Development of simple process flowsheet for a silica sand sample to produce high grade silica sand concentrate from Ratnagiri district, Maharashtra

Abstract

The production of silica sand in India is 3921 thousand tonnes. Andhra Pradesh, the leading producer accounted for 55% production followed by Rajasthan, Maharashtra and Gujarat. Since last few years due to market trend and more demand in domestic industries like glass, ferro-silicon, iron and steel, refractory, foundry, ceramic, etc. there is steep increase in the production of silica sand (rise of about 48% in production was reported from that of previous year). Iron being the most deleterious element in glass manufacturing industry, attempts were made on a high iron bearing silica sand sample with a view to reduce the Fe2O3 content to ≤0.04% with maximum SiO2 recovery. The Ore Dressing Division of Indian Bureau of Mines, Nagpur conducted a detailed study on the sample and a simple eco-friendly beneficiation process route was evolved by deploying various equipments like attrition scrubber, vibrating screen (wet), magnetic separator, etc. The silica sand sample studied from Ratnagiri region contained mostly quartz as the principal valuable mineral, other minerals present in the sample in minor to trace amounts are mica, amphibole, tourmaline, rutile, iron oxides, zircon and feldspar. The sample assayed 98.312% SiO2, 0.28% Fe2O3, 0.028% TiO2, 0.61% Al2O3, 79 ppm Cr2O3, 0.023% CaO, 0.01% MgO, 0.077% K2O and 0.23% LOI. On wet screening cum attrition scrubbing of –30 mesh fraction followed by magnetic separation of deslimed sand (–30+100 mesh) fraction produced a silica sand concentrate (non-mag) assaying 99.42% SiO2, 0.042% Fe2O3 with wt.% yield 86.4. This concentrate confirms to the specification for Grade I silica sand for use in glass making.