| DOWA METALS & MINING CO., LTD. Patent applications |
| Patent application number | Title | Published |
|---|
| 20110027167 | IRON ARSENATE POWDER - There is provided an iron arsenate powder which is produced from an arsenic containing solution and wherein the concentration of arsenic eluted or released from the powder is very low. The iron arsenate powder is a powder of dihydrate of iron arsenate, which has a crystal structure of rhombic system and which has lattice constants of a=0.8950 to 0.8956 nm, b=1.0321 to 1.0326 nm and c=1.0042 to 1.0050 nm at room temperatures and atmospheric pressure. The iron arsenate powder can be produced by a method comprising the steps of: adding ferrous ions to an arsenic containing solution to cause the molar ratio (Fe/As) of iron to arsenic in the solution to be not lower than 1; adding an oxidizing agent to the solution; heating the solution to a temperature of not lower than 70° C. while stirring the solution, to allow a reaction; and carrying out a solid-liquid separation to wash the obtained solid part. | 02-03-2011 |
| 20110001279 | APPARATUS FOR RECOVERING PLATINUM GROUP ELEMENTS - A method for recovering platinum group elements comprises charging into a closed electric furnace and melting, together with flux components and a reducing agent, a platinum group element-containing substance to be processed and a copper source material containing copper oxide, sinking molten metal of primarily metallic copper below a molten slag layer of primarily oxides, and enriching the platinum group elements in the molten metal sunk below, and is characterized in that molten slag whose copper content has decreased to 3.0 wt % or less is discharged from the electric furnace and that the copper source material charged into the electric furnace is a granular copper source material of a grain diameter of not less than 0.1 mm and not greater than 10 mm. | 01-06-2011 |
| 20100215570 | METHOD OF ALKALI PROCESSING SUBSTANCE CONTAINING ARSENIC - To provide a method of generating, with good reproducibility and ease and without complicated operations, scorodite which satisfies the elution standard (in accordance with Notification of No. 13 of Japanese Environment Agency) and which has good filterbility and stability for processing arsenic contained in a non-ferrous smelting intermediate, particularly, for processing a diarsenic trioxide form. A method of processing diarsenic trioxide, including: a leaching step of adding water and alkali to a non-ferrous smelting intermediate that contains diarsenic trioxide to produce slurry, heating the slurry, and leaching arsenic; a solution adjusting step of adding an oxidizing agent to the leachate to oxidize trivalent arsenic to pentavalent arsenic so as to obtain an adjusted solution; and a crystallizing step of converting arsenic in the adjusted solution to scorodite crystal. | 08-26-2010 |
| 20100196231 | Method Of Processing Non-Ferrous Smelting Intermediates Containing Arsenic - The object is to remove arsenic in a stable form from an arsenic-containing smelting intermediate product. Thus, disclosed is a method for treating an arsenic-containing nonferrous smelting intermediate product, which comprises: a leaching step of subjecting a mixed slurry of a nonferrous smelting intermediate product containing arsenic in the form of a sulfide and a nonferrous smelting intermediate product containing arsenic and metal copper to the oxidation/leaching in an acidic range to produce a leaching solution; a solution preparation step of adding an oxidizing agent to the leaching solution to oxidize trivalent arsenic into pentavalent arsenic, thereby producing a preparation solution; and a crystallization step of converting arsenic contained in the preparation solution into a scorodite crystal. | 08-05-2010 |
| 20100196230 | METHOD OF PROCESSING NON-FERROUS SMELTING INTERMEDIATE CONTAINING ARSENIC - Provided is a method of easily producing easily-filterable and stable scorodite that meets the leaching standard (conformance to Japanese Environmental Agency Notice 13) with excellent reproducibility and without using complex operations, when processing arsenic that is included in non-ferrous smelting intermediates, and particularly when processing arsenic in the form of a sulfide. Scorodite is produced by a leaching step of leaching arsenic from a non-ferrous melting intermediate containing arsenic in the weakly acid region, a solution adjusting step of oxidizing trivalent arsenic to pentavalent arsenic by adding an oxidizing agent to the leaching solution, and a crystallizing step of converting the arsenic in the adjusted solution to scorodite crystals. | 08-05-2010 |
| 20100175509 | METHOD OF PROCESSING COPPER ARSENIC COMPOUND - Provided is a method of easily producing scorodite which is stable and has excellent filtering properties with excellent reproducibility and without using complex operations, when processing arsenic that is included in non-ferrous smelting intermediates, and particularly when processing copper arsenic compounds in the form of an intermetallic compound. Scorodite is produced by a leaching step of leaching arsenic from a non-ferrous melting intermediate containing a copper arsenic compound in the form of an intermetallic compound in the presence of a sulfidizing agent and an oxidizing agent, a solution adjusting step of oxidizing trivalent arsenic to pentavalent arsenic by adding the oxidizing agent to the leaching solution, and a crystallizing step of converting the arsenic in the adjusted solution to scorodite crystals. | 07-15-2010 |
| 20090291307 | IRON ARSENATE POWDER - There is provided an iron arsenate powder which is produced from an arsenic containing solution and wherein the concentration of arsenic eluted or released from the powder is very low. The iron arsenate powder is a powder of dihydrate of iron arsenate, which has a mean particle diameter of not smaller than 8 micrometers, preferably not smaller than 10 micrometers, and a BET specific surface area of not greater than 2 m | 11-26-2009 |
