Synthesis of Kieserite fertilizer by using natural magnesite Ore as raw material

Magnesite ore is one kind of rare minerals that can be found in area of Aceh Besar District Province of Aceh, NTT Province and Southeast Sulawesi Province. The further treatment of this rare magnesite mineral containing mainly magnesium to form kieserite fertilizer product with composition magnesium and sulphur would be more benefit. The purpose of this study is to synthesize kieserite fertilizer from magnesite ore as raw material with addition of sulphur and to see whether the composition of prepared product meet the specification of kieserite fertilizer as stated in SNI 02-2807-1992. The synthesis was carried out by mixing the treated natural magnesite ore and the solid sulphur in a ball mill. The product of kieserite fertilizer was then analyzed according to SNI 02-2807-1992. The results showed that kieserite fertilizer can be produced from raw material of magnesite ore and a product met the SNI 02-2807-1992. The prospective product of kieserite fertilizer was obtained after mixing magnesite ore with addition 20 wt% of solid sulphur. The composition of prepared kieserite fertilizer was in range of 26.72 - 30.20 wt% for MgO, 20.29 - 23.93 wt% for S and 0.40 - 0.76 wt% for free water content with the prospective product composition was 30.20 wt% for MgO, 23.93 wt% for S and 0.45 wt% for free water content.