurity aluminum in the desiliconized solution and the vanadium loss rate are shown in Table 3.

As can be seen from Table 3, when only the inorganic desiliconization agent polyaluminum chloride was added, it was difficult to remove the silicon ions in the solution to a low concentration, and if it is desired to reduce the silicon content to less than 5ppm, a large amount of the desiliconization agent was added. Meanwhile, the content of impurity aluminum in the desiliconized solution is relatively high, and the vanadium loss rate is also high.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (15)

1. The method for extracting and preparing high-purity vanadium oxide from high-chlorine vanadium-containing solution is characterized by comprising the following steps of:

step S1, adding a composite desiliconization reagent into the high-chlorine vanadium-containing solution for desiliconization treatment to obtain a desiliconized solution;

step S2, extracting the desiliconized solution by using a composite extraction system to obtain a first vanadium-loaded organic phase;

step S3, washing the first vanadium-loaded organic phase to obtain a second vanadium-loaded organic phase;

step S4, performing back extraction on the second vanadium-loaded organic phase by using a composite back extraction agent to obtain vanadium-containing precipitate;

step S5, calcining the vanadium-containing precipitate to obtain the high-purity vanadium oxide;

wherein the total vanadium concentration in the high-chlorine vanadium-containing solution is 20-40 g/L, and the chloride ion concentration is 5-15 g/L;

the composite desiliconization reagent comprises an inorganic desiliconization agent and an organic desiliconization agent, wherein the inorganic desiliconization agent comprises inorganic aluminum salt and/or polymeric aluminum iron, and the organic desiliconization agent is one or more of a nonionic organic desiliconization agent, a cationic organic desiliconization agent and an anionic organic desiliconization agent;

the composite extraction system comprises a composite extractant and a diluent, the composite extractant comprises a first extractant and a second extractant, the first extractant is a neutral extractant, the neutral extractant comprises one or more of isomeric C10 alcohol, isomeric C13 alcohol, sec-octanol, isodecanol and n-octanol, and the second extractant is an amine extractant and/or a phosphorus extractant; the diluent comprises a composition of isoparaffin and sulfonated kerosene, and the volume ratio of the isoparaffin to the sulfonated kerosene is (50-100) to (0-50).

2. The method of claim 1, wherein the complex desiliconization reagent,

in the inorganic desiliconization agent, the inorganic aluminum salt comprises one or more of aluminum sulfate, aluminum chloride, aluminum hydroxide, ammonium aluminate, sodium metaaluminate, potassium aluminate, potassium metaaluminate and alum; preferably, the polyaluminum ferric comprises one or more of polyaluminum sulfate, polyaluminum chloride, polyferric sulfate and polyaluminum ferric sulfate chloride;

in the organic desiliconization agent, the nonionic organic desiliconization agent is one or more of acrylamide, polyacrylamide, polyethylene oxide and polyvinyl pyridine; the cationic organic desiliconization agent is one or more of poly diallyl dimethyl ammonium chloride, poly epoxy chloropropane amine polymer, polyether amine D230, polyether amine D400 and polyether amine EC 301; the anionic organic desiliconization agent is one or more of polyacrylic acid, sodium polyacrylate and calcium polyacrylate.

3. The method according to claim 1 or 2, wherein in the composite desiliconization reagent, the inorganic desiliconization reagent is one or more of polyaluminium sulfate, polyaluminium chloride and polyferric sulfate; the organic desiliconization agent is one or more of polyacrylamide, polydiallyl dimethyl ammonium chloride and sodium polyacrylate.

4. The method of claim 1, wherein the volume ratio of the composite extracting agent to the diluent in the composite extracting system is (20-45): (55-80), and the composite extracting system comprises 5-15% of the first extracting agent by volume percentage.

5. The method of claim 4, wherein in the complex extractant, the amine-based extractant comprises one or more of N-octylamine, dodecylamine, N-decylamine, hexadecylamine, N1519, N1923, Primene 81-R, Primene JMT, Aliquat 336, HYHAPR-OD, and HYHAPR-SD; the phosphorus extractant comprises one or more of P350, TRPO and TOPO.

6. The process of claim 5, wherein the first extractant is one or more of the isomeric C13 alcohols, sec-octanol and isodecanol; the second extractant is one or more of P350, TRPO, N-dodecylamine, N-decylamine, N1923, Primene 81-R, Primene JMT, Aliquat 336 and HYHAPR-OD.

7. The method according to claim 4, further comprising a step of salting and removing impurities from the composite extraction system with 0.01 to 50wt.% of an aqueous solution of an inorganic acid and/or an aqueous solution of an organic acid before the extraction of the desiliconized solution using the composite extraction system.

8. The method according to claim 1 or 2, wherein the molar ratio of the inorganic desiliconization agent to the total silicon in the high-chlorine vanadium-containing solution is (0.6-2): 1; the organic desiliconization agent is 0.01-1% of the total volume of the high-chlorine vanadium-containing solution.

9. The method according to claim 8, wherein in step S1, before the desiliconization treatment, the pH of the high-chlorine vanadium-containing solution is adjusted to 8-10; after the desiliconization treatment is carried out, adjusting the pH value of the desiliconized liquid to 7.5-8.5; and the temperature of the desiliconization treatment is 30-80 ℃, and the time of the desiliconization treatment is 60-180 min.

10. The method according to claim 1, wherein in the step S2, the volume ratio of the composite extraction system to the desilication solution is 3: 1-1: 10; before the extraction step, the pH value of the desiliconized liquid is adjusted to 2.5-8, the number of extraction stages is 2-20, the single-stage extraction time is 3-20 min, and the extraction temperature is 5-60 ℃.

11. The method according to claim 1, wherein in the step S3, the washing solution is one or more of water, 2-50 g/L of sodium sulfate aqueous solution, 2-50 g/L of ammonium sulfate aqueous solution, and ammonia aqueous solution with mass concentration less than 10 wt.%; the volume ratio of the first vanadium-loaded organic phase to the washing liquid is 10: 1-1: 2.

12. The method according to claim 11, wherein in the step S3, the volume ratio of the first vanadium-loaded organic phase to the washing solution is 5: 1-1: 1; the number of washing stages is 1-10; the single-stage washing time is 3-10 min; the washing temperature is 5-60 ℃.

13. The method according to claim 1, wherein in the step S4, the composite stripping agent comprises at least two or more of ammonia, ammonium chloride, ammonium sulfate, ammonium oxalate, ammonium carbonate and ammonium bicarbonate; the back extraction time is 5-180 min, the back extraction temperature is 0-100 ℃, and the pH value of the back extraction end point water phase is 8-13.

14. The method according to claim 13, wherein in the step S4, the volume ratio of the second vanadium-loaded organic phase to the stripping agent is 10: 1-1: 3; the molar ratio of ammonium ions in the stripping agent to the total vanadium in the second vanadium-loaded organic phase is (1-2.5): 1.

15. The method according to claim 1, wherein in the step S5, the calcination temperature is 200 to 800 ℃, the calcination time is 30 to 240min, and the calcination air flow is 0 to 1000 mL/min.