Method for extracting vanadium from vanadium slag through blank roasting

Abstract

The invention relates to the technical field of vanadium oxide preparation, and discloses a method for extracting vanadium from vanadium slag through blank roasting, which comprises the following steps: carrying out blank roasting on the vanadium slag to obtain vanadium-containing clinker; adding reuse water into the vanadium-containing clinker, pulping to obtain a mixture, controlling the mixture to be in a first liquid-solid ratio, adjusting the pH value by adopting a calcium-containing oxide, and continuously reacting to complete a first leaching stage; adding leaching mother liquor into the mixture, controlling the mixture to be in a second liquid-solid ratio, adjusting the pH value of the solution by adopting sulfuric acid, and continuously reacting to complete a second leaching stage; and carrying out solid-liquid separation to obtain vanadium-containing leachate and residues, and pulping and washing the residues to obtain washing water as leaching mother liquor and tailings. According to the method, the blank roasting-acid leaching process is adopted for the vanadium slag, namely, the vanadium extraction method for acid leaching clinker after high-temperature blank roasting is directly conducted on the vanadium slag is adopted, material consumption is reduced, waste gas is not discharged, the method is environmentally friendly and free of pollution, and meanwhile the high vanadium leaching rate is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of vanadium oxide preparation, in particular to a method for extracting vanadium by blank roasting of vanadium slag. Background Art

[0002] Vanadium is mainly used in the steel industry and can significantly improve the performance of steel. Currently, the main processes for extracting vanadium from vanadium slag include calcification roasting and acid leaching and sodium roasting and water leaching. Among them, the calcification roasting and acid leaching process is highly regarded as a green, clean and low-cost vanadium extraction process.

[0003] CN200810305601.8 discloses a clean production method for vanadium oxide, which includes the steps of preparing roasting raw materials, calcification roasting, leaching, solid-liquid separation, ammonium salt vanadium precipitation, calcination deamination or reduction to prepare vanadium oxide, and the vanadium extraction wastewater is neutralized with lime milk and then returned to the system for recycling, thereby achieving zero wastewater discharge, improving the vanadium recovery rate, making it higher than the current process, and reducing production costs.

[0004] CN201410223423.X discloses a method for extracting vanadium from blank roasted vanadium slag, the method comprising the following steps: crushing the vanadium slag and subjecting the crushed vanadium slag to high-temperature blank roasting to obtain clinker; crushing the cooled clinker and mixing the crushed clinker with water, adding sulfuric acid for leaching, and filtering to obtain a vanadium-containing leaching solution and tailings, wherein the vanadium slag is vanadium-containing molten iron vanadium blowing vanadium slag.

[0005] However, there are still many problems in the prior art. The effect of vanadium slag calcification roasting is particularly affected by the particle size of vanadium slag, the amount of calcium salt added, the uniformity of calcium salt mixing and the magnetic content of vanadium slag. If the quality of vanadium slag is not good, the calcium salt mixing effect is not good, and the vanadium oxide calcification effect deteriorates during the vanadium slag calcification roasting process, which is manifested as the pentavalent vanadium oxide not effectively combining with the calcium salt to form calcium vanadate salt, resulting in poor acid solubility of vanadium-containing substances, poor leaching effect, and thus reducing the leaching effect. The vanadium slag calcification roasting acid leaching process has high requirements for the mixed roasting equipment, and the operating range of the process parameters is narrow, and the adaptability to vanadium slag is poor. Blank roasting acid leaching vanadium has the problems of high impurity content and low leaching rate.

[0006] Therefore, there is a need in the prior art for improving the method for extracting vanadium by blank roasting of vanadium slag. Summary of the invention

[0007] In view of this, the purpose of the embodiment of the present invention is to propose a method for extracting vanadium by blank roasting of vanadium slag, wherein the vanadium slag completes the oxidation of low-valent vanadium during the roasting process, and the roasted clinker uses calcium salts such as calcium oxide in a high pH environment in the first leaching stage to complete vanadate calcification, thereby increasing the acid solubility of vanadium-containing substances, and sulfuric acid is used in the second leaching stage to separate vanadium from slag. The method has the advantages of high vanadium recovery rate, high leaching rate, simple process, and wide adaptability of vanadium slag.

