Nurjaman, Dadan Mohamad (2025) Kajian Metode Pelindian Sianida yang Produktif, Adaptif dan Ramah Lingkungan pada Pertambangan Emas Rakyat. Doctoral thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Pertambangan Emas Rakyat (PER) masih banyak menggunakan merkuri dalam pengolahan emas sehingga berpotensi menimbulkan pencemaran lingkungan, penurunan kualitas kesehatan, dan degradasi lahan. Meskipun PER di Desa Tatelu dan Talawaan telah mengenal metode pelindian sianida, tingkat perolehan emas masih rendah (<60%) dan belum dilengkapi dengan pengolahan limbah yang memadai. Penelitian ini bertujuan menyusun rekomendasi teknis yang adaptif, produktif, dan ramah lingkungan bagi PER melalui evaluasi kinerja proses penggilingan, optimalisasi pelindian sianida, dan optimalisasi destruksi sianida bebas agar memenuhi baku mutu lingkungan. Tahap observasi lapangan pada unit pengolahan emas telah dilakukan sebelum penelitian. Tahun pertama dilakukan analisis laboratorium dengan parameter ukuran butir, kandungan sianida bebas, emas, perak, tembaga dan belerang, pada sampel dari lokasi studi. Tahun kedua dilakukan evaluasi kinerja proses penggilingan dengan media penggiling batu andesit endapan sungai, bola baja dan batang baja, dan optimalisasi pelindian sianida berdasarkan ukuran butir dan densitas lumpur. Tahun ketiga optimalisasi destruksi limbah sianida menggunakan proses sulfur dioksida dan udara dengan pendekatan metode permukaan respon (RSM). Hasil evaluasi kinerja proses penggilingan menggunakan tromol berukuran 12” × 12” pada sampel 7,5 kg menunjukkan bahwa penggunaan media giling batu andesit, dengan parameter operasi yang tepat, mampu menghasilkan tepung bijih emas sesuai target kehalusan, yaitu 75% lolos 74 µm dalam 4 jam dan 75% lolos 44 µm dalam 6 jam. Kondisi ini mendukung peningkatan kelarutan dan perolehan emas secara optimal. Studi optimalisasi pelindian sianida menggunakan tangki berkapasitas 25 L pada sampel 5 kg, berdasarkan variasi ukuran butir dan densitas lumpur, menunjukkan bahwa ukuran butir 75% lolos 44 µm dengan densitas lumpur 25% padatan memberikan tingkat kelarutan emas tertinggi, yaitu 87,43% pada 48 jam dan 89,08% pada 72 jam. Sementara itu, kombinasi ukuran butir 75% lolos 74 µm dan densitas lumpur 35% padatan, dengan tingkat kelarutan masing-masing 80,74% pada 48 jam dan 84,26% pada 72 jam, direkomendasikan sebagai kondisi optimum untuk aplikasi operasional pada PER. Kapasitas tangki pelindian pada PER di Tatelu dan Talawaan rata-rata sekitar 40.000 L. Dengan kapasitas tersebut, ukuran butir 75% lolos 74 µm dengan densitas lumpur 35% padatan dapat mengolah sekitar 14 ton bijih emas, sedangkan ukuran butir 75% lolos 44 µm dengan densitas lumpur 25% padatan dapat mengolah sekitar 8,5 ton bijih emas. Hasil optimalisasi destruksi limbah sianida pada volume 2,8 L menggunakan metode permukaan respon melalui proses sulfur dioksida dan udara yang dikatalisis tembaga (II) menunjukkan bahwa kondisi optimum dicapai pada rasio massa SO₂/CN⁻ = 10, konsentrasi katalis Cu²⁺ = 50 mg/L, dan waktu proses 4 jam. Kondisi tersebut efektif menurunkan konsentrasi CN⁻ dari 200 mg/L menjadi <0,5 mg/L sehingga memenuhi baku mutu lingkungan. Secara keseluruhan, penelitian ini menghasilkan rekomendasi teknologi pelindian sianida dan pengolahan limbah yang teruji secara eksperimental, mampu meningkatkan perolehan emas secara signifikan > 20% dibandingkan praktik PER eksisting, dan memenuhi prinsip produktivitas, adaptivitas, dan keberlanjutan lingkungan. Penerapan teknologi tersebut berpotensi meningkatkan keberlanjutan PER dan mendukung eliminasi merkuri secara permanen.
