Shaft kiln’s energy conservation. The inner shaft kiln is divided into reheating zone, calcimining zone and cooling zone from the top to bottom. The cooling air is blown into the kiln from the bottom of the cooling zone. After heat exchange, the product is cooled while the cooling air is preheated. The cooling air carrying heat enters the calcining zone to participate in combustion to reduce energy consumption.

Shaft kiln’s heat preservation. The kiln skin is built of four layers of refractory material, so the kiln skin temperature can be controlled at about 60 °C above the ambient temperature, and the energy-saving is remarkable.

Shaft kiln’s refractory material’s long service life. The material does not directly collide with the refractory material’s working surface but relies on gravity settlement and friction of the working surface. This greatly reduces the wear rate of the refractory material, so normally the refractory material can be used for 6 to 10 years.

Shaft kiln’s good sealing. The concentration of CO2 in the flue gas can reach more than 35%, and the recovery cost of CO2 is low, which is more suitable for the nanometer calcium carbonate industry.

Shaft kiln’s fuel adaptability’s extensive. The mixed kiln can use block coal such as lump coal, coke, and petroleum coke; the gas kiln can use high calorific value fuel such as natural gas, coke oven gas, petroleum gas, etc or low calorific value fuels such converter gas, blast furnace gas, calcium carbide, furnace tail gas, blue carbon gas, and producer gas; oil kiln can use liquid fuel such as heavy oil and diesel oil.

Shaft kiln’s small floor space. The vertical kiln is arranged upright. The single-hopper hoist is arranged at a large angle, and the functional areas are compactly arranged to greatly reduce the floor space.

Shaft kiln’s less investment. The kiln steel structure has fewer machining parts and lower processing costs. The installation difficulty is not high, and the refractory masonry is not difficult.