The basic common sense of ferrochrome：

Medium, low and micro carbon ferrochrome is generally made of silicochrome alloy, chromite and lime as raw materials. It is refined and desilicated by electric furnace of 1500 ~ 6000 kV A and operated by high basicity furnace slag (CaO/SiO2 is 1.6 ~ 1.8).Low and micro carbon ferrochrome is also produced by hot mixing method on a large scale.Two electric furnaces are used in production, one for smelting silicon chrome alloy and the other for melting slag composed of chrome ore and lime.The refining reaction is divided into two stages in two tanks: (1) After the slag from the slag furnace is injected into the first tank, the silicon chromium alloy that has been initially desiliconized is added into the other tank. Due to the large excess amount of oxidizing agent in the slag and the sufficient desiliconization, micro-carbon ferrochrome containing less than 0.8% silicon and as low as 0.02% carbon can be obtained.② After the slag (containing about 15% Cr2O3) after reaction in the first tank is moved to the second tank, the silicon chromium alloy (containing 45% silicon) prepared in the silicon chromium electric furnace is heated into the slag. After reaction, the silicon chromium alloy (containing about 25% silicon) which is initially desilicated is obtained and added into the first tank for further desilication. The slag containing less than 2 ~ 3% Cr2O3 can be discarded.

The medium and low carbon ferrochrome is refined by oxygen blowing method. Liquid carbon ferrochrome is used as raw material. A small amount of lime and fluorite are added to the molten pool to make slag during blowing, and silicon chromium alloy or ferrosilicate is added before iron extraction to recover chromium in the slag.The blowing of micro – carbon ferrochrome is possible under a certain vacuum.

Vacuum solid-state decarburization process refined, with fine grinding of high carbon ferrochrome as raw material, the fine grinding of high carbon ferrochrome, part of the oxidizing roasting as oxidant and water glass or other adhesives, pressure ball, after low temperature drying, the car type vacuum furnace, the vacuum degree is 0.5 ~ 10 mm hg, temperature of 1300 ~ 1400 ℃ heating reduction under 35 ~ 50 hours,Microcarbon ferrochrome containing less than 0.03% carbon or even less than 0.01% carbon can be obtained.

Bulk verification sampling: when the batch is less than 10 tons, no less than 10 samples should be randomly taken from different parts;If the batch is more than 10 tons, less than 30 tons, no less than 20 samples should be randomly taken from different parts;When the batch is more than 30 tons, no less than 30 samples should be randomly taken from different parts.Each sample weight should be approximately equal, its lumpiness is not less than 20*20mm.The sampling amount shall not be less than 0.03% of the lot.All samples taken should be broken to less than 10mm and quartered to 1-2kg. After mixing, they should be divided into two equal parts, one for sample preparation and the other for retention.

Under normal circumstances, it is to check the content of chromium, followed by the content of carbon assay, chromium content under normal circumstances should be in 60%±0.5.