STUDI PERILAKU PELINDIAN BIJIH NIKEL LIMONIT DARI PULAU HALMAHERA DALAM LARUTAN ASAM NITRAT [Study on the Leaching Behaviour of Limonite Nickel Ore From Halmahera Island in Nitric Acid Solution]

Abstract

pelindian bijih nikel laterit maupun meregenerasi reagen pelindi menjadi fokus perhatian peneliti dan dunia industri dalam beberapa tahun belakangan ini. Salahsatu teknologi yang dikembangkan adalah pelindian bijih nikel laterit asam nitrat, dimana >95% asam nitrat yang digunakan dapat diregenerasi kembali. Pada paper ini didiskusikan perilaku pelindian bijih nikel laterit yang diperoleh dari Pulau Halmahera dalam larutan asam nitrat. Serangkaian percobaan pelindian dalam larutan asam nitrat telah dilakukan dengan variasi konsentrasi asam nitrat, persen padatan dan temperatur. Analisis ekeperimental faktorial desain 2³ digunakan untuk mempelajari pengaruh variabel temperatur, konsentrasi asam dan persen padatan serta interaksi antara variabel-variabel tersebut dalam proses pelindian. Hasil percobaan menunjukkan bahwa ekstraksi Ni tertinggi yaitu 94% diperoleh pada pelindian selama 8 jam dengan konsentrasi asam 6M, 10% padatan dan temperatur 95°C. Variabel yang paling berpengaruh pada ekstraksi Ni adalah temperatur dengan persen kontribusi mencapai 78%. Selektivitas (S) pelindian Ni terhadap Fe dan Mg relatif rendah, dengan nilai rata-rata S_Ni/Fe dan S_Ni/Mg masing-masing 0,53 dan 0,50. Konsumsi asam cukup tinggi, dimana konsumsi tertinggi pada temperatur 95°C, konsentrasi asam 4M dan 10% padatan yaitu 1010 kgh./ton biji.

Abstract

Efforts to reduce the consumption of leaching agent either by increasing selectivity of nickel laterite ore
leaching and regeneration of the leaching agent, are being the focus of researchers and industries in recent
years. One of technologies that is developed is the leaching of laterite ore in nitric acid, through which more
than 95% of nitric acid being used can be regenerated.In this paper, leaching behavior of nickel laterite ore
from Halmahera Island is discussed. A series of leaching experiments in nitric acid solution has been carried
out under variations of nitric acid concentration, solid percentage and temperature. Analysis using
experimental factorial design of 23 was performed to determine the effects of temperature, acid concentration
and solid percentage as well as the interaction between these variables toward nickel extraction during
leaching. The experimental results show that the highest nickel extraction of 94%, was obtained from the
leaching test for 8 hours using acid concentration of 6 M, 10% solid at temperature of 95 °C. The most
influencing variable on nickel extraction is temperature with contribution of 78%. Selectivity of Ni leaching
to Fe and Mg is relatively low, with average values of SNi/Fe and SNi/Mg of 0.53 and 0.50, respectively.
Acid consumption in leaching process is relatively high, which the highest consumption was at leaching
temperature of 95°C, acid concentration 4 M and 10% solid, namely 1010 kg/ton ore.