Ceramsite use clay, silt clay, coal gangue, fly ash and other inorganic materials as the main raw materials, through compounding, pelletizing and then roasting into the artificial lightweight aggregate under the high temperature. The internal has closed pore structure, is lead gray or grayish black ceramic like material. the surface layer has a dense and hard enamel, which is brownish gray, iron gray or dark red.

One. The classification of ceramic
Due to the classification of the different varieties of ceramsite, there are mainly the following classification methods.

1. According to the main raw material classification
(1) Clay ceramsite: It uses the clay or silt clay as the main raw material, through pelletizing and sintering into a kind of artificial light material.

(2) Shale ceramsite: It uses the shale, slate, etc as the main raw material, sintering into a kind of artificial lightweitght material after crushing, screening, grinding and pelletizing.

(3) Fly ash aggregate: It uses the coal ash as the main material, sintering or burning into a kind of an artificial lightweight aggregate after pelletizing.

(4) Coal gangue: It uses the coal gangue as main raw material, sintering and expanding into an artificial lightweight aggregate after crushing, grinding, pelletizing.

And so on, as there are tailings ceramsite, etc..

2. According to the ceramic properties classification
(1) A super lightweight aggregate: The bulk density is not greater than the 500kg/m3 for the insulation or the structure thermal insulation use cermasite.
(2) Ordinary ceramic: The bulk density is greater than 510kg/m3;
(3) High strength ceramic: The strength of the structure use cermasite is not less than 25MPa.

3. According to the shape of the ceramic
(1) Globe type: A spherical or cylindrical granular ceramsite
(2) Ordinary type: It referes to the non crushing shale ceramsite by the dry process production, mainly is the irregular, the sub-rounded, or subangular.
(3) Crushed rock type: It refers to the burnt and expanded shale block or the ceramic aggregate, after the process of crushing, which is the ceramsite in the shape of stone.

4. According to the production process
(1) Burning expansion type ceramic: It refers to the ceramsite with volume expansion in the process of sintering.
(2) Sintered type ceramsite: It refers to the ceramsite without the volume expansion in the process of sintering, with great density, commonly fly ash sintered ceramic.