Heap leaching: several technical points-3

Leaching of Gold Concentration:
Generally, according to the theoretical spray gold concentration, the gold grade of the precious liquid at the peak period of leaching is 5 times or more than that of the original ore, that is, the grade of the original ore is 3g/t. In actual production, due to various conditions, it is less than 5 times, but at least 2 to 3 times, especially for granulation heap leaching, adding suitable sodium cyanide solution for granulation and suitable heaping (without compacting the ore particles) , Appropriate spray amount, the precious liquid gold grade should reach the peak period between the 1st and 3rd day, reaching more than 6g/m3, and then gradually decrease later, so that the spray time does not need to be delayed for a long time, reaching 1g/m3. Below m3 is nearing the end. If the gold concentration does not reach the expected concentration or there is no obvious peak period, or the peak period is delayed and prolonged, it means that the heap leaching has failed, the leaching rate will not be too high, and the laboratory test index will not be met. This is all related to spray intensity or sodium cyanide concentration, pH value, etc., and should be checked and analyzed immediately, otherwise it will prolong the leaching time and reduce the leaching rate, waste sodium cyanide, which is not good for the next step of activated carbon adsorption, not only increasing the amount of adsorbed carbon, And the impurities will be adsorbed on the carbon, reducing the amount of gold adsorption, but also increasing the cost of electrolysis.
The difference between gold leaching rate and laboratory leaching rate:
In general, if the leaching rate of the column leaching test in the laboratory is 70%, it is understandable that the leaching rate on site should be 60-65%, because the laboratory conducts the column leaching simulation test under ideal conditions, but the field should not be very different, otherwise it should be Find out why.