[0008] Based on the above purpose, an embodiment of the present invention provides a method for extracting vanadium by blank roasting of vanadium slag, comprising: S1 blank roasts the vanadium slag to obtain vanadium-containing clinker; S2: adding recycled water to the vanadium-containing clinker for pulping to obtain a mixture, controlling the mixture to have a first liquid-to-solid ratio, adjusting the pH value with calcium oxide and reacting to complete the first leaching stage; S3: adding leaching mother liquor to the mixture, controlling the mixture to have a second liquid-to-solid ratio, adjusting the pH value of the solution with sulfuric acid and reacting to complete the second leaching stage; S4 separates the solid and liquid to obtain the vanadium-containing leaching solution and the residue, pulps the residue, washes it multiple times, and filters it to obtain the tailings. The washing water is recycled as the leaching mother liquor.

[0009] In some embodiments, in S1, vanadium-containing clinker is obtained by blank roasting vanadium slag at a temperature of 820-1000° C. for 1.5-4 h in an air atmosphere.

[0010] In some embodiments, in S1, the vanadium slag includes, by mass percentage, TV of 7%-9%, P of 0.05-0.2%, Te of 29-31.4%, and Mn of 7-8%. By volume percentage, the particle size of the vanadium slag is +120 mesh <10%.

[0011] In some embodiments, in S2, in the first leaching stage, the particle size of the vanadium-containing clinker is 50um~200um, the pulping temperature is 20~70°C, and the first liquid-solid ratio is (1~1.5):1.

[0012] In some embodiments, in S2, the pH of the recycled water is 7-9, and the recycled water includes: Mn < 0.01 g / L, V < 0.05 g / L, NH4, 2-3 g / L, Ca < 0.03 g / L, P < 0.01 g / L, Si < 0.01 g / L.

[0013] In some embodiments, in S2, the calcium oxide is calcium oxide or calcium hydroxide, the pH value of the slurry is adjusted to 10-13, and the reaction time is 20-60 min.

[0014] In some embodiments, the ratio of the amount of calcium oxide or calcium hydroxide added to the amount of vanadium pentoxide is 0.1 to 0.6 by mass percentage.

[0015] In some embodiments, in S3, in the second leaching stage, the second liquid-to-solid ratio is (3-4):1, the reaction temperature is 30-50°C, sulfuric acid is added to adjust the pH value to 2.4-3.2, and the reaction time is 45-60 min.

[0016] In some embodiments, in S3, the mass fraction of sulfuric acid is 40% to 60%.

[0017] In some embodiments, in S4, the residue is washed and filtered three times to obtain tailings. The third washing water is recycled water, and the amount of washing water is 2 to 3 times the mass of clinker. The third washing filtrate is obtained by filtration; The third washing filtrate is used as the second washing water, the washing water volume is 2 to 3 times the mass of the clinker, and the second washing filtrate is obtained by filtering; The second washing filtrate is used as the first washing water, the washing water volume is 20% to 40% of the clinker mass, and the first washing filtrate is obtained by filtering; The remaining second washing filtrate is recycled as leaching mother liquor, and the first washing filtrate is incorporated into the leaching liquor for subsequent vanadium precipitation stage.

[0018] The present invention has at least the following beneficial technical effects: The present invention adopts a blank roasting-acid leaching process for vanadium slag, that is, a method for extracting vanadium by directly performing blank roasting at high temperature on vanadium slag and then acid leaching clinker, which reduces material consumption, does not emit waste gas, is environmentally friendly and pollution-free, and simultaneously obtains a higher vanadium leaching rate. Washing water in the leaching process can be recycled, reducing wastewater treatment costs. The present invention is simple and easy to use, has low equipment requirements, is easy to operate, has a wide range of applications, is low in cost, and has very good social and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other embodiments can be obtained based on these drawings without paying creative work.

[0020] Figure 1 This is a schematic diagram of an embodiment of a method for extracting vanadium by blank roasting of vanadium slag provided by the present invention. DETAILED DESCRIPTION

[0021] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the embodiments of the present invention are further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0022] The terms "including" and "having" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions; the terms "first", "second", etc. in the specification and claims of the present invention or the above-mentioned drawings are used to distinguish different objects rather than to describe a specific order. "Multiple" means two or more, unless otherwise clearly and specifically defined.

