Process for the extraction and elimination of deleterious material from natural manganese dioxide and concentrate of manganese dioxide obtained by said process

A process for extracting and eliminating deleterious material from natural manganese dioxide (NMD) comprising:

• feeding a reactor with a solution consisting of HCl and water, heating said solution with stirring to a reaction temperature ranging from about 80° C. to 95° C. and maintaining the HCl concentration in said solution within a range of about 9% to 25% w/w;
• maintaining the temperature of said HCl solution in said reactor at a temperature of from about 80° C. to 95° C.;
• feeding said reactor containing said HCl solution with crushed NMD ore to provide a reaction pulp concentration of from about 10% to 40%;
• leaching said reaction pulp with said HCl solution for a period of about 10 to 60 minutes;
• filtering the contents of said reactor to recover the concentrate of manganese dioxide (MnO2);
• and
• washing and drying the recovered concentrate of MnO2.