Preliminary Studies on Recovery of Placer Chromite from Central West Coast of India

Abstract

The placer minerals commonly found in the beach sand of India typically include ilmenite, garnet, and sillimanite as the primary heavy minerals, along with rutile, zircon, and monazite as minor heavy minerals. Interestingly, the Maharashtra coast in western India also contains additional placer heavy minerals such as chromite and magnetite. These associated minerals pose a problem in separation of ilmenite and zircon from chromite and magnetite. This study focuses on the recovery of chromite from these associated heavy minerals. Initial analysis reveals that the raw sample contains coarse pebbles with a chromite content of 13% (8.8% Cr₂O₃), which has been crushed to below 1 mm size and subjected to spiral concentrators. The continuous spiral concentrators produced a product which contains 18.2% (12.5% Cr₂O₃). The resulting spiral product has been further processed to a size of 0.5 mm and underwent continuous beneficiation studies in two approaches. In the first approach, the 0.5 mm size product has been to subjected to gravy tables to recover total heavy minerals and the total heavy minerals further subjected to low and high intensity magnetic separators followed by further cleaning with gravity table on the non magnetic product which resulting in a final product with a chromite content of 52.3% (35.8% Cr₂O₃). In the second approach, the total heavy minerals have been subjected to high-tension separators, followed by high-intensity magnetic separators. The resulting non-conductive and non-magnetic product contains 77.8% (52.8% Cr₂O₃) chromite and 20.4% zircon. Further separation is difficult because chromite and zircon both are heavy minerals and non magnetic and non conducting minerals. The other method flotation may be the choice to separate chromite from zircon. However the present recovered product is suitable for applications in refractory industries due to the refractory properties of chromite and zircon.