CN101066778A - Process for Extracting Vanadium Pentoxide from Stone Coal Mine - Google Patents

Abstract

The invention relates to a method for extracting vanadium pentoxide from stone coal ores, which comprises the following steps: calcifying roasting, acid leaching, ion exchange, vanadium precipitation and roasting deamination. The method has the advantages that: short production period, simple process, easy operation, high purity of vanadium pentoxide product which can reach more than 99.0 percent, low production cost and suitability for large-scale production.

Description

Process for Extracting Vanadium Pentoxide from Stone Coal Mine

technical field

The invention relates to a production method of vanadium pentoxide, in particular to a production method for extracting vanadium pentoxide from stone coal mines.

Background technique

The proven reserves of carbon-bearing shale (referred to as stone coal mine) in Hunan, Hubei, Zhejiang, Anhui and other provinces are 618.8×10 ⁸ t, and the grade of vanadium pentoxide is mostly between 0.3% and 1.0%. The total reserves of vanadium are 117,690kt, accounting for more than 85% of the total reserves of vanadium in China. The vanadium in stone coal mines in most areas is mainly stable acid-base insoluble trivalent, so it is difficult to extract vanadium pentoxide. big.

The application number is CN90105503.4 and has reported the method for extracting vanadium pentoxide from vanadium ore, and this method vanadium leaching liquid adopts extraction technology, and method is complicated and complicated. The application number is CN91102560.X, which reports a method for producing vanadium pentoxide by decomposing stone coal mines with hydrofluoric acid. The disadvantages of this preparation method are that hydrofluoric acid has a high cost, is highly toxic to the human body, and is extremely corrosive to equipment.

In order to overcome the above problems, application number CN200510032012.3 has reported the method for extracting vanadium pentoxide from vanadium ore, and this method comprises calcification roasting, dilute acid leaching, vanadium liquid purification, ion exchange, pyrolytic deamination make _V2 O ₅ . In this technical solution, although the vanadium solution is purified before entering the ion exchange column, and the pH value is adjusted to 2.0-3.0, the eluent uses sodium hydroxide, and the purity of the obtained V ₂ O ₅ is still not high enough.

Contents of the invention

The technical problem solved by the invention is to provide a production method for extracting vanadium pentoxide from stone coal mines. The method has short production cycle, simple production method, and the purity of the extracted vanadium pentoxide can be as high as 99.0%.

The production method for extracting vanadium pentoxide provided by the invention includes calcification roasting, acid leaching, ion exchange, vanadium precipitation, roasting and deamination to prepare V ₂ O ₅ . Specifically include the following steps:

a. Calcification roasting: Grind and mix stone coal ore, calcium oxide and coal evenly, add water to form pellets, and roast for 1h to 6h in an aerobic atmosphere at a temperature of 800°C to 980°C to obtain cooked balls;

Among them, the amount of calcium oxide is 4% to 15% of the mass of the stone coal mine, and the amount of coal is 5% to 40% of the mass of the stone coal mine;

b. Acid leaching: soak the boiled balls obtained in step a with a sulfuric acid solution with a concentration of 10% to 25% to obtain a leachate, and when the pH value of the leachate reaches 1.5 to 5.0, filter the leachate to remove solid impurities or suspended matter for later use;

c, ion exchange: carry out ion exchange with the filtrate that b step obtains through macroporous weak base type ion exchange resin, metavanadate is adsorbed on the ion exchange resin, and other ions enter the exchange liquid;

Using a mixture of 1-5mol/L ammonium chloride and 0.1-3mol/L ammonia water as a desorbent to desorb the ion-exchange resin adsorbed with metavanadate to obtain a desorption solution;

d, vanadium precipitation: add vanadium precipitation agent to precipitate vanadium in the desorption liquid obtained in step c, and filter the crude vanadium obtained;

e, refined vanadium: dissolve the crude vanadium obtained in step d with 1 to 10% sodium hydroxide solution, add calcium chloride to stir, filter, add a vanadium precipitation agent to the filtrate to precipitate vanadium, filter and collect the filter cake;

f. Deamination by roasting: drying the filter cake obtained in step e and roasting at 450° C. to 600° C. to obtain vanadium pentoxide. The specific flow chart is shown in Figure 1.

