System and method for removing silicon from tungsten-molybdenum extraction feed liquid by using carbon dioxide

Abstract

The invention introduces a system and a method for removing silicon from tungsten-molybdenum extraction feed liquid by using carbon dioxide, and relates to the technical field of metallurgical processes, the system comprises an autoclave liquid buffer unit, a CO2 ventilation reaction unit, a pH adjusting unit and a solid-liquid separation unit; the method comprises the following specific steps: S1, buffering feed liquid; s2, adjusting the pH value of the feed liquid; s3, carrying out CO2 ventilation reaction; s4, standing and precipitating; s5, carrying out solid-liquid separation; and S6, subsequent conveying. According to the method, through CO2 regulation and control and multi-parameter cooperative control, the content of Si in the tungsten-molybdenum-containing extraction feed liquid can be reduced from larger than or equal to 2 g / L to smaller than or equal to 0.8 g / L, the silicon removal rate reaches 65% or above, and the influence of silicon on subsequent extraction is thoroughly eliminated; the silicon removal efficiency is remarkable; the targeting property is strong without loss; the method is green and pollution-free; the process controllability is high; and the adaptability is high.

Description

Technical Field

[0001] This invention relates to the field of metallurgical process technology, and in particular to a system and method for removing silicon from tungsten-molybdenum extraction solution using carbon dioxide. Background Technology

[0002] In the hydrometallurgical process of tungsten concentrate, the extraction liquid obtained after pressure leaching of tungsten concentrate contains not only 90-120 g / L of tungsten trioxide and 8-15 g / L of molybdenum, but also ≥2 g / L of silicon. Silicon mainly exists in the form of soluble silicates or silica colloids. In the subsequent alkaline extraction process, excessive silicon content will cause the organic phase to form a three-phase emulsion system, which will seriously hinder the separation of liquid and liquid phases. This will not only reduce the extraction efficiency of tungsten and molybdenum, but also cause the loss of organic phase, ultimately affecting the purity of the product and the continuity of production.

[0003] Existing silicon removal technologies mostly employ the addition of chemical reagents such as calcium and magnesium salts to form silicate precipitates. However, such methods easily introduce new metallic impurities, and the precipitation reaction conditions are difficult to control. They are also prone to co-precipitation with tungsten and molybdenum, resulting in the loss of target elements. Some processes remove silicon by directly adjusting the pH value, but they lack precise parameter coordination control, resulting in unstable silicon removal efficiency and difficulty in meeting the stringent silicon content requirements of subsequent extraction processes. Therefore, developing a high-efficiency, green silicon removal technology that does not affect tungsten and molybdenum extraction has become a key requirement for the production of ammonium paratungstate (APT). Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a system and method for removing silicon from tungsten-molybdenum extraction solution using carbon dioxide. By precisely controlling key conditions such as aeration parameters, temperature, and pH value, efficient and targeted removal of silicon is achieved, ensuring that the silicon-removed solution meets the requirements for subsequent alkaline extraction.

[0005] The technical solution adopted in this invention is: A system for removing silicon from tungsten-molybdenum extraction liquid using carbon dioxide is characterized by comprising a pressure cooking liquid buffer unit, a pH adjustment unit, a CO2 aeration reaction unit, and a solid-liquid separation unit. The pressure cooking liquid buffer unit includes a plate and frame filter press and a reaction vessel, with the outlet of the plate and frame filter press connected to the inlet of the reaction vessel via a pipeline. The pH adjustment unit includes a sulfuric acid storage tank, a liquid alkali storage tank, and an online pH meter. The sulfuric acid storage tank and the liquid alkali storage tank are connected to the reaction vessel via a metering pump. The online pH meter is installed on the reaction vessel to monitor the pH value of the liquid in the reaction vessel in real time and control the adjustment accuracy to ±0.1. The CO2 venting reaction unit includes a CO2 storage tank, a flow regulating valve, and a perforated venting coil; the outlet of the CO2 storage tank is connected to the bottom of the reactor through the perforated venting coil, and the flow regulating valve is installed on the perforated venting coil. The solid-liquid separation unit is connected to the outlet of the reaction vessel via a pipeline. The solid-liquid separation unit is a plate and frame filter press or a vacuum filter.

