Gold loaded carbon desorption electrolysis
2020-09-04 09:51Introduction：Gold loaded carbon desorption electrolysis After the removal of wood chips and slime, the gold-loadedcarbon was desorbed by desorption of gold and silver on a desorption column. At present, there are four methods for desorption of gold loa
Gold loaded carbon desorption electrolysis
After the removal of wood chips and slime, the gold- loaded carbon was desorbed by desorption of gold and silver on a desorption column. At present, there are four methods for desorption of gold loaded carbon in production:
1.Zadra process: this was a famous process invented by Zadra in the United States in 1952. In this process, the hot mixture solution of 1% NaOH and 0.1% NaCN from 85 ℃ to 95 ℃ was used in this process through two analytical columns from the bottom up to top, and the desorption solution was sent to deposit gold and silver. The demineralized solution (barren solution) was returned to the No. 1 desorption column, and the desorption time was about 40 to 72 hours. The desorption time is 50 hours and the residual gold content in the carbon is 150 g / ton. This process can be applied to the gold beneficiation plant with small processing capacity, and the equipment investment and production cost are lower.
2. Organic solvent process : a process invented by Haining of the US Mining Administration, also known as alcohol desorption. The desorption of alcohol10~20%, NaOH1%0.1% and NaCN0.1% hot solution (80 ℃) was carried out under normal pressure, and the desorption time was 5 ~ 6 hours. The activated carbon can be reactivated every 20 cycles . The disadvantages of this process are that alcohol is volatile, toxic, flammable and explosive, and a good condensing system is needed to capture alcohol vapor to prevent fire or explosion. These shortcomings limit the popularization and application of this process .
3. High pressure process : invented for Porter of the US Bureau of Mines. The desorption was carried out at 160 ℃ and 354.64 kPa (3.5 atmospheres) with 1%NaOH and 0.1% NaCN solution for 2 ~ 6 hours. The disadvantage of this process is that it needs high temperature and high pressure, and the equipment cost is high. Its advantages are to reduce desorption time, desorption agent consumption and carbon storage. This process can be used in gold beneficiation plants with large amount of production and high gold content of activated carbon.
4. The South African Anglo-American Company Process (A.R.R.L): this process was proposed by Davydsson of the Anglo American Research Laboratory in Johannesburg, South Africa. In the desorption column, 10% NaOH solution (or 5%NaCN +2%NaOH solution) with 0.5 %~ 1 %carbon volume (93 ℃~110 ℃)was circulated for 2 to 6 hours, and then eluted with hot water of 5to 7 times carbon volumes. The flow rate of the eluent was 3 times carbon volumes per hour. The total desorption time is 9 ~ 20 hours, and its advantages are similar to those of high pressure desorption process, but the multi-channel liquid flow equipment is required, which increases the complexity of the system.
The gold solution was replaced with gold or zinc powder to replace gold and activated carbon for regeneration.
