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US 9,458,038 B2Granted
Wastewater treatment process
AssigneeSumitomo Metal Mining Co., Ltd.
InventorsHideki Ohara, Yoshitomo Ozaki
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AssigneeSumitomo Metal Mining Co., Ltd.
InventorsHideki Ohara, Yoshitomo Ozaki
Estimating the term…
A wastewater treatment process capable of selectively and efficiently separating and removing a manganese precipitate with high purity from sulfuric acid-acidic wastewater containing aluminum, magnesium, and manganese. In the wastewater treatment for a sulfuric acid-acidic wastewater containing aluminum, magnesium, and manganese, a magnesium oxide is used for part or all of the neutralizing agent to be added, the magnesium oxide is produced through the following steps (1) to (4): (1) effluent wastewater obtained by separating aluminum and manganese from sulfuric acid-acidic wastewater is concentrated, and calcium contained in the effluent wastewater is precipitated as a calcium sulfate; (2) the solution obtained in (1) is further concentrated, and magnesium is precipitated and separated as a magnesium sulfate; (3) the magnesium sulfate separated in (2) is roasted together with a reducing agent to obtain a magnesium oxide and sulfurous acid gas; and (4) the magnesium oxide obtained in (3) is washed.
A wastewater treatment process in which a first neutralizing agent is added into sulfuric acid-acidic wastewater containing aluminum, magnesium, and manganese to separate an aluminum hydroxide precipitate and obtain a solution after dealumination, then a second neutralizing agent and an oxidizing agent are added to the solution after dealumination to separate a manganese precipitate and obtain a solution after demanganization, and then a third neutralizing agent is added to the solution after demanganization to obtain a wastewater precipitate and effluent wastewater, comprising,
Dependencies are inferred from the claim text.