Granular calcium carbideWhat's the main ingredient, you know?
Calcium carbide, the main components of calcium carbide, are inorganic compounds, white crystals, industrial products for gray-black lumps, the section is purple or gray. There is an immediate and intense reaction in the water, which produces acetylene and emits heat.
Calcium carbide is an important basic chemical raw material, mainly used to produce acetylene gas. Also used in organic synthesis, oxygen-acetylene welding and so on. A list of carcinogens released by the World Health Organization's International Agency for Research on Cancer, October 27, 2017, was initially collated and calcium carbide produced in the list of 3 carcinogens
Physical and chemical properties: The ore is yellowish brown or black block solid, pure is white crystal (including CaC2 higher is purple). Density 2.22 g/cubic centimeter, melting point 2,300 ℃ (related to CaC2 content), in the event of immediate and intense reaction, the formation of acetylene, and release heat, calcium carbide content of different melting point also changes. Impurities: Calcium carbide (Ca3 As2), calcium phosphate (Ca3 P2) and other impurities, with the action of water at the same time release hydrogen arsenide (AsH3), phosphine (PH3) and other toxic gases, so the use of calcium carbide produced by the acetylene toxic.
The CaC2 common crystalline genus is a quadrilateral crystal system, which is stable between 298K and 720K, and its structure is shown in the image on the right. The crystal structure of the quadrilateral CaC2 is similar to that of the NaCl type, but because [: c≡c:]2-ions are elliptical, directional arrangement, the crystal belongs to the Quadrilateral crystal system. In the [: c≡c:]2-ions of the CaC2 crystal, the c-c distance is 120pm, equivalent to the key length of the carbon-carbon three keys, and the distance between the CA and C is 259 and 282pm
Emergency treatment isolates leaking contaminated areas and restricts access. Cut off the fire. Emergency handlers are advised to wear self-contained positive pressure respirators and wear chemical protective clothing. Do not touch the leak directly. Small leakage: Mix with sand, dry lime or soda ash. Use a spark-free tool to collect in a dry, clean, covered container and move to a safe place. A large number of leaks: covered with plastic sheets and canvas. Liaise with relevant technical departments to determine the removal method.
Fire extinguishing methods: Prohibit water use or foam to extinguish the fire. Carbon dioxide is also ineffective. Fire must be used with dry graphite powder or other dry powder (such as dry sand).