Background
The vanadium slag of the converter is a main raw material for producing vanadium oxide, and has two production processes of sodium treatment and calcification. The converter vanadium slag is subjected to a calcification vanadium extraction process to generate calcification vanadium extraction tailings, and V of the tailings2O5The content is about 2.1-3.5%, and the further vanadium extraction value is still realized. The calcified vanadium extraction tailings contain a large amount of CaSO4The traditional method for extracting vanadium by sodium modification and re-roasting-water leaching is difficult to apply, and the method of reducing pH can be adopted to re-leach to obtain acidic low-concentration vanadium solution and vanadium extraction tailings, wherein the vanadium solution V2O5The content of V in tailings is about 1-10 g/L2O5The content can be reduced to 0.8-1.5%. The vanadium liquid is acidic, the pH value is about 1-2, and V is2O5The content is low, the impurity content is high, and the vanadium is difficult to directly precipitate to prepare vanadium oxide products.
Vanadium production enterprises at home and abroad adopt a lot of low-grade vanadium-containing raw materials to extract vanadium, vanadium is extracted from the obtained low-concentration vanadium-containing leachate by a vanadium enrichment method, and the vanadium extraction method mainly comprises an ion exchange method, an extraction method, an evaporation concentration method and the like, wherein the two methods have the advantage of high purity of the obtained vanadium pentoxide, but have the defects of long process flow and high cost, and are very similar to the stone coal vanadium extraction process; the evaporation concentration method is a method for preparing crude vanadium pentoxide, and has the advantages of short process, but has the prominent defects of unqualified vanadium pentoxide product quality, large evaporation concentration water amount and high cost. The three vanadium extraction processes are comprehensively compared, so that the problems of high cost and certain environmental protection risks exist, and the industrialization prospect is great due to the market change of vanadium pentoxide.
CN101412539 discloses a method for producing vanadium oxide by calcium salt roasting vanadium slag, mixing vanadium slag and calcium salt additive, oxidizing and roasting to obtain roasted clinker, adding water to prepare slurry, stirring, adding sulfuric acid solution, leaching to obtain vanadium-containing leachate; CN105833608A discloses a method for enriching high-concentration vanadium liquid, which uses low-concentration vanadium liquid to replace production washing water to reduce production cost. CN101260470 discloses a method for treating low-concentration vanadium-containing acid leaching solution to obtain vanadium-rich slag and then roasting and leaching the vanadium-rich slag; however, the process requires the additional addition of FeSO4·7H2And O, precipitating vanadium in the low-concentration vanadium solution by using iron, roasting, leaching and circularly leaching to obtain high-concentration vanadium solution, and precipitating to obtain a vanadium product, wherein the process is long.
Disclosure of Invention
The invention aims to solve the technical problems of high difficulty and high cost in recycling vanadium in acidic low-concentration vanadium liquid.
The technical scheme adopted by the invention for solving the technical problems is to provide a method for preparing vanadium oxide from acidic low-concentration vanadium liquid, which is characterized by comprising the following steps: the method comprises the following steps:
A. mixing the acidic low-concentration vanadium solution with water, and adding acid to adjust the pH value to obtain a leaching agent;
B. adding calcified vanadium extraction tailings into the leaching agent obtained in the step A, stirring and reacting to obtain leaching slurry;
C. b, carrying out solid-liquid separation on the leached slurry obtained in the step B to obtain an acidic vanadium solution;
D. c, dividing the acid vanadium liquid obtained in the step C into two parts, namely acid vanadium liquid a and acid vanadium liquid b, and returning the acid vanadium liquid a to the step A to circularly leach calcified vanadium extraction tailings;
E. and the acid vanadium solution b and the calcification vanadium extraction reuse water are jointly used for washing residues obtained by solid-liquid separation after acid leaching of the calcification clinker, the washing solution is used as a leaching agent for acid leaching of the calcification clinker to obtain calcification vanadium extraction tailings and qualified solution, and the qualified solution is subjected to vanadium precipitation and calcination to obtain vanadium oxide.
