A method for controlling the feeding mode of tantalum-niobium concentrate leaching

Abstract

This invention discloses a method for controlling the feeding mode in the leaching of tantalum-niobium concentrate, relating to the field of tantalum-niobium hydrometallurgical technology. Addressing the problems of high volatilization, high acid consumption, and acid mist pollution caused by the single addition of HF in existing tantalum-niobium concentrate leaching processes, this invention controls the addition mode of acid solution and tantalum-niobium concentrate during the leaching process, adding HF and tantalum-niobium concentrate in multiple stages to achieve a coupling match of the required HF amount for the reaction. This invention effectively limits the concentration of free HF in the system and reduces its high-temperature residence time, significantly reducing HF volatilization and the formation of fluorinated acid mist, effectively reducing acid consumption, production costs, and environmental pressure, while increasing the tantalum-niobium leaching rate under the same acid consumption conditions.

Description

Technical Field

[0001] This invention relates to the field of hydrometallurgical technology, and more specifically, to a method for controlling the feeding mode of tantalum-niobium concentrate leaching. Background Technology

[0002] Tantalum and niobium are elements in the same group, with similar and stable chemical properties. They have advantages such as high melting point, high ductility, and excellent electrical and thermal conductivity, and play an important role in aerospace, weaponry, precision electronic components, medical devices and other fields.

[0003] Currently, conventional hydrometallurgical methods for tantalum and niobium, both domestically and internationally, involve leaching valuable metals from ores using high-concentration hydrofluoric acid (mass concentration >60%) or a mixture of high-concentration hydrofluoric acid (HF) and concentrated sulfuric acid (H2SO4). Further extraction, crystallization, and precipitation are then used to obtain K2TaF7 or Ta2O5, providing raw material support for subsequent pyrometallurgical reduction processes. However, this process faces significant challenges in actual production, including severe HF volatilization and the generation of fluoroacid mist, resulting in substantial environmental pressure on subsequent treatment processes. Traditional concentrate leaching typically involves adding all metered acid solution at once, followed by batch leaching of the ore. Because a large amount of HF remains at high temperatures for extended periods, and its concentration remains high even after mixing with sulfuric acid, significant HF volatilization occurs. Data indicates that HF ​​volatilization losses in traditional methods are approximately 10%, which not only significantly increases acid consumption and production costs during leaching but also creates substantial environmental pressure due to the formation of fluoroacid mist, severely hindering the green transformation and development of the tantalum and niobium industry. Summary of the Invention

[0004] To address the shortcomings of existing technologies in the leaching process of tantalum and niobium concentrate, such as the one-time addition of industrial HF leading to prolonged high-temperature residence time, high HF volatilization, and environmental pressure due to acid mist formation, the present invention aims to provide a method for controlling the feeding mode in the leaching of tantalum and niobium concentrate. By controlling the acid and ore addition mode during the leaching process, HF is added in multiple stages to achieve a coupling and matching of the amount of HF required for the reaction, thereby reducing the high-temperature residence time of HF, effectively reducing HF acid consumption and acid mist formation, and thus lowering production costs and environmental pressure.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: A method for controlling the feeding mode of tantalum-niobium concentrate leaching includes the following steps: Step a: Using tantalum-niobium concentrate as raw material, ball mill the tantalum-niobium concentrate to a suitable particle size; calculate the total amount of leaching agent to be added based on the content of valuable metals in this batch of tantalum-niobium concentrate and the total amount of ore added; Step b: Add the calculated amounts of sulfuric acid, a portion of hydrofluoric acid, and a portion of tantalum-niobium concentrate to the reactor, and perform water bath heating and stirring; then, add the remaining industrial HF in stages, and add the remaining tantalum-niobium concentrate at regular intervals. The staged addition of HF and tantalum-niobium concentrate is a feeding mode that is coupled and matched according to the reaction consumption phases in the leaching and smelting process.

[0006] Preferably, in step b, the water bath temperature is 60~90℃, the leaching time is 6~9h, and the stirring rate is 300~600rpm.

[0007] Preferably, in step a, the particle size of the tantalum-niobium concentrate after ball milling is 200 mesh.