[0023] In addition, reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0024] like Figure 1 The method for extracting vanadium by blank roasting of vanadium slag provided by the present invention comprises the following steps: S1 blank roasts the vanadium slag to obtain vanadium-containing clinker; S2: adding recycled water to the vanadium-containing clinker for pulping to obtain a mixture, controlling the mixture to have a first liquid-to-solid ratio, adjusting the pH value with calcium oxide and reacting to complete the first leaching stage; S3: adding leaching mother liquor to the mixture, controlling the mixture to have a second liquid-to-solid ratio, adjusting the pH value of the solution with sulfuric acid and reacting to complete the second leaching stage; S4 separates the solid and the liquid to obtain a vanadium-containing leaching solution and a residue, and washes the residue by pulping to obtain washing water as a leaching mother liquor and tailings.

[0025] Further, in S1, the vanadium slag is blank roasted at a temperature of 820-1000° C. for 1.5-4 hours under an air atmosphere to obtain vanadium-containing clinker. In some embodiments, the vanadium slag comprises, by mass percentage, 7%-9% TV, 0.05-0.2% P, 29-31.4% Te, 7-8% Mn, and by volume percentage, the particle size of the vanadium slag is <10% of +120 mesh.

[0026] Further, in S2, recycled water is added to the vanadium-containing clinker, wherein the recycled water refers to the upper layer liquid produced by the overflow liquid vanadium precipitation process, which is obtained by adding lime treatment. The pH of the recycled water is 7-9, and the recycled water includes: Mn < 0.01g / L, V < 0.05g / L, NH4, 2-3g / L, Ca < 0.03g / L, P < 0.01g / L, Si < 0.01g / L. In the first leaching stage, the particle size of the vanadium-containing clinker is 50um~200um, and the pulping temperature is 20~70℃. The first liquid-solid ratio is controlled to be (1~1.5): 1, the calcium oxide added is calcium oxide or calcium hydroxide, the slurry pH is adjusted to 10~13, and the reaction time is 20~60min. In some embodiments, the ratio of the amount of calcium oxide or calcium hydroxide added to the amount of vanadium pentoxide is 0.1~0.6 in mass percentage.

[0027] Further, in S3, in the second leaching stage, the second liquid-to-solid ratio is (3-4):1, the reaction temperature is 30-50°C, sulfuric acid is added to adjust the pH value to 2.4-3.2, and the reaction time is 45-60 minutes. In some embodiments, the mass fraction of sulfuric acid is 40%-60%.

[0028] Further, in S4, the residue is washed three times. The third washing water is recycled water, and the amount of washing water is 2 to 3 times the mass of clinker. The third washing filtrate is obtained by filtration; The third washing filtrate is used as the second washing water, the washing water volume is 2 to 3 times the mass of the clinker, and the second washing filtrate is obtained by filtering; The second washing filtrate is used as the first washing water, the washing water volume is 20% to 40% of the clinker mass, and the first washing filtrate is obtained by filtering; The first washing filtrate is incorporated into the leaching solution, and the remaining second washing filtrate is used as the leaching mother liquor.

[0029] The present invention will be further explained below in conjunction with specific embodiments.

[0030] The method for extracting vanadium by blank roasting of vanadium slag provided by the present invention adopts vanadium slag (TV is 7%-9%, P is 0.05-0.2%, Te29-31.4%, Mn7-8%) as raw material, roasts under certain conditions to obtain vanadium-containing clinker (TV is 6.5%-8%, P is 0.05-0.2%, Te25-29.7%, Mn7-8%), and adds recycled water (pH7-9, Mn<0.01g / L, V<0.05 g / L, NH4, 2-3g / L, Ca<0.03g / L, P<0.01g / L, Si<0.01g / L) is slurried at a certain liquid-solid ratio, calcium oxide / calcium hydroxide is used to adjust the pH value, and the reaction is carried out for a certain time; the leaching mother liquor is added to control the total liquid-solid ratio to a certain value, and sulfuric acid is used to adjust the pH value under certain temperature conditions. After reacting for a certain time, the solid-liquid is separated to obtain a vanadium-containing leaching solution and a residue. The residue is slurried and washed at a certain liquid-solid ratio to obtain washing water and tailings.

