Today there are several successful case histories demonstrating the suitability and long service life of fiber reinforced polymer, FRP, based equipment in hydrometallurgical extraction plants used to refine copper, nickel, cobalt, and rare earth metals. FRP is being considered as a material of choice for construction of lithium extraction systems from geothermal water or other traditional sources. The chemical environments found in modern extraction systems are extremely corrosive. These systems must be fabricated from materials that are durable against corrosion, meet mechanical requirements, and perform economically over the life of the plant. In these systems, FRP provides improved durability relative to alternative materials of construction. This paper will compare corrosion performance of plant equipment fabricated with corrosion resistant alloys, rubber lined steel, and FRP made with epoxy vinyl ester thermoset resins. Case histories for FRP piping, storage tanks, extraction vessels, and electrowinning cells combined with laboratory-based corrosion studies will be reviewed to demonstrate how FRP materials are selected for hydrometallurgical equipment. Data showing the suitability of FRP for lithium extraction will also be reviewed.
Rare earth elements (REE) and lithium are metals that are considered critical materials due to their use in electronics, magnets, batteries, and a wide variety of industrial processes important for the economy and military preparedness [1]. Today, these metals are commonly harvested as metal oxide, halide or hydroxide minerals. Fiber reinforced p with even greater design temperatures lastic (FRP) has been used with great success for more than 50 years to build corrosion resistant mineral processing equipment. Epoxy vinyl ester resin based FRP has demonstrated that can meet the aggressive operating conditions associated with hydrometallurgical processes [2]. These processes require materials of construction that can withstand strong bases, acids, and acid halides at temperatures around 80 to 100°C with design temperatures. Common metallic materials of construction are not compatible with these conditions. Metals that are capable of meeting performance requirements have higher material and fabrication costs. As the volume of successful case histories grows, more and more design engineers are confidently specifying fiberglass reinforced plastics as the material of construction for new mineral processing equipment. Today, FRP is commonly used for construction of leaching vessels with abrasion resistant liners, electrowinning cells, storage and processing vessels, extraction towers, linings for CCD vessels, acid and abrasion resistant piping, ducting and acid plants. With the growing demand of virgin REE and lithium, FRP is expected to play a large role in construction of new mineral processing plants. In the following sections the authors will demonstrate the suitability of FRP to meet these needs.
