Treated manganese ore, process for producing the same, and use thereof

Abstract

An object of the invention is to provide: a treated manganese ore for use in manganese sulfate production therefrom which has a high degree of manganese dissolution when dissolved in sulfuric acid and which can hence be effective in reducing the amount of slags generating in a production step and can be reduced in potassium content according to need; a process for producing the treated manganese ore easily and economically; manganese dioxide which is useful in primary batteries, secondary batteries, etc.; and a process for easily producing the manganese dioxide. A treated manganese ore for use in producing manganese sulfate therefrom, the treated ore having a degree of manganese dissolution of 98.0% by weight or higher based on the manganese contained in the treated manganese ore when dissolved in sulfuric acid; a process for producing the treated ore; manganese dioxide obtained from the treated ore; and a process for producing the manganese dioxide are described.

What is claimed is:  
     
         1 . A treated manganese ore for use in producing manganese sulfate therefrom, said treated ore having a degree of manganese dissolution of 98.0% by weight or higher based on the manganese contained in the treated manganese ore when dissolved in sulfuric acid.  
     
     
         2 . The treated manganese ore of  claim 1 , which has a degree of iron dissolution of 70% by weight or higher based on the iron contained in the treated manganese ore when dissolved in sulfuric acid.  
     
     
         3 . The treated manganese ore of  claim 1 , wherein the ratio of the amount of potassium soluble in sulfuric acid to that of manganese contained in the treated manganese ore (K/Mn) by weight is 0.001 or lower.  
     
     
         4 . The treated manganese ore of  claim 1 , which is one obtained by bringing a manganese ore into contact with a reducing gas at a temperature of from 400 to 790° C.  
     
     
         5 . A treated manganese ore obtained by immersing the treated manganese ore of  claim 4  in water having a temperature of from 70° C. to the boiling point thereof as measured at atmospheric pressure.  
     
     
         6 . The treated manganese ore of  claim 1  or  5 , which has a particle size of 500 μm or smaller.  
     
     
         7 . A process for producing the treated manganese ore for use in producing manganese sulfate therefrom, said treated ore having a degree of manganese dissolution of 98.0% by weight or higher based on the manganese contained in the treated manganese ore when dissolved in sulfuric acid, which comprises bringing a manganese ore into contacted with a reducing gas at a temperature of from 400 to 790° C. to obtain a reduced ore.  
     
     
         8 . The process for producing a treated manganese ore of  claim 7 , wherein the manganese ore is pulverized to a particle size of 500 μm or smaller before the reduced ore is obtained therefrom.  
     
     
         9 . The process for producing a treated manganese ore of  claim 7 , wherein the manganese ore is kept in contact with the reducing gas at a temperature of from 400 to 790° C. for a period not shorter than the reduction saturation time.  
     
     
         10 . A process for producing the treated manganese ore for use in producing manganese sulfate therefrom, said treated ore having a degree of manganese dissolution of 98.0% by weight or higher based on the manganese contained in the treated manganese ore when dissolved in sulfuric acid, which comprises bringing a manganese ore into contacted with a reducing gas at a temperature of from 400 to 790° C. to obtain a reduced ore, and the reduced ore obtained is immersed in water having a temperature of from 70° C. to the boiling point thereof as measured at atmospheric pressure.  
     
     
         11 . The process for producing a treated manganese ore of  claim 10 , wherein the reduced ore obtained is immersed in water having a temperature of from 70° C. to the boiling point thereof as measured at atmospheric pressure, and washed.  
     
     
         12 . The process for producing a treated manganese ore of  claim 10 , wherein the reduced ore obtained is immersed in water having a temperature of from 70° C. to the boiling point thereof as measured at atmospheric pressure, washed and filtered.  
     
     
         13 . The process for producing a treated manganese ore of  claim 7 , wherein the reducing gas comprises one or more members selected from the group consisting of hydrogen, carbon monoxide, sulfur dioxide, hydrogen sulfide, and methane.  
     
     
         14 . The process for producing a treated manganese ore of  claim 7 , wherein the reducing gas is used in an amount of from 1.0 to 2.0 times the theoretical amount thereof necessary for the reduction of the manganese ore.  
     
     
         15 . The process for producing a treated manganese ore of  claim 13 , wherein the reducing gas is one obtained by diluting said reducing gas with an inert gas.  
     
     
         16 . The process for producing a treated manganese ore of  claim 7 , wherein the time period of the contact of the reducing gas with the manganese ore is from 20 to 120 minutes.  
     
     
         17 . The process for producing a treated manganese ore of  claim 7 , wherein the contact of the reducing gas with the manganese ore is conducted continuously with a rotary kiln.  
     
     
         18 . The process for producing a treated manganese ore of  claim 17 , wherein the rotary kiln has a cylindrical or prismatic shape.  
     
     
         19 . The process for producing a treated manganese ore of  claim 17 , wherein the rotary kiln is equipped with a device for mixing the ore with the reducing gas.  
     
     
         20 . The process for producing a treated manganese ore of  claim 19 , wherein the device for mixing the ore with the reducing gas comprises one or more movable stirring blades installed in the kiln or one or more stirring blades fixed to the inner wall of the kiln.  
     
     
         21 . The process for producing a treated manganese ore of  claim 7 , which is conducted continuously.  
     
     
         22 . The process for producing a treated manganese ore of  claim 8 , which is conducted continuously.  
     
     
         23 . The process for producing a treated manganese ore of  claim 10 , which is conducted continuously.  
     
     
         24 . The process for producing a treated manganese ore of  claim 10 , wherein the reduced ore is cooled in a nonoxidizing atmosphere and then immersed in water.  
     
     
         25 . The process for producing a treated manganese ore of  claim 10 , wherein the reduced ore is immersed in water and then cooled in a nonoxidizing atmosphere.  
     
     
         26 . The process for producing a treated manganese ore of  claim 24 , wherein the cooling is conducted continuously.  
     
     
         27 . The process for producing a treated manganese ore of  claim 25 , wherein the cooling is conducted continuously.  
     
     
         28 . The process for producing a treated manganese ore of  claim 10 , wherein the immersion of the reduced ore in water is conducted so as to yield a slurry in which the concentration of the reduced ore is from 10 to 40% by weight.  
     
     
         29 . The process for producing a treated manganese ore of  claim 10 , wherein the immersion of the reduced ore in water is conducted for a period of from 1 to 24 hours.  
     
     
         30 . The process for producing a treated manganese ore of  claim 10 , wherein the immersion of the reduced ore in water is conducted in one or more stirring tanks for continuous processing.  
     
     
         31 . Electrolytic manganese dioxide for use in batteries which is obtained by dissolving the treated manganese ore of  claim 1  or  5  in sulfuric acid, purifying the resultant solution, and electrolytically oxidizing the resultant manganese sulfate.  
     
     
         32 . A process for producing electrolytic manganese dioxide which comprises adding sulfuric acid to the treated manganese ore of  claim 1  or  5  to dissolve the ore and thereby obtain an aqueous solution of manganese sulfate, purifying the resultant aqueous solution of manganese sulfate, and then subjecting the solution to electrolytic oxidation to oxidize the manganese sulfate.  
     
     
         33 . A process for producing electrolytic manganese dioxide which comprises obtaining a treated manganese ore by the process of  claim 7 , adding sulfuric acid to the treated manganese ore to dissolve the ore and thereby obtain an aqueous solution of manganese sulfate, purifying the resultant aqueous solution of manganese sulfate, and then subjecting the solution to electrolytic oxidation to oxidize the manganese sulfate.