The industrial technical requirements for granite have different focuses due to different uses.
1. The main requirements for natural granite blocks:
The main requirements of the building materials industry standard (JC-204-92) for natural granite blocks are as follows:
The blocks must have the shape of a right-angled parallelepiped. The large surface of the block should be parallel to the joint surface or pattern direction of the rock.
The size of the block requires a length greater than or equal to 140cm, a width greater than or equal to 60cm, and a height greater than or equal to 60cm.
Appearance quality requires that the hue, pattern and grain structure of the same batch of blocks should be basically the same. The quality requirements for the missing corners, missing edges, cracks, color lines and stains of the blocks shall meet the requirements of Table 4.24.6.
Physical performance requirements: density not less than 2.50g/cm3; water absorption not more than 1.0%; dry compressive strength not less than 60.0MPa; bending strength not less than 8.0MPa.
2. Quality requirements for acid and alkali-resistant granite:
(1) Quality requirements for acid-resistant granite Main chemical composition requirements: SiO2>70%～75%, the higher the content, the better the acid resistance; Al2O3>13%～15%; Fe2O3<0.5%; CaO<0.8%; MgO<0.4 %; Acid resistance is greater than 97.5%. hard. The thermal resistance (compressive strength after 10-40 thermal changes) is greater than 16.2MPa, the melting point is 1610°C, the expansion coefficient is less than 8×10-3, and the water absorption is less than 1.5%.
(2) The quality requirements of alkali-resistant granite require high CaO and MgO content. The higher the content, the better the alkali resistance. Some acid-resistant stones have high SiO2 content, but have low porosity and can also be used as alkali-resistant stones. The chemical composition of the alkali-resistant granite products produced by Qingdao Liushi General Factory is as follows: SiO276.6%, Al2O314.39%, (K2O+Na2O)9.07%, Fe2O31.14%, CaO1.34%, MgO0.68%.