[0008] Preferably, in step a, the sum of the contents of tantalum oxide and niobium oxide in the tantalum-niobium concentrate, i.e., the mass fraction of (Ta2O5+Nb2O5), is 20%~60%.

[0009] Preferably, the leaching agent calculated in step a is a mixed acid of industrial HF and industrial H2SO4; wherein the mass concentration of the industrial HF is 40%~60%, and its molar concentration is 22.6mol / L~36.0mol / L; the mass concentration of the industrial H2SO4 is 98%, and its molar concentration is 18.4mol / L.

[0010] Preferably, in step b, the remaining tantalum-niobium concentrate is added in batches at regular intervals every 10 minutes, with the same amount added each time.

[0011] Preferably, in step b, the initial amount of hydrofluoric acid added accounts for 50% of the total amount of hydrofluoric acid added, and the remaining hydrofluoric acid is added to the reactor in equal or decreasing amounts in 2 to 4 stages within 90 minutes after the start of the reaction.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention changes the traditional method of adding HF all at once. By using a segmented HF addition mode and coupling it with the timed addition of ore and the leaching process, the amount of HF volatilization can be significantly reduced, the tantalum and niobium leaching rate can be increased, and thus the HF acid consumption can be reduced.

[0013] 2. By limiting the concentration of free HF in the system and the high-temperature residence time, this invention can effectively suppress the formation of fluorinated acid mist and reduce the environmental pressure of acid mist treatment.

[0014] 3. Under the same acid consumption conditions, the present invention can improve the leaching rate and effectively reduce the production cost of the wet leaching process of tantalum and niobium. Attached Figure Description

[0015] Figure 1This is a schematic diagram showing the changes in acid addition and feeding mode during leaching of tantalum-niobium concentrate in Example 1 of the present invention over time. Figure 2 This is a schematic diagram showing the changes in the acid addition and feeding mode of tantalum-niobium concentrate leaching over time in Example 2 of the present invention; Figure 3 This is a schematic diagram showing the changes in the acid addition and feeding mode of tantalum-niobium concentrate leaching over time in Example 3 of the present invention. Detailed Implementation

[0016] The present invention will be further described in detail below through specific embodiments. Those skilled in the art will understand that the following embodiments are for illustrative purposes only and do not limit the scope of protection of the present invention in any way.

[0017] Example 1

[0018] Tantalum-niobium concentrate from a certain region was selected as raw material. Its Ta₂O₅ content was determined to be 10.36 wt%, and its Nb₂O₅ content to be 13.80 wt%. The tantalum-niobium concentrate was ball-milled to a particle size of 200 mesh. The total amount of tantalum-niobium concentrate added in this batch was set at 100 g. The calculated total amount of leaching agent required was: 200 ml of 55% industrial HF and 55 ml of 98% concentrated H₂SO₄.

[0019] The specific acid and feed addition process is as follows: First, add 55 ml of concentrated sulfuric acid, 100 ml of industrial HF, and 10 g of tantalum-niobium concentrate to the reactor. Keep the reactor at 80°C in a water bath for 6 hours, with the stirring speed set to 300 rpm. Then, start the staged feed addition: at 30 min and 60 min of reaction, add 50 ml of 55% industrial HF to the reactor respectively; in the first 90 min after the start of the reaction, add 10 g of tantalum-niobium concentrate to the reactor every 10 min until all 100 g of concentrate has been added.

[0020] After 6 hours of heat treatment and leaching, the samples were filtered and dried. Testing showed that the leaching rates of tantalum and niobium were 96.4% and 96.9%, respectively; the volatilization of 55% HF was determined to be 24.0 ml using the gas absorption method. Compared with the traditional one-time HF addition method, the leaching rates of tantalum and niobium increased by 1.2% and 1.1%, respectively, while the HF volatilization decreased by 20%.

[0021] Example 2

[0022] The same tantalum-niobium concentrate raw material as in Example 1 (Ta₂O₅ 10.36wt%, Nb₂O₅ 13.80wt%) was used and ball-milled to 200 mesh. The total amount of concentrate added was 100g, and the total amount of leaching agent added was calculated to be: 55% HF 200 ml, 98% H₂SO₄ 55 ml.

