tailieunhanh - Production of dicalcium phosphate from Lao Cai second grade apatite ore leached by dilute hydrochloric acid

The production of dicalcium phosphate from Lao Cai second grade apatite was investigated by leaching with dilute hydrochloric acid. Various factors affecting the process such as particle size, leaching time, leaching temperature, phosphate rock/hydrochloric acid ratio and mixing stirring speed and temperature have been studied to estimate the favor phosphate ore dissolution in relation to impurity. | Journal of Science and Technology 55 (2) (2017) 209-219 DOI: PRODUCTION OF DICALCIUM PHOSPHATE FROM LAO CAI SECOND GRADE APATITE ORE LEACHED BY DILUTE HYDROCHLORIC ACID Trinh Xuan Hiep1, *, Nguyen Xuan Truong1, Nguyen Van Dung2, Vu Van Chinh2 1 2 Institute of Materials Science - Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet street, Cau Giay District, Ha Noi Ha Noi AT Applied Technology Joint Stock Company, No 4 – 54/218 Lac Long Quan stree, Tay Ho District, Ha Noi * Email: trixuhi@ Received: 9 May 2016; Accepted for publication: 1 February 2017 ABSTRACT The production of dicalcium phosphate from Lao Cai second grade apatite was investigated by leaching with dilute hydrochloric acid. Various factors affecting the process such as particle size, leaching time, leaching temperature, phosphate rock/hydrochloric acid ratio and mixing stirring speed and temperature have been studied to estimate the favor phosphate ore dissolution in relation to impurity. These parameters were fixed at a leaching time of 16 min, stirring speed of 400 rpm, temperature of 25 oC, hydrochloric acid concentration of 10 % and acid/phosphate ore mass ratio of 25 ml/ 5 g and particle size ≤ 450 µm. The produced aqueous acidic solution was neutralized in such a way that a pure dicalcium phosphate CaHPO4, which precipitated to be used as animal fooder. The production efficiency was %. Keywords: Lao Cai second grade apatite, carbonate-phosphate ore, low-grade phosphate ore, dicalcium phosphate production, dilute hydrochloric acid leaching. 1. INTRODUCTION Dicalcium phosphate is the calcium phosphate with the formula CaHPO4. The "di" prefix in the common name arises because the formation of the HPO42– anion involves the removal of two protons from phosphoric acid, H3PO4. It is also known as dibasic calcium phosphate or calcium monohydrogen phosphate. There are three crystalline forms: a dihydrate, (DPCD), the mineral .