[0031] Example 1 100g of vanadium slag was blank roasted at 820℃ for 1.5h in air atmosphere to obtain vanadium-containing clinker; recycled water was added at 20℃ with a liquid-to-solid ratio of 1:1 for pulping, calcium oxide (CaO / V2O5=0.1) was added, the pH value was adjusted to 10, and the reaction was carried out for 20min to complete the first leaching stage; the leaching mother liquor was added to control the total liquid-to-solid ratio to 3:1, sulfuric acid (40% mass fraction concentration of dilute sulfuric acid) was used to adjust the pH value to 2.4 at 30℃, and the reaction was carried out for 45m in, the second leaching stage is completed; solid-liquid separation is performed to obtain vanadium-containing leaching solution and residue, the residue is washed three times, the third washing water is recycled water, the washing water volume is twice the mass of clinker, the second washing water is the third washing filtrate, the washing volume is twice the mass of clinker, the first washing water is the second washing filtrate, the washing volume is 20% of the mass of clinker, the first washing filtrate is incorporated into the leaching solution, and the remaining second washing filtrate is used as the leaching mother liquor, which is filtered to obtain tailings, and the TV content of the tailings is 0.442%.

[0032] Example 2 100g of vanadium slag was blank roasted at 900℃ for 2.5h in air atmosphere to obtain vanadium-containing clinker; recycled water was added at 45℃ with a liquid-to-solid ratio of 1.25:1 for pulping, calcium oxide (CaO / V2O5=0.3) was added, the pH value was adjusted to 11, and the reaction was carried out for 40min to complete the first leaching stage; the leaching mother liquor was added to control the total liquid-to-solid ratio to 3.5:1, sulfuric acid (50% mass fraction concentration of dilute sulfuric acid) was used to adjust the pH value to 2.8 at 40℃, and the reaction was carried out for 50min. min later, the second leaching stage is completed; solid-liquid separation is performed to obtain vanadium-containing leaching solution and residue, the residue is washed three times, the third washing water is recycled water, the washing water volume is 2.5 times the mass of clinker, the second washing water is the third washing filtrate, the washing volume is 2.5 times the mass of clinker, the first washing water is the second washing filtrate, the washing volume is 30% of the mass of clinker, the first washing filtrate is incorporated into the leaching solution, and the remaining second washing filtrate is used as the leaching mother liquor, which is filtered to obtain tailings, and the TV content of the tailings is 0.322%.

[0033] Example 3 100g of vanadium slag was blank roasted at 1000℃ for 4h in air atmosphere to obtain vanadium-containing clinker; recycled water was added at 70℃ with a liquid-to-solid ratio of 1.5:1 for pulping, calcium oxide (CaO / V2O5=0.6) was added, the pH value was adjusted to 13, and the reaction was carried out for 60min to complete the first leaching stage; the leaching mother liquor was added to control the total liquid-to-solid ratio to 4:1, sulfuric acid (60% mass fraction concentration of dilute sulfuric acid) was used to adjust the pH value to 3.2 at 30℃, and the reaction was carried out for 60min. min later, the second leaching stage is completed; solid-liquid separation is performed to obtain vanadium-containing leaching solution and residue, the residue is washed three times, the third washing water is recycled water, the washing water volume is 3 times the mass of clinker, the second washing water is the third washing filtrate, the washing volume is 3 times the mass of clinker, the first washing water is the second washing filtrate, the washing volume is 40% of the mass of clinker, the first washing filtrate is incorporated into the leaching solution, and the remaining second washing filtrate is used as the leaching mother liquor, which is filtered to obtain tailings, and the TV content of the tailings is 0.314%.

[0034] The above are exemplary embodiments disclosed in the present invention, but it should be noted that various changes and modifications may be made without departing from the scope disclosed in the embodiments of the present invention as defined in the claims. The functions, steps and / or actions of the method claims according to the disclosed embodiments described herein do not need to be performed in any particular order. In addition, although the elements disclosed in the embodiments of the present invention may be described or required in individual form, they may also be understood as multiple unless explicitly limited to the singular.

[0035] It should be understood that, as used herein, the singular forms "a", "an" are intended to include the plural forms as well, unless the context clearly supports an exception. It should also be understood that, as used herein, "and / or" refers to any and all possible combinations including one or more of the associated listed items.