In step a of the above technical solution, if the particle size of the powder is too large, the mixing of materials will be uneven; if the particle size is too small, the requirements for equipment will be high. If the particle size of the pellets is too large, the reaction will not be complete during the roasting process, and leaching will be difficult; if the particle size is too small, the difficulty of pelletizing will increase, and the calcination operation in the flat kiln will be difficult. Many experiments have proved that the particle size of the powder is preferably 74 μm to 250 μm, and the particle size after pelletizing is preferably 0.1 mm to 20 mm. The optimal temperature for roasting is 920°C-960°C, and the time is 3h-5h.

If the concentration of the sulfuric acid solution used to soak cooked balls in step b is too low, the leaching effect will not be good. If the concentration is too high, a large number of impurity elements in the minerals such as Fe, Al, Ni, Si, etc. will be acidolyzed and consume sulfuric acid. The amount of impurity elements in the medium will increase greatly, and the difficulty of purification will increase. If the pH value of the leach solution is lower than 1.5, it will not meet the requirement of the ion exchange resin for the pH value of the exchange liquid, and it cannot directly enter the ion exchange column for ion exchange. The ion exchange step is carried out in between, so that the utilization rate of sulfuric acid is improved, and the pH value of the leachate is adjusted.

Vanadium exists in the form of anion groups in the leaching solution, and the particle size is relatively large, so a macroporous anion exchange resin is required. When the pH value of the leaching solution is below 1.5, vanadium exists in the form of cationic groups. In order to use anion exchange resin to adsorb vanadium anions, it is necessary to adjust the pH value of the leachate to above 1.5. Different resins have different requirements for the pH value of the acidic environment of the exchange liquid. If the pH value of the leachate is required to be above 2.0, the pH value of the leachate needs to be adjusted. During the process of adjusting the pH value of the leachate, some metal cations will be precipitated At the same time, a large amount of silica precipitates will be formed, and vanadium anions will be adsorbed by these precipitates, resulting in the loss of vanadium. However, the resin used in the present invention can fully satisfy the condition that the pH value of the leachate is 1.5 for ion exchange, therefore, it is not necessary to adjust the pH value of the leachate. In addition, in the initial stage of ion exchange, the pH value of the leaching solution gradually increases, and some precipitates will be generated and stay in the resin, which may affect the adsorption of vanadium anions by the resin. And the ion-exchange resin AMBERLITE IRA96RF that the present invention adopts, AMBERLITE IRA96CRF are macroporous weak base type, are produced by Rohm and Haas Company. Its matrix structure is styrene/divinylbenzene copolymer, and its functional group is a tertiary amine. It has a stable structure and limited reversible expansion rate. Due to the structure of the resin itself, the pores of the resin are not easily blocked by the precipitate produced, and The precipitate is also easily washed out of the resin with water.

In actual production, the cooked balls can be soaked in a flowing water manner: that is, the newly prepared sulfuric acid solution is used for re-soaking the cooked balls, and the leaching solution after soaking for a certain period of time is used to soak new cooked balls. Adopting such a soaking method can significantly improve the leaching effect and reduce the acid consumption compared with the repeated soaking method.

The ammonium metavanadate in the crude vanadium obtained in step d contains many impurities such as SiO ₂ , phosphate and the like. Vanadium refining step: the ammonium metavanadate precipitate is dissolved in 1-10% sodium hydroxide solution, calcium chloride is added and stirred, and impurities such as solid silicon and phosphorus are removed by filtration. The amount of calcium chloride added is determined according to the amount of phosphate.

If the phosphorus content in vanadium products is too high and the quality does not meet the requirements of the national standard, phosphorus will seriously affect the quality of the product when used in the metallurgical industry. After the present invention refines the obtained vanadium crude product, the purity is high and fully reaches the national standard. During the soaking process, impurities such as silicates and phosphates in the cooked balls enter the leachate. Since the anion exchange resin has the characteristics of selective and preferential adsorption to anion groups, the ion exchange resin selected in the present invention will preferentially adsorb vanadium anion groups during ion exchange. Therefore, only a very small amount of silicate and phosphate ions are adsorbed on the resin, and enter into the ammonium metavanadate precipitation during desorption and vanadium precipitation. In the step of refining vanadium, when sodium hydroxide and calcium chloride are added to remove phosphorus, the SiO ₂ precipitate does not react with sodium hydroxide and can be removed together with insoluble phosphate during filtration.

