Method for extracting vanadium through calcium carbide slag calcification, negative-pressure roasting, pressurizing and acid leaching

Abstract

The invention provides a method for extracting vanadium through calcium carbide slag calcification, negative-pressure roasting, pressurization and acid leaching, and relates to the field of efficient and clean utilization of vanadium slag. The pressure of a roasting system is 0.01-1 atm, and the roasting temperature is 500-800 DEG C; the system pressure is 0.1-2 Mpa, the concentration of a sulfuric acid solution is 100-200 g / L, the leaching temperature is 60-200 DEG C, the leaching time is 10-180 min, and the stirring rotating speed is 300-900 rpm. According to the method, the roasting efficiency and the leaching efficiency of the vanadium slag are improved in a mode of combining shaft furnace roasting and closed pressurized sulfuric acid leaching, the temperature is 100-400 DEG C lower than that of normal-pressure calcification roasting, the calcification time is shortened by 60-180 min, the leaching rate of vanadium is larger than 95%, the leaching rate is improved by 5-8%, the production cost is reduced, and efficient utilization of the vanadium slag is achieved.

Description

Technical Field

[0001] This invention belongs to the field of efficient and clean utilization of vanadium slag, and particularly relates to a method for extracting vanadium by negative pressure roasting and pressurized acid leaching of calcium carbide slag. Background Technology

[0002] Vanadium is considered a "vitamin of modern industry," an indispensable strategic resource for the development of modern industry, national defense, and new energy technologies. Currently, the main resource for vanadium extraction is still the vanadium slag produced during the smelting of vanadium-titanium magnetite. The vanadium-titanium magnetite is processed using pyrometallurgical methods to obtain vanadium-containing molten iron. This molten iron is then oxidized to produce converter vanadium slag, which enriches the vanadium for reuse. The extraction of vanadium from converter vanadium slag primarily employs a "vanadium extraction-leaching" production model.

[0003] Patent CN201611138533.1 provides a method for extracting vanadium from vanadium slag using microwave calcination roasting. In step three, the pressed mixture is placed in a microwave environment and roasted for 1-2 hours under certain temperature and microwave conditions to obtain clinker. After air cooling to room temperature, it is crushed to a particle size ≤200 mesh. Using microwave heating requires higher power to meet the roasting temperature, which is 700℃~900℃. In addition, patent CN201210066735.5 discloses a method for extracting vanadium from vanadium slag clinker by leaching with ammonium carbonate. In this method, the roasting temperature reaches 700℃~900℃, and an ammonium carbonate solution with a concentration of 200~800g / L is used for leaching. Both the roasting temperature and the solution concentration are very high to achieve a high leaching rate.

[0004] The aforementioned patents mostly employ a "roasting-leaching" process, which results in high energy consumption, high cost, and low resource utilization. Therefore, a method is needed to reduce roasting energy consumption and roasting cost for vanadium leaching. Summary of the Invention

[0005] One of the technical problems that this invention aims to solve is that the existing "roasting-leaching" process has high energy consumption, low resource utilization, and consumes a lot of costs.

[0006] To solve the above technical problems, the present invention provides a method for extracting vanadium by negative pressure roasting and pressurized acid leaching of calcium carbide slag, comprising the following steps: S1, mixing vanadium slag and calcium carbide slag in a certain proportion, crushing them to a certain particle size and then making mixed briquettes;

[0007] S2. The mixed pellets from S1 are roasted in a vertical furnace to obtain calcified slag;

[0008] The calcination system pressure is 0.01-1 atm;

[0009] S3. The calcified slag in S2 is leached with sulfuric acid under closed pressure to obtain leaching residue and vanadium-containing leaching residue.

[0010] The acid leaching system pressure is 0.1–2 MPa.

[0011] S4. Collect the leaching residue and vanadium-containing leachate.

[0012] In some embodiments, the aforementioned method for extracting vanadium by negative pressure roasting and pressurized acid leaching is wherein the carbide slag in S1 includes calcium hydroxide, and the particle size of the vanadium slag and carbide slag is 0.1 to 200 μm.

[0013] In some embodiments, the aforementioned method for extracting vanadium by negative pressure roasting and pressurized acid leaching is wherein the mixing ratio of vanadium slag and carbide slag is the mass ratio of V2O5 in the vanadium slag to CaO in the carbide slag, and the mass ratio of V2O5 to CaO is 1 to 10:1.

[0014] In some embodiments, the aforementioned method for extracting vanadium by negative pressure roasting and pressurized acid leaching is wherein the diameter of the mixing briquette is 6 to 25 mm.

[0015] In some embodiments, the aforementioned method for extracting vanadium by negative pressure roasting and pressurized acid leaching is wherein the roasting temperature of the vertical furnace in S2 is 400–900°C and the roasting time is 5–90 min.

