Method for producing sodium tungstate, method for collecting tungsten, apparatus for producing sodium tungstate, and method for producing sodium tungstate aqueous solution

Patent metadata

Field	Value
Publication number	US-9249479-B2
Application number	US-201314139598-A
Country	US
Kind code	B2
Filing date	Dec 23, 2013
Priority date	Mar 11, 2009
Publication date	Feb 2, 2016
Grant date	Feb 2, 2016

Abstract

Provided are a method for producing sodium tungstate by supplying an oxidant made of sodium nitrate or sodium nitrite to bring a tungsten containing material and the oxidant into contact with each other in an atmosphere containing oxygen to thereby continuously produce a reaction product; a method for collecting tungsten using the method; and an apparatus for producing sodium tungstate. Also provided are a method for producing a sodium tungstate aqueous solution in which a reductant is introduced into a melt containing the above-described reaction product which is then dissolved in water; and a method for collecting tungsten using the method.

First claim

The invention claimed is:

1. A method for producing a sodium tungstate aqueous solution, said method comprising the steps of:
introducing a reductant into a melt containing a reaction product obtained by heating at least one of a tungsten containing material and an oxidant made of one of sodium nitrate and sodium nitrite to cause a reaction between said oxidant and said tungsten containing material; and
dissolving, in water, the melt into which said reductant was introduced,
wherein the reductant is a material that allows a decrease in a valence of metallic elements of an impurity metal in the melt.

2. The method for producing a sodium tungstate aqueous solution according to claim 1 , wherein a temperature of the melt containing said reaction product into which said reductant is introduced is 700° C. or more and 850° C. or less.

3. The method for producing a sodium tungstate aqueous solution according to claim 1 , wherein said reductant includes a soft scrap and a roasted soft scrap.

4. The method for producing a sodium tungstate aqueous solution according to claim 1 , wherein an amount of said reductant to be introduced is 0.05 times or more and 0.45 times or less of a mass of the melt containing said reaction product.

5. The method for producing a sodium tungstate aqueous solution according to claim 1 , wherein an acid is added to an aqueous solution obtained by dissolving said melt in water, to adjust a pH to fall within a range of 8.5 or more and 10 or less.

6. The method for producing a sodium tungstate aqueous solution according to claim 1 , wherein a pressure is applied to the inside of a container containing said melt to cause said melt to be pushed out and introduced into a container containing said water.

Assignees

• Almt Corp
• Sumitomo Elec Hardmetal Corp
• Sumitomo Electric Industries

Inventors

• Yamamoto Yoshiharu
• Sasaya Kazuo
• Fudo Takayuki
• Nakano Akira
• Yamanaka Syunsuke
• Iguchi Takahisa
• Sato Fumiatsu
• Ikegaya Akihiko

Classifications

• C01G23/005

  Alkali titanates · CPC title

• C01G41/003

  Preparation involving a liquid-liquid extraction, an adsorption or an ion-exchange · CPC title

• C01G37/14

  Chromates; Bichromates · CPC title

• C01G41/00

  Compounds of tungsten · CPC title

• Y02W30/54

  Cross-Sectional Technologies · mapped topic