The main components are silica, alumina, iron oxide, calcium oxide, magnesium oxide and so on.
The chemical composition is 240-50% of silicon dioxide, 330-35% of aluminum oxide, 24-20% of iron oxide, 20-5% of calcium oxide and a small amount of magnesium, sulfur and carbon.
Its mineral composition mainly includes: anorthite, syenite, mullite, magnetite and pyrite, a large number of silicon-containing glass bodies (Al2O3 2SiO2), active SiO2, active Al2O3 and a small amount of unburned coal.
As long as the combustion is sufficient, there are not many harmful substances. In addition, when burning bricks, there is a special process to remove sulfur-containing components.
As long as the product is tested, you can build a house.