[0006] A method for removing silicon from tungsten-molybdenum extraction solution using carbon dioxide, comprising the following steps: S1: Feed liquid buffer; After the tungsten concentrate is boiled, it is filtered by a plate and frame filter press. The filtered extraction liquid is introduced into an empty reactor. The reactor is started to heat the liquid to 90-100℃, and the stirring is started at a speed of 150-200r / min to mix the liquid evenly. The initial Si content is sampled and tested: WO3 content in the liquid is 90-120g / L, Mo content is 8-15g / L, and Si content is ≥2g / L. S2: pH adjustment of the feed solution; by adding liquid alkali or sulfuric acid dropwise through the pH adjustment unit, the pH value of the feed solution is stabilized between 9 and 10; S3: CO2 aeration reaction; Open the flow regulating valve to introduce CO2 from the CO2 storage tank into the reactor. The aeration flow rate is dynamically adjusted according to the volume of the liquid. The CO2 flow rate corresponding to each liter of liquid is 0.5-2.0 L / min, and the aeration reaction time is 0.5-2 h. S4: Settle and settle; turn off CO2 ventilation and reactor stirring, and run the reactor temperature control unit to let the liquid stand at 90-100℃ for 1-3 hours to allow sodium silicate to fully precipitate. S5: Solid-liquid separation; The settled liquid is introduced into the solid-liquid separation unit, filtered to remove sodium silicate precipitate, and the filtrate is collected as the desiliconized extraction liquid. S6: Subsequent transport; when the Si content in the feed liquid is reduced to ≤0.8g / L, the desiliconized extract feed liquid is sent to the alkaline extraction section through a pipeline.

[0007] Specifically, in step S3, the CO2 aeration flow rate is dynamically adjusted according to the volume of the liquid, with a CO2 flow rate of 0.8-1.5 L / min per liter of liquid.

[0008] Specifically, in step S3, the reaction time is positively correlated with the initial Si content. When the initial Si content is 2-3 g / L, the reaction time is 0.5-1 h, and when the initial Si content is >3 g / L, the reaction time is 1-2 h.

[0009] Specifically, in step S2, the sulfuric acid mass concentration is 95%-98%, the liquid alkali mass concentration is 30%-32%, and the dropping rate is automatically controlled by an online pH meter signal.

[0010] Due to the adoption of the technical solution described above, the present invention has the following advantages: (1) Significant silicon removal efficiency: Through CO2 regulation and multi-parameter synergistic control, the Si content in the tungsten-molybdenum extraction solution can be reduced from ≥2g / L to ≤0.8g / L, with a silicon removal rate of over 65%, thus completely eliminating the impact of silicon on subsequent extraction; (2) Highly targeted and lossless: CO2 reacts with silicon to form silica precipitate, but does not react with tungsten or molybdenum. The loss rate of WO3 and Mo during silicon removal is less than 1%, ensuring the recovery rate of target elements. (3) Green and pollution-free: CO2 is used as the reaction medium to replace the traditional metal salt precipitant, avoiding the introduction of impurities such as calcium and magnesium. Moreover, the silica precipitate is easy to filter and separate, and there is no secondary pollution. (4) High process controllability: A closed-loop system is formed by temperature control, pH adjustment and flow control. Each parameter can be precisely controlled to meet the treatment needs of liquids with different initial silicon content, and the silicon removal effect is stable. (5) Strong adaptability: It can be seamlessly connected with the existing tungsten concentrate pressure cooking-extraction process without the need for large-scale modification of existing equipment, and is easy to promote industrially. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the system connection of the present invention.

[0012] Figure 2 This is a process flow diagram of the present invention.

