Calcium Metal Properties
Silver-white metal. The relative density is 1.54. Melting point (839 ± 2) ° C. The boiling point is 1484°C. Soluble in acid and liquid ammonia, slightly soluble in alcohol, and insoluble in benzene. The higher its purity, the slower its surface darkens in the air. When it encounters strong heat in the air, it will burn to generate calcium oxide and calcium nitride. Calcium hydride is slowly formed by reacting with hydrogen above 400°C. It reacts mildly with water at room temperature to form a calcium hydroxide protective film and reacts violently with water to release hydrogen when heated. The chemical properties are very lively, with a strong reducing ability, and it is easy to combine with halogen, sulfur, nitrogen, and so on. It can reduce almost all metal oxides when heated. And flammable.
Calcium Metal Preparation Method
There are electrolysis and reduction methods for the preparation of metallic calcium.
1. Electrolysis method: Put the dried anhydrous calcium chloride into the electrolytic cell, spray and melt the raw materials next to the anode (graphite) in the electrolytic cell with an oxyacetylene flame, then turn on the cooling water, put down the cathode (round steel), and touch The surface of the feed liquid is passed through an electric current. Let the molten material flow to the cathode to connect the circuit. After most of the raw material is melted, continue to add new material until it is 2-3cm away from the edge of the tank and the temperature is normal. Calcium metal is deposited on the cathode, and the current is 350-450A. The voltage is 20-25V, and the current should be reduced to 50100A before striking the calcium metal deposited on the cathode. After the knocked-off metal calcium is put into the oil, the cathode contacts the electrolyte liquid level again, and then the current is increased by 50-100A. In order to maintain the temperature of the electrolytic cell, feed should be added successively. Chlorine gas escapes from the anode and is recycled.
2. Reduction method: Limestone is usually used as raw material, calcined into calcium oxide, aluminum powder is used as a reducing agent, mixed in proportion after crushing, pressed into blocks, reacted under vacuum and temperature to generate calcium vapor and calcium aluminate, and reduced to crystallization Calcium is melted and cast into ingots to obtain calcium ingots.
Calcium Metal Applications
It is used as a deoxidizer for alloys, a reducing agent for high-quality metal smelting, a desulfurized and decarburized iron and iron alloys, a grain size regulator for special steel, and a cleaning agent for magnesium casting surfaces. Used in the manufacture of bearing alloys and dehydrating agents for oils. It is the raw material for the production of vitamin A and the manufacture of calcium hydride. It is also used to make various batteries, alloy electrodes, etc.
Calcium Metal Safety
Combustible items when wet. Hazard code number: GB 4.3 category. UN No.1401; IMDG CODE4335 page, category 4.3. The product is packed in metal barrels or bottles and is packed with argon or other sealed packages. The net weight of each barrel is 25, 50, and 100kg. The words “flammables” and “moisture-proof” are marked on the outer packaging. It should be stored in a warehouse in a cool, ventilated, dry and non-corrosive atmosphere, and open storage are strictly prohibited. Do not contact water and acid. During transportation, it should be waterproof, fireproof, and moisture-proof. The fine powder can spontaneously ignite when it meets humid air at room temperature, and there is a danger of combustion and explosion when exposed to high heat or strong oxidant. Can burn eyes and skin. Inhalation of dust can irritate the respiratory tract and lungs, causing coughing and difficulty breathing. Irritating to eyes, and even causing burns, causing permanent damage. When contacted or inhaled, immediately move away from the scene to a place with fresh air, and rinse with plenty of flowing water for at least 15 minutes to keep the respiratory tract unobstructed. If breathing is difficult, give oxygen. If not breathing, give artificial respiration immediately. Seek medical attention. If swallowed by mistake, rinse your mouth with water and drink milk or egg white. Seek medical attention. In case of fire, dry sand, and dry powder fire extinguishers can be used to extinguish the fire, and water is strictly prohibited.