Faktor Apa Saja yang Menentukan Tingkat Pemulihan Amalgamasi Emas?

Penggabungan emas is a traditional method of extracting gold by binding it with mercury to form an amalgam, which is then heated to isolate pure gold. While historically significant, this process presents concerns due to mercury’s toxicity and environmental risks. The recovery rate—the efficiency of gold extraction via amalgamation—is influenced by multiple factors, including gold particle size, mercury quality, slurry concentration, pH levels, and temperature. Modern mining increasingly favors safer alternatives like cyanide leaching, but understanding amalgamation’s mechanics remains relevant for legacy operations and regulatory contexts.

Apa yang dimaksud dengan Amalgamasi Emas?

Penggabungan emas is a method of extracting gold from its ores by mixing it with mercury. It is an ancient gold separation method. This process forms a campuran emas-merkuridi mana partikel emas terikat secara kimiawi dengan merkuri. Amalgam kemudian dipanaskan untuk menguapkan merkuri, meninggalkan emas. Teknik ini secara historis telah digunakan dalam penambangan emas, terutama di daerah-daerah di mana emas tersebar halus dalam bijih dan mungkin tidak mudah diperoleh dengan metode lain.

Tingkat Pemulihan Amalgamasi Emas

The tingkat pemulihan amalgamasi emas mengacu pada persentase emas yang berhasil diperoleh melalui proses amalgamasi. Angka ini mengukur efisiensi metode ekstraksi emas yang melibatkan penggunaan merkuri untuk membentuk amalgam emas-merkuri.

Tingkat perolehan kembali dihitung dengan membandingkan jumlah emas yang diperoleh kembali melalui proses amalgamasi dengan jumlah total emas yang ada dalam bijih atau konsentrat. Angka ini dinyatakan dalam bentuk persentase dan memberikan gambaran tentang keefektifan proses amalgamasi dalam menangkap dan mengekstraksi emas dari bahan baku.

Tingkat perolehan yang lebih tinggi menunjukkan bahwa sebagian besar emas dalam bijih berhasil digabungkan dan diperoleh kembali. Tingkat pemulihan yang lebih rendah menunjukkan bahwa sejumlah besar emas tetap tidak terpulihkan atau hilang selama proses tersebut. Praktik pertambangan modern bertujuan untuk memaksimalkan tingkat perolehan kembali sekaligus meminimalkan risiko lingkungan dan kesehatan yang terkait dengan penggunaan merkuri dalam proses amalgamasi emas.

Faktor-faktor yang Mempengaruhi Tingkat Pemulihan Amalgamasi Emas

Tingkat pemulihan emas selama penggabungan merkuri tergantung pada the particle size and shape of natural gold, the color of gold particles, the quality of mercury, the mercury amalgamation temperature, the slurry concentration, the mercury amalgamation method, and equipment factors, etc.

1. Gold Particle Size and Shape

The particle size, shape, and monomer dissociation degree of gold are mainly related to the grinding operation. In particular, the degree of monomer dissociation has a more significant impact. Increasing the grinding fineness can improve the recovery rate of mercury amalgamation operations. Gold particles suitable for mercury amalgamation generally are 0.2-0.3 mm. The lower limit of the mercury amalgamation plate particle size in the grinding cycle is 0.015 mm, but the fine gold particles are lost with the slurry.

2. Kehalusan Butiran Emas

Warna emas placer lebih tinggi daripada warna emas vena, and the color of gold in the oxidation zone is higher than that of primary ore. Gold with a high color is prone to amalgamation with mercury. If the surface of gold particles is contaminated, their amalgamation ability will significantly reduce.

3. Metode Amalgamasi Merkuri

Amalgamasi merkuri dibagi menjadi penggabungan merkuri internal dan penggabungan merkuri eksternal. External mercury amalgamation is mixing mercury to extract gold outside the crushing chamber. External mercury amalgamation is commonly used in China with fixed and vibrating mercury amalgamation plates. Internal mercury amalgamation is performed outside the crushing chamber. During the grinding operation cycle, mercury amalgamation is used to extract gold. Gold mines in South Africa and the United States often use mercury amalgamation in ramming machines. Small and medium-sized gold mines in the Soviet Union often use disc rollers. In China, mercury amalgamation cylinders are often used. The efficiency of internal mercury amalgamation is higher than that of external mercury amalgamation, and the quality of mercury gold is good. The concentration of external amalgamated mercury slurry should not be too high to form a loose, thin slurry flow, and the flow rate should not be too high to allow gold particles to settle onto the mercury plate. The concentration of internal mercury slurry should be 30-50%, and the mercury should be suspended.

4. pH Bubur

pH lumpur memiliki pengaruh yang besar terhadap efek penggabungan merkuri. Efek penggabungan merkuri baik dalam media asam dan larutan sianida, tetapi ketika ada banyak lendir, media asam tidak dapat menggumpalkan lendir, dan lendir mencemari permukaan partikel emas, yang mempengaruhi efek penggabungan merkuri. Ketika merkuri dicampur dalam media basa, seperti menggunakan kapur sebagai pengatur untuk mengendapkan garam yang dapat larut dan menghilangkan efek buruk dari kualitas minyak, dampak pencampuran merkuri lebih baik ketika PH = 8-8,5.

5. Massa Merkuri

Kualitas raksa sangat mempengaruhi efek penggabungan raksa. Raksa murni tidak baik untuk membasahi emas. Merkuri yang mengandung sejumlah kecil emas, perak, dan logam dasar dapat mengurangi tegangan permukaan merkuri dan meningkatkan efek pembasahan. Oli motor, bahan organik lainnya, dan lumpur halus akan mencemari permukaan partikel emas. Bijih sulfida, bedak, grafit, dan arsenida dalam bijih dengan mudah menempel pada permukaan merkuri, yang juga mempengaruhi kemampuan pembasahan merkuri terhadap emas.

When mixing mercury, add an appropriate amount of mercury. Too much will reduce the elasticity and consistency of the mercury paste, causing the amalgam to be lost with the slurry. Insufficient addition of mercury makes the mercury paste hard and loses its elasticity, reducing its gold-capturing performance. After the mercury board is put into production, the initial mercury coating amount is 15-30 grams/cubic meter, and mercury is added after 6-12 hours. The amount of mercury added is 2-5 times the gold content of the ore, and the consumption of mercury is usually 3-8 g/ton of ore.

6. Suhu Amalgamasi

In addition, temperature also affects the effect of mercury amalgamation. If the temperature is too low, it will increase the viscosity of mercury and affect the mercury amalgamation effect. If the temperature is too high, it will increase the fluidity of mercury, causing some of it to be lost. Therefore, the mercury amalgamation index is prone to seasonal changes. The mercury amalgamation temperature should generally be greater than 15 degrees. Adding mercury and adjusting the slurry concentration are used to eliminate the influence of temperature.

Conclusion: Balancing Efficiency and Sustainability

While amalgamation can achieve high recovery rates under optimal conditions, its reliance on toxic mercury demands caution. Modern alternatives such as cyanide leaching and gravity separation now dominate the industry, prioritizing environmental and worker safety. For operations still employing amalgamation, meticulous control of the above factors—particle size, gold purity, method selection, slurry chemistry, mercury quality, and temperature—is essential to maximize yields and minimize harm.