Flotation process patentIn 1898, English brothers Alexander and Francis El applied for a British patent (No. 21,948) for their flotation process to separate valuable ore, such as copper, from the gangue (worthless rock) with which it is associated when mined. It was the first practical equipment to extract metals from low-content ore. Pulverized ore is mixed with water and brought into contact with thick oil. The oil entraps the metallic constituents, which are afterwards separated, and gangue passed away with the water. Today, flotation methods remain vital in the mining industry, processing millions of tons of ores each year. |