In the method for preparing vanadium oxide from the acidic low-concentration vanadium liquid, in the step A, the acidic low-concentration vanadium liquid contains V2O51-10 g/L, Mn 5-12 g/L, P0.03-0.40 g/L, Fe 0.1-1.5 g/L, and pH 0.5-2.2.
In the method for preparing vanadium oxide from the acidic low-concentration vanadium liquid, in the step A, the water is calcified vanadium extraction reuse water or clear water.
Preferably, in the method for preparing vanadium oxide from the acidic low-concentration vanadium liquid, in the step a, the water is reuse water for extracting vanadium through calcification.
In the method for preparing vanadium oxide from the acidic low-concentration vanadium liquid, in the step A, the mixing volume ratio of the acidic low-concentration vanadium liquid to water is 10: 90-90: 10.
preferably, in the method for preparing vanadium oxide from the acidic low-concentration vanadium solution, in the step a, the mixing volume ratio of the acidic low-concentration vanadium solution to water is 50: 50.
in the method for preparing vanadium oxide from the acidic low-concentration vanadium liquid, in the step A, sulfuric acid is used for adjusting the pH value to 0.5-1.8.
Preferably, in the method for preparing vanadium oxide from the acidic low-concentration vanadium liquid, in the step A, sulfuric acid is used for adjusting the pH value to 0.8-1.1.
In the method for preparing vanadium oxide from the acidic low-concentration vanadium liquid, in the step B, the liquid-solid mass ratio of the leaching agent to the calcified vanadium extraction tailings is 0.8-2: 1.
preferably, in the method for preparing vanadium oxide from the acidic low-concentration vanadium solution, in the step B, the liquid-solid mass ratio of the leaching agent to the calcified vanadium extraction tailings is 1.5-1.8: 1.
in the method for preparing vanadium oxide from the acidic low-concentration vanadium liquid, in the step B, the stirring reaction time is 5-60 min.
Preferably, in the method for preparing vanadium oxide from the acidic low-concentration vanadium liquid, in the step B, the stirring reaction time is 15 min.
In the step D, the method for preparing vanadium oxide from the acidic low-concentration vanadium solution comprises the following steps of: 90-90: 10, dividing the acidic vanadium solution into a part and a part b.
Preferably, in the step D, the method for preparing vanadium oxide from the acidic low-concentration vanadium solution comprises the following steps of: and 50, dividing the acidic vanadium solution into a part and a part b.
In the step E, during washing, the mass liquid-solid ratio of the total volume of the acidic vanadium solution b and the calcification vanadium extraction reuse water to the residue is 2-3: 1.
the invention has the beneficial effects that:
the method comprises the steps of carrying out cyclic leaching on acidic low-concentration vanadium liquid obtained from vanadium extraction tailings obtained in the high-acidity leaching production process, controlling the pH of a cyclic system by using calcified vanadium extraction reuse water, dividing the acidic vanadium liquid into two parts, wherein one part is used for cyclically leaching vanadium slag, and the other part is used for washing and leaching calcified clinker, so that water cyclic utilization is basically realized, no waste water is generated in the whole vanadium extraction process, the resource waste is reduced, the process is simple to implement, and the production cost is greatly reduced.
Detailed Description
Specifically, the method for preparing vanadium oxide from acidic low-concentration vanadium liquid is characterized by comprising the following steps: the method comprises the following steps:
A. mixing the acidic low-concentration vanadium solution with water, and adding acid to adjust the pH value to obtain a leaching agent;
B. adding calcified vanadium extraction tailings into the leaching agent obtained in the step A, stirring and reacting to obtain leaching slurry;
C. b, carrying out solid-liquid separation on the leached slurry obtained in the step B to obtain an acidic vanadium solution;
D. c, dividing the acid vanadium liquid obtained in the step C into two parts, namely acid vanadium liquid a and acid vanadium liquid b, and returning the acid vanadium liquid a to the step A to circularly leach calcified vanadium extraction tailings;
E. and the acid vanadium solution b and the calcification vanadium extraction reuse water are jointly used for washing residues obtained by solid-liquid separation after acid leaching of the calcification clinker, the washing solution is used as a leaching agent for acid leaching of the calcification clinker to obtain calcification vanadium extraction tailings and qualified solution, and the qualified solution is subjected to vanadium precipitation and calcination to obtain vanadium oxide.
