Secondary Industry View
In the above-mentioned reports, associated minerals have been mentioned which are co-concentrated with the known rare-earth minerals (“REM”). It has also been documented that fluorite, zircon (source of zirconium), apatite (source of phosphorous) and associated silicates like feldspar and nepheline occur in economic concentrations. It is estimated that based on exploration results, and viable processing methods, these minerals could be concentrated and applied as feed to various other industries:
- Feldspar, nepheline and nepheline syenite applied in glassmaking (improving hardness, durability, and resistance to chemical corrosion), in ceramics (as a ﬂux, which lowers the melting temperature of a mixture);
- Fluorite is used in steel and aluminium production to lower the melting point of raw materials. Intermediate grade fluorite utilised to manufacture enamels, cooking utensils and coloured glass, and the highest grade of fluorite is used to create the chemical compounds hydrogen fluoride and hydrofluoric acid, by breaking down the mineral with sulfuric acid;
- Apatite is processed into fertilisers such as superphosphate, triple superphosphate and phosphoric acid;
- Zircon is used in the production of ceramics, zirconia, zirconium-based chemicals, refractories, and foundry and casting applications. Zircon is also used as a natural gemstone and may be processed to produce cubic zirconia, a synthetic gemstone and diamond simulant. Zirconium metal is used in corrosive environments, nuclear fuel cladding, and various specialty alloys. Zirconium oxide exhibits high light reflectivity and good thermal stability and is primarily used as an opacifier and pigment in glazes and colours for pottery and other ceramic products. Yttria-stabilised zirconia (YSZ) was used in the manufacture of oxygen sensors that control combustion in automobile engines and furnaces. YSZ was also used in the manufacture of a diverse array of products, including cubic zirconia, fibre optic connector components, refractory coatings, and engineering and structural ceramics. YSZ was used in dental applications, such as bridges, crowns, and inlays, because it has two to three times the fracture resistance and 1.4 times the strength of similar alumina products. Zircon, used for facings on foundry moulds, increases resistance to metal penetration and gives a uniform finish to castings. Milled or ground zircon was used in refractory paints for coating the surfaces of moulds. In the form of refractory bricks and blocks, zircon was used in furnaces and hearths for containing molten metals. Glass tank furnaces use fused-cast and bonded alumina-zirconia-silica-base refractories.
Based on the above, at least five commodities besides REE can be concentrated and (a) exported as an economic by-product, (b) provided as feed to current industries (i.e. Namhung Youth Chemical Complex (in the city of Anju), which is a national chemical and fertiliser plant which produces ammonia, urea, Na2CO3, a range of chemicals, gasses, liquids, plastics, nylon, rubber, ceramics, fillers and electronics, or (c) applied to initiate new industries, focussing on the above-mentioned commodities. These industries, like the Namhung Youth Chemical Complex, could employ several thousand staff members.