EVALUATION OF THERMALLY PROMOTED REACTION-PRODUCTS OF SOME SELECTED PHOSPHATE ROCKS FROM INDIA

Phosphate rocks (PRs) from Jordan and others from Kasipatnam (Andhra P radesh), Purulia (West Bengal) and Mussoorie (Uttar Pradesh) (all from India) were heated either alone or with Na2CO3 or KCl at 300, 500, 70 0 and 900-degrees-C in the weight ratio of 1:0.5, 1:0.25 and 1:0.15. T he utilisation of KCl in the PR-KCl mixture was very low. The products obtained by heating PR-KCl mixtures of different weight ratios at dif ferent temperatures (300-900-degrees-C) contained much lower amount of available P compared to those of PR-Na2CO3 mixtures. The water- and c itrate-soluble P content of these products decreased with a change in the PR:Na2CO3 ratio from 1:0.5 to 1:0.15. The amount of Na2CO3 in the 1:0.25 and 1:0.15 ratio of the PR additive mixture was found to be ins ufficient to complete the reactions. About 72-98.6% of the total P con tent of the product obtained by heating PR-Na2CO3 mixture in the 1:0.5 ratio at 900-degrees-C was in the available form. The inherent access ory minerals present in the PRs might have taken part in the thermally promoted reactions of PR-Na2CO3 mixture resulting in a product which has got most of its P in the available form. The contribution from the accessory minerals present in the Jordan PR was not sufficient to mee t the requirement of the reactions which resulted in lower amount of a vailable P in the product.