Method for manufacture of a composite copper-arsenic compound mixture
AssigneeSumitomo Metal Mining Co., Ltd.
InventorsNobuo Takahashi, Hirao Toda
Life of this patent
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Abstract
From a refinery's intermediate byproduct composed of a sulfide, oxide or arsenide containing copper and arsenic, a liquid extract containing copper and arsenic at a concentration ratio of not less than 1.0 is obtained. The liquid extract is cooled to a predetermined temperature to achieve solid-liquid phase separation, and the liquid resulting from the phase separation is neutralized to pH 6-7 to isolate copper and arsenic in the form of a composite precipitate. The composite copper-arsenic compound mixture thus obtained has a high purity and low production cost and can be converted through a simple treatment into an effective antiseptic for wood.
Claims13
A method of manufacturing a composite copper-arsenic compound mixture in the form of copper arsenate and copper hydroxide, said composite copper-arsenic compound mixture being useful in the formation of antiseptic agents, said method comprising
- a first step wherein a raw material which is composed of a sulfide containing copper and arsenic and is obtained as an intermediate byproduct from a nonferrous smelter or refinery is added to water to form a slurry;
- and wherein the copper and arsenic in the slurry are extracted into a liquid extract as copper sulfate and arsenic acid by adding a water-soluble cupric salt to the slurry, the extraction being conducted at a partial pressure of oxygen of not less than 1 kg/cm.sup.2, a temperature of not less than 100.degree. C. and a time period of not less than three hours, the water-soluble cupric salt, which acts as an accelerating agent for the oxidation of As(III) and the extraction of the copper sulfide, being adding in an amount sufficient to provide a copper concentration of not less than 20 g/liter of water in the slurry and thus provide a liquid extract having a Cu/As concentration ratio of not less than 1.0,
- a second step of cooling the liquid extract obtained in the first step to a predetermined temperature to thereby effect solid-liquid separation of the liquid extract, and
- a third step of adjusting the pH of the liquid resulting from the second step to a range of 6 to 7 to thereby cause copper and arsenic to precipitate as a composite mixture of copper arsenate and copper hydroxide, the mixture having a Cu/As concentration ratio of not less than 1.0.
A method of manufacturing a composite copper-arsenic compound mixture in the form of a mixture of copper arsenate and copper hydroxide, said composite copper-arsenic compound mixture being useful in the formation of antiseptic agents, said method comprising
- a first step wherein a raw material which is composed of an arsenide and an oxide containing copper and arsenic and is obtained as an intermediate byproduct from a nonferrous smelter or refinery is added to water to form a slurry;
- and wherein the copper and arsenic in the slurry are extracted into a liquid extract as copper sulfate and arsenic acid by adding sulfuric acid to the slurry, the extraction being conducted at a temperature of not less than 50.degree. C. and with the injection of blown air for a time period of not less than three hours, the sulfuric acid being added in an amount, sufficient to provide a Cu/As concentration of not less than 1.0 in the liquid extract,
- a second step of cooling the liquid extract obtained in the first step to a predetermined temperature to thereby effect solid-liquid separation of the liquid extract, and
- a third step of adjusting the pH of the liquid resulting from the second step to a range of 6 to 7 to thereby cause copper and arsenic to precipitate as a composite mixture of copper arsenate and copper hydroxide, the mixture having a Cu/As concentration ratio of not less than 1.0.
Dependencies are inferred from the claim text.