Luoyang Judian Metal Hot Processing Equipment Co., LTD is mainly engaged in the manufacture of complete sets of equipment in the metal thermal processing industry and the integration of the entire production line.
Answer: The world is composed of various substances. Matter is categorized into organic and inorganic substances; inorganic substances are further divided into metallic and non-metallic materials. Among the 107 discovered elements, 85 are metallic elements. Aluminum belongs to the category of metallic substances.
Metals come in various colors. Based on color classification, iron and steel appear grayish-black and are called "ferrous metals" (black metals); other metals are collectively referred to as "non-ferrous metals." Based on density, using 4.5g/cm³ as the standard, metals with a density lower than this value are called "light metals" (such as lithium, magnesium, titanium, etc.), while those with a density higher than this value are called "heavy metals" (such as copper, lead, zinc, etc.). The theoretical density of aluminum at room temperature is 2.69872g/cm³, and the density of industrial pure aluminum is 2.705g/cm³. Therefore, aluminum is a light non-ferrous metal.
2. What is the abundance of aluminum in the Earth's crust?
Answer: The aluminum content in the Earth's crust is second only to oxygen and silicon. It is the most widely distributed metallic element in the Earth's crust, accounting for approximately 8.2% of the crust's total weight.
There are about 250 types of aluminum-bearing minerals in nature, the most common being aluminosilicates and their weathering product—clay. Aluminum-rich ores used for industrial production are called bauxite, such as Boehmite ($Al_2O_3 \cdot H_2O$), Diaspore ($Al_2O_3 \cdot H_2O$), and Gibbsite (Hydrargillite). The proven bauxite reserves in China, except for a few regions, are mostly of the diaspore type characterized by low iron and high aluminum content.
3. Does metallic aluminum exist in a natural state?
Answer: Although aluminum is the most widely distributed metal in the Earth's crust, it has high chemical activity and reacts easily with other elements, especially with oxygen to form alumina ($Al_2O_3$). To date, aluminum has not been found in a metallic state in nature.
In 1825, Danish scientist H.C. Oersted discovered the element aluminum. Subsequently, many scientists researched methods for extracting metallic aluminum from aluminum-bearing minerals. Currently, the most widely used industrial production method in the world is molten salt electrolysis, which was proposed simultaneously by Paul Héroult of France and Charles Martin Hall of the United States in 1886 and applied to industrial production in 1890. The metallic aluminum widely used in human society is all produced artificially.
