Proses Pelindian Tumpukan Bijih Emas

Gold ore heap leaching is a widely used proses ekstraksi emas for low-grade and suitably permeable gold ores. The basic heap leaching process involves crushing and preparing the ore, stacking it on a properly designed and lined leach pad, distributing a suitable leaching solution over the heap, and collecting the gold-bearing pregnant solution at the bottom for subsequent recovery. Compared with conventional gold processing methods, heap leaching generally requires less equipment and lower energy consumption, making it an economical option for certain low-grade gold deposits. However, the performance of gold ore heap leaching depends strongly on ore mineralogy, particle size, permeability, cyanide and oxygen conditions, solution distribution, drainage, and leaching temperature. Therefore, proper ore preparation, heap construction, irrigation, solution collection, and process control are essential for improving gold recovery and maintaining stable heap leaching operation.

 

What Is Gold Ore Heap Leaching?

Pencucian timbunan is a process in which a prepared ore heap is irrigated with a suitable leaching solution. The solution passes through the ore under gravity, dissolving valuable components and carrying them into the collection system at the bottom of the heap.

Depending on the characteristics of the ore and the storage method, heap leaching can generally be classified as:

• Ore heap leaching: Used for crushed and prepared ore with sufficient permeability and suitable mineralogy.
• Waste-rock heap leaching: Applied to low-grade waste or marginal material containing recoverable valuable metals.
• Surface heap leaching: The ore is stacked on a prepared, lined surface and irrigated from above.
• Permanent heap leaching: Ore is placed in a long-term leach pad or permanent storage area rather than being removed after each leaching cycle.

Metode pelindian timbunan terutama digunakan dalam penambangan bijih tembaga, bijih uranium, bijih emas, dan bijih perakserta mengolah terak peleburan dan tailing pabrik yang mengandung bahan-bahan yang bermanfaat.

Metode pelindian heap leaching memiliki proses yang sederhana, peralatan yang lebih sedikit, dan konsumsi energi yang rendah, sehingga investasi infrastruktur dan biaya produksi juga rendah. Kerugian utamanya adalah tingkat pelindian komponen berharga dalam bijih rendah.

Tindakan Pencegahan Selama Ekstraksi Emas dengan Pelindian Tumpukan

 

Memperbaiki Proses Pelindian Timbunan

 

1. Penerapan teknologi granulasi yang tepat untuk meningkatkan pelindian emas

Praktik tersebut telah membuktikan bahwa material berbutir halus dan bijih dengan kandungan lempung yang terlalu tinggi tidak cocok untuk dilakukan pelindian secara langsung. Prapengolahan granulasi diperlukan untuk meningkatkan permeabilitas timbunan bijih sebelum pelindian timbunan. Praperlakuan granulasi dapat sangat memperkuat pelindian emas and speed up the gold leaching rate. In most cases, it can also improve the gold leaching rate.

Granulasi biasanya menggunakan kapur dan semen sebagai pengikat, tetapi dosisnya harus tepat.

 

2. Optimize Heap Construction and Leaching Methods

Produksi pelindian timbunan di luar negeri tidak menggunakan metode satu timbunan dan satu pembongkaran, tetapi menggunakan tempat penyimpanan permanen. Biasanya, tempat penyimpanan dipilih di lembah, atau tempat dengan area bawah yang luas. Metode penyemprotan untuk membangun tumpukan secara bergantian dalam lapisan, partisi, atau bagian diadopsi. Metode penyemprotan dapat sangat meningkatkan manfaat ekonomi perusahaan.

Permeabilitas gas pada tumpukan bijih dan permeabilitas larutan merupakan faktor kunci dalam menentukan efek pelindian tumpukan bijih.

Di beberapa tambang domestik, tabung bambu dan tongkat kayu dikubur di dalam timbunan, dan benda-benda yang terkubur ini ditarik keluar setelah periode pencucian, sehingga timbunan bijih akan menjadi longgar, dan peningkatan permeabilitas kondusif untuk pencucian bijih emas. Kementerian Geologi dan Sumber Daya Mineral Komprehensif Setelah periode pelindian tumpukan bijih oleh lembaga penelitian, peledakan pelonggaran lokal digunakan pada bagian yang tergenang air, yang juga berperan dalam melonggarkan tumpukan bijih dan meningkatkan permeabilitas; selain itu, pipa yang dibor dengan banyak lubang kecil terkubur di tumpukan bijih, Isi pipa dengan larutan sianida, dan larutan sianida menembus ke sekitarnya melalui lubang-lubang kecil; Bagi beberapa area di bagian atas tumpukan bijih sesuai dengan penetrasi yang cepat, dan suplai larutan sianida sesuai dengan luas dan volume yang sama, sehingga larutan sianida di area dengan penetrasi lambat Volume lindi sama dengan volume lindi yang cepat tembus, untuk mencapai tujuan infiltrasi yang seragam pada timbunan bijih.

