Calcium oxide is an inorganic compound whose chemical formula is CaO, commonly known as quicklime. The physical property is a white powder on the surface, the impure ones are off-white, the ramming material is hygroscopic when it contains impurities.
production method
Limestone calcination method
The limestone is coarsely crushed to 150mm, fine slag below 30-50mm is screened out. Anthracite coke requires a particle size of less than 50mm, the low melting point ash content in it should be too much. The amount of anthracite coke added is 7.5% to 8.5% (weight) of limestone. The selected limestone fuel are added into the kiln the top of the kiln in a fixed quantitative amount, calcined at 900-1200℃, then cooled to obtain the finished product. Carbon dioxide (CO₂) is by-produced in the calcination process. Its chemical equation is CaCO₃[△]→CaO+CO₂↑;
Pure nitric acid to dissolve marble
Boil it to remove CO₂. Add lime milk to the hot solution, filter to remove the hydroxide precipitates such as Cu, Fe, Mg, heat the filtrate when it is close to boiling pass CO₂ to produce Ca(HCO₃)₂, the amount of Ca(HCO₃)₂ is equivalent to the added Ca (OH) The amount of ₂. When the solution is boiled, Ca(HCO₃)₂ is decomposed into calcium carbonate precipitate, carrying trace amounts of Fe. Ca(NO₃)₂ in the filtrate is cooled added with 1/3 volume of concentrated ammonia water concentrated (NH₄)₂CO₃, another CaCO₃ precipitates. The CaCO₃ precipitate is washed dried, placed in a quartz crucible burned on an electric furnace to obtain pure calcium oxide. If you want to make high-purity calcium oxide, you should first synthesize high-purity calcium nitrate high-purity ammonium carbonate into calcium carbonate: after the precipitate is refined, it is dried in an oven, then burned (the temperature is gradually increased). Keep it at a constant temperature of 1000°C for 8 hours, take it out a little cold, store it in a dry state. The product is 99.999% high-purity calcium oxide.
Calcium carbonate calcination method
Firstly, calcium carbonate hydrochloric acid are reacted to form calcium chloride, then ammonia water is added for neutralization, standing for precipitation, filtration, sodium bicarbonate is added to react to form calcium carbonate precipitation, which is centrifuged dehydrated, dried, calcined, crushed Screened prepared medicinal calcium oxide products