Process for Ekstraktion gold (Au) and silver (Ag) of ore can use
cedimentation system (precipitation) zinc (Zn) powder. But lately the conventional
process is already considered almost inefficient and not selective, because
metals other than gold and silver are precipitate (Dayton, SH, 1987). The current
attention focused on absorption system using activated carbon for the extraction
of gold and silver in the processing of mineral called carbon in leach (CIL).
Activated carbon is used to process the CIL has its own characteristics. So,
activated carbon required a special study to obtain activated carbon according to
the characteristics of CIL process and the important think of activated carbon is
number of iodine (iodine number) so that could be optimal for absorption process.
Activated carbon from coal sub - bituminous PT.BA with activation
performed in this study has not been reached in accordance with the required
characteristics for CIL process that is supposed to be iodine number of 700 mg /
g and only reached a maximum of 493 mg / g. Likewise, the relative ash content
that should not meet that 4% to 4.1188% results. While the other parameters
have been reached as required.
the highest iodine number of 493 mg / g achieved with variable temperature
experiments at 900oC with -48 +100 mesh fraction for 1 hour with iodine number
of 493 mg / g, and also have a percentage of loss during the activation process
smallest 45.15%.
Here are the specifications of activated carbon from sub - bituminous coal
results and qualified of activation process for the purification process using the
CIL:
Percent moisture : 2,5187 % (max 5%)
Percent ash : 4,1188 % (max 4%)
Percent fix carbon : 88,5027 % (min 80 %)
Iodin Number : 493 mg/g (min 700 mg/g)
Based on the study in making activated carbon using iodine number coalite
to obtain up to 1000 mg / g required a specific study using the chemical activation
process or physical activation with rotary kiln system.
Proses pembuatan karbon aktif untuk mengekstraksi logam emas (Au) dan perak (Ag) dari bijihnya pada dasarnya memiliki karakteristik tersendiri untuk proses carbon in leach (CIL). Karbon aktif yang berasal dari batubara sub – bituminus PT.BA dengan aktifasi yang dilakukan dalam penelitian ini belum mencapai karakteristik sesuai dengan yang dipersyaratkan untuk proses CIL yaitu nilai iodin yang seharusnya 700 mg/g dan baru tercapai maksimal 493 mg/g. Demikian juga kadar abu relatif belum memenuhi yang seharusnya yaitu maksimal 4% dengan hasil 4,1188 %. Sedangkan parameter yang lainnya sudah tercapai sesuai yang dipersyaratkan. Nilai iodin tertinggi yaitu 493 mg/g yang dicapai dengan variabel percobaan pada suhu 900OC dengan fraksi -48 +100 mesh selama 1 jam dengan nilai iodin sebesar 493 mg/g, dan juga memiliki persentase kehilangan selama proses aktifasi terkecil yaitu 45,15%. Berdasarkan kajian dalam membuat karbon aktif dengan menggunakan coalite untuk didapat nilai iodin hingga 1000 mg/g diperlukan kajian khusus dengan menggunakan proses aktivasi kimia atau aktivasi fisik dengan sistem rotary kiln.