In order to save production costs, the exchange solution in step c of the above technical solution can be added with sulfuric acid and returned to the acid leaching process b to soak the cooked balls. Above-mentioned step d filters gained filtrate and can add ammonium chloride and ammoniacal liquor and return step c to be used as desorbent.

The inventive method advantage:

(1) use the inventive method, without discharge of three wastes;

(2) because the ion-exchange resin of the inventive method has selected AMBERLITE IRA96RF or AMBERLITE IRA96CRF for use, so just saved the step of vanadium liquid purification and pH adjustment, operation simplification;

(3) In the step of sinking vanadium, the method of the present invention adopts the method of sinking crude vanadium earlier, after dissolving the crude vanadium, and then sinking refined vanadium, so the produced vanadium pentoxide product has high purity, which can reach more than 99.0%;

(4) The exchange liquid and the residual liquid after precipitation of vanadium pentoxide can be recycled, the production cost is low, and it is very suitable for large-scale production.

Description of drawings

Fig. 1 is the flow chart of the method for extracting vanadium pentoxide from stone coal mines.

Detailed ways

Mix and grind dry stone coal ore with calcium oxide with 4% to 15% of stone coal ore mass and anthracite with 5% to 40% of stone coal ore mass to obtain a powder with a particle size of 74 μm to 250 μm, and add the mass of the mixture to the mixture 10% to 20% water to make balls with a diameter of 0.1mm to 20mm and then dry them; place the dried balls in a flat kiln or a rotary kiln, and roast them at a temperature of 800°C to 1000°C for 1h to 6h in an aerobic atmosphere Get cooked balls. Low-valence vanadium ions (mainly trivalent vanadium ions) in minerals are oxidized to high-valence vanadium ions, and high-valence vanadium ions react with calcium oxide to form calcium metavanadate. Put the roasted cooked balls in air to cool to room temperature, and add sulfuric acid solution Soak to get the leachate, its main chemical reaction formula is as follows:

        

Ca(VO ₃ ) ₂ +SO ₄ ^2- ＝CaSO ₄ ↓+VO ₃ ^2-

When the pH value of the leachate is 1.5-5.0, filter, and the filtrate enters the ion-exchange resin for ion exchange to obtain the exchange liquid; the resin with metavanadate adsorbed is mixed with 1-5mol/L ammonium chloride and 0.1-3mol/L ammonia water Desorb as a desorbent to obtain a desorbed liquid. During the desorption process of the ion exchange resin, the ammonium root will react with the desorbed metavanadate ion to form ammonium metavanadate precipitate, but this will not affect the desorption of the resin, and the precipitate will flow out of the ion exchange column together with the desorption liquid. Enter the sunken vanadium pentoxide tank. Add vanadium-precipitating agent containing ammonium root to the desorption solution to precipitate vanadium, filter to obtain filtrate I and filter cake I; add ammonium chloride and ammonia water to filtrate I and return it as desorbent, filter cake I is dissolved with sodium hydroxide solution, and added chlorine Calcium, stirring, filtering, the obtained filtrate II enters the vanadium pentoxide sink tank, and adds a vanadium-containing agent containing ammonium root to the filtrate II to precipitate vanadium, such as one or more of ammonia water, ammonium chloride, ammonium sulfate, etc. , filter to obtain filter cake II; filter cake II is dried and roasted at a temperature of 400°C to 600°C for 20min to 90min to obtain vanadium pentoxide with a purity of ≥99.0%. The main chemical reaction formula is as follows:

3Ca ²⁺ +2PO ₃ ^3- ＝Ca ₃ (PO ₃ ) ₂ ↓ NH ₄ ⁺ +VO ₃ ^- ＝NH ₄ VO ₃ ↓

2NH ₄ VO ₃ ＝V ₂ O ₅ +2NH ₃ ↑+H ₂ O↑

The present invention will be further described below in conjunction with embodiment.