[0013] In the diagram: 1-Plate and frame filter press, 2-Reaction vessel, 3-CO2 storage tank, 4-Flow regulating valve, 5-Sulfuric acid storage tank, 6-Liquid alkali storage tank, 7-Metering pump, 8-Solid-liquid separation unit, 9-Pressure cooking vessel. Detailed Implementation

[0014] The present invention will be further explained and described below with reference to the accompanying drawings and embodiments. However, this should not be construed as limiting the scope of protection of the present invention. The purpose of disclosing the present invention is to protect all technical improvements within the scope of the present invention.

[0015] Combined with appendix Figure 1-2 The system shown is for removing silicon from tungsten-molybdenum extraction liquid using carbon dioxide, including a pressure cooking liquid buffer unit, a pH adjustment unit, a CO2 aeration reaction unit, and a solid-liquid separation unit 8.

[0016] The pressure cooking liquor buffer unit includes a plate and frame filter press 1 and a reaction vessel 2. The outlet of the plate and frame filter press 1 is connected to the inlet of the reaction vessel 2 via a pipeline. The CO2 aeration reaction unit includes a CO2 storage tank 3, a flow regulating valve 4, and a perforated venting coil. The outlet of the CO2 storage tank 3 is connected to the bottom of the reaction vessel 2 via the perforated venting coil, and the flow regulating valve 4 is installed on the perforated venting coil. The pH adjustment unit includes a sulfuric acid storage tank 5, a liquid alkali storage tank 6, and an online pH meter. Both the sulfuric acid storage tank 5 and the liquid alkali storage tank 6 are connected to the reaction vessel 2 via a metering pump 7. The online pH meter is installed on the reaction vessel 2 to monitor the pH value of the liquid in the reaction vessel 2 in real time and control the adjustment accuracy to ±0.1. The solid-liquid separation unit 8 is connected to the outlet of the reaction vessel 2 via a pipeline. The solid-liquid separation unit 8 is a plate and frame filter press or a vacuum filter. Example 1

[0017] A method for removing silicon from tungsten-molybdenum extraction solution using carbon dioxide, comprising the following steps: S1: Feed solution buffer; Tungsten concentrate is leached in pressure cooking kettle 9 at a leaching temperature of 205℃. After holding at this temperature for 2 hours, it is filtered by plate and frame filter press 1. 100L of the filtered extraction solution is introduced into an empty reaction kettle 2. The reaction kettle 2 is started to heat the solution to 95℃, and stirring is started at a speed of 200r / min. The solution is stirred for 10 minutes to make it uniformly mixed. The initial Si content is sampled and tested: WO3 content in the solution is 105g / L, Mo content is 12g / L, and Si content is 2.5g / L. S2: pH adjustment of the feed solution; by adding 98% sulfuric acid dropwise through the pH adjustment unit, the pH value of the feed solution is reduced to below 10, and then the pH value of the feed solution is stabilized at 9.5 by adding liquid alkali dropwise. S3: CO2 aeration reaction; Open the flow regulating valve 4 to introduce CO2 from CO2 storage tank 3 into reactor 2. The aeration flow rate is dynamically adjusted according to the volume of liquid material. The CO2 flow rate corresponding to each liter of liquid material is 1.0 L / min, and the aeration reaction time is 1 h. S4: Settle and settle; turn off CO2 ventilation and stirrer 2, and run the temperature control unit of reactor 2 to let the liquid stand at 95℃ for 2 hours to allow sodium silicate to fully precipitate. S5: Solid-liquid separation; The settled liquid is introduced into the solid-liquid separation unit 8 for pressure filtration separation, the sodium silicate precipitate is removed by filtration, and the filtrate is the desiliconized extraction liquid. S6: Subsequent transport; The desiliconized extraction solution is transported to the alkaline extraction section via pipeline, and the Si content in the solution is detected to be 0.6 g / L. Example 2