[0016] In some embodiments, the aforementioned method for extracting vanadium by negative pressure roasting and pressurized acid leaching includes a sulfuric acid solution concentration of 100–200 g / L in S3, a leaching temperature of 100–200 °C, a leaching time of 10–60 min, and a stirring speed of 300–900 rpm.

[0017] Through the above technical solution, the present invention provides a method for extracting vanadium from calcium carbide slag under negative pressure roasting and pressurized acid leaching, which has the following beneficial effects:

[0018] In this method, a negative pressure device is installed during the calcination roasting of vanadium slag to maintain the roasting system pressure at 0.01-1 atm, thereby reducing the initial reaction temperature of the calcination roasting reaction by 100-400℃ and shortening the roasting time by 60-180 minutes compared to the normal pressure calcination time, thus reducing roasting energy consumption and roasting costs. In addition, during the acid leaching process of the calcined slag, by pressurizing the leaching system, the sulfuric acid concentration is reduced by 50-100 g / L, increasing the vanadium leaching rate in the vanadium slag by 5-8%, and the vanadium leaching rate is >95%, thereby improving the vanadium recovery efficiency in the vanadium slag. Attached Figure Description

[0019] Figure 1 The flowchart of a method for extracting vanadium by negative pressure roasting and pressurized acid leaching of calcium carbide slag provided by the present invention is shown. Detailed Implementation

[0020] The above embodiments should be understood as being used only to illustrate the present invention more clearly, and not to limit the scope of the present invention. Modifications of the present invention by those skilled in the art in various equivalent forms all fall within the scope defined by the appended claims.

[0021] The vanadium slag composition used in the embodiments of the present invention is shown in Table 1 by mass percentage.

[0022] Table 1 Chemical composition of converter vanadium slag (mass percentage / %)

[0023]

[0024] Example 1

[0025] S1. Crush vanadium slag and calcium carbide slag to 0.1μm, and mix them evenly in a ratio of V2O5 mass in vanadium slag to CaO mass in calcium carbide slag of 1:1. Form the mixture into pellets to obtain pellets with a diameter of 6 to 25 mm.

[0026] S2. Pelletizing in a vertical shaft furnace, with a calcination system pressure of 0.01 atm, a calcination temperature of 500℃, and a calcination time of 10 min, yields calcified slag.

[0027] S3. The calcified slag is leached in a closed pressurized sulfuric acid system at a pressure of 2 MPa, a sulfuric acid solution concentration of 200 g / L, a leaching temperature of 200 °C, and a leaching time of 60 min.

[0028] This roasting temperature is 400℃ lower than that of atmospheric pressure calcification, and the roasting time is 180 minutes shorter than that of atmospheric pressure calcification. The pressure acid leaching reduces the sulfuric acid concentration by 50 g / L compared to atmospheric pressure acid leaching, and increases the vanadium leaching rate in the vanadium slag by 8%, with a vanadium leaching rate of 98%.

[0029] Example 2

[0030] S1. Crush vanadium slag and calcium carbide slag to 200μm, and mix them evenly at a ratio of V2O5 mass in vanadium slag to CaO mass in calcium carbide slag of 6:1. Form the mixture into pellets with a diameter of 6 to 25 mm.

[0031] S2. Pelletizing in a vertical shaft furnace, with a calcination system pressure of 0.7 atm, a calcination temperature of 800℃, and a calcination time of 60 min, yields calcified slag.

[0032] S3. The calcified slag is leached in a closed pressurized sulfuric acid system with a leaching system pressure of 0.5 MPa, a sulfuric acid solution concentration of 100 g / L, a leaching temperature of 100 °C, and a leaching time of 10 min.

[0033] This roasting temperature is 100°C lower than that of atmospheric pressure calcification, and the roasting time is shortened by 60 minutes. The pressure acid leaching reduces the sulfuric acid concentration by 100 g / L compared to atmospheric pressure acid leaching, and increases the vanadium leaching rate in the vanadium slag by 5%, reaching 95%.

[0034] Example 3

[0035] S1. Crush vanadium slag and calcium carbide slag to 100μm, and mix the vanadium slag and calcium carbide slag evenly at a ratio of V2O5 mass in vanadium slag to CaO mass in calcium carbide slag of 5:1. Form the mixture into pellets to obtain pellets with a diameter of 6 to 25 mm.

[0036] S2. Pelletizing in a vertical shaft furnace, with a calcination system pressure of 0.4 atm, a calcination temperature of 600℃, and a calcination time of 30 min, yields calcified slag.

