Aluminium carbide is a solid compound of aluminium and carbon that appears in the form of pale yellow to brown crystals. It is very hard and heat-resistant. It is used for reducing metal oxides in the metallurgical industry, as a chemical reaction catalyst and for advanced ceramic materials. It is also used as a cutting and grinding material. It reacts with water to produce methane gas, so it is hazardous to handle and inhale. It can cause a range of health problems, including asthma-like symptoms, if exposed to it for long periods.
Secondary aluminium dross, which contains a significant amount of aluminium sulphide, can be hydrolysed to produce toxic and inflammable gases. It can also decompose to form nitrides and carbides. The resulting gases can be reused for various applications, but their volume is low and it is necessary to discover methods that increase the generation of these gases.
For example, an aluminate solution can be used to stabilize dross and prevent it from reacting with water to