Venue Facilities Materials Knowledge

Product Overview:

Calcium oxide, commonly known as lime or lime, chemical formula CaO, is a common inorganic compound. Calcium oxide is usually obtained from limestone or shells, and the calcium carbonate containing material is heated to 900Â° C. to decompose it into calcium oxide and carbon dioxide. This is a small number of prehistoric chemical reactions.

Calcium oxide production method:

1. Limestone calcination method:

Limestone is coarsely crushed to 150 mm and fine slag of 30-50 mm or less is screened out. The particle size of anthracite or coke is less than 50 mm, and the low melting point ash content should not be too much. The amount of anthracite or coke added is 7.5% to 8.5% (by weight) of limestone. The selected limestone and fuel are timed and quantitatively added from the top of the kiln to the kiln, calcined at 900-1200Â°C, and then cooled to obtain the finished product. Carbon dioxide is by-produced during the calcination process.

2. Dissolve marble with pure nitric acid:

Boil it to remove clean CO2. Lime milk is added to the hot solution, and the precipitates of hydroxides such as Cu, Fe, Mg are removed by filtration, and the filtrate is heated to reach CO2 to produce Ca(HCO3)2 when it is close to boiling. The amount of Ca(HCO3)2 is equivalent to the added Ca. The amount of (OH)2. When the solution is boiled, Ca(HCO3)2 is decomposed into a precipitate of calcium carbonate and carries trace amounts of Fe. After the Ca(NO3)2 in the filtrate is cooled, 1/3 volume of concentrated ammonia and concentrated (NH4)2CO3 are added, and CaCO3 is precipitated. The CaCO3 precipitate was washed and dried and placed in a quartz crucible and calcined on an electric furnace to obtain pure calcium oxide. To obtain high-purity calcium oxide, high-purity calcium nitrate and high-purity ammonium carbonate should first be used to synthesize calcium carbonate: After the precipitate is refined, it should be dried in an oven and then burned (control temperature gradually increases). After being kept at 1000Â°C for 8 hours, it was taken out and cooled, and then stored dry. The product obtained was 99.999% of high purity calcium oxide.

3, calcium carbonate calcining method:

The calcium carbonate is first reacted with hydrochloric acid to generate calcium chloride, then ammonia is added for neutralization, the precipitate is allowed to stand still, filtered, then sodium bicarbonate is added to react to produce calcium carbonate precipitate, dehydrated by centrifugation, dried, calcined and crushed, Screening, finished pharmaceutical calcium oxide products.

The use of calcium oxide:

1, can be used as filler, for example: as a filler for epoxy adhesives;

2. It is used as an analytical reagent, used as a carbon dioxide absorbent in gas analysis, spectroscopic analysis reagents, high purity reagents for epitaxy and diffusion processes in semiconductor production, laboratory ammonia drying and alcohol dehydration.

3, as raw materials, can produce calcium carbide, soda ash, bleaching powder, etc., but also for leather, wastewater purification, calcium hydroxide and various calcium compounds;

4, can be used as building materials, metallurgical flux, cement accelerator, phosphor flux;

5, used as a vegetable oil decolorizer, drug carrier, soil conditioner and calcium fertilizer;

6, can also be used for refractory materials, desiccants;

7, can be prepared agricultural machinery 1, 2 plastic and underwater epoxy adhesive, also used as a pre-reaction with 2402 resin reactant;

8, for acidic wastewater treatment and sludge conditioning;

9. It can also be used as a boiler stop protection agent, using the moisture absorption capacity of lime to keep the metal surface of boiler steam system dry and prevent corrosion. It is suitable for the long-term decommissioning protection of low-pressure, medium-pressure and small-capacity drum boilers;

10. It can react with water to prepare calcium hydroxide. The reaction equation: CaO+H2O==Ca(OH)2 belongs to the compounding reaction.

11, as a desiccant

Emergency monitoring method for calcium oxide:

1, laboratory monitoring methods: automatic F-2400 surface area analyzer BET test

Direct Conductivity Determination of Free Calcium Oxide in Cement Clinker

2. Environmental standards:

The highest allowable concentration of harmful substances in the atmosphere of the former Soviet Union workshop is 1mg/m3

3, emergency treatment and disposal methods:

(1) Emergency response

Isolation of contaminated areas and restrictions on access. It is recommended that emergency personnel wear self-absorbing filter type dust masks and wear anti-acid and alkaline work clothes. Do not touch the spill directly. A small amount of leakage: Avoid dust, collect with a clean shovel in a dry, clean, covered container. A lot of leaks: spray-like water controls dust and protects personnel.

(2) Protective measures

Respiratory Protection: It is advisable to wear a self-absorbing filter type dust respirator when it may come into contact with dust.

Eye protection: Wear chemical safety goggles when necessary.

Protective clothing: wear anti-acid work clothes.

Hand protection: wear rubber gloves.

Others: No smoking, eating and drinking in the workplace. Wash hands before meals. After work, take a shower and change clothes. Pay attention to personal hygiene.

(3) first aid measures

Skin contact: Immediately remove contaminated clothing and wash with vegetable oil or mineral oil. Rinse with plenty of running water. Get medical attention.

Eye contact: Lift eyelids and wash with vegetable oil. Get medical attention.

Inhalation: quickly from the scene to fresh air. Keep the airway open. If breathing is difficult, give oxygen. If breathing stops, give artificial respiration immediately. Get medical attention.

Ingestion: Wrong mouth rinse with water and drink milk or egg white. Get medical attention.

Extinguishing methods: Extinguishing media: carbon dioxide, dry sand, dry powder.

environmental impact:

I. Health hazards

Invasive route: inhalation, ingestion.

Health hazards: This product is a basic oxide, which reacts with water in the human body to generate strong alkali hydroxide and release a lot of heat, which has stimulatory and corrosive effects. Irritating to the respiratory tract, inhalation of dust can cause chemical pneumonia. Eye and skin irritation, can cause burns. Oral irritation and burning of the digestive tract. Long-term exposure to this product can cause palmar skin keratinization, palpebral fissure, finger deformation (spoon).

Two, toxicology information and environmental behavior

Hazardous characteristics: Can react violently with acids. Has a strong corrosive nature.

Combustion (decomposition) product: Calcium oxide.

It stimulates mucous membranes and causes sneezing, especially saponification of fats. It absorbs water, solubilizes proteins, stimulates and erodes tissues.