Humic acid wet sulfuric acid bismuth extraction process
Humic acid wet sulfuric acid bismuth (HASB) extraction process is a kind of hydrometallurgical process used to extract bismuth from raw ore. Compared with the traditional dry roasting smelting process, this process can achieve higher metal recovery efficiency and lower atmospheric emissions.
The wet sulfuric acid bismuth extraction process is based on the chemical reaction between sulfuric acid, humic acid and metal bismuth. The HASB process can enjoy the synergistic effect between organic acid and inorganic acid and improve the metal bismuth extraction efficiency. The process consists of four steps, leaching, precipitation, neutralization and filtration. The extraction process of bismuth from the waste of zinc smelting is as follows.
1.Leaching: Add sulfuric acid, humic acid and flocculant to the bismuth concentrate waste, adjust the water content and pH value, then put the material into the leaching tank to leach the bismuth out. The leachate is pumped to the crystal precipitation tank.
2. Preciptation: adjust the pH value of the leachate to 6.0-7.0, add sodium sulfide and flocculant to make bismuth sulfide precipitate out of the solution. The precipitated bismuth is washed and collected, then dried and concentrated.
3.Neutralization: After the precipitation of bismuth sulfide, the leachate contains residual acid and humic acid, which needs to be neutralized by adding calcium hydroxide or other alkali to the precipitation tank.
4.Filtration: Finally filter out the residual slag from the leachate with filter press.
This process is effective for the recovery of bismuth from bismuth concentrate and other low grade bismuth containing materials. Compared with the traditional smelting and roasting process, the HASB process can produce bismuth with a higher concentration and a larger yield, with fewer emissions and lower energy consumption.
The main disadvantages of hasb extraction process are the high humic acid consumption and the strict requirements for slurry concentration. The requirements for humic acid are especially stringent and the environmental impact of humic acid is another issue. In order to reduce the environmental load and improve the efficiency of the extraction process, several improvements have been made in the extraction process, including the use of various additives, such as surfactants and polymers, to reduce the amount of humic acid used.
To sum up, humic acid wet sulfuric acid bismuth extraction process is a kind of effective hydrometallurgical process for the extraction of bismuth from ores, wastes, etc. Compared with the traditional smelting and roasting process, this process can produce bismuth with a higher concentration and a larger yield, with fewer emissions and lower energy consumption. In addition, some improvement measures have also been proposed to reduce the environmental load and improve the efficiency of the extraction process.