[0036] The serial numbers of the embodiments disclosed in the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0037] A person skilled in the art should understand that the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope of the disclosure of the embodiments of the present invention (including the claims) is limited to these examples; under the concept of the embodiments of the present invention, the technical features in the above embodiments or different embodiments can also be combined, and there are many other changes in different aspects of the above embodiments of the present invention, which are not provided in detail for the sake of simplicity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present invention should be included in the protection scope of the embodiments of the present invention.

Claims

1. A method for extracting vanadium by blank roasting of vanadium slag, characterized in that: include: S1 blank roasts the vanadium slag to obtain vanadium-containing clinker; S2: adding recycled water to the vanadium-containing clinker for pulping to obtain a mixture, controlling the mixture to have a first liquid-to-solid ratio, adjusting the pH value with calcium oxide, and continuing the reaction to complete the first leaching stage; S3: adding leaching mother liquor to the mixture, controlling the mixture to have a second liquid-to-solid ratio, adjusting the pH value of the solution with sulfuric acid and continuing the reaction to complete the second leaching stage; S4 solid-liquid separation obtains vanadium-containing leaching solution and residue, the residue is pulped, washed multiple times, filtered to obtain tailings, and the washing water is recycled as leaching mother liquor.

2. The method for extracting vanadium by blank roasting of vanadium slag according to claim 1, characterized in that: In S1, the vanadium slag is blank roasted at a temperature of 820-1000° C. for 1.5-4 h in an air atmosphere to obtain vanadium-containing clinker.

3. The method for extracting vanadium by blank roasting of vanadium slag according to claim 1, characterized in that: In S1, the vanadium slag includes, by mass percentage, TV 7%-9%, P 0.05-0.2%, Te 29-31.4%, and Mn 7-8%. By volume percentage, the particle size of the vanadium slag is +120 mesh <10%.

4. The method for extracting vanadium by blank roasting of vanadium slag according to claim 1, characterized in that: In S2, in the first leaching stage, the particle size of the vanadium-containing clinker is 50um~200um, and the pulping temperature is 20~70℃.

5. The method for extracting vanadium by blank roasting of vanadium slag according to claim 1, characterized in that: In S2, the pH of the recycled water is 7-9, and the recycled water includes: Mn<0.01g / L, V<0.05g / L, NH4, 2-3g / L, Ca<0.03g / L, P<0.01g / L, Si<0.01g / L.

6. The method for extracting vanadium by blank roasting of vanadium slag according to claim 1, characterized in that: In S2, the first liquid-solid ratio ml / g is controlled to be (1-1.5):1, the calcium-containing oxide added is calcium oxide or calcium hydroxide, the pH value of the slurry is adjusted to 10-13, and the reaction time is 20-60 min.

7. The method for extracting vanadium by blank roasting of vanadium slag according to claim 6, characterized in that: In terms of mass percentage, the ratio of the amount of calcium oxide or calcium hydroxide added to the amount of vanadium pentoxide is 0.1-0.

6.

8. The method for extracting vanadium by blank roasting of vanadium slag according to claim 1, characterized in that: In S3, in the second leaching stage, the second liquid-to-solid ratio ml / g is (3-4):1, the reaction temperature is 30-50°C, sulfuric acid is added to adjust the pH value to 2.4-3.2, and the reaction time is 45-60 min.

9. The method for extracting vanadium by blank roasting of vanadium slag according to claim 8, characterized in that: In S3, the mass fraction of sulfuric acid is 40% to 60%.

10. The method for extracting vanadium by blank roasting of vanadium slag according to claim 1, characterized in that: In S4, the residue is washed three times and then filtered to obtain tailings, wherein: The third washing water is recycled water, and the amount of washing water is 2 to 3 times the mass of clinker. The third washing filtrate is obtained by filtration; The third washing filtrate is used as the second washing water, the amount of washing water is 2 to 3 times the mass of the clinker, and the second washing filtrate is obtained by filtering; The second washing filtrate is used as the first washing water, the amount of washing water is 20% to 40% of the mass of the clinker, and the first washing filtrate is obtained by filtering; The remaining second washing filtrate is recycled as leaching mother liquor, and the first washing filtrate is incorporated into the leaching liquor for subsequent vanadium precipitation stage to precipitate vanadium.

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