[0018] A method for removing silicon from tungsten-molybdenum extraction solution using carbon dioxide, comprising the following steps: S1: Feed solution buffer; Tungsten concentrate is leached in pressure cooking kettle 9 at a leaching temperature of 205℃. After holding at this temperature for 2 hours, it is filtered by plate and frame filter press 1. 100L of the filtered extraction solution is introduced into an empty reaction kettle 2. The reaction kettle 2 is started to heat the solution to 95℃, and stirring is started at a speed of 200r / min. The solution is stirred for 10 minutes to make it uniformly mixed. The initial Si content is sampled and tested: WO3 content in the solution is 90g / L, Mo content is 8g / L, and Si content is 2.0g / L. S2: pH adjustment of the feed solution; by adding sulfuric acid with a mass concentration of 98% through the pH adjustment unit, the pH value of the feed solution is quickly reduced to below 10, and then the pH value of the feed solution is stabilized at 9.5 by adding liquid alkali. S3: CO2 aeration reaction; Open the flow regulating valve 4 to introduce CO2 from CO2 storage tank 3 into reaction vessel 2. The aeration flow rate is dynamically adjusted according to the volume of liquid material. The CO2 flow rate corresponding to each liter of liquid material is 0.8 L / min, and the aeration reaction time is 40 min. S4: Settle and settle; turn off CO2 ventilation and stirring of reactor 2, keep the temperature control unit running, and let the liquid stand at 98℃ for 1.5h to allow sodium silicate to fully precipitate; S5: Solid-liquid separation; The settled liquid is introduced into the solid-liquid separation unit 8 for pressure filtration separation, the sodium silicate precipitate is removed by filtration, and the filtrate is the desiliconized extraction liquid. S6: Subsequent transport; The desiliconized extraction solution is transported to the alkaline extraction section via pipeline, and the Si content in the solution is detected to be 0.5 g / L. Example 3

[0019] A method for removing silicon from tungsten-molybdenum extraction solution using carbon dioxide, comprising the following steps: S1: Feed solution buffer; Tungsten concentrate is leached in pressure cooking kettle 9 at a leaching temperature of 205℃. After holding at this temperature for 2 hours, it is filtered by plate and frame filter press 1. 100L of the filtered extraction solution is introduced into an empty reaction kettle 2. The reaction kettle 2 is started to heat the solution to 96℃, and stirring is started at a speed of 200r / min. The solution is stirred for 10 minutes to make it uniformly mixed. The initial Si content is sampled and tested: WO3 content in the solution is 120g / L, Mo content is 14g / L, and Si content is 3.5g / L. S2: pH adjustment of the feed solution; by adding sulfuric acid with a mass concentration of 98% through the pH adjustment unit, the pH value of the feed solution is quickly reduced to below 10, and then the pH value of the feed solution is stabilized at 9.5 by adding liquid alkali. S3: CO2 aeration reaction; Open the flow regulating valve 4 to introduce CO2 from the CO2 storage tank 3 into the reaction vessel 2. The aeration flow rate is dynamically adjusted according to the volume of the liquid, with a CO2 flow rate of 1.5 L / min per liter of liquid and a reaction time of 1.5 h. S4: Settle and settle; turn off CO2 ventilation and stirring of reactor 2, keep the temperature control unit running, and let the liquid stand at 99℃ for 3 hours to allow sodium silicate to fully precipitate; S5: Solid-liquid separation; The settled liquid is introduced into the solid-liquid separation unit 8 for pressure filtration separation, the sodium silicate precipitate is removed by filtration, and the filtrate is the desiliconized extraction liquid. S6: Subsequent transport; if the Si content in the feed solution is detected to be 0.5 g / L, the desiliconized extract solution is sent to the alkaline extraction section through a pipeline.

[0020] The parts of this invention not described in detail are prior art.

[0021] The embodiments selected herein for the purpose of disclosing the inventive objectives are currently considered suitable; however, it should be understood that the invention is intended to include all variations and modifications of the embodiments that fall within the scope of this concept and invention.

