Method for preprocessing scheelite and preparing ferro-tungsten

Abstract

The invention relates to a method for tungsten hydrometallurgy, in particular to a method for preprocessing scheelite and preparing ferro-tungsten. The method comprises the following steps: preprocessing scheelite with hydrochloric acid and repeatedly utilizing remaining acid to decompose scheelite in an aright device having no pressure; and preprocessing slag to restore melting ferro-tungsten. Compared with the prior art, the method has the advantages as follows: in order to solve the defects in the background art, the closed circuit of hydrochloric acid is utilized to decompose scheelite, thereby reducing the consumption amount of hydrochloric acid and energy consumption, realizing the effective enrichment of CaCl2, reducing the production cost of subsidiary products, and improving the economic benefits of technology; the aright device having no pressure reduces the requirements on leaching equipment, and also reduces the investment of fixed assets; high-qualified ferro-tungsten can be prepared under the hydrogen reduction environment by just mixing iron powder and coarse tungstic acid according to a proper proportion, so that the energy consumption is reduced and the smelting process is simplified.

Description

technical field

[0001] The invention relates to a tungsten hydrometallurgy method, in particular to a method for pretreating scheelite and preparing tungsten-iron alloy. Background technique

[0002] In the prior art, hydrochloric acid decomposes scheelite mainly in an open reactor, adding excess acid, and decomposing the pulp at boiling point temperature and negative pressure ventilation conditions to produce tungstic acid, that is, acid decomposition method. This method consumes a lot of hydrochloric acid, and the negative pressure ventilation also increases the energy loss, consumes a lot of raw and auxiliary materials, causes great environmental pollution, and has low productivity.

[0003] It is also reported that the closed acid decomposition high temperature (≥boiling temperature) pressure treatment method is adopted, such as the Chinese patent CN1177944C disclosed on December 1, 2004, which adopts this method, because it has a certain pressure (0.1-0.6Mpa) , so that...

Examples

Embodiment 1

[0020] Use a 1L reactor to feed 150g tungsten concentrate, -325 mesh accounts for 75%, L / S=4:1, the amount of concentrated hydrochloric acid is 1.5 times the theory (102ml), and stir in a closed container open to the atmosphere for pretreatment 3 hours, filter. Add new ore, measure the amount of acid in the aforementioned filtrate, according to 1.5 times the theoretical acid amount, add insufficient acid, continue leaching, after two cycles, the tungsten concentrate WO 3 The grade is maintained at around 83%. Moreover, after two cycles of leaching, the calcium concentration in the pretreatment solution increased significantly.

[0021] The pretreatment slag is roasted at 500°C for 1 hour to generate crude tungstic acid. The crude tungstic acid and iron powder are mixed according to the Fe:W ratio of 1:4, and transferred to an atmosphere furnace filled with hydrogen for reduction smelting at 1600°C to prepare high-quality ferro-tungsten alloy.

Embodiment 2

[0023] Use a 1L reactor to feed 300g tungsten concentrate, -325 mesh accounts for 85%, L / S=2:1, the amount of concentrated hydrochloric acid is twice the theoretical amount (272ml), stir in a closed container open to the atmosphere for pretreatment 2 hours, filter. Add acid to the filtrate, add new ore, and continue leaching. After three cycles like this, the tungsten concentrate WO 3 The grade was maintained at about 77%, and after three cycles of leaching, the calcium concentration of the pretreatment solution increased to 110g / L.

[0024] The pretreated slag is roasted at 400°C for 2 hours to generate crude tungstic acid. The crude tungstic acid and iron powder are mixed according to the Fe:W ratio of 2:3, and transferred to an atmosphere furnace filled with hydrogen for reduction smelting at 1500°C to prepare high-quality ferro-tungsten alloy.

Embodiment 3

[0026] Use a 1L reactor to feed 300g of tungsten concentrate, -325 mesh 95%, L / S=1:1, the amount of concentrated hydrochloric acid is twice the theoretical amount (272ml), and stir in a closed container open to the atmosphere for 1 hour pretreatment ,filter. Add acid to the filtrate, add new ore, and continue leaching. After two cycles, the tungsten concentrate WO 3 The grade is maintained at around 82%.