[0037] S3. The calcified slag is leached in a closed pressurized sulfuric acid system with a leaching system pressure of 0.5 MPa, a sulfuric acid solution concentration of 150 g / L, a leaching temperature of 150 °C, and a leaching time of 40 min.

[0038] This roasting method uses a 300°C lower temperature than atmospheric pressure calcination and a 120-minute shorter roasting time. The pressurized acid leaching reduces the sulfuric acid concentration by 100 g / L compared to atmospheric pressure acid leaching, increasing the vanadium leaching rate in the vanadium slag by 6% to 96%.

[0039] Example 4

[0040] S1. Crush vanadium slag and calcium carbide slag to 50μm, and mix them evenly at a ratio of V2O5 mass in vanadium slag to CaO mass in calcium carbide slag of 6:1. Form the mixture into pellets to obtain pellets with a diameter of 6 to 25 mm.

[0041] S2. The pellets are roasted in a vertical furnace at a pressure of 0.2 atm, a temperature of 550°C, and a time of 30 min to obtain calcified slag.

[0042] S3. The calcified slag is leached in a closed pressurized sulfuric acid system with a leaching system pressure of 0.8 MPa, a sulfuric acid solution concentration of 100 g / L, a leaching temperature of 200℃, and a leaching time of 60 min.

[0043] This roasting temperature is 350℃ lower than that of atmospheric pressure calcification, and the roasting time is shortened by 90 minutes. The pressure acid leaching reduces the sulfuric acid concentration by 100g / L compared to atmospheric pressure acid leaching, and increases the vanadium leaching rate in the vanadium slag by 7%, with a vanadium leaching rate of 97%.

[0044] Example 5

[0045] S1. Crush vanadium slag and calcium carbide slag to 150μm, and mix the vanadium slag and calcium carbide slag evenly at a ratio of V2O5 mass in vanadium slag to CaO mass in calcium carbide slag of 8:1. Form the mixture into pellets to obtain pellets with a diameter of 6 to 25 mm.

[0046] S2. Pelletizing in a vertical shaft furnace, with a calcination system pressure of 0.5 atm, a calcination temperature of 700℃, and a calcination time of 20 min, yields calcified slag.

[0047] S3. The calcified slag is leached in a closed pressurized sulfuric acid system with a leaching system pressure of 0.1 MPa, a sulfuric acid solution concentration of 120 g / L, a leaching temperature of 120 °C, and a leaching time of 30 min.

[0048] This roasting method uses a 200°C lower temperature than atmospheric pressure calcination and a 100-minute shorter roasting time. The pressurized acid leaching reduces the sulfuric acid concentration by 100 g / L compared to atmospheric pressure acid leaching, increasing the vanadium leaching rate in the vanadium slag by 7% to 97%.

Claims

1. A method for extracting vanadium from calcium carbide slag under negative pressure roasting and pressurized acid leaching, characterized in that, Includes the following steps: S1. Mix vanadium slag and calcium carbide slag in a certain proportion, crush them to a certain particle size and then make mixed briquettes. S2. The mixed pellets from S1 are roasted in a vertical furnace to obtain calcified slag; The calcination system pressure is 0.01-1 atm; S3. The calcified slag in S2 is subjected to closed pressure and leached with sulfuric acid to obtain leaching residue and vanadium-containing leaching residue. The acid leaching system pressure is 0.1–2 MPa. S4. Collect the leaching residue and vanadium-containing leachate.

2. The method for extracting vanadium from calcium carbide slag under negative pressure roasting and pressurized acid leaching according to claim 1, characterized in that, The carbide slag mentioned in S1 includes calcium hydroxide, and the particle size of the vanadium slag and carbide slag is 0.1 to 200 μm.

3. The method for extracting vanadium from calcium carbide slag under negative pressure roasting and pressurized acid leaching according to claim 1, characterized in that, The mixing ratio of vanadium slag and calcium carbide slag is the mass ratio of V2O5 in vanadium slag to CaO in calcium carbide slag, and the mass ratio of V2O5 to CaO is 1 to 10:

1.

4. The method for extracting vanadium by negative pressure roasting and pressurized acid leaching of calcium carbide slag according to claim 1, characterized in that, The diameter of the mixed pressure ball is 6-25 mm.

5. The method for extracting vanadium from calcium carbide slag under negative pressure roasting and pressurized acid leaching according to claim 1, characterized in that, The roasting temperature of the vertical furnace in S2 is 400–900℃, and the roasting time is 5–90 min.

6. The method for extracting vanadium by negative pressure roasting and pressurized acid leaching of calcium carbide slag according to claim 1, characterized in that, The sulfuric acid solution concentration in S3 is 100-200 g / L, the leaching temperature is 100-200℃, the leaching time is 10-60 min, and the stirring speed is 300-900 rpm.

Images