A method for dissolving tantalum-niobium ore by removing impurities with dilute sulfuric acid and then adding hydrofluoric acid

Abstract

The present invention relates to a method for dissolving tantalum-niobium ore by adding hydrofluoric acid after removing impurities with dilute sulfuric acid, comprising: soaking the tantalum-niobium ore with sulfuric acid, and then adding hydrofluoric acid to soak the tantalum-niobium ore for dissolving the ore. By first adding dilute sulfuric acid to dissolve the tantalum-niobium ore, some metal oxides therein are first dissolved in the dilute sulfuric acid, thereby reducing the subsequent acid consumption of hydrofluoric acid. In the prior art, only hydrofluoric acid is used to dissolve the ore, and the mass ratio of hydrofluoric acid to tantalum-niobium ore is (1.2-1.5):1. Compared with dissolving with hydrofluoric acid alone, the method of the present invention can save 30-50% of hydrofluoric acid, greatly reducing the production cost. At the same time, due to the reduction in the amount of hydrofluoric acid used, the toxic waste gas generated in the production process is also reduced, reducing pollution; by first adding dilute sulfuric acid, the ore powder is formed into an emulsion under stirring, which is convenient for subsequent acid addition reaction, and the dissolution and reaction are more sufficient, so that the tantalum-niobium leaching rate is above 99%.

Description

Technical Field

[0001] The invention belongs to the technical field of tantalum-niobium metal production, and specifically relates to a method for dissolving tantalum-niobium ore by adding hydrofluoric acid after removing impurities with dilute sulfuric acid. Background Art

[0002] Niobium and tantalum are in the VB group of the periodic table, and their properties are very similar. They are rare and insoluble metals with a wide range of uses. Niobium and tantalum have excellent properties such as high strength, corrosion resistance, thermal conductivity, superconductivity, unipolar conductivity and gas absorption; they have advantages such as good cold processing performance and good electrical properties of oxide films, and are widely used in metallurgy, machinery, chemicals, ceramics, glass and building materials, especially in the military and aerospace fields.

[0003] There are three main methods for decomposing tantalum-niobium concentrate in industry: alkaline decomposition, acid decomposition and chlorination decomposition. In addition, there are fluorination decomposition and electrolytic decomposition. Large-scale industrial production generally adopts acid decomposition. High-grade concentrate is difficult to dissolve in conventional inorganic acids and can only be dissolved with hydrofluoric acid. Therefore, the amount of hydrofluoric acid used in the tantalum-niobium ore dissolution process is very large, resulting in high costs and generating more hydrofluoric acid waste gas. In order to reduce the amount of hydrofluoric acid used and reduce the cost of dissolution, a new dissolution method needs to be proposed. Summary of the invention

[0004] In order to reduce the amount of hydrofluoric acid used in the tantalum-niobium ore dissolution process and reduce the dissolution cost, the present invention proposes a method for dissolving tantalum-niobium ore by adding hydrofluoric acid after removing impurities with dilute sulfuric acid, which can reduce the amount of hydrofluoric acid used by 30%-50% and greatly save costs.

[0005] To achieve the above purpose, the specific technical scheme adopted by the present invention is: a method of removing impurities with dilute sulfuric acid and then adding hydrofluoric acid to dissolve the ore, comprising: soaking tantalum-niobium ore with sulfuric acid, and then adding hydrofluoric acid to soak the tantalum-niobium ore to dissolve the ore.

[0006] Furthermore, the time for soaking the tantalum-niobium ore in sulfuric acid is 20-50 minutes.

[0007] Furthermore, the concentration of the sulfuric acid is 1-5 mol / L.

[0008] Furthermore, the mass ratio of the sulfuric acid to the tantalum-niobium ore is (0.1-0.2):1.

[0009] Furthermore, the mass ratio of the hydrofluoric acid to the tantalum-niobium ore is (0.6-1):1.

[0010] Furthermore, the concentration of the hydrofluoric acid is 2-6 mol / L.

[0011] Furthermore, during the ore dissolution process, the solution temperature is controlled to be ≤90°C.

[0012] Furthermore, stirring is performed during the soaking process, and the stirring speed is controlled to be 100-300 r / min.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] The present invention first adds dilute sulfuric acid to dissolve the tantalum-niobium ore, so that some metal oxides therein are first dissolved in the dilute sulfuric acid, thereby reducing the subsequent acid consumption of hydrofluoric acid. In the prior art, only hydrofluoric acid is used to dissolve the ore, and the mass ratio of hydrofluoric acid to tantalum-niobium ore is (1.2-1.5):1. Compared with dissolving with only hydrofluoric acid, the method of the present invention can save 30-50% of hydrofluoric acid, greatly reducing the production cost. At the same time, due to the reduced amount of hydrofluoric acid, the toxic waste gas generated in the production process is also reduced, reducing pollution;

[0015] By first adding dilute sulfuric acid, the mineral powder is made emulsified under stirring, which is convenient for the subsequent acid addition reaction, and the dissolution and reaction are more complete, so that the tantalum niobium leaching rate is above 99%; at the same time, it makes the reaction more gentle and the safety factor higher. DETAILED DESCRIPTION

[0016] The present invention is described in detail below through specific examples. Those skilled in the art will appreciate that these examples are only used to illustrate the present invention and do not limit the scope of the present invention in any way.

[0017] Example 1

[0018] A method for dissolving ore by adding hydrofluoric acid after removing impurities with dilute sulfuric acid comprises: preparing dilute sulfuric acid with a concentration of 3 mol / L in a decomposition tank, pouring tantalum-niobium ore into the tank, and the mass ratio of sulfuric acid to tantalum-niobium ore being 0.15:1.

