Pengaruh kandungan sulfur (2,68% dan 5%) dalam reduktor antrasit dengan variasi penambahan (0,0625-0,25 stoikiometri) pada proses reduksi selektif Bijih Nikel Laterit Jenis Limonit = The effect of sulphur contents (2,68% and 5%) in anthracite reductor with addition variations (0,0625 - 0,25 Stoichiometry) on Selective Reduction of Limonite Type Laterite Nickel Ore