Bacterial leaching of copper mineral materials - bacterial l
2020-11-16 11:17Introduction：Bacterial leaching of copper mineral materials- bacterial leaching production practice 2 At present, the bacterial leaching process of copper and uranium is mature, and the leaching of copper can be recovered by extract-electrodeposition o
Bacterial leaching of copper mineral materials - bacterial leaching production practice 2
At present, the bacterial leaching process of copper and uranium is mature, and the leaching of copper can be recovered by extract-electrodeposition or iron display-flotation.
There are many examples of using bacteria in mineral processing in China, such as bacteria leaching from a copper mine in Guangdong province, a copper mine in Anhui province, and a copper mine in Hunan province.
The technological process of bacterial leaching for tailings is shown in Fig6-5.Because of the fine size of tailings, so leachate leaching is done in leachate pool.Acid was first added in order to acidify water and alkaline gangue in ore. When pH reached about 2.0, The leaching solution containing microbial high iron (Fe3+) was added for recycling leaching until the concentration of copper and rare metals in leachate was very low.Then the bacteria leachate of copper and a very low leaching solution of rare metals is added. When the concentration of leachate is lower, it can be washed for 2 to 3 days,then it can be discharged.The leaching time of tailing is 20 days, and the leaching results are shown in table 6-6.
Table 6-6 results of tailing bacteria leaching
| Leaching tank number | inventory /t | Sulfuric acid consumption /kg.t-1 | temperature /℃ | Leaching cycle /days | copper grade /% | Rare metal leaching rate /% | ||
| Head ore | Leaching residue | Leaching rate | ||||||
|
1 2 3 |
100 100 100 |
34 32 30 |
25~35 25~35 25~35 |
27 18 23 |
0.81 1.25 1.51 |
0.17 0.48 0.44 |
79.02 61.60 70.86 |
86.4 51.85 80.37 |
After adsorption of rare metals in the leachate solution, the tailings solution contains about 1.5 ~ 2.0g/L of copper. Iron replacement is adopted to precipitate copper as sponge copper. The chemical reaction formula is as follows:
Fe+CuSO4→FeSO4+Cu↓
Operating conditions of iron displacement:
1. The higher the copper content is, the better; the iron content is as low as possible. pH value =1.8~2.0;
2. When the pH value of the solution is around 1.5 and the copper concentration is 2-4g /L, the iron consumption ratio is 2.0-2.5 times of that of copper;When pH value is around 2 and copper concentration is high, iron consumption ratio is 1.5 times of copper.
3. Iron displacement time, which is related to temperature, quality and quantity of waste iron, acidity of solution and displacement mode.Generally the temperature is greater than 20 ℃, ventilation conditions, 6 hours can replacement to complete;
4. Discharge tailings immediately after replacement, adjust the Fe2+ concentration and acidity in tailings, and return to bacterial culture for use.
Main technical and economic indicators:
1. The total recovery rate of copper is 70% ~ 75%;The total recovery rate of rare metals is 75% ~ 80%;
2. The grade of sponge copper is 60% ~ 65%;
3. 40 ~ 45kg of sulphuric acid is consumed per ton of ore;Copper consumption per ton is 2.5 tons;
4. Converted pure metal copper costs 2000 yuan per ton.
