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Method for removing chromium during recycling sodium tungstate from waste tungsten

A technology of sodium tungstate and crude sodium tungstate, applied in chemical instruments and methods, tungsten compounds, inorganic chemistry, etc., can solve problems such as increased sulfate radicals, excessive chromium elements, and unseen problems, achieving simple process flow and low investment The effect of low cost and large processing volume

Active Publication Date: 2009-12-30
XIAMEN TUNGSTEN
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AI Technical Summary

Problems solved by technology

[0003] At present, the main methods of recycling waste cemented carbide include mechanical crushing method, direct electrolysis method, zinc melting method, cold flow method, leaching method and other methods, but most of these methods have immature technology and poor adaptability to industrial production And other shortcomings, can not be well adapted to the recycling of various waste tungsten materials, and the purity of the regenerated tungsten can not fully meet the requirements for the production of high-quality tungsten materials
[0004] At present, the saltpeter (the main component is sodium nitrate) smelting process for recycling waste tungsten is relatively mature and has wide adaptability. Different metal elements can be selected for recycling. Chromium enters the sodium tungstate solution in the form of chromium, which causes the chromium element in the sodium tungstate solution to exceed the standard, which cannot meet the production of high-purity tungsten products
At present, the method of chromium removal basically adopts the method of passing sulfur dioxide and sulfite to reduce hexavalent chromium to trivalent chromium, but it will cause the increase of sulfate. In order to find the ideal removal of impurity element chromium in sodium tungstate solution, a lot According to the research, the inventor has successfully provided a chromium removal method with simple operation, large processing capacity, simple process flow, high chromium removal rate and low input cost, and no relevant research reports have been seen yet.

Method used

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Examples

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example 1

[0016] Waste tungsten is leached out sodium tungstate solution through saltpeter smelting, WO 3 The concentration is 150g / L, the alkali concentration is 20g / L, the chromium concentration is 800mg / L, and the sodium tungstate solution is poured into a volume of 10m 3 In the reaction tank, heat up to 80°C, then add 30kgNaHS, heat and stir the reaction, control the reaction temperature to 80°C, control the pH to 9.5 during the reaction, stir and keep warm for 4 hours, and filter out the chromium residue through a plate and frame filter press. Obtain high-purity sodium tungstate solution, and measure the WO of sodium tungstate solution after chromium removal 3 The concentration is 152g / L, the alkali concentration is 16.2g / L, and the chromium concentration is 0.

example 2

[0018] Waste tungsten is leached out sodium tungstate solution through saltpeter smelting, WO 3 The concentration is 212g / L, the alkali concentration is 10g / L, the chromium concentration is 1600mg / L, and the sodium tungstate solution is poured into a volume of 10m 3 In the reaction tank, heat up to 90°C, then add 50kgKHS, heat and stir the reaction, control the reaction temperature to 85°C, control the pH to 8.5 during the reaction, stir and keep warm for 6 hours, and filter out the chromium residue through a plate and frame filter press. Obtain high-purity sodium tungstate solution, and measure the WO of sodium tungstate solution after chromium removal 3 The concentration is 217g / L, the alkali concentration is 9g / L, and the chromium concentration is 0.1mg / L.

example 3

[0020] Waste tungsten is leached out sodium tungstate solution through saltpeter smelting, WO 3 The concentration is 256g / L, the alkali concentration is 5g / L, the chromium concentration is 3000mg / L, and the sodium tungstate solution is poured into a volume of 10m 3 In the reaction tank, heat up to 75°C, then add 40kgNaHS, heat and stir the reaction, control the reaction temperature to 80°C, control the pH to 8.0 during the reaction, stir and keep warm for 7 hours, and filter out the chromium residue through a plate and frame filter press. Obtain high-purity sodium tungstate solution, and measure the WO of sodium tungstate solution after chromium removal 3 The concentration is 259g / L, the alkali concentration is 5g / L, and the chromium concentration is 0.

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Abstract

The invention discloses a method for removing chromium during recycling sodium tungstate from waste tungsten. The method comprises the following steps of: smelting the waste tungsten saltpeter with saltpeter to leach alkaline coarse sodium tungstate solution; keeping the temperature of the sodium tungstate solution between 60 and 90 DEG C under an alkaline condition; adding a proper amount of precipitating agent into the solution in a ratio of 10m<3> per 10 to 50 Kg; heating the solution and keeping the temperature under a condition of stirring for precipitation reaction; ensuring the pH of the sodium tungstate solution is more than 8.0 in the reaction process; stirring the solution and keeping the temperature for 2 to 10 hours; and finally, filtering the solution to remove chromium slag sediment generated by the reaction, and obtaining the qualified high-purity sodium tungstate solution. The method is simple in operation, large in processing capacity and simple in process flow, achieves a chromium removal rate up to 99 percent and a chromium loss rate less than 0.1 percent, is low in investment cost and suitable for industrialized production, can effectively remove impurity element chromium in the sodium tungstate solution, and meets the requirements of high-quality tungsten products.

Description

technical field [0001] The invention belongs to the technical field of waste tungsten recovery and reuse, and in particular relates to a method for removing chromium from waste tungsten recovery of sodium tungstate. Background technique [0002] With the rapid development of the economy, industries such as machinery manufacturing, geological mining, construction, electronics, military industry and chemical industry have an increasing demand for cemented carbide, especially metal tungsten materials, and various metals that make up cemented carbide materials Most of the elements are rare elements, the grade of tungsten ore in the world is becoming increasingly depleted, the composition is gradually complex, the difficulty of smelting is increasing, and the technical requirements are getting higher and higher. It is increasingly urgent to comprehensively utilize various tungsten resources. Over the years, people in the industry have done a lot of work on the comprehensive util...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01G41/00
Inventor 宋阜苏志宏朱桂容
Owner XIAMEN TUNGSTEN
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