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Community Gold Mining (CGM) still widely uses mercury in gold processing, which poses risks of environmental pollution, health deterioration, and land degradation. Although miners in Tatelu and Talawaan Villages are familiar with cyanide leaching methods, gold recovery remains low (<60%) and adequate waste treatment has not yet been implemented. This study aims to develop adaptive, productive, and environmentally sound technical recommendations for CGM activities through: evaluating the performance of the grinding process to obtain the optimum particle size; optimizing the cyanide leaching process to enhance gold dissolution; and optimizing the destruction of free cyanide to ensure compliance with effluent quality standards. Preliminary field observations at the gold processing units were conducted prior to the research activities. In the first year, laboratory analyses were carried out to determine particle size distribution, free cyanide content, and concentrations of gold, silver, copper, and sulfur in samples collected from the study area. In the second year, the performance of the grinding process was evaluated using andesitic river-deposit rock media, steel balls, and steel rods, followed by cyanide leaching optimization based on particle size and slurry density. In the third year, 0ptimization of cyanide waste destruction was performed using the sulfur dioxide and air process with a response surface methodology (RSM) approach. The performance evaluation of the milling process using a 12” × 12” trommel with a 7.5-kg sample showed that the use of andesite grinding media, under appropriate operating parameters, was able to produce gold ore powder meeting the target fineness, namely 75% passing 74 µm in 4 hours and 75% passing 44 µm in 6 hours. These conditions support improved gold dissolution and optimal recovery. The cyanide leaching optimization study using a 25-L tank with a 5-kg sample, based on variations in particle size and slurry density, indicated that a particle size of 75% passing 44 µm with a slurry density of 25% solids achieved the highest gold dissolution rate, reaching 87.43% at 48 hours and 89.08% at 72 hours. Meanwhile,the combination of 75% passing 74 µm and a slurry density of 35% solids—with dissolution rates of 80.74% at 48 hours and 84.26% at 72 hours—is recommended as the optimum condition for 0perational applications in CGM. The cyanidation tanks used for CGM operations in Tatelu and Talawaan have an average capacity of approximately 40,000 L. At this capacity, the 75% passing 74 µm particle size with a slurry density of 35% solids can process about 14 tons of ore, while the 75% passing 44 µm size with a slurry density of 25% solids can process about 8.5 tons of ore.
The optimization of cyanide waste destruction at a 2.8 L waste sample using a response surface methodology through the sulfur dioxide and air process catalyzed by copper(II) showed that the optimum conditions were achieved at an SO₂/CN⁻ mass ratio of 10, a Cu²⁺ catalyst concentration of 50 mg/L, and a reaction time of 4 hours. Under these conditions, free cyanide was effectively reduced from 200 mg/L to <0.5 mg/L, meeting environmental quality standards. Overall, this study provides experimentally validated cyanide leaching and waste treatment technologies that significantly improve gold recovery > 20% compared to existing CGM practices, while adhering to principles of productivity, adaptability, and environmental sustainability. The implementation of these technologies has strong potential to enhance ASGM sustainability and support the permanent elimination of mercury use.
| Item Type: | Thesis (Doctoral) |
|---|---|
| Uncontrolled Keywords: | PER, optimalisasi pelindian sianida, pengolahan limbah, produktif, adaptif, ramah lingkungan |
| Subjects: | T Technology > TD Environmental technology. Sanitary engineering > TD194.6 Environmental impact analysis |
| Divisions: | Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Environmental Engineering > 25001-(S3) PhD Thesis |
| Depositing User: | Dadan Mohamad Nurjaman |
| Date Deposited: | 24 Dec 2025 00:59 |
| Last Modified: | 24 Dec 2025 00:59 |
| URI: | http://repository.its.ac.id/id/eprint/129141 |
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