Claims

1. A system for removing silicon from tungsten-molybdenum extraction solutions using carbon dioxide, characterized in that: It includes a pressure cooking liquid buffer unit, a pH adjustment unit, a CO2 aeration reaction unit, and a solid-liquid separation unit; The pressure cooking liquid buffer unit includes a plate and frame filter press and a reaction vessel, with the outlet of the plate and frame filter press connected to the inlet of the reaction vessel via a pipeline. The pH adjustment unit includes a sulfuric acid storage tank, a liquid alkali storage tank, and an online pH meter. The sulfuric acid storage tank and the liquid alkali storage tank are connected to the reaction vessel via a metering pump. The online pH meter is installed on the reaction vessel to monitor the pH value of the liquid in the reaction vessel in real time and control the adjustment accuracy to ±0.

1. The CO2 venting reaction unit includes a CO2 storage tank, a flow regulating valve, and a perforated venting coil; the outlet of the CO2 storage tank is connected to the bottom of the reactor through the perforated venting coil, and the flow regulating valve is installed on the perforated venting coil. The solid-liquid separation unit is connected to the outlet of the reaction vessel via a pipeline. The solid-liquid separation unit is a plate and frame filter press or a vacuum filter.

2. A method for removing silicon from tungsten-molybdenum extraction solution using carbon dioxide, characterized in that: The specific steps are as follows: S1: Feed liquid buffer; After the tungsten concentrate is boiled, it is filtered by a plate and frame filter press. The filtered extraction liquid is introduced into an empty reactor. The reactor is started to heat the liquid to 90-100℃, and the stirring is started at a speed of 150-200r / min to mix the liquid evenly. The initial Si content is sampled and tested: WO3 content in the liquid is 90-120g / L, Mo content is 8-15g / L, and Si content is ≥2g / L. S2: pH adjustment of the feed solution; by adding liquid alkali or sulfuric acid dropwise through the pH adjustment unit, the pH value of the feed solution is stabilized between 9 and 10; S3: CO2 aeration reaction; Open the flow regulating valve to introduce CO2 from the CO2 storage tank into the reactor. The aeration flow rate is dynamically adjusted according to the volume of the liquid. The CO2 flow rate corresponding to each liter of liquid is 0.5-2.0 L / min, and the aeration reaction time is 0.5-2 h. S4: Settle and settle; turn off CO2 ventilation and reactor stirring, and run the reactor temperature control unit to let the liquid stand at 90-100℃ for 1-3 hours to allow sodium silicate to fully precipitate. S5: Solid-liquid separation; The settled liquid is introduced into the solid-liquid separation unit, filtered to remove sodium silicate precipitate, and the filtrate is collected as the desiliconized extraction liquid. S6: Subsequent transport; when the Si content in the feed liquid is reduced to ≤0.8g / L, the desiliconized feed liquid is sent to the alkaline extraction section through a pipeline.

3. The method for removing silicon from tungsten-molybdenum extraction solution using carbon dioxide according to claim 2, characterized in that: In step S3, the CO2 aeration flow rate is dynamically adjusted according to the volume of the liquid, with a CO2 flow rate of 0.8-1.5 L / min per liter of liquid.

4. The method for removing silicon from tungsten-molybdenum extraction solution using carbon dioxide according to claim 2, characterized in that: In step S3, the reaction time is positively correlated with the initial Si content. When the initial Si content is 2-3 g / L, the reaction time is 0.5-1 h, and when the initial Si content is >3 g / L, the reaction time is 1-2 h.

5. The method for removing silicon from tungsten-molybdenum extraction solution using carbon dioxide according to claim 2, characterized in that: The sulfuric acid used in step S2 has a mass concentration of 95%-98%, the liquid alkali has a mass concentration of 30%-32%, and the dropping rate is automatically controlled by an online pH meter signal.

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