Laboratory First to do of brick Plant
The raw materials chemical composition and physical properties (including the internal combustion heat, etc.) need to test, meanwhile measure the moisture of green bricks when just formed.
Chemical Analysis Chemical composition analysis is usually measured as SiO2, Al2O3, Fe2O3, MgO, CaO, magnesium oxide, sulfur gangue and loss on ignition, etc.
SiO2: Content is too high, lower plasticity, although good for fast-drying, however the finished products with low compressive strength;
Al2O3: If less than 12%, the mechanical strength of the products is reduced; If more than 24%, the firing temperature is increase, increasing the amount of coal;
Fe2O3: Content too high will reduce the products refractoriness, resulting in low of sintering temperature;
CaO: Presenting In a state of CaCo3 in raw materials, classified as hazardous substances, If the particles larger than 2mm, it is likely to cause crisp brick or burst when burning.
MgO: More less much better, otherwise, products easily growing generate magnesium, causing white hoarfrost；
Sulfur Dagan: Being sulphate in raw material, the content should not exceed 1%. When burning, it will make SO2 and corrode production line equipment, damage workers’ health workers.
Loss on ignition: It caused by organic in raw material. More organic, bigger gap rate in the products.
| Basic Items | Content | Percent |
| Name | Item |
| Chemical Component | SiO2 | Limited | 55～70 |
| Available | 55～80 |
| Al2O3 | Limited | 15～20 |
| Available | 10～25 |
| Fe2O3 | Limited | 4～10 |
| Available | 3～15 |
| CaO | Available | 0～10 |
| MgO | Available | 0～3 |
| SO3 | Available | 0～1 |
| Loss on Ignition | Available | 3～15 |
| Calcareous Content | ＜0.5mm | Limited | 0～25 |
| 2～0.5mm | Available | 0～2 |
Physical Performance Analysis Usually measure particles composed, plasticity, shrinkage, drying sensitivity and sinterability.
Particles Composed
| Particles category | Particle diameter | Reasonable composition |
| Plastic particles | <0.05mm | 35~50% |
| Filler particles | 0.05mm-1.2mm | 20~65% |
| Skeleton particles | 1.2mm-2mm | <30% |
Plasticity : When plasticity index is 7 to 15, most suitable for middle plastic mud extrusion;
Shrinkage: If linear shrinkage <6%, It is too high to lead to cracking, affecting the quality;
Drying sensitivity: the higher raw material plasticity, the finer of the particles, also the higher of drying sensitivity. Sensitivity coefficient determines the drying process design, too high lead green bricks surface cracking.
Relationship of forming moisture content and drying sensitivity | Green brick molding moisture | 20 | 26 |
| The critical water of green bricks | 14 | 16 |
| Drying sensitivity coefficient | 0.78 | 1.10 |
Chemical analysis of raw materials, physical properties and body molding moisture decide the feasibility of using raw materials and affect the next process design, equipment selection, kiln structure, product quality and other aspects of the production system
