Method of metal recovery

A recovery method and metal technology, applied in chemical instruments and methods, improvement of process efficiency, control of water treatment parameters, etc., can solve problems such as washing liquid waste

Inactive Publication Date: 2005-08-24
CABOT SUPERMETALS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] However, if the agglomerate is washed in this way, there is a problem that part of tantalum and niobium dissolves in the washing liquid in the form of a water-soluble compound and is discarded together with the washing liquid.
[0006] In addition, in the past, such a method for effectively recovering dissolved tantalum and niobium compounds has not been found. For the recovery of other metals, such as heavy metals, only research on the pH of aqueous waste liquids has been carried out (for example, refer to Japanese Patent Application No. 2002-80915 Bulletin)

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] The tantalum raw material compound and the reducing agent are put into the diluted salt heated to about 870°C and in a molten state, and the reduction reaction is carried out. Here, the K 2 TaF 7 It is used as a tantalum raw material compound, KF is used as a diluent salt, and Na is used as a reducing agent.

[0048] After the reduction reaction is finished, the molten reaction solution in the molten state is cooled, and the prepared agglomerate is firstly washed with water. The wastewater prepared here is referred to as the first wastewater. Next, washing was performed with 3% hydrofluoric acid. The wastewater prepared here is referred to as the second wastewater. Then wash with 1.5% hydrogen peroxide water and 9% nitric acid. The wastewater prepared here is referred to as the third wastewater.

[0049] The first wastewater was analyzed by ICP. In terms of metal, the first wastewater contained 610 ppm of tantalum and / or tantalum compounds, but the dissolved tanta...

Embodiment 2～3

[0055] About 1st waste water and 2nd waste water, it processed similarly to Example 1.

[0056] On the other hand, in addition to changing the amount of the pH adjustment solution and the oxidation-reduction potential adjustment solution added to the third wastewater, and making the pH and oxidation-reduction potential of the third wastewater the values ​​shown in Table 1, the same as in Example 1 The 3rd waste water was processed similarly.

[0057] Moreover, the 1st waste water, the 2nd waste water, and the 3rd waste water were mixed similarly to Example 1, and this was recovered by membrane processing. As a result, 95% (in terms of metal) of tantalum and / or tantalum compounds contained in the first wastewater, the second wastewater, and the third wastewater could be recovered.

Embodiment 4～13

[0064] About 1st waste water and 2nd waste water, it processed similarly to Example 1.

[0065] On the other hand, instead of adding the pH adjustment solution to the third wastewater, only the oxidation-reduction potential adjustment solution was added, and the amount was appropriately changed so that the pH and oxidation-reduction potential of the third wastewater were the values ​​shown in Tables 2 to 3. The third wastewater was treated in the same manner as in Example 1.

[0066] Moreover, the 1st waste water, the 2nd waste water, and the 3rd waste water were mixed similarly to Example 1, and this was recovered by membrane processing. As a result, 99% (in terms of metal) of tantalum and / or tantalum compounds contained in the first waste water, the second waste water, and the third waste water could be recovered.

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Abstract

A method by which tantalum compounds and niobium compounds dissolved in water such as a liquid detergent are insolubilized and recovered. An aqueous solution containing tantalum compounds and/or niobium compounds dissolved therein is regulated so as to have a pH and an oxidation-reduction potential E which satisfy E<60x(10-pH) to thereby insolubilize the tantalum compounds and/or niobium compounds. The tantalum compounds and/or niobium compounds thus insolubilized are recovered through a membrane treatment. Thus, the metal compounds can be more effectively recovered. This method is especially suitable for use in the treatment of a wastewater generated in the production of a tantalum powder or niobium powder through the reduction of a raw tantalum compound and/or raw niobium compound in a diluting salt.

Description

technical field [0001] The present invention relates to a method of recovering insoluble tantalum compounds and niobium compounds having high solubility in water. Background technique [0002] Solid electrolytic capacitors having a cathode electrode made of tantalum are rapidly spreading as parts of mobile phones, word processors, and the like because of their small size, low ESR, and high capacity. In addition, niobium, which is a congener element of tantalum, is less expensive than tantalum, and niobium oxide has a large dielectric constant, so its use in cathode electrodes has been studied. The cathode electrode is formed by sintering tantalum powder and niobium powder to form a porous sintered body, and aging and oxidizing the porous sintered body. [0003] The tantalum powder and niobium powder used as cathode electrode raw materials as described above are prepared by reducing raw material compounds such as tantalum salt, niobium salt, etc., with sodium, etc. After th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D61/16C02F1/44C02F1/66C02F1/70C22B3/44C22B7/00C22B9/02C22B34/20C22B34/24
CPCC02F2101/10C22B3/44C02F1/66B01D61/147C02F2209/04B01D61/16C02F1/444B01D61/145B01D2311/04C22B34/20C22B7/006Y02P10/20B01D2311/18B01D2311/2684
Inventor 守屋则雄松川寿
Owner CABOT SUPERMETALS
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