Experimental study and production practice of flotation recovery gold in a gold mine cyanide tailings

Mine ore properties belonging to a refractory gold ore, more than 90% gold package, a mine, two medium-temperature atmospheric beneficiation plant preoxidation - Cyanide gold extraction process, production capacity of 300t / d, a cyano end 2005 The tailings are about 500,000 tons, with an average gold grade of 1.52 g/t and a metal content of 760 kg.

After laboratory analysis, gold mainly exists in carbonaceous materials. In view of the high grade and high metal content of cyanide tailings, the company carried out flotation recovery gold test on its tailings in 2005 and successfully enriched in the laboratory. On the basis of the industrial production of the tailings, the annual processing capacity is 66,000 tons. After the production practice in 2006, the gold recovery rate is 83.11%, the recovered gold reaches 83.378kg, and the tailings average grade is 0.26g/t. The cost per ton of mine is 52.33 yuan, and other economic and technical indicators are close to the laboratory test indicators, meeting the expected design requirements. It is feasible to recover the gold resources of a gold mine cyanide tailings by flotation process, which creates economic and social benefits for the company.

First, flotation test

(1) Cyanide tailings properties

Cyanide tailing hematite as a main component, a carbonaceous material, quartz, calcite, feldspar, lime (lime desulfurization is added, the solid arsenic carried incoming) and the like, minor ingredients pyrite, white mica.

Since the ore is pre-existing with medium-temperature and atmospheric pressure chemistry, 90% of pyrite has been oxidized, cyanide tailings contain a small amount of pyrite, and process minerals research shows that gold mainly occurs in carbonaceous matter, accounting for all metals. 83% of the amount, gold in pyrite accounts for about 15%, and other forms of gold account for about 2%. Among the carbonaceous materials are finely divided activated carbon and organic carbon, both of which contain gold in a ratio of 3:7.

(2) Flotation test process

The flotation test flow is shown in Figure 1.

Table 1 Multi-element analysis results of cyanide tailings

The gold and silver mass fraction units are g/t.

Figure 1 Cyanide tailings flotation process

The gold grade of the sample is 1.52g/t, the fineness of the slurry is -43μm, accounting for 90%, and the solid concentration is 25%. The crude selection, three sweeps, and three selective closed-circuit flotation tests are used. The gold concentrate grade is 41.33g/ t, the tailings grade dropped to 0.25 g / t, the theoretical recovery was 84.02%, and the yield was 3.09%. The test results show that the cyanide tailings have easy flotation performance. It adopts one rough selection, three sweeps, and three selective closed-circuit flotation tests. The gold spirit grade is 41.33g/t, and the tailing grade is reduced to 0.25g/t. The theoretical recovery was 84.02% and the yield was 3.09%. The test results show that the cyanide tailings have easy flotation performance, and it is economical and practical to use the flotation method to recover the gold.

Second, industrial production

On the basis of experimental research, it was transferred to production applications and succeeded. Formally put into industrial production in early 2006, the daily processing capacity is 200t, the recovery rate is 83.11%, the gold concentrate grade is 42.11g/t, the actual yield is 3.00%, the tailings grade is 0.26g/t, and the annual output is Jinjing. The mine is 1980.0t and the metal amount is 83.378kg. The production cost is 52.33 yuan / t.

Third, economic benefit analysis

Due to the high gold price, high flotation recovery rate and relatively low production cost in recent years, the economic benefits are considerable. The gold price of 42.11g/t gold concentrate is about 120 yuan/g. In 2006, the annual output value was 10,005,300 yuan. The annual production cost was 3,453,800 yuan and the profit was 6,551,500 yuan. The flotation plant, equipment and infrastructure invested 5 million yuan, the test cost was 860,000 yuan, and the profit for the year was 691,500 yuan. The main production indicators for 2006 and 2007 are shown in Table 2.

Table 2 Main economic and technical indicators for 2006 and 2007

Fourth, the conclusion

The success of the gold mine cyanide tailings flotation gold test and production application has created profits for the company, which is very beneficial to the development and utilization of the two resources, and also solved the employment of many local laborers.

(1) Because of the high gold grade of the tailings, the amount of metal is high and has a high recovery value.

(2) The gold of the cyanide tailings of the gold mine is mainly embedded in carbonaceous materials. The carbonaceous materials are mainly graphite and fine-grained activated carbon, and the carbonaceous materials are easy to float.

(3) Compared with the production practice in 2006, the flotation test is close to all the indicators, of which the recovery rates are 84.02% and 83.11%, respectively, and the yields are 3.09% and 3.00%, respectively, slightly decreasing. The gold concentrate grades are respectively 41.33g / t, 42.11g / t, tailings grades are 0.25g / t, 0.26g / t.

(4) Due to the soaring price of gold and the slight increase in processing volume, the profit in 2007 was 1,603,700 yuan more than that in 2006.

(V) The success of the cyanide tailings recovery gold provides a reference for the company in the development and utilization of secondary resources, which promotes the life of the mine and realizes the resource utilization of the mine enterprise.

(VI) The cyanide tailings recovery gold project created a profit of 6,552,500 yuan for the company in 2006. In 2007, it created a profit of 8,552,200 yuan, solved the employment of 40 people, and promoted the local economic growth.