Core Insights - The article discusses the various types of alumina, its applications, and the leading companies in the industry, highlighting China's dominance in alumina production and the significance of different alumina products in various sectors. Group 1: Types of Alumina - Alumina, represented by the chemical formula Al2O3, is a compound consisting of aluminum and oxygen, and can be categorized into anhydrous and hydrated forms [1][16] - Anhydrous alumina includes various crystalline forms such as α-Al2O3, β-Al2O3, and γ-Al2O3, with over nine types identified in China [1][16] - Hydrated alumina is composed of Al3+, O2-, and OH- ions, and common forms include industrial hydrated alumina and various types of bauxite [1][16] Group 2: Metallurgical and Non-Metallurgical Alumina - Alumina can be divided into metallurgical grade, which is used primarily for aluminum production, and non-metallurgical grade (fine alumina), with metallurgical grade accounting for over 90% of total alumina production [2][18] Group 3: China's Alumina Production - China is the largest producer of alumina, with a projected output of 85.52 million tons in 2024, representing a year-on-year growth of 3.9% and accounting for 60% of global production [4][20] - Among the top ten global alumina producers, five Chinese companies, including China Aluminum and China Hongqiao, collectively produced 61.82 million tons, making up 63.77% of the total [4][20] Group 4: High-Purity Alumina - High-purity alumina (4N and above) is characterized by its high purity, hardness, strength, and thermal stability, making it a valuable material in high-tech industries such as electronics and aerospace [5][20] - Research on high-purity alumina in China began in the 1990s, with significant advancements made in production techniques, although challenges remain in particle size and dispersion compared to Japanese counterparts [6][22] Group 5: Specialized Alumina Products - Ultra-fine hydrated alumina, with particle sizes below 3μm, is primarily used in green halogen-free flame retardants and as a precursor for various applications, including lithium-ion battery separators [8][25] - Boehmite, a precursor for active alumina, is utilized in lithium battery components to enhance safety and performance [9][28] - Spherical alumina, known for its high thermal conductivity and flowability, is widely used in polymer composites and ceramics [11][28] Group 6: High-Temperature Calcined Alpha Alumina - High-temperature calcined alpha alumina is produced through a calcination process at 1450°C, resulting in a white powder with excellent mechanical and electrical insulation properties [13][30] - This product is extensively used in ceramics, refractory materials, and high-performance applications [15][32]