[0019] The tantalum-niobium ore is soaked in dilute sulfuric acid for 30 minutes, and then hydrofluoric acid with a concentration of 3 mol / L is added to soak the tantalum-niobium ore for dissolution; the mass ratio of hydrofluoric acid to tantalum-niobium ore is 0.8:1.

[0020] During the ore dissolution process, the solution temperature is controlled to be ≤90°C. During the immersion process, stirring is continued at a speed of 100r / min to make the ore powder emulsified.

[0021] According to ICP-AES analysis, the leaching rates of tantalum and niobium in the tantalum-niobium ore are 99.2% and 99.5% respectively.

[0022] Example 2

[0023] A method for dissolving ore by adding hydrofluoric acid after removing impurities with dilute sulfuric acid comprises: preparing dilute sulfuric acid with a concentration of 5 mol / L in a decomposition tank, pouring tantalum-niobium ore into the solution, wherein the mass ratio of sulfuric acid to tantalum-niobium ore is 0.1:1.

[0024] The tantalum-niobium ore is soaked in dilute sulfuric acid for 40 minutes, and then hydrofluoric acid with a concentration of 2 mol / L is added to soak the tantalum-niobium ore for dissolution; the mass ratio of hydrofluoric acid to tantalum-niobium ore is 1:1.

[0025] During the ore dissolution process, the solution temperature is controlled to be ≤90°C. During the immersion process, stirring is continued at a speed of 200r / min to make the ore powder emulsified.

[0026] According to ICP-AES analysis, the leaching rates of tantalum and niobium in the tantalum-niobium ore are 99.1% and 99.2% respectively.

[0027] Example 3

[0028] A method for dissolving ore by adding hydrofluoric acid after removing impurities with dilute sulfuric acid comprises: preparing dilute sulfuric acid with a concentration of 1 mol / L in a decomposition tank, pouring tantalum-niobium ore into the decomposition tank, and the mass ratio of sulfuric acid to tantalum-niobium ore being 0.18:1.

[0029] The tantalum-niobium ore is soaked in dilute sulfuric acid for 20 minutes, and then hydrofluoric acid with a concentration of 5 mol / L is added to soak the tantalum-niobium ore for dissolution; the mass ratio of hydrofluoric acid to tantalum-niobium ore is 0.6:1.

[0030] During the ore dissolution process, the solution temperature is controlled to be ≤90°C. During the immersion process, stirring is continued at a speed of 150r / min to make the ore powder emulsified.

[0031] According to ICP-AES analysis, the leaching rates of tantalum and niobium in the tantalum-niobium ore are 99.0% and 99.1% respectively.

[0032] Example 4

[0033] A method for dissolving ore by adding hydrofluoric acid after removing impurities with dilute sulfuric acid comprises: preparing dilute sulfuric acid with a concentration of 4 mol / L in a decomposition tank, pouring tantalum-niobium ore into the solution, wherein the mass ratio of sulfuric acid to tantalum-niobium ore is 0.2:1.

[0034] The tantalum-niobium ore is soaked in dilute sulfuric acid for 50 minutes, and then hydrofluoric acid with a concentration of 4 mol / L is added to soak the tantalum-niobium ore for dissolution; the mass ratio of hydrofluoric acid to tantalum-niobium ore is 0.9:1.

[0035] During the ore dissolution process, the solution temperature is controlled to be ≤90°C. During the immersion process, stirring is continued at a speed of 300r / min to make the ore powder emulsified.

[0036] According to ICP-AES analysis, the leaching rates of tantalum and niobium in the tantalum-niobium ore are 99.3% and 99.5% respectively.

[0037] The present invention achieves a higher tantalum and niobium leaching rate (more than 99%) by first adding dilute sulfuric acid to remove impurities and then adding hydrofluoric acid to dissolve the ore. At the same time, the amount of hydrofluoric acid used is greatly reduced. Ordinary industrial sulfuric acid can be directly used to dissolve the ore. The cost of each ton of industrial sulfuric acid is only about 5% of that of hydrofluoric acid. While ensuring the leaching effect, the production cost is greatly reduced, and the process flow is simple.

Claims

1. A method for dissolving tantalum-niobium ore by removing impurities with dilute sulfuric acid and then adding hydrofluoric acid, characterized in that: include: Tantalum-niobium ore is soaked in sulfuric acid, and then hydrofluoric acid is added to soak the tantalum-niobium ore to dissolve the ore; the mass ratio of the hydrofluoric acid to the tantalum-niobium ore is (0.6-1):1, and the mass ratio of the sulfuric acid to the tantalum-niobium ore is (0.1-0.2):1; the concentration of the sulfuric acid is 1-5 mol / L, and the concentration of the hydrofluoric acid is 2-6 mol / L.

2. The method of claim 1, wherein the dilute sulfuric acid is used to remove impurities and then the hydrofluoric acid is added to dissolve the tantalum-niobium ore, characterized in that: The time for soaking the tantalum-niobium ore in sulfuric acid is 20-50 minutes.

3. The method of claim 1, wherein the dilute sulfuric acid is used to remove impurities and then the hydrofluoric acid is added to dissolve the tantalum-niobium ore, characterized in that: During the ore dissolution process, the solution temperature is controlled to be ≤90°C.

4. The method of claim 1, wherein the dilute sulfuric acid is used to remove impurities and then the hydrofluoric acid is added to dissolve the tantalum-niobium ore, characterized in that: Stirring is performed during the soaking process, and the stirring speed is controlled to be 100-300 r / min.