Nittetsu Mining Co., Ltd.

Sugita Wire, Ltd.

Yasuie Mikami

Nobuyoshi Iyatomi

Susumu Takayama

Shigemi Kodama

Yasuo Morimoto

Ippo Takei

Masaaki Iosaki

Masao Shibasaki

Shigeo Kimura

Minoru Orikasa

Kazuo Soma

Provided is a purifying material capable of highly efficiently removing contaminant components from wastewater. A water purifying material having a composition of 30 to 40% total iron, 1 to 5% titanium, 0.1 to 1% magnesium, and 0.1 to 0.8% silica (silicon), and a method for manufacturing the water purifying material including: adding caustic soda to a solution containing 200 to 100 mg/L of bivalent iron, 20 to 100 mg/L of titanium ions, 5 to 50 mg/L of magnesium, and 3 to 30 mg/L of silica under conditions of 30 to 50° C. and pH 6.8 to 7.2 to carry out neutralization and reaction; separating and collecting an obtained solid at 100° C. or less; and drying the collected solid.

Water purifying material having iron as main component, and method for manufacturing same

For the purpose of efficiently and easily regenerating a sulfuric acid solution having a high concentration and a low impurity content from a metal sulfate-containing waste sulfuric acid solution and waste liquor formed during acid cleaning which are discharged from titanium (IV) oxide-production process carried out according to the sulfuric acid method, titanium present in the metal sulfate-containing waste sulfuric acid solution is removed through a solvent-extraction treatment and then the solution obtained after the solvent-extraction is subjected to a diffusive dialysis treatment.

Method for reclaiming metal sulfate-containing waste sulfuric acid

A process for treating sodium hydroxide waste liquor containing aluminum, comprising the steps of: adding, to aluminum-containing sodium hydroxide waste liquor, at least one of MgO and Mg(OH).sub.2 in an amount of 0.5 to 3 moles with respect to 1 mole of aluminum to cause a reaction at 70.degree. C. or more; and separating and removing a precipitated magnesium-aluminum compound is disclosed. The present invention makes it possible to recover recyclable sodium hydroxide from an aluminum-containing sodium hydroxide waste liquor. Even if the recovering procedure is repeated, no carbonate ions are accumulated. Therefore, it is possible to prevent degradation of the treating solution containing sodium hydroxide. Further, the by-product is a useful compound, and thus, there is no problem in the reprocessing or disposal of the by-product.

Process for treatment of sodium hydroxide waste liquor containing

In order to efficiently and easily recover a spent sulfuric acid exhasuted, for example, in an acid washing liquid or in producing titanium dioxide by a sulfate method in a large amount, as highly concentrated sulfuric acid, bivalent iron ions in the spent sulfuric acid containing metal sulfate are first oxidized into trivalent iron ions, hydrochloric acid is added to such a liquid and then solvent extraction is carried out.

Process for recovering sulfuric acid from metallic sulfate-containing

In order to ensure an easy operation, a decreased cost in maintenance and installation, and a safe and effective use of chlorine gas generated in a closed system, a new method for treating an etchant is offered. The method comprises the following steps of; 1 treating an etchant including copper (I) chloride or ferric chloride containing copper by means of an electrolysis using a diaphragm to withdraw copper electrolytically deposited in a cathode cell, 2 supplying chlorine gas generated in an anode cell into another etchant used in an etching process, thereby enabling the etchant to be regenerated.

Method for treating etchant

Hexagonal plate crystals of aluminum sulfate are produced in chemically pure form by a process which comprises cooling a heated saturated solution of chemically impure aluminum sulfate acidified with sulfuric acid to precipitate crystals of aluminum sulfate, heating the slurry of the cooled solution containing the precipitated aluminum sulfate crystals to a predetermined temperature wherein the temperature is maintained for a time sufficient to dissolve a portion of the crystals in the solution, cooling the heated slurry to precipitate aluminum sulfate crystals, and separating the precipitated crystals from the slurry.

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Tokyo, Japan

Yasuie Mikami