2026/01/10
Raw materials unsuitable for granulation with a double roller press granualtor are primarily those lacking plasticity, unable to withstand high-pressure extrusion molding, or those that easily damage equipment or affect product quality after extrusion. Specifically, these include the following categories:
1. Lightweight powder raw materials without binding properties
Such as light calcium carbonate, talc powder, fly ash, etc. These raw materials lack self-binding properties, and cannot form dense sheets after extrusion. After crushing, they mostly remain as powder, resulting in extremely low molding rates; even with the addition of binders, the particle strength is difficult to meet standards, and it will significantly increase production costs.
2. High-fiber and untreated raw materials
Coarse and hard agricultural and forestry wastes such as uncrushed and unfermented straw, sawdust, and branches have strong fiber toughness. During high-pressure extrusion, they easily wrap around the pressure rollers, causing equipment blockage and jamming, and accelerating the wear of the roller surface, reducing the service life of the equipment.
3. High-moisture, easily adhesive raw materials
Composted livestock and poultry manure, urban sludge, etc., with a moisture content exceeding 30%, will adhere to the surface of the pressure rollers and the inner wall of the equipment during extrusion, preventing the formation of uniform sheets, and also causing subsequent crushing and screening processes to malfunction.
4. Raw materials containing large hard impurities
Raw materials that have not been screened to remove impurities and contain stones, metal fragments, and glass fragments will directly damage the wear-resistant layer on the surface of the pressure rollers during high-pressure extrusion, and may even cause the rollers to crack, seriously affecting the safe operation of the equipment.
5. Heat-sensitive and easily decomposable raw materials
Some functional microbial agents and organic additives that are sensitive to pressure and frictional heat will become ineffective due to the local temperature rise and excessive pressure generated during extrusion. These raw materials are more suitable for processing using a low-temperature disc granulation production line.
