Crucible furnace gold alchemy is carried out in the crucible furnace. The crucible furnace is built with ordinary clay refractory bricks, with a cone shape. The upper part has a smaller diameter than the bottom. The bottom of the furnace is staggered with 2~3 layers of refractory bricks, and the brick joints are built with refractory mud. The furnace shell is made of 3 mm steel plate. The furnacelining is refractory brick masonry. Fill asbestos dust or diatomaceous earth between the inner lining and the furnace shell. The furnace roof is compressed with refractory bricks to ensure the temperature in the furnace. Fuels usually include heavy oil, diesel and gas, which are supplied from the side of the furnace. Without the above conditions, a coke oven can be used instead.
The crucible furnace gold alchemy process is as follows:
(1) Heating and baking: slowly increase the furnace temperature and bake the crucible. Slow heating is to prevent the damp crucible from bursting due to sudden heat.
(2) Heating and feeding: When the temperature continues to rise to 800°C, take out the crucible from the furnace, carefully add the stirred charge into it, and cover a small amount of borax on the upper part of the charge. When the charge in the crucible is melted, stop the oil and wind, add part of the charge wrapped in paper, and continue heating. The charge can be added multiple times.
(3) Melting: After the charge is full, it will enter the full melting stage. Usually a 20# crucible can melt 10-15 kg of gold mud at a time. The melting takes 1.5 hours. After the melting is completed, stop the oil and wind, and use special tongs to remove the crucible from the furnace. Take it out, and quickly pour the melt into a squat tank (a cone-shaped cast iron tank with a big bottom and tip) for layer cooling, pour it out after condensation, and separate the slag from the gold and silver alloy with a small hammer.
(4) Ingot casting: After smelting, all gold nuggets are concentrated for ingot casting.
Crucible gold alchemy is mostly found in small mines. It is suitable for smelting placer gold, mercury paste and gold-containing steel wool, and can also be used for smelting cyanide gold mud.
Post time: Jan-07-2021