阅读说明：本技术 一种从高碱性溶液回收钨钼钒并再生氢氧化钠的方法 (Method for recovering tungsten, molybdenum and vanadium from high-alkaline solution and regenerating sodium hydroxide ) 是由 曹才放 缪建 麦秋娴 王瑞祥 李玉虎 聂华平 杨亮 员壮壮 庞振升 于 2020-11-19 设计创作，主要内容包括：本发明公开了一种从高碱性溶液回收钨钼钒并再生氢氧化钠的方法,包括：将氧化锶加入至含有钨、钼、钒一种或几种元素的高碱性溶液,在60～80℃下进行一次苛化沉淀反应,得到一次锶盐沉淀和一次苛化后液；将一次锶盐沉淀干燥脱水后,配入碳粉,进行煅烧得到一次煅烧渣；将一次煅烧渣加入至一次苛化后液,在80～100℃下进行二次苛化沉淀反应,得到二次锶盐沉淀和二次苛化后液；将二次锶盐沉淀与碳酸钠溶液混合反应,得到稀有金属富集液和碳酸锶渣；将碳酸锶渣干燥脱水,配入碳粉进行煅烧,得到氧化锶。本发明利用无毒性的锶元素在系统内循环,实现了高碱性溶液的碳酸根脱除和稀有金属的提取,并使氢氧化钠再生。(The invention discloses a method for recovering tungsten, molybdenum and vanadium from a high-alkaline solution and regenerating sodium hydroxide, which comprises the following steps: adding strontium oxide into a high-alkaline solution containing one or more elements of tungsten, molybdenum and vanadium, and carrying out a primary causticization precipitation reaction at 60-80 ℃ to obtain a primary strontium salt precipitate and a primary causticized liquid; drying and dehydrating the primary strontium salt precipitate, adding carbon powder, and calcining to obtain primary calcined slag; adding the primary calcined slag into the primary causticized liquid, and performing secondary causticized precipitation reaction at 80-100 ℃ to obtain secondary strontium salt precipitate and secondary causticized liquid; mixing the secondary strontium salt precipitate with a sodium carbonate solution for reaction to obtain a rare metal enrichment solution and strontium carbonate slag; and drying and dehydrating the strontium carbonate slag, and adding carbon powder to calcine to obtain strontium oxide. The invention realizes the removal of carbonate and the extraction of rare metals from the high alkaline solution by utilizing the circulation of nontoxic strontium element in the system, and regenerates the sodium hydroxide.)

1. A method for recovering tungsten, molybdenum and vanadium from high-alkaline solution and regenerating sodium hydroxide is characterized by comprising the following steps:

(1) adding strontium oxide and/or the primary calcined slag containing strontium oxide obtained in the step (2) and/or the strontium oxide obtained in the step (5) into a high-alkaline solution containing one or more elements of tungsten, molybdenum and vanadium according to a certain proportion, carrying out a causticization precipitation reaction at 60-80 ℃ to enable strontium ions and carbonate to form precipitates and causticize the precipitates to generate sodium hydroxide, and carrying out solid-liquid separation to obtain a primary strontium salt precipitate and a primary causticized liquid;

(2) drying and dehydrating the primary strontium salt precipitate obtained in the step (1), adding a certain amount of carbon powder, and performing calcination decomposition operation at 1100-1250 ℃ to convert strontium carbonate into strontium oxide to obtain primary calcination slag;

(3) adding the primary calcined slag containing strontium oxide obtained in the step (2) into the primary causticized liquid obtained in the step (1) according to a certain proportion, and performing secondary causticization precipitation reaction at the temperature of 80-100 ℃ to obtain secondary strontium salt precipitate and secondary causticized liquid;

(4) mixing the secondary strontium salt precipitate obtained in the step (3) with a sodium carbonate solution in proportion, carrying out carbonation reaction at a certain temperature, and carrying out solid-liquid separation to obtain a rare metal enrichment liquid and strontium carbonate slag;

(5) and (4) drying and dehydrating the strontium carbonate slag obtained in the step (4), adding a certain amount of carbon powder, and performing calcination decomposition operation at 1100-1250 ℃ to convert strontium carbonate into strontium oxide.

