Extraction of tin consists of three parts, i.e. tin ore concentration, smelting and refining. Cassiterite is the main source of tin ore, with specific gravity of 6.8-7g/cm³, density larger than most of gangue. Therefore, 90% of tin concentrate is mainly obtained from cassiterite through gravity separation. Meanwhile, flotation, magnetic separation, electric separation as well as roasting, leaching and volatility are also combined used to improve the tin recovery rate, reduce impurity content and collect valuable metals.

Metalcess uses the well-built pilot plant for all kinds of ore beneficiation tests to determine the optimized concentration process for our customer.

Reduction smelting is the dominant process to extract tin metal from tin concentrate. Metalcess suggests electrical arc furnace for tin smelting because of its relatively low cost, short process and smart iron removal.

The electrical arc furnace smelting produces crude tin, which can be further refined by getting rid of some other impurities, including removal of iron and arsenic by centrifugal filter, removal of lead and bismuth by continuous spiral finned electrical-heating crystallizer. High purity tin can be obtained directly through refining by spiral finned crystallizer. Alternatives can be electro-refining to treat crude tin with precious metal to produce high quality tin and collect precious metals.

During the refining of crude tin by continuous electric-heating crystallizer, a kind of byproduct soldering tin is produced. The soldering tin, mainly contains lead and tin, can be refined by vacuum distillation furnace. Metalcess uses multiple-stage distillation to reduce tin loss in lead vapor and get crude tin (Sn >99%) and crude lead (Pb> 98%).