Gold-silver ore beneficiation technology

In addition to gold, gold - silver ore contains tens to hundreds of grams of silver per t ore. Silver is also a variety of silver minerals, such as snail-silver-silver ore, deep red-silver ore, and brittle, in addition to natural silver. Silver ore, sulphur- bismuth- copper- silver ore, pale red-silver ore, and horny silver ore exist. Some sulfides, such as galena, chalcopyrite, pyrite and stibnite often enriched in fine particles of silver.

Since silver often appears in various states in gold-silver ore, it is often treated by a combined process of two or more methods. The characteristics of silver in ore and its recovery methods are shown in Table 1.

Table 1 Characteristics of silver in ore and its recovery method

1 The coarse fraction of the mineral can be recovered by re-election.

Japanese Chitose gold - gold silver beneficiation plant process - silver ores, natural minerals metallic gold, argentite, magenta silver, pink silver, brittle silver, silver stibnite, chalcopyrite, tetrahedrite chalcopyrite, galena, sphalerite and pyrite. In addition to the presence of natural gold, gold is also encased in pyrite, with gold particles ranging from 10 to 50/μm and some from 100 to 150 μm. The gangue minerals are mainly quartz , chlorite, feldspar , zeolite and calcite , followed by a small amount of barite .

When mainly treating sulfide ore, a single flotation is used to recover gold and silver. If the oxidized ore with a high grade is treated, the coarse gold is recovered by a re-election method (a suede chute and a shaker). If the effect of the flotation method is not good, some gold and silver can be recovered by cyanidation.

The process flow is shown in Figure 1. Production indicators and dosages are shown in Tables 2 and 3.

Figure 1 Principle process of gold-silver ore production process in Chitose Mineral Processing Plant, Japan

Table 2 Production indicators

Table 3 dosage of chemicals (for ore supply)

Another example is the treatment of gold-silver-silica vein type ore in Japan. Multi effect of clay mineral subjected to gold silvery gold (Au50% ~ 60%) is present forms, mainly silver and argentite quartz or clay present in conjunction with gold. The ore gold grade is 0-12g/t, and the ratio of gold to silver is 1:15-30.

The plant uses the re-election- amalgam -cyanide-flotation combined process to recover gold and silver, and the main output of gold and silver alloy, amalgam tailings and flotation concentrate are sold as separate products. 2.

Figure 2 Process flow of production process of ore in Japan

The characteristics of the production process are: 1 using recycled cyanide de-gold solution in grinding, jigging and grading operations. 2 In the grinding classification circuit, coarse gold and sulfide are recovered by a jig and a fleece chute. When the ore contains Au7.8g/t and Ag225g/t, the re-elected concentrate contains Au405.8g/t, containing Ag2406g/t, the recovery rate of re-selection gold is 10.86%, and the silver is 2.0%. 3 Re-election concentrate was treated by amalgamation method, the gold recovery rate was 81.8%, and the silver was 53.4%. 4 Add the No. 20 coagulant (ultra-short fiber) to the thickener to prevent the sludge from rising to accelerate the sedimentation speed of the slime and improve the processing capacity of the cylindrical vacuum filter. 5 Because the content of slime in the gold-containing solution is greatly reduced, the pore blockage of the filter cloth of the filter press in the zinc powder displacement and sedimentation process is overcome, and the consumption of zinc powder, fuel and solvent is reduced. 6 Concentrated products containing Au6.3g / t, Ag175g / t, cyanide leaching after 120 ~ 160h, gold cyanidation recovery rate of 93.9%, silver 87.1%. 7 In order to fully recover gold and silver, the cyanide tailings are pulverized with water and degreased by a hydrocyclone, and the grit is treated by flotation to recover gold and silver.