2. The method for recovering tungsten, molybdenum and vanadium from an overbased solution and regenerating sodium hydroxide as claimed in claim 1 wherein the concentration of sodium hydroxide in the overbased solution in step (1) is greater than 100 g/L.

3. The method for recovering tungsten, molybdenum and vanadium from the overbased solution and regenerating sodium hydroxide as claimed in claim 1, wherein the strontium oxide is added in an amount of 1.1 to 1.3 times of the molar amount of carbonate in the overbased solution in the step (1), and the reaction time of the first causticization precipitation is 0.5 to 2 hours.

4. The method for recovering tungsten, molybdenum and vanadium from highly alkaline solution and regenerating sodium hydroxide according to claim 1, wherein the amount of strontium oxide added in step (3) is 0.8-1.0 times of the total molar amount of tungsten, molybdenum and vanadium in the solution after the first causticization, and the reaction time of the second causticization precipitation is 0.5-2 hours.

5. The method for recovering W, Mo and V and regenerating NaOH from highly alkaline solution as claimed in claim 1, wherein the amount of Na carbonate used in the carbonation reaction of step (4) is 2-4 times of the total molar amount of W, Mo and V in the secondary strontium salt precipitation, the reaction temperature is 120-180 ℃, and the reaction time is 0.5-1.0 h.

6. The method for recovering tungsten, molybdenum and vanadium and regenerating sodium hydroxide from highly alkaline solution according to claim 1, wherein the carbon powder charge in the calcination decomposition operation in step (2) and step (5) is 8 wt.% to 16 wt.%.

Technical Field

The invention relates to the technical field of rare metal extraction, in particular to a method for recovering tungsten, molybdenum and vanadium from a high-alkaline solution and regenerating sodium hydroxide.

Background

Tungsten, molybdenum and vanadium are important rare metal elements and are active ingredients of catalysts for petroleum refining, organic synthesis, flue gas denitration and the like. In alkaline solution, tungsten, molybdenum and vanadium can form soluble tungstate radical, molybdate radical and vanadate radical, so that the sodium hydroxide leaching method is an important method for treating solid materials containing tungsten, molybdenum and vanadium.

Because the content of tungsten, molybdenum and vanadium in the catalyst is low, and the tungsten, molybdenum and vanadium phase structure of the catalyst tends to be stable under the working condition of long-term high temperature or after oxidation roasting, tungsten oxide, molybdenum oxide or vanadium oxide in the catalyst is difficult to dissolve out. In order to obtain higher extraction efficiency of tungsten, molybdenum and vanadium, the addition amount of sodium hydroxide far exceeds the theoretical amount, so that the dissolution liquid contains a large amount of excess sodium hydroxide. On the other hand, in each link of leaching, liquid-solid separation and solution storage, the sodium hydroxide absorbs carbon dioxide in the air, so that the carbon dioxide is gradually converted into sodium carbonate with weak tungsten, molybdenum and vanadium oxide dissolving capacity. If the sodium hydroxide and the sodium carbonate in the dissolution liquid are neutralized by adding acid, not only is the reagent consumption cost increased, but also a large amount of waste salt is generated. If calcium oxide or calcium hydroxide is used to convert sodium carbonate into sodium hydroxide by using Bayer process causticization process, the concentration of sodium hydroxide in the dissolution liquid needs to be diluted to be below 2mol/L to play the causticization role of calcium hydroxide. If the sodium carbonate is converted into sodium hydroxide by barium oxide or barium hydroxide, toxic and harmful barium carbonate is generated, and the chemical property of the barium sulfate generated in the process is very stable, so that the barium sulfate is difficult to recycle in a system.