Example 1

Add 120g of calcium oxide (CaO ≥ 90%) and 100g of anthracite (C ≥ 80%) to 2000g of dry stone coal, grind and mix evenly, add 200g of water to make pellets, the diameter of which is about 20mm, and place them in the air to dry naturally Then put it into a high-temperature furnace connected to the air for roasting, the roasting temperature is 980°C, and the roasting time is 3 hours to obtain cooked balls, take out the cooked balls and place them in the air to cool to room temperature, divide them into two parts on average, and record them as cooked balls I and cooked balls respectively. Ball II. Soak cooked balls I with 1060g of sulfuric acid solution with a concentration of 10%. After soaking for 48 hours, soak cooked balls II with the obtained leachate until the pH value of the leachate reaches 1.5, filter, and the filtrate is ion-exchanged with AMBERLITE IRA96RF anion exchange resin, resin adsorption After saturation, use 1.5mol/L NH ₄ Cl and 0.2mol/L NH ₃ ·H ₂ O mixed solution for desorption. Add ammonia water to the desorption solution to precipitate vanadium, filter, dissolve the obtained filter cake with sodium hydroxide solution, then add 5 g of calcium chloride, stir, filter, and then use ammonia water to precipitate vanadium from the filtrate, dry the filter cake, and burn at 450 ° C. Burn for 30 minutes to obtain powdery vanadium pentoxide with a purity of 99.1% and a yield of 55.2% for the whole process.

Example 2

Add 160g of calcium oxide (CaO ≥ 90%) and 200g of anthracite (C ≥ 80%) to 2000g of dry stone coal, grind and mix evenly, add 260g of water to make pellets, the diameter of which is about 15mm, and place them in the air to dry naturally Then put it into a high-temperature furnace connected to the air for roasting, the roasting temperature is 950°C, and the roasting time is 4 hours to obtain cooked balls, take out the cooked balls and cool them to room temperature in the air, divide them into two parts on average, and record them as cooked balls I and cooked balls respectively. Ball II. Use 1060g of sulfuric acid solution with a concentration of 15% to soak cooked balls I, soak for 48 hours, then soak cooked balls II with the obtained leachate until the pH value of the leachate reaches 2.0, filter, and the filtrate is ion-exchanged with AMBERLITE IRA96CRF anion exchange resin, resin After adsorption saturation, use 2mol/L NH ₄ Cl and 0.5mol/L NH ₃ ·H ₂ O mixed solution for desorption. Add a mixture of ammonia and ammonium chloride to the desorption liquid to precipitate vanadium, filter, dissolve the obtained filter cake with sodium hydroxide solution, then add 4g of calcium chloride, stir, filter, and then use ammonia and chloride Precipitate vanadium from the ammonium mixture, dry the filter cake, and burn at 500°C for 40 minutes to obtain powdery vanadium pentoxide with a purity of 99.2%. The yield of vanadium pentoxide in the whole process is 56.5%.

Example 3

Add 300g of calcium oxide (CaO ≥ 90%) and 450g of anthracite (C ≥ 80%) to 3000g of dry stone coal, grind and mix evenly, add 450g of water to make pellets, the diameter of which is about 12mm, and place them in the air to dry naturally Then put it into a high-temperature furnace connected to the air for roasting. The roasting temperature is 960° C., and the roasting time is 5 hours to obtain cooked balls. The cooked balls are taken out and placed in the air to cool to room temperature. Ball II and Cooking Ball III. Soak cooked ball I with 2000g of sulfuric acid solution with a concentration of 20%, soak for 48 hours, then soak cooked ball II with the obtained leachate, and then soak cooked ball III after 24 hours, until the pH value of the leachate reaches 3.0, filter, and use AMBERLITE IRA96RF anion for the filtrate The exchange resin is used for ion exchange, and after the resin is adsorbed and saturated, it is desorbed with a mixed solution of 2.5 mol/L NH ₄ Cl and 0.8 mol/L NH ₃ ·H ₂ O. Add a mixed solution of ammonia water and ammonium sulfate to the desorption solution to precipitate vanadium, filter, dissolve the obtained filter cake with sodium hydroxide solution, add 6 g of calcium chloride, stir, filter, and use the mixed solution of ammonia water and ammonium sulfate to the filtrate Precipitate vanadium, dry the filter cake, and burn at 550°C for 50 minutes to obtain powdery vanadium pentoxide with a purity of 98.6% and a yield of 56.7% throughout the process.