 

3. Improve Pregnant Solution Collection and Drainage

Laying rich liquid collection pipes at the bottom of the ore heap can speed up the flow of the solution, eliminate ore accumulation water, increase the gold leaching speed, and prevent the ore heap from collapsing and causing landslides. In foreign heap leaching production, the bottom of the ore heap is almost entirely covered with liquid collecting pipes. In the domestic heap leaching production of Shanghang Zijinshan Gold Mine in Fujian and Kanggur Gold Mine in Xinjiang, etc., they have designed and laid liquid collecting pipes by themselves, and the effect is good. No rich liquid is found around the heap leaching field. The effluent solution was also quite clear. The Comprehensive Institute of the Ministry of Geology and Mineral Resources also adopted this measure during granulation and heap leaching and achieved obvious results.

 

4. Control Leaching Temperature

The reaksi sianidasi harus dilakukan pada suhu yang sedikit lebih tinggi, sehingga pada daerah beriklim dingin, masalah utama pelindian timbunan adalah larutan dan suhu. Ketika suhu pelindian lebih rendah dari 10°C, laju pelarutan emas akan menurun drastis. Untuk mengatasi kekurangan ini dan memperpanjang musim pelindian timbunan, larutan dipanaskan terlebih dahulu dan kemudian dikirim ke timbunan bijih.

 

5. Optimize Sprinkler and Drip Irrigation

Spraying and dripping are two different liquid distribution methods in the heap-leaching process. Both can produce a uniform liquid distribution effect, and uniform liquid distribution is one of the key factors in improving the gold leaching rate. The rotary swinging spray equipment widely used at home and abroad has the advantages of a large spraying area, uniform spraying liquid, no atomization, not easy to block, and convenient loading and unloading. The loss and wind entrainment loss are relatively large.

Drip leaching is suitable for heap leaching production under the natural conditions of drought, high temperature, strong wind, and water shortage in the Gobi desert area. Due to the unique advantages of drip leaching equipment, it has been widely used abroad. For example, 80% of heap leaching in the United States uses the drip method used to extract gold; with the success of the Saidu Gold Mine’s first application of drip equipment in my country, the trickle technology is also gradually popularized and applied in my country.

Investasi untuk meneteskan adalah 40% lebih kecil daripada investasi untuk peralatan penyemprotan, penguapan larutan berkurang dari 27% menjadi 6%, puncak pelindian emas muncul satu minggu lebih awal, dan waktu pelindian berkurang dari 109 hari menjadi 72 hari. Laju pelindian meningkat dari 70,5% menjadi 78,6%.

 

Meningkatkan Lingkungan Kerja Agen dan Meningkatkan Pencucian Bijih Emas

 

Application of Leaching Aids

Oxygen plays an extremely important role in the cyanidation process, and the use of oxidants is an important technical measure to improve gold ore heap leaching. Batt studied the promotion of barium, strontium, and calcium peroxides on cyanide leaching, and found that they can release oxygen into the solution. For example, for some ores, when adding 1.5kg/Ca0p, the heap leaching process can be sped up by 20 d.

An appropriate amount of impregnating or wetting agent is added to the cyanide solution to facilitate the penetration of the cyanide solution and react with the wrapped gold. Pre-alkali treatment before heap leaching can reduce the influence of harmful gold ions on cyanide leaching, reduce the amount of cyanide, and maximize the gold leaching rate. Multi-stage leaching can obtain precious liquid with a gold content of up to 4ppm, significantly higher than single-stage heap leaching.

 

Kesimpulan

Gold ore heap leaching is a relatively simple and cost-effective method for recovering gold from suitable low-grade ores, but achieving a high gold leaching rate requires careful control of the entire heap leaching process. Key factors include appropriate crushing and granulation, good ore heap permeability, uniform sprinkler or drip irrigation, efficient pregnant solution collection and drainage, suitable leaching temperature, and adequate oxygen and reagent conditions. In particular, improving solution distribution and maintaining good gas and liquid permeability can significantly enhance the contact between the leaching solution and gold-bearing minerals. For ores containing high clay content, fine particles, or other characteristics that restrict solution flow, pretreatment and process optimization are especially important. By selecting the appropriate heap construction method and leaching conditions according to the ore characteristics, mining operations can improve gold recovery, shorten the leaching cycle, reduce reagent and energy consumption, and achieve more stable and economical gold ore heap leaching results.