[0023] The specific acid and feed addition process is as follows: First, add 55 ml of concentrated sulfuric acid, 100 ml of industrial HF, and 10 g of tantalum-niobium concentrate to the reactor. Maintain the reactor in a water bath at 80°C for 6 hours, with the stirring speed set to 300 rpm. Then, begin staged feeding: at 30 min, 60 min, and 90 min of reaction time, add 50 ml, 25 ml, and 25 ml of 55% industrial HF to the reactor, respectively. After the reaction begins, add 10 g of tantalum-niobium concentrate to the reactor every 10 min until the reactor is filled with the remaining 90 g of concentrate.

[0024] After leaching, the leaching was completed and then filtered and dried. Testing showed that the leaching rates of tantalum and niobium were 97.5% and 97.6%, respectively; the volatilization of 55% HF was measured to be 23.1 ml. Compared with the traditional one-time addition method, the leaching rates of tantalum and niobium increased by 2.3% and 1.8%, respectively, while the HF volatilization decreased by 23%.

[0025] Example 3

[0026] The same tantalum-niobium concentrate raw material as in Example 1 was selected and ball-milled to 200 mesh. The total amount of concentrate added was 100g, and the total amount of leaching agent added was 200 ml of 55% HF and 55 ml of 98% H2SO4.

[0027] The specific acid and feed addition process is as follows: First, add 55 ml of concentrated sulfuric acid, 100 ml of industrial HF, and 10 g of tantalum-niobium concentrate to the reactor. Maintain the mixture in a water bath at 80°C for 6 hours with a stirring speed of 300 rpm. Subsequently, add 30 ml, 25 ml, 25 ml, and 20 ml of 55% industrial HF to the reactor at 30 min, 60 min, 80 min, and 90 min, respectively. The tantalum-niobium concentrate is also added in batches at a frequency of 10 g every 10 min.

[0028] After leaching, the leaching was completed and then filtered and dried. Testing showed that the leaching rates of tantalum and niobium were 98.1% and 98.5%, respectively; the volatilization of 55% HF was measured to be 22.1 ml. Compared with the traditional one-time addition method, the leaching rates of tantalum and niobium increased by 2.9% and 2.7%, respectively, while the HF volatilization decreased by 26%.

Claims

1. A method for controlling the feeding mode in leaching tantalum-niobium concentrate, characterized in that, Includes the following steps: Step a: Using tantalum-niobium concentrate as raw material, the tantalum-niobium concentrate is ball-milled, and the total amount of hydrofluoric acid and sulfuric acid required for this batch of leaching agent is calculated based on the effective component content of the tantalum-niobium concentrate and the total amount added in a single batch. Step b: Add all of the sulfuric acid, part of the hydrofluoric acid, and part of the tantalum-niobium concentrate to the reactor, and perform water bath heating and stirring; During the heat preservation reaction, the remaining hydrofluoric acid is added in a segmented manner, and the remaining tantalum-niobium concentrate is added in batches at regular intervals for leaching reaction.

2. The method for controlling the feeding mode of tantalum-niobium concentrate leaching according to claim 1, characterized in that: The segmented addition of HF and tantalum-niobium concentrate is a feeding mode that corresponds to the smelting conditions.

3. The method for controlling the feeding mode of tantalum-niobium concentrate leaching according to claim 1, characterized in that: In step b, the water bath temperature is 60~90℃, the leaching time is 6~9h, and the stirring rate is 300~600rpm.

4. The method for controlling the feeding mode of tantalum-niobium concentrate leaching according to claim 1, characterized in that: In step a, the particle size of the tantalum-niobium concentrate after ball milling is 200 mesh.

5. The method for controlling the feeding mode of tantalum-niobium concentrate leaching according to claim 1, characterized in that: In step a, the sum of the contents of tantalum oxide and niobium oxide in the tantalum-niobium concentrate, i.e., the mass fraction of (Ta2O5+Nb2O5), is 20%~60%.

6. The method for controlling the feeding mode of tantalum-niobium concentrate leaching according to claim 1, characterized in that: The leaching agent calculated in step a is a mixed acid of industrial HF and industrial H2SO4; wherein the mass concentration of the industrial HF is 40%~60%, and its molar concentration is 22.6mol / L~36.0mol / L; the mass concentration of the industrial H2SO4 is 98%, and its molar concentration is 18.4mol / L.

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