Example 4

Add 450g of calcium oxide (CaO ≥ 90%) and 150g of anthracite (C ≥ 80%) to 3000g of dry stone coal, grind and mix evenly, add 450g of water to make pellets, the diameter of which is about 8mm, and place them in the air to dry naturally Then put it into a high-temperature furnace connected to the air for roasting. The roasting temperature is 800° C., and the roasting time is 6 hours to obtain cooked balls. Take out the cooked balls and place them in the air to cool to room temperature. Ball II and Cooking Ball III. Soak cooked ball I with 3200g of sulfuric acid solution with a concentration of 20% for 48 hours, then soak cooked ball II with the obtained leach solution, and then soak cooked ball III after 24 hours until the pH value of the leach solution reaches 4.0, filter, and use AMBERLITE IRA96RF anion for the filtrate The exchange resin is used for ion exchange. After the resin is saturated with adsorption, it is desorbed with a mixed solution of 3 mol/L NH ₄ Cl and 0.9 mol/L NH ₃ ·H ₂ O. Add ammonia water to the desorption solution to precipitate vanadium, filter, dissolve the obtained filter cake with sodium hydroxide solution, then add 8g of calcium chloride, stir, filter, and the filtrate is ammonia water to precipitate vanadium, dry the filter cake, and burn at 550°C After 40 minutes, powdery vanadium pentoxide was obtained with a purity of 99.0%, and the yield of the whole process was 46.2%.

Example 5

Add 240g of calcium oxide (CaO ≥ 90%) and 900g of anthracite (C ≥ 80%) to 3000g of dry stone coal, grind and mix evenly, add 450g of water to make pellets, the diameter of which is about 5mm, and place them in the air to dry naturally Then put it into a high-temperature furnace connected to the air for roasting. The roasting temperature is 850° C., and the roasting time is 4 hours to obtain cooked balls. Take out the cooked balls and place them in the air to cool to room temperature. Ball II and Cooking Ball III. Soak cooked ball I with 4000g of sulfuric acid solution with a concentration of 25%. After soaking for 48 hours, soak cooked ball II with the obtained leach solution. After 24 hours, soak cooked ball III until the pH value of the leach solution reaches 3.0. Filter the filtrate with AMBERLITE IRA96RF The anion exchange resin is used for ion exchange, and after the resin is adsorbed and saturated, it is desorbed with a mixed solution of 4 mol/L NH ₄ Cl and 1.0 mol/L NH ₃ ·H ₂ O. Add ammonia water to the desorption solution to precipitate vanadium, filter, dissolve the obtained filter cake with sodium hydroxide solution, then add 10 g of calcium chloride, stir, filter, and then use ammonia water to precipitate vanadium from the filtrate, dry the filter cake, and burn at 550 ° C. Burn for 40 minutes to obtain powdery vanadium pentoxide with a purity of 99.5%, and a yield of 48.5% for the whole process of vanadium pentoxide.

Example 6

Add 240g of calcium oxide (CaO ≥ 90%) and 1200g of anthracite (C ≥ 80%) to 3000g of dry stone coal, grind and mix evenly, add 360g of water to make pellets, the diameter of which is about 2mm, and place them in the air to dry naturally Then put it into a high-temperature furnace connected to the air for roasting. The roasting temperature is 900° C., and the roasting time is 3.5 hours to obtain cooked balls. The cooked balls are taken out and placed in the air to cool to room temperature. Cooking Ball II and Cooking Ball III. Soak boiled balls I with 3200g of 15% sulfuric acid solution for 48 hours, then use the obtained leachate to soak boiled balls II, and after 48 hours, soak boiled balls III until the pH value of the leachate reaches 5.0, filter, and use AMBERLITE for the filtrate The IRA96CRF anion exchange resin is used for ion exchange. After the resin is saturated, it is desorbed with a mixed solution of 4.5 mol/L NH ₄ Cl and 0.8 mol/L NH ₃ ·H ₂ O. Add ammoniacal liquor and ammonium chloride to precipitate vanadium in the desorption liquid, filter, dissolve the filter cake obtained with sodium hydroxide solution, add calcium chloride 8g again, stir, filter, and the filtrate uses ammoniacal liquor and ammonium chloride to precipitate vanadium again, filter The cake was dried and burned at 550° C. for 30 minutes to obtain powdery vanadium pentoxide with a purity of 99.1%, and the yield of vanadium pentoxide throughout the process was 57.3%.

