Experiments of gold and silver elution were conducted using several parameters, either fixed or varying parameters. Ethanol volume, temperature and percent solid belonged to varying parameters while loaded carbon, stirring rate, concentrations of NaOH and NaCN served as fixed parameters. The experiment results showed that the optimum condition for such a process included 20% of ethanol volume, 80°C of temperature and solid fraction of 25%. Using such condition, the experiment was conducted for 10-hour contact time and yielded the highest desorption percentages for gold and silver, namely 80.10 and 70.73% respectively. The derived contents of gold and silver were 295.16 and 159.38 ppm while their achieved weights were 56.080 and 30.601 µ g. The fact that the achieved contents of gold and silver was close to the requirements for electrowinning process, it is suggested that the next process using a semicontinue one in terms of gaining a result that satisfies the requirement for electrowinning.

Bijih emas primer yang digunakan dalam tulisan ini berasal dari desa Kedondong, Kecamatan Kedondong, Kabupaten Pesawaran, Lampung. Conto diambil pada titik koordinat 05032'20" LS dan 1050 01'45" BTyang masuk ke dalam WIUP PT.Karya Bukit Utama.Karakter bijih emas yang akan diolah dianalisis dengan metode fire assay, analisis mikroskop, analisis ayak, derajat liberasi, bentuk dan ukuran butiran emas. Data karakter hasil analisis dapat digunakansebagai dasar untuk menentukan metode pengolahan.Data karakterisasi menunjukkan bahwa bijih emas di daerah penelitian dapat diolah dengan cara konsentrasi gaya berat, proses akhir terhadap produk konsentrat dapat dilakukan cara peleburan atau sianidasi.Hasil uji pengolahan memakai alat Knelson Concentrator terhadap conto kode TK.24 dapat meningkatkan kadar emas dari 21,87 g/t menjadi 399,76 g/t dengan recovery 91,57 %, dan terhadap conto kode TK.27 bisa meningkatkan kadar emas dari 8,93 g/t menjadi 165,80 g/t dengan recovery 87,26%.