Impact Minerals Ltd Annual Report 2023 11 Review of Operations continued ABOUT HIGH PURITY ALUMINA AND THE MARKET FOR ITS PRODUCTS High Purity Alumina is aluminium oxide (“alumina” - Al2O3) with a generally accepted purity that exceeds 99.99%, or “4N” (four nines). HPA has superior physical and chemical properties, such as high brightness, superior hardness, and superior corrosion resistance. It has traditionally found applications in: – LED light bulbs are a significant growth market for HPA as they are substantially replacing incandescent lighting systems because they are sustainable, durable, and safe. – Protective coatings (in powdered form) as an inert, incombustible and non-conductive ceramic filler in electronics applications. – Anode-cathode coatings and separators in lithium-ion batteries. – Phosphor substrate material in plasma displays. – Semiconductor substrates. – A precursor for sapphire glass, optical lenses and specialty ceramics used in high-technology imaging and bio‑medical devices. – Defence and protective uses as a hard, chemically resistant and inert barrier. In addition to the HPA, the final calcined ceramic form of the mineral, various precursor aluminium salts, including sulphates, nitrates, chlorides, and silicates (clays), also have important end-market uses. These uses, which include critical parts of the lithium-ion battery manufacturing process, are summarised in Table 4. Aluminium Chemicals Overview α-Al2O3 Aluminium Oxide • Calcined alumina: HPA. Typical product target 99.99% purity • LEDs, sapphire, LiB, Catalysts, Abrasives Al2(NO3)2.9H2O Aluminium Nitrate • Precursor chemical; Requires 4N to 5N purity • Cathode cementation, stabilisation, electrolyte chemical, etc Alx[OH]y variations Hydroxides • Precursor chemical to alumina; Requires 5N or better • Catalysts, electrolytes, precursor feedstock for HPA Al2Cl6.12H2O Chlorides • Precursor chemical – not traded in bulk; Requires 5N to produce 4N HPA • LiB electrolytes, specialty chemicals Al2[SO4]3 Sulphates • Industrial chemical flocculant, and by-product • Mining by-product used for HPA in China (3N usually) [K,Al]2Si2[OH]5 Silicates • Sourced from granites, sediments • Chemically stable, require2 calcination; Hydrochloric acid route only Table 4. End uses of HPA and precursor chemicals. Growing awareness of ultra-high purity (UHP) intermediate aluminium salts and hydroxides as a revenue opportunity has been shown in ASX releases by Alpha HPA Limited. Impact is exploring its options to product these products as part of the Pre-feasibility Study.
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