Low Grade Molybdenum Ore Reduction
Molybdenum is a silvery-gray metal which is used to make steel and other alloying elements in many industries. Molybdenum is also useful in catalytic processes, like oil refining. Molybdenum ore is composed of molybdenum oxides and other materials, such as sulfur and iron. Low grade molybdenum ore refers to those ores with molybdenum concentrations that are lower than the industry-standard of 1.5%. Such materials are not practical for direct smelting. However, these lower grade materials can be refined and recycled at an economic cost, which offers an economic and environmental alternative to coal based operations.
Reduction of low grade molybdenum ore can take one of two paths. Direct reduction uses a low temperature process that produces a final product with a high molybdenum content. This method is often used for various molybdenum alloys and is more efficient for those materials that contain higher levels of molybdenum. Alternatively, thermal reduction requires a higher temperature and is often employed to produce molybdenum powder, which can be used in various industries and is seen as a byproduct generated in the molybdenum refining process.
Direct reduction of low grade molybdenum ore uses a blast furnace and malic or calcic fluxes. The ore is placed in the bottom of the furnace, and a layer of the flux is spread over the surface of the ore. The firing of the furnace raises the temperature of the ore and fluxes, causing them to mix. The reaction between the molybdenum oxides and the flux material produces a molybdenum-rich slag. This material is then separated from the slag, usually through the utilization of a high temperature hydrodynamic separator.
The product of direct reduction of low grade molybdenum ore has primarily molybdenum in it, but there are also various other elements found in the product. The final composition of the product depends on the composition of the ore and the temperatures reached during the reduction process. Therefore, it is important to properly assess the material that is being processed and use appropriate temperatures and fluxing agents to ensure that the desired product is manufactured.
Thermal reduction of low grade molybdenum ore is performed in open-top rotary kilns. This method utilizes extremely high temperatures to transform the ore into molybdenum powder. The powder is then used to make molybdenum alloys or other products. This method of reduction is also more suitable for materials that have a lower molybdenum concentration.
Both direct and thermal reduction of low grade molybdenum ore have their own advantages and disadvantages. Direct reduction is more efficient but requires higher temperatures and more precise control. Thermal reduction is more suitable for low grade ore, but tends to produce a less precise product. In either case, it is important to understand the composition of the material being processed and to utilize the proper process and techniques in order to make the most of the reduction process.
