1. Grinding fineness test
The monomer dissociation of gold or the exposed gold surface is a necessary condition for cyanide leaching or new non-toxic leaching. Therefore, appropriately increasing the grinding fineness can increase the leaching rate. However, over-grinding not only increases the grinding cost, but also increases the possibility of leachable impurities entering the leach solution, resulting in the loss of cyanide or gold leaching agent and dissolved gold. In order to select the appropriate grinding fineness, a grinding fineness test must first be carried out.
2. Pretreatment agent selection test
Gold mine leaching requires a pretreatment agent selection test. It is usually necessary to compare commonly used pretreatment agents such as calcium peroxide, sodium hypochlorite, sodium peroxide, hydrogen peroxide, citric acid, lead nitrate, etc. with those without pretreatment agents under normal circumstances. The purpose is to determine whether preprocessing operations are required.
Calcium peroxide, sodium hypochlorite, and sodium peroxide are very stable and widely used multifunctional inorganic peroxides, and have the characteristics of long-term oxygen release. They can slowly release oxygen in the leaching slurry for a long time, which is beneficial to improving the leaching rate of gold. .
Hydrogen peroxide and citric acid provide enough oxygen during the leaching process and are the main reagents for oxygen generation. The lead ions of lead nitrate (appropriate amount) can destroy the passivation film of gold during the cyanide leaching process, speed up the dissolution rate of gold, and reduce the cyanidation time to increase the leaching rate of gold.
3. Protection soda lime dosage test
In order to protect the stability of the sodium cyanide solution or non-toxic gold leaching agent and reduce the chemical loss of the gold leaching agent, an appropriate amount of alkali must be added during leaching to maintain a certain alkalinity of the slurry. The alkalinity is within a certain range. As the alkali concentration increases, the gold leaching rate remains unchanged, and the amount of gold leaching agent decreases accordingly. If the alkalinity is too high, the dissolution rate and leaching rate of gold will decrease instead. For this reason, it is necessary to determine Appropriate protective alkali dosage and slurry pH value. Lime, which is widely sourced and cheap, is usually used as the leaching protective alkali in tests and production. In order to determine its specific usage and provide guidance for actual production.
4. Gold immersion agent dosage test
In the gold leaching process, the dosage of gold leaching agent is directly proportional to the gold leaching rate within a certain range. However, when the dosage of gold leaching agent is too high, it will not only increase the production cost, but also the gold leaching rate will not change much. For this reason, based on the grinding fineness test, in order to further reduce the dosage of gold leaching agent and the cost of production reagents, a gold leaching agent dosage test was conducted to determine the appropriate dosage.
5. Leaching time test
In order to achieve a high leaching rate during the leaching process, the leaching time can be extended to fully dissolve the gold particles to increase the leaching rate. As the leaching time is extended, the gold leaching rate gradually increases and finally reaches a stable value. However, if the leaching time is too long, other impurities in the slurry will continue to dissolve and accumulate, hindering the dissolution of gold. To determine the appropriate leaching time, perform a leaching time test.
6. Slurry concentration test
During leaching, the concentration of the slurry will directly affect the leaching rate and leaching rate of gold. The greater the concentration, the greater the viscosity of the slurry and poor fluidity, the lower the leaching rate and rate of gold. When the slurry concentration is too low, although the gold leaching speed and leaching rate are high, the equipment volume and equipment investment will be increased, and the dosage of gold leaching agents and other chemicals will also be proportionally increased, correspondingly increasing production costs. In order to determine the appropriate leaching slurry concentration, a leaching slurry concentration test was conducted.
7. Activated carbon pretreatment test
For the carbon leaching method, hard and wear-resistant activated carbon must be used to prevent fine-grained carbon from entering the leaching residue due to wear during the stirring and leaching process, causing gold loss and reducing the gold recovery rate. The test generally uses coconut shell activated carbon, with a particle size range of 6 to 40 mesh. Activated carbon pretreatment, conditions are: water: carbon = 5:1, stirring for 4 hours, stirring speed 1700 rpm. After stirring for 4 hours, the activated carbon is sieved through 6-mesh and 16-mesh sieves. Remove fine carbon particles under the sieve. That is, activated carbon with a particle size of 6 to 16 mesh is selected for carbon leaching and carbon adsorption tests.
8. Bottom carbon density test
In gold mine leaching tests, it is generally determined to use coconut shell activated carbon with a particle size of 6-16 mesh to adsorb and recover the leached dissolved gold. After the gold-loaded carbon is produced, mature activated carbon is used to analyze and electrolyze the finished gold. The density of the bottom carbon directly affects the carbon adsorption rate. In order to select a suitable bottom carbon density, a bottom carbon density test will be conducted.
9. Carbon adsorption time test
In order to determine the appropriate carbon leaching (carbon adsorption) time and reduce the wear of gold-loaded carbon, after determining the total leaching time, it is necessary to conduct pre-leaching and carbon leaching (carbon adsorption) time tests.
10. Parallel test on comprehensive conditions of carbon leaching process
In order to verify the stability of the carbon leaching test and the repeatability of the test results, it is necessary to conduct a comprehensive condition parallel test of the entire process of the carbon leaching test. That is, after determining the above 9 detailed condition tests, it is necessary to conduct the best conditions for each final condition test. Comprehensive verification testing.
Post time: Jul-09-2024