In the invention, the acidic low-concentration vanadium solution is obtained by further leaching calcified vanadium extraction tailings by using sulfuric acid and contains V2O51-10 g/L, Mn 5-12 g/L, P0.03-0.40 g/L, Fe 0.1-1.5 g/L, and pH 0.5-2.2; compared with vanadium liquid (V) in the calcium salt vanadium extraction process2O530-60 g/L and pH of 2.5-3.5), the concentration of TV and the pH are lower, and the method is difficult to be used for directly precipitating to obtain a vanadium product.
In the step A of the invention, the water is calcified vanadium extraction reuse water or clear water. The calcified vanadium extraction reuse water is known to those skilled in the art, and refers to water which can be recycled after the precipitated vanadium wastewater of the calcified vanadium extraction process is neutralized by lime or is subjected to electrolysis treatment, so the calcified vanadium extraction reuse water is preferred.
In the method, the acidic low-concentration vanadium liquid is circulated in the whole calcification vanadium extraction process, and water balance needs to be adjusted based on the consideration of the whole calcification vanadium extraction process, so the acidic low-concentration vanadium liquid is mixed with water. In order to avoid overlarge pH change of a water system in the circulating process, in the step A, the mixing volume ratio of the acidic low-concentration vanadium liquid to water is 10: 90-90: 10; preferably 50: 50.
in the step A of the method, sulfuric acid is adopted to adjust the pH value to 0.5-1.8, so that the leaching effect of the leaching agent on the calcified vanadium extraction tailings is improved; preferably, the pH is adjusted to 0.8-1.1 by using sulfuric acid.
In the step B of the method, the calcified vanadium extraction tailings are derived from residues obtained by acid leaching of calcified clinker and contain V2O51.5-3.5 wt%, for further recycling vanadium in the calcified vanadium extraction tailings, reducing the content of vanadium in the secondary vanadium extraction tailings, and controlling the liquid-solid mass ratio of the leaching agent to the calcified vanadium extraction tailings to be 0.8-2: 1; preferably 1.5-1.8: 1.
in the step B, stirring is to stir and mix the slurry, the stirring speed is not limited to stirring speed, and different stirring speeds are required to be set according to different equipment scales, for example, the laboratory generally selects 300-650r/m, and the industrial application can select 60-100 r/m; the leaching time is generally 5-60 min, and preferably 15 min.
In the step B of the method, the acid vanadium liquid with a certain volume can be obtained by controlling the dosage ratio of the leaching agent to the calcified vanadium extraction tailings; in the step D, the volume ratio is 10: 90-90: 10, the acidic vanadium solution is divided into a part a and a part b, so that the problem that the leaching rate of vanadium is influenced due to the change of acid leaching process parameters caused by the overlarge pH change of the whole circulation system is avoided; preferably, the volume ratio is 50: and 50, dividing the acidic vanadium solution into a part and a part b.
In the step E of the method, the clinker leaching is the same as that of the prior art, namely the clinker quality is fixed during the clinker leaching, namely the washing water quantity required by residue washing is determined, and the recycling water quantity for calcification vanadium extraction is determined when the quantity of the acid vanadium liquid b is determined. Generally speaking, in the step E, the mass liquid-solid ratio of the total volume of the acidic vanadium solution b and the calcification vanadium extraction reuse water to the residue is 2-3: 1.
in the method, the acidic vanadium liquid obtained in the step C can be recycled, the qualified liquid obtained in the step E can be treated to obtain calcified vanadium extraction reuse water which can also be recycled, water circulation is basically realized, no wastewater is generated in the whole vanadium extraction process, the recovery and utilization of the acidic low-concentration vanadium liquid and the calcified vanadium extraction tailings are realized, the resource waste is reduced, the process is simple to implement, and the production cost is greatly reduced.
The present invention is further illustrated by the following examples, which are not intended to limit the scope of the invention.