Example 7

Add 80g of calcium oxide (CaO ≥ 90%) and 800g of anthracite (C ≥ 80%) to 2000g of dry stone coal, grind and mix evenly, add 360g of water to make pellets, the diameter of which is about 0.5mm, and place them in the air naturally After drying, put it into a high-temperature furnace connected to the air for roasting. The roasting temperature is 920°C, and the roasting time is 3 hours to obtain cooked balls. Take out the cooked balls and place them in the air to cool to room temperature. Cooked Ball II. Soak cooked balls I with 2200g of sulfuric acid solution with a concentration of 15% for 24 hours, then soak cooked balls II with the obtained leachate until the pH value of the leachate reaches 1.5, then filter, and the filtrate is ion-exchanged with AMBERLITE IRA96RF anion exchange resin, and the resin adsorption is saturated Afterwards, use a mixed solution of 3.5 mol/L NH ₄ Cl and 0.5 mol/L NH ₃ ·H ₂ O for desorption. Add ammonia water to the desorption solution to precipitate vanadium, filter, dissolve the obtained filter cake with sodium hydroxide solution, then add 15 g of calcium chloride, stir, filter, and then use ammonia water to precipitate vanadium from the filtrate, dry the filter cake, and burn at 600 ° C. Burn for 30 minutes to obtain powdery vanadium pentoxide with a purity of 99.6%, and the yield of the whole process of vanadium pentoxide is 56.4%.

Claims (6)

1, extract the method for vanadium pentoxide from stone coal mine, comprise the following steps: a. Calcification roasting: Grind and mix stone coal ore, calcium oxide and coal evenly, add water to form pellets, and roast for 1h to 6h in an aerobic atmosphere at a temperature of 800°C to 980°C to obtain cooked balls; Among them, the amount of calcium oxide is 4% to 15% of the mass of the stone coal mine, and the amount of coal is 5% to 40% of the mass of the stone coal mine; b. Acid leaching: soak the boiled balls obtained in step a with a sulfuric acid solution with a concentration of 10% to 25% to obtain a leaching solution, and when the pH value of the leaching solution reaches 1.5 to 5.0, filter to obtain a filtrate for subsequent use; c, ion exchange: carry out ion exchange with the filtrate that b step obtains through macroporous weak base type ion exchange resin, metavanadate is adsorbed on the ion exchange resin, and other ions enter the exchange liquid; Using a mixture of 1-5mol/L ammonium chloride and 0.1-3mol/L ammonia water as a desorbent to desorb the ion-exchange resin adsorbed with metavanadate to obtain a desorption solution; d, vanadium precipitation: add vanadium precipitation agent to precipitate vanadium in the desorption liquid obtained in step c, and filter to obtain crude vanadium; e, refined vanadium: the crude vanadium obtained in the d step is dissolved with 1-10% sodium hydroxide solution, added calcium chloride to stir, filtered, added a vanadium precipitation agent to precipitate vanadium in the filtrate, and filtered to collect the filter cake; f. Deamination by roasting: drying the filter cake obtained in step e and roasting at 450° C. to 600° C. to obtain vanadium pentoxide. 2. The method for extracting vanadium pentoxide from stone coal mines according to claim 1, characterized in that: in step a, the particle size of the powder is 74 μm to 250 μm, and the particle size of the balls after pelletizing is 0.1 mm to 20 mm. 3. The method for extracting vanadium pentoxide from stone coal mines according to claim 1, characterized in that in step a, the roasting temperature is 920°C-960°C, and the roasting time is 3h-5h. 4. The method for extracting vanadium pentoxide from stone coal mines according to claim 1, characterized in that: the acid leaching in step b adopts flowing water immersion. 5. The method for extracting vanadium pentoxide from stone coal mines according to claim 1, characterized in that: add sulfuric acid to the exchange solution in step c and return to the acid leaching process to soak cooked balls. 6. The method for extracting vanadium pentoxide from stone coal mines according to claim 1, characterized in that: the filtrate obtained by filtering in step d is added with ammonium chloride and ammonia water and returned as a resin desorbent.

Images