JPS62280331A - Method for recovering au - Google Patents

Abstract

PURPOSE:To recover Au at a high yield from a base body made of a metallic oxide by mixing the recovered material of an electronic material coated with Au on the above-mentioned base body with carbon, and bringing the mixture into contact with gaseous chloride such as phosgene and carbon tetrachloride while heating the mixture. CONSTITUTION:The recovered material of the electronic material such as printed circuit board formed by coating Au on the metallic oxide base body such as alumina, silica or titania is ground and is mixed with the carbon powder. Such mixture 1 is put into a chloridization vessel 4 in which glass fibers 3 are laid on the bottom. Such vessel is heated in an electric furnace to the dissociation temp. or decomposition temp. of the Au chloride or above and 400-1,200 deg.C above the b.p. of the chloride of the metallic component forming the base body. At the same time, gaseous chloride such as phosgene (COCl2), carbon tetrachloride (CCl4) or thionyl chloride (SOCl2) is introduced into the vessel from a gas introducing pipe. The metallic oxide of the base body is evaporated as metallic chloride and is captured by a solid trap 6. The residue in the vessel 4 is subjected to a gravity sepn. to separate the metallic Au from the carbon and unreacted base body material. The Au is thus separated and recovered at a high yield.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Industrial Application Field) The method of the present invention involves a chloridation reaction of Au and a base metal oxide, a dissociation reaction of Au chloride, and a chlorination reaction of the base metal chloride. This relates to a method for recovering Au by performing evaporative separation.

(Prior art and its problems) Ceramic packages in which Au is coated on metal oxide substrates such as titanium, alumina, silica, and chikunia, and printed substrates have been used in large quantities.

Such electronic materials are replaced with new ones when the life of the device or component reaches its end. Also, a large amount of scrap is generated during the manufacturing process.

However, a considerable amount of expensive Au still remains in these materials, and it is industrially important to recover and effectively utilize this.

Conventional methods include aqua regia dissolution, but these methods require a long time for the dissolution step.

In addition, large equipment is required to put the base metal oxide into the liquid, and when separating Au and the base metal, the base metal hydroxide may precipitate, and a large amount of water is required for cleaning. Therefore, it is inefficient and cannot be said to be an industrially optimal recovery method.

(Object of the Invention) The present invention was made in view of the above circumstances, and its purpose is to provide a method for simply and efficiently recovering Au from a material in which Au is retained in a base metal oxide. .

(Structure of the Invention) The Au recovery method of the present invention involves heating a recovered material containing Au and a base metal oxide, or a mixture thereof with carbon, while recovering phosgene (2 in COC), carbon tetrachloride (CC7!4), etc.
, thionyl chloride (SOCZ□), sulfuric chloride (Sz
Cj! By flowing a chlorine compound gas such as Characterized by evaporating substances.

In chloridation, a recovered material containing Au and a base metal oxide, or a mixture of it and carbon is heated and a chlorine compound gas such as phosgene, carbon tetrachloride, thionyl chloride, or sulfuric acid chloride is passed through the material to convert the Au into chlorides. The base metal oxide turns into chloride, but if the recovered material is in excess of the amount of chlorine, the gas will almost completely react and the partial pressure of chlorine will become extremely small, causing the AU chloride to easily undergo a dissociation reaction and convert into metal Au. become.

Generally used base metal oxides do not easily undergo dissociation reactions, and it is easy to maintain the chlorine partial pressure such that the dissociation temperature of Au chloride is higher than the boiling point of the base metal chloride. Chloride can be transported out of the reaction system as a gas phase.

The temperature of the reaction part is preferably 400°C or higher. This is because the chlorination reaction is difficult to occur at temperatures lower than this.

Further, at temperatures higher than 1200° C., expensive high-temperature equipment is required.

The properties of Au and typical chlorides of the base metal are as follows.

AuCl3 Dissociated chlorine pressure 16.4mm11g/1
70℃ 〃 19
9.3 Sodium mHg/240 °C AlCl3 Dissociated chlorine pressure 46.7 DragonHg/170'C〃 397.2
mmHg/240℃Al2CN, sublimation point 182
．． 7℃TiC7! , boiling point 136.4℃Zr C1a 331℃S i C14
〃 57.57℃TaCffa
242℃S n Cla 〃
Below 114.1°C Examples and conventional examples will be described based on the drawings.

(Example 1) 6 kg of material containing Au on alumina (1% Au
) was pulverized and mixed with 1060 g of carbon powder, and as shown in the figure, this mixture 1 was placed in a chloride container 4 equipped with a glass fiber 3 at the bottom, and the chloride container 4 was heated in an electric furnace 2.
was heated to 1000° C., and CC7!4 (carbon tetrachloride) gas was flowed through the gas introduction pipe 5 at 5 f/min to evaporate the base metal oxide into chloride, which was captured by the solid trap 6.

After continuing this for 6 hours, the remaining material was taken out and the unreacted material and carposi powder were separated by specific gravity separation to recover the metal Au powder.The purity of Au was over 99% and the recovery rate was 99%.
% or more.

(Example 2) 3 kg of material containing Au on alumina (1% Au
) was pulverized and the collected material 1 was placed in a chloride container 4 equipped with glass fiber 3 at the bottom as shown in the figure, and the chloride container 4 was heated to 1000°C using an electric furnace 2.
<thionyl chloride) gas from the gas introduction pipe 5 at 5A/mi
The base metal oxide was converted into chloride and evaporated by flowing n, which was captured by the solid trap 6.

After continuing this for 5 hours and 30 minutes, the remaining material was taken out and the unreacted material and carbon powder were separated by specific gravity separation.
When the powder was collected, the purity of Au was 99% or more and the recovery rate was also 99% or more.

(Conventional example) When the above material was recovered by dissolving 3 kg in aqua regia and extracting the Au aqua regia liquid using 'aA, the recovery rate of Au was 95.
%Met.

However, in order to increase the recovery rate, there were problems such as a significant increase in the amount of liquid required for washing during filtration.

(Effects of the Invention) As detailed above, the present invention has higher efficiency (
Since Au can be separated and recovered from the base metal oxide and does not require a multi-stage wet treatment process unlike the conventional method, it is possible to recover the Au economically and in a short time.

[Brief explanation of drawings]

The figure is a schematic diagram of the recovery AM used in the Au recovery method of the present invention. Applicant: Tanaka Kikinzoku Kogyo Co., Ltd.

Claims (3)

[Claims] (1) Oxidation of the base metal by flowing a chlorine compound gas such as phosgene, carbon tetrachloride, thionyl chloride, or sulfuric chloride while heating the recovered material containing Au and the base metal oxide, or a mixture of the recovered material and carbon. An Au recovery method characterized by converting a substance into chloride and separating it by evaporation. (2) The method according to claim 1, wherein the heating temperature is higher than the dissociation or decomposition temperature of the Au chloride and higher than the boiling point of the base metal chloride. (3) The method according to claim 1 or 2, wherein the heating temperature is 400°C to 1200°C.