[0027] The pretreatment slag is roasted at 500°C for 2 hours to generate crude tungstic acid. The crude tungstic acid and iron powder are mixed according to the Fe:W ratio of 2:3, and transferred to an atmosphere furnace filled with hydrogen for reduction melting at 1600°C to prepare high-quality ferro-tungsten alloy.

technical field

[0001] The invention relates to a tungsten hydrometallurgy method, in particular to a method for pretreating scheelite and preparing tungsten-iron alloy. Background technique

[0002] In the prior art, hydrochloric acid decomposes scheelite mainly in an open reactor, adding excess acid, and decomposing the pulp at boiling point temperature and negative pressure ventilation conditions to produce tungstic acid, that is, acid decomposition method. This method consumes a lot of hydrochloric acid, and the negative pressure ventilation also increases the energy loss, consumes a lot of raw and auxiliary materials, causes great environmental pollution, and has low productivity.

[0003] It is also reported that the closed acid decomposition high temperature (≥boiling temperature) pressure treatment method is adopted, such as the Chinese patent CN1177944C disclosed on December 1, 2004, which adopts this method, because it has a certain pressure (0.1-0.6Mpa) , so that...

Examples

Embodiment 1

[0020] Use a 1L reactor to feed 150g tungsten concentrate, -325 mesh accounts for 75%, L / S=4:1, the amount of concentrated hydrochloric acid is 1.5 times the theory (102ml), and stir in a closed container open to the atmosphere for pretreatment 3 hours, filter. Add new ore, measure the amount of acid in the aforementioned filtrate, according to 1.5 times the theoretical acid amount, add insufficient acid, continue leaching, after two cycles, the tungsten concentrate WO 3 The grade is maintained at around 83%. Moreover, after two cycles of leaching, the calcium concentration in the pretreatment solution increased significantly.

[0021] The pretreatment slag is roasted at 500°C for 1 hour to generate crude tungstic acid. The crude tungstic acid and iron powder are mixed according to the Fe:W ratio of 1:4, and transferred to an atmosphere furnace filled with hydrogen for reduction smelting at 1600°C to prepare high-quality ferro-tungsten alloy.

Embodiment 2

[0023] Use a 1L reactor to feed 300g tungsten concentrate, -325 mesh accounts for 85%, L / S=2:1, the amount of concentrated hydrochloric acid is twice the theoretical amount (272ml), stir in a closed container open to the atmosphere for pretreatment 2 hours, filter. Add acid to the filtrate, add new ore, and continue leaching. After three cycles like this, the tungsten concentrate WO 3 The grade was maintained at about 77%, and after three cycles of leaching, the calcium concentration of the pretreatment solution increased to 110g / L.

[0024] The pretreated slag is roasted at 400°C for 2 hours to generate crude tungstic acid. The crude tungstic acid and iron powder are mixed according to the Fe:W ratio of 2:3, and transferred to an atmosphere furnace filled with hydrogen for reduction smelting at 1500°C to prepare high-quality ferro-tungsten alloy.

Embodiment 3

[0026] Use a 1L reactor to feed 300g of tungsten concentrate, -325 mesh 95%, L / S=1:1, the amount of concentrated hydrochloric acid is twice the theoretical amount (272ml), and stir in a closed container open to the atmosphere for 1 hour pretreatment ,filter. Add acid to the filtrate, add new ore, and continue leaching. After two cycles, the tungsten concentrate WO 3 The grade is maintained at around 82%.

[0027] The pretreatment slag is roasted at 500°C for 2 hours to generate crude tungstic acid. The crude tungstic acid and iron powder are mixed according to the Fe:W ratio of 2:3, and transferred to an atmosphere furnace filled with hydrogen for reduction melting at 1600°C to prepare high-quality ferro-tungsten alloy.