Calcium Carbide (CaC2), commonly known as calcium carbide, is one of the basic materials of organic synthetic chemical industry. It is an important raw material for acetylene chemical industry. Acetylene made from calcium carbide is widely used in metal welding and cutting.
Production methods are aerobic heating method and electrothermal method.
Calcium carbide is usually produced by electrothermal method, that is, quicklime and carbon-containing raw materials (coke, anthracite or petroleum coke) are produced in the furnace by arc melting reaction at high temperature.
The main production processes are: raw material processing; proportioning; adding the mixture into the electric furnace through the entrance or pipeline of the upper end of the furnace, heating it in an open or closed electric furnace to about 2000 C, and forming calcium carbide according to the following reaction: GaO+3C_CaC2+CO. The melted calcium carbide is taken out from the bottom of the furnace and packed as finished product after cooling and crushing. Carbon monoxide produced in the reaction is discharged in different ways according to the type of calcium carbide furnace: in the open furnace, carbon monoxide burns on the material surface, and the resulting flame spreads outward along with dust; in the semi-closed furnace, part of carbon monoxide is extracted by the suction hood placed on the furnace, and the remaining part is still burning on the material surface; In an airtight furnace, all carbon monoxide is extracted.
(1) Calcium carbide production process
After crushing and screening, the burned lime is sent to the lime warehouse for storage. The lime and coke which meet the demand of calcium carbide production are proportioned according to the prescribed proportion. The burden is sent to the top hopper of the electric furnace by a bucket elevator. The charge is fed into the electric furnace through the charge pipe. The charge is heated through the electric arc pad of the electrode and the resistance of the charge to form calcium carbide in the electric furnace. Calcium carbide is discharged regularly and put into the pot of calcium carbide. After cooling, it is crushed into a certain size specification, and the finished calcium carbide is obtained. In a calcium carbide furnace, the heat generated by arc and resistance heats the burden to 1900-2200 C. The total chemical reaction formula is: CaO+3C=CaC2+CO+10800 kcal.
(2) Production process of calcium carbide furnace
1. Ingredients, Feeding and Top Distribution
Qualified raw materials are metered and proportioned in the raw material processing workshop, then fed into the hopper of the electric furnace workshop by the bucket elevator, and fed into the annular hopper on the top of the furnace by the top distribution facilities, fixed belt conveyor and annular distributor. The burden distribution facilities on the top of the furnace distribute the burden into the bin as needed, and the charging pipe of the electric furnace is added into the furnace in batches.
2. Electric Furnace
Semi-enclosed calcium carbide furnace is composed of furnace body, furnace cover, electrode holder, electrode discharge and electrode lifting device, and is the main equipment for producing calcium carbide. The electric furnace is powered by transformer. The charge reacts at high temperature in the furnace to produce calcium carbide, and releases carbon monoxide gas. The generated calcium carbide is discharged from the outlet of the furnace. The furnace is opened by a burner, and the molten calcium carbide flows into the calcium carbide pot of the cooling car.
The pressure release of the electrode is controlled by oil pressure. A single-layer oil cylinder is used to hold the conical ring cylinder of the lifting electrode to press the conductive jaw plate. The normal elevation of the electrode is controlled by three Hoists on the fourth floor. The elevation, pressure release, holding and cutting control of the electrode are all controlled by buttons in the second floor operating room. The electric furnace is powered by a transformer. The charge reacts at high temperature in the furnace to produce calcium carbide and emits carbon monoxide gas. The resulting calcium carbide is discharged from the outlet of the furnace. The outlet is opened by a burner, and the molten calcium carbide flows into the calcium carbide pot of the cooling car.
The outlet furnace is equipped with a shield and an arc drilling rack, and a smoke exhaust hood is arranged above the outlet. The smoke generated during the extraction of the furnace is extracted by a fan.
3. Cooling, Crushing and Packaging of Electric Furnace
The molten calcium carbide is cooled in the carbide pot by a crane to corridor or packing room. After the carbide ballast solidifies, the carbide ballast is lifted out by a bridge crane and a single clamp and cooled on the cast iron floor. After cooling to a moderate degree, the carbide is crushed to a qualified size, and then packaged by grading poles and sent to the finished product warehouse.