Disclosure of Invention

The invention aims to provide a method for recovering tungsten, molybdenum and vanadium from a high-alkaline solution and regenerating sodium hydroxide, and aims to solve the problems of rare metal extraction and sodium hydroxide regeneration and recycling of the existing high-alkaline solution.

In order to achieve the above purpose, the invention provides a method for recovering tungsten, molybdenum and vanadium from high-alkaline solution and regenerating sodium hydroxide, which comprises the following steps:

(1) adding strontium oxide and/or the primary calcined slag containing strontium oxide obtained in the step (2) and/or the strontium oxide obtained in the step (5) into a high-alkaline solution containing one or more elements of tungsten, molybdenum and vanadium according to a certain proportion, carrying out a causticization precipitation reaction at 60-80 ℃ to enable strontium ions and carbonate to form precipitates and causticize the precipitates to generate sodium hydroxide, and carrying out solid-liquid separation to obtain a primary strontium salt precipitate and a primary causticized liquid;

(2) drying and dehydrating the primary strontium salt precipitate obtained in the step (1), adding a certain amount of carbon powder, and performing calcination decomposition operation at 1100-1250 ℃ to convert strontium carbonate into strontium oxide to obtain primary calcination slag;

(3) adding the primary calcined slag containing strontium oxide obtained in the step (2) into the primary causticized liquid obtained in the step (1) according to a certain proportion, and performing secondary causticization precipitation reaction at the temperature of 80-100 ℃ to obtain secondary strontium salt precipitate and secondary causticized liquid;

(4) mixing the secondary strontium salt precipitate obtained in the step (3) with a sodium carbonate solution in proportion, carrying out carbonation reaction at a certain temperature, and carrying out solid-liquid separation to obtain a rare metal enrichment liquid and strontium carbonate slag;

(5) and (4) drying and dehydrating the strontium carbonate slag obtained in the step (4), adding a certain amount of carbon powder, and performing calcination decomposition operation at 1100-1250 ℃ to convert strontium carbonate into strontium oxide.

Preferably, the concentration of sodium hydroxide in the highly alkaline solution in step (1) is more than 100 g/L.

Preferably, the strontium oxide adding amount in the step (1) is 1.1-1.3 times of the molar amount of carbonate in the high-alkaline solution, and the reaction time of the first causticization precipitation is 0.5-2 hours.

Preferably, the strontium oxide adding amount in the step (3) is 0.8-1.0 time of the total molar amount of tungsten, molybdenum and vanadium in the solution after the first causticization, and the reaction time of the second causticization precipitation is 0.5-2 hours.

Preferably, the amount of sodium carbonate used in the carbonation reaction in the step (4) is 2-4 times of the total molar amount of tungsten, molybdenum and vanadium in the secondary strontium salt precipitate, the reaction temperature is 120-180 ℃, and the reaction time is 0.5-1.0 hour.

Preferably, the carbon powder addition amount in the calcination decomposition operation in the step (2) and the step (5) is 8-16 wt.%.

The technical principle adopted by the invention is as follows:

the invention utilizes strontium oxide to realize the extraction of rare metal elements of tungsten, molybdenum and vanadium in high alkaline solution, and causticizes sodium carbonate into sodium hydroxide. In order to improve the content of rare metals in the strontium salt precipitate, the method is realized by two-stage causticization precipitation: the primary causticization precipitation mainly aims at decarburization causticization, namely most carbonate in alkali liquor is removed to obtain primary strontium salt precipitation mainly containing strontium carbonate, and then the primary strontium salt precipitation is calcined at high temperature for decarburization to obtain primary calcination slag mainly containing strontium oxide; the primary causticization precipitation mainly aims at enriching rare metals, and the primary calcined slag is added into the primary causticized liquid to obtain secondary strontium salt precipitation with high rare metal grade. Further, sodium carbonate and secondary strontium salt are used for precipitation reaction, so that strontium salt is converted into strontium carbonate, tungsten, molybdenum and vanadium are converted into sodium salt to enter solution, and strontium carbonate slag and high-concentration rare metal enrichment solution are obtained. The strontium carbonate slag is dried, calcined and decomposed to be converted into renewable and recyclable strontium oxide.

