Bio-beneficiation of kaolin and feldspar and its effect on fired characteristics of triaxial porcelain

Presence of iron compounds as impurities in kaolin and feldspar, impart reddish colour to ceramic products manufactured using these minerals. The quality of kaolin and feldspar was enriched mainly through iron removal by biological methods. Bacteria isolated from kaolin of Indian origin were used for bioleaching. Biotreatment of kaolin and feldspar using indigenous bacteria not only lowered the iron content of the minerals but also improved their whiteness. The porcelain prepared with these biobeneficiated minerals was compared to that prepared with non-beneficiated one. Physico-mechanical properties of porcelain were distinctly improved by using biobeneficiated kaolin and feldspar, without affecting the individual mineralogical compositions of kaolin and feldspar.