Mining geomembranes are typically manufactured through a process known as extrusion.The first step is selecting the appropriate polymer resin for the desired properties and performance of the geomembrane. Common polymer resins used in mining geomembranes include HDPE (High-Density Polyethylene), LLDPE (Linear Low-Density Polyethylene), PVC (Polyvinyl Chloride), and EPDM (Ethylene Propylene Diene Monomer). The resin selection depends on factors such as chemical resistance, flexibility, strength, and durability requirements. The selected polymer resin is then prepared by blending it with additives and modifiers to enhance specific properties. Additives may include antioxidants, UV stabilizers, slip agents, and colorants. These additives improve the geomembrane's resistance to environmental factors, such as oxidation, UV degradation, and temperature variations.
The prepared polymer resin is fed into an extruder, which is a specialized machine for melting and processing the resin. The extruder applies heat and pressure to melt the resin, creating a homogenous molten polymer.After extrusion, the molten polymer is typically processed through either a calendering or blown film process to form the geomembrane. In the calendering process, the molten polymer is passed between a series of heated rollers, which shape and cool the material into a continuous flat sheet. The thickness of the sheet is controlled by the gap between the rollers. In the blown film process, the molten polymer is extruded through a circular die, forming a tube. The tube is then expanded using air pressure, and as it cools, it is flattened into a flat sheet.
