One of the processes most used in gold mining for extraction metallurgical is the Merrill Crowe Process, whose creators were Charles Merrill and Thomas Crowe, around 1900.
Obtaining the highest amount of values after melting the precipitates, as well as reducing the amount of values in the slag are the primary objectives of this process.
To make the precipitation of metals such as gold and silver, you start with the clarification of the pregnant solution, this is derived from previous processes (such as heap leaching). This clarification is carried out in filters that contain metal meshes with synthetic filter cloth.
When the rich solution has been filtered, the next step is to take it to the vacuum tower, where the dissolved oxygen is removed from the solution. This process is very important since the precipitation of the values can be inefficient in the presence of oxygen.
As the process progresses, the next step is to add zinc dust, which triggers a chemical reaction of oxidation and reduction, which results in gold covering the zinc particles, along with other compounds such as mercury and silver.
Subsequently, the precipitate of gold and silver is obtained after passing the solution by filter presses, then precipitation will be melted in an oven from where the mercury is extracted mixed with fluxes.
The next step is to send it to an induction furnace in which it will be melted in order to separate the gold and the values of silver from other base metals. The final product is called Dore and it is poured into molds in order to form bars..
DINCO specializes in the manufacture of Vacuum Towers under ASME code. We have provided several equipment for repetitive customers in various countries as far away as Russia, using the Merrill Crowe process to excel in quality and efficiency.
Did you know that DINCO designed, manufactured and delivered to the United States one of the largest mining vacuum towers of the continent? It is a tower of 200,000 gallon capacity weighing 200 tons of steel.