The invention has the following beneficial effects:

the method organically combines hydrometallurgy and pyrometallurgy, utilizes nontoxic strontium element to circulate in a system, realizes carbonate removal of high alkaline solution and extraction of rare metal, regenerates sodium hydroxide, returns the obtained causticized liquid to the front stage rare metal high alkaline solution leaching process, and further separates and extracts the obtained rare metal enriched liquid to obtain single rare metal material. The extraction rate of tungsten, molybdenum and vanadium in the whole process can reach more than 95%, 92% and 85%.

Detailed Description

The invention provides a method for recovering tungsten, molybdenum and vanadium from a high-alkalinity solution and regenerating sodium hydroxide, which comprises the following steps:

(1) adding strontium oxide and/or the primary calcined slag containing strontium oxide obtained in the step (2) and/or the strontium oxide obtained in the step (5) into a high-alkaline solution containing one or more elements of tungsten, molybdenum and vanadium according to a certain proportion, carrying out a causticization precipitation reaction at 60-80 ℃ to enable strontium ions and carbonate to form precipitates and causticize the precipitates to generate sodium hydroxide, and carrying out solid-liquid separation to obtain a primary strontium salt precipitate and a primary causticized liquid;

(2) drying and dehydrating the primary strontium salt precipitate obtained in the step (1), adding a certain amount of carbon powder, and performing calcination decomposition operation at 1100-1250 ℃ to convert strontium carbonate into strontium oxide to obtain primary calcination slag;

(3) adding the primary calcined slag containing strontium oxide obtained in the step (2) into the primary causticized liquid obtained in the step (1) according to a certain proportion, and performing secondary causticization precipitation reaction at the temperature of 80-100 ℃ to obtain secondary strontium salt precipitate and secondary causticized liquid;

(4) mixing the secondary strontium salt precipitate obtained in the step (3) with a sodium carbonate solution in proportion, carrying out carbonation reaction at a certain temperature, and carrying out solid-liquid separation to obtain a rare metal enrichment liquid and strontium carbonate slag;

(5) and (4) drying and dehydrating the strontium carbonate slag obtained in the step (4), adding a certain amount of carbon powder, and performing calcination decomposition operation at 1100-1250 ℃ to convert strontium carbonate into strontium oxide.

The present invention will be further illustrated by the following examples, but is not limited thereto.

Example 1

A high-alkalinity solution obtained by treating vanadium-titanium series waste SCR catalyst by a sodium hydroxide leaching method is disclosed, wherein the concentration of sodium hydroxide is 157g/L, the concentration of sodium carbonate is 12g/L, and the contents of tungsten, molybdenum and vanadium are respectively 9.6, 1.3 and 1.1 g/L.

And 3 parts of the high-alkalinity solution is taken, calcium oxide, strontium oxide and barium oxide are respectively added to carry out causticization precipitation reaction, the addition amount of divalent ions is 1.2 times of the molar amount of carbonate, the reaction temperature is 80 ℃, and the reaction time is 0.5 hour. The test conditions and results are shown in the following table.

Numbering	Causticizing precipitant species	Carbon deposition rate	Vanadium deposition rate	Rate of tungsten deposition	Molybdenum deposition rate
						1-1	Calcium oxide	12％	10％	0.1％	0.1％
1-2	Strontium oxide	89％	43％	23％	9％
						1-3	Barium oxide	51％	55％	2.2％	1.3％

As can be seen from the results in the table above, the low carbon precipitation rate of calcium oxide is not suitable for causticization of high alkaline solution; the strontium oxide has good carbonate precipitation rate, and XRD results show that strontium salt precipitates are mainly diffraction peaks of strontium carbonate and strontium tungstate; the barium oxide has a certain causticization precipitation effect, but the precipitation rate is low, and XRD results show that barium sulfate phase exists in barium salt precipitation, and the barium sulfate is stable in chemical property and not beneficial to the regeneration and cyclic utilization of barium element in a system.

