Gravity concentration tends to recover the pyrite with the gold, and only removes the lighter minerals, such as quartz, from the ore. The most difficult particles to gravity concentrate are the fines, and 75 microns to 2 microns are definitely very fine.
One method of separating gold from other metals, something commonly done with household electronics, involves using a tilting furnace to create a liquid metal mixture known as "slag." This slag is then heated, and the gold separates from other metals by dissolving away from it. You need a tilting ...
Learning how to separate the ingredients in a mixture allows us to separate out the valuable components from raw materials. For example, the whole purpose of mining is to take soil and rock and separate out the valuable ingredients such as gold, silver, copper, or other elements.
Quartz and gold are commonly found together, but this is where the two minerals' similarities end. Quartz is a plentiful mineral, whereas gold is rare and prized. Even though the minerals are found together physically, their structural differences make them easy to separate.