Example 1
100mL of acidic low-concentration vanadium solution (P0.289 g/L, V)2O52.81g/L, Mn 6.5g/L, Fe 0.52g/L, pH 1.3) and 100mL of calcified vanadium extraction reuse water were added to a vessel and mixed, H was added2SO4Adjusting pH to 1.0, adding 150g of calcified vanadium extraction tailings (V)2O52.74wt percent) is reacted for 15min under the stirring rotating speed of 450r/min, and solid-liquid separation is carried out to obtain secondary vanadium extraction tailings and 140mL acidA neutral vanadium solution;
mixing 70mL of acid vanadium liquid and 70mL of calcification vanadium extraction reuse water, adjusting the pH value to 1.0, and using the mixture as a leaching agent for the next round for circulation;
and (3) washing the solid-liquid separation residues after the acid leaching of the calcified clinker by using the residual 70ml of acidic vanadium liquid and calcified vanadium extraction reuse water together, leaching the calcified clinker by using the obtained washing liquid to obtain calcified vanadium extraction tailings and qualified liquid, and performing vanadium precipitation and calcination on the qualified liquid according to conventional process parameters to obtain a vanadium oxide product.
The obtained vanadium oxide product meets the industrial standard of YB/T5304-addition 2017, and the generated secondary vanadium extraction tailings V2O5The content was 0.98 wt%.
Example 2
100mL of an acidic low-concentration vanadium solution (P0.244 g/L, V)2O52.43g/L, Mn 6.7g/L, Fe 0.63g/L, pH 1.5) and 100mL of calcified vanadium extraction reuse water were added to a vessel and mixed, H was added2SO4Adjusting pH to 1.0, adding 100g of calcified vanadium extraction tailings (V)2O52.98wt percent) under the stirring speed of 500r/min for reacting for 15min, and carrying out solid-liquid separation to obtain secondary vanadium extraction tailings and 150mL of acid vanadium liquid;
mixing 75mL of acid vanadium solution and 75mL of calcification vanadium extraction reuse water to adjust the pH value to 1.0, and using the mixture as a leaching agent for the next round for circulation;
and (3) washing the solid-liquid separation residues after acid leaching of the calcified clinker by using the residual 75mL of acidic vanadium liquid and calcified vanadium extraction reuse water together, leaching the calcified clinker by using the obtained washing liquid to obtain calcified vanadium extraction tailings and qualified liquid, and performing vanadium precipitation and calcination on the qualified liquid according to conventional process parameters to obtain a vanadium oxide product.
The obtained vanadium oxide product meets the industrial standard of YB/T5304-addition 2017, and the generated secondary vanadium extraction tailings V2O5The content was 1.27 wt%.
Example 3
100mL of an acidic low-concentration vanadium solution (P0.172 g/L, V)2O51.43g/L, Mn 7.9g/L, Fe 0.82g/L, pH 2.0) and 100mL of calcified vanadium extraction reuse water were added to a vessel and mixed, H was added2SO4Adjusting pH to 1.1, adding 140g of calcified vanadium extraction tailings (V)2O52.66wt%),Reacting for 15min at the stirring speed of 500r/min, and performing solid-liquid separation to obtain secondary vanadium extraction tailings and 142mL of acidic vanadium solution;
mixing 71mL of acid vanadium liquid and 71mL of calcification vanadium extraction reuse water to adjust the pH value to 1.0, and using the mixture as a leaching agent for the next round for circulation;
and (3) washing the solid-liquid separation residues after the acid leaching of the calcified clinker by using the residual 71mL of acidic vanadium liquid and calcified vanadium extraction reuse water together, leaching the calcified clinker by using the obtained washing liquid to obtain calcified vanadium extraction tailings and qualified liquid, and performing vanadium precipitation and calcination on the qualified liquid according to conventional process parameters to obtain a vanadium oxide product.
The obtained vanadium oxide product meets the industrial standard of YB/T5304-addition 2017, and the generated secondary vanadium extraction tailings V2O5The content was 1.13 wt%.
The method provided by the invention aims at recycling vanadium from the low-concentration vanadium liquid obtained by acid leaching of the calcified vanadium extraction tailings, the low-concentration vanadium liquid is circulated in the system, the vanadium recovery rate in the acidic low-concentration vanadium liquid can reach 99% after the vanadium leaching liquid is subjected to a vanadium precipitation process, and the residual vanadium in the calcified vanadium extraction tailings can be further recycled.