Example 2

A high-alkalinity solution obtained by treating vanadium-titanium series waste SCR catalyst by a sodium hydroxide leaching method is disclosed, wherein the concentration of sodium hydroxide is 122g/L, the concentration of sodium carbonate is 17g/L, and the contents of tungsten, molybdenum and vanadium are respectively 11.2g/L, 1.9g/L and 1.6 g/L. Adding strontium oxide into high-alkaline solution to perform a causticization precipitation reaction, wherein the addition amount of the strontium oxide is 1.3 times of the molar amount of carbonate, the reaction temperature is 70 ℃, and the reaction time is 1 hour, so as to obtain a strontium salt precipitate and a causticized solution. The carbon deposition rate, the vanadium deposition rate, the tungsten deposition rate and the molybdenum deposition rate are respectively 92%, 46%, 29% and 22%.

And drying the primary strontium salt precipitate, adding 16 wt.% of carbon powder, calcining for 1.5 hours at 1100 ℃, and performing a hot water dissolution test on a small amount of calcined slag, wherein the water dissolution rate is 61 wt.%, which indicates that most of strontium carbonate in the primary strontium salt precipitate is converted into strontium oxide which can be dissolved by hot water.

Equally dividing the primary causticized liquid into 4 parts, adding the primary calcined slag according to different conditions, and carrying out secondary causticization precipitation reaction by utilizing strontium oxide in the primary calcined slag to respectively obtain secondary strontium salt precipitate and secondary causticized liquid.

The test conditions and results are shown in the following table.

And (3) uniformly mixing the 4 parts of secondary strontium salt precipitate, adding a sodium carbonate solution to perform carbonation reaction, wherein the using amount of the sodium carbonate is 3 times of the total molar amount of tungsten, molybdenum and vanadium in the secondary strontium salt precipitate, the reaction temperature is 180 ℃, and the reaction time is 1.0 hour. Filtering and washing to obtain strontium carbonate slag. Drying and dehydrating the strontium carbonate slag, equally dividing into 3 parts, respectively calcining and decomposing at different temperatures, and characterizing the decomposition rate of the strontium carbonate slag through a hot water washing experiment. The test conditions and results are shown in the following table.

Numbering	Calcination temperature	Amount of carbon powder blended	Calcination time	Water solubility
					2-5	1100℃	15wt.％	1.5 hours	96wt.％
2-6	1180℃	10wt.％	1.0 hour	97wt.％
					2-7	1250℃	0	0.5 hour	95wt.％

As can be seen from the above table, the strontium carbonate slag is decomposed by calcination, and most of strontium is converted into strontium oxide which can be dissolved by hot water.

Example 3

A vanadium-containing high-alkalinity solution obtained by leaching stone coal oxidizing roasting slag with sodium hydroxide is provided, wherein the concentration of the sodium hydroxide is 151g/L, the concentration of the sodium carbonate is 23g/L, and the content of the vanadium is 5.9 g/L. Adding strontium oxide into high-alkaline solution to perform a causticization precipitation reaction, wherein the addition amount of the strontium oxide is 1.1 times of the molar amount of carbonate, the reaction temperature is 60 ℃, and the reaction time is 2 hours, so as to obtain a strontium salt precipitate and a causticized solution. The carbon deposition rate and the vanadium deposition rate are 87 percent and 43 percent respectively.

And drying the primary strontium salt precipitate, adding 8 wt.% of carbon powder, calcining for 1.5 hours at 1120 ℃, and performing a hot water dissolution test on a small amount of calcined slag, wherein the water dissolution rate is 72 wt.%, which indicates that most of strontium carbonate in the primary strontium salt precipitate is converted into strontium oxide which can be dissolved by hot water.

