Abstract:
Apatite mined f r om Eppawala (Eppawala Rock Phosphate - ERP) cannot be directly
used as a fertilizer for armual crops such as paddy and vegetables because of its low
water solubility. It is difficult to manufacture water soluble phosphate fertilizers
from ERP due to its stable chemical formation and impurities in ERP. This study
focuses on impurities i n ERP and methods of their removal. Removing the
impurities in ERP will help to produce water soluble phosphate fertilizers for
annual crops. Literature shows high contents of Fe203, AI2O3 and chlorine as
impurities i n ERP. This investigation helped us to reduce combined Fe203 and AI2O3
content from 12.36% to 6.42% i n test 1 of this study and to 4.61% i n test 2 by using
froth floatation technique. Acceptable level of combined Fe203 and AI2O3 content for
the production of water soluble phosphate fertilizer is less than 5%. Therefore, the
concentrate of test 2 is suitable for the production process, but high chlorine content
in the concentrate w i l l create difficulties in the formation of water soluble phosphate
fertilizers.
Citation:
Weerasooriya, H.M.J.C., Waisundara, W.M.L.B., Lakmal, K.P.T., Hemalal, P.V.A., Rohitha, L.P.S., & Ratnayaka, N.P. (2018). Impurities in Eppawala rock phosphate and removal methods. In A.M.K.B. Abeysinghe & G.V.I. Samaradivakara (Eds.), Proceedings of International Symposium on Earth Resources Management & Environment 2018 (pp. 79-84). Department of Earth Resources Engineering, University of Moratuwa.