Adding the primary calcined slag into the primary causticized liquid in proportion, performing secondary causticization precipitation reaction by using strontium oxide in the primary calcined slag, wherein the addition amount of the strontium oxide is 1.0 time of the molar amount of vanadium in the primary causticized liquid, reacting for 80 minutes at 90 ℃, and performing solid-liquid separation to obtain secondary strontium salt precipitate and secondary causticized liquid. The vanadium precipitation rate in the process is 81 percent, the total vanadium precipitation rate of twice causticization precipitation is 89 percent, and the solution after twice causticization has no strontium residue and can return to the leaching process.

And adding the secondary strontium salt precipitate into a sodium carbonate solution for carbonation reaction, wherein the using amount of the sodium carbonate is 4 times of the molar amount of vanadium in the secondary strontium salt precipitate, the reaction temperature is 120 ℃, and the reaction time is 0.5 hour. Filtering and washing to obtain strontium carbonate slag and vanadium enriched liquid, wherein the vanadium leaching rate is 92%. After drying the strontium carbonate slag, adding 8 wt.% of carbon powder, calcining for 1.5 hours at 1120 ℃, and performing a hot water washing experiment on a small amount of calcined slag, wherein the water solubility is 96 wt.%, which indicates that most of strontium carbonate in the strontium carbonate slag is converted into strontium oxide which can be dissolved by hot water.

Example 4

A high-alkaline solution containing vanadium and molybdenum, which is obtained by oxidizing roasting slag of a vanadium-molybdenum series waste catalyst leached by sodium hydroxide, is characterized in that the concentration of the sodium hydroxide is 133g/L, the concentration of the sodium carbonate is 19g/L, and the contents of the vanadium and the molybdenum are 23g/L and 5.6g/L respectively. Adding strontium oxide into high-alkaline solution to perform a causticization precipitation reaction, wherein the addition amount of the strontium oxide is 1.3 times of the molar amount of carbonate, the reaction temperature is 60 ℃, and the reaction time is 2 hours, so as to obtain a strontium salt precipitate and a causticized solution. The carbon deposition rate, the vanadium deposition rate and the molybdenum deposition rate are respectively 89%, 27% and 19%.

And drying the primary strontium salt precipitate, adding 12 wt.% of carbon powder, calcining for 1.5 hours at 1100 ℃, and performing a hot water washing experiment on a small amount of calcined slag, wherein the water solubility is 43 wt.%, which indicates that most of strontium carbonate in the primary strontium salt precipitate is converted into strontium oxide which can be dissolved by hot water.

Adding the primary calcined slag into the primary causticized liquid in proportion, performing secondary causticization precipitation reaction by using strontium oxide in the primary calcined slag, wherein the addition amount of the strontium oxide is 1.0 time of the total molar amount of molybdenum and vanadium in the primary causticized liquid, reacting for 100 minutes at 95 ℃, and performing solid-liquid separation to obtain secondary strontium salt precipitate and secondary causticized liquid. The vanadium deposition rate and the molybdenum deposition rate in the process are respectively 83 percent and 90 percent, the total vanadium deposition rate and the total molybdenum deposition rate of twice causticization deposition are 87.6 percent and 92 percent, the solution after twice causticization has no strontium residue and can return to the leaching process.

And adding the secondary strontium salt precipitate into a sodium carbonate solution for carbonation reaction, wherein the using amount of the sodium carbonate is 2.2 times of the molar amount of vanadium in the secondary strontium salt precipitate, the reaction temperature is 160 ℃, and the reaction time is 1 hour. Filtering and washing to obtain strontium carbonate slag and vanadium-molybdenum enriched liquid, wherein the vanadium leaching rate and the molybdenum leaching rate are respectively 95% and 96%. After drying the strontium carbonate slag, adding 9 wt.% of carbon powder, calcining for 1.5 hours at 1200 ℃, and performing a hot water washing experiment on a small amount of calcined slag, wherein the water solubility is 97 wt.%, which indicates that most of strontium carbonate in the strontium carbonate slag is converted into strontium oxide which can be dissolved by hot water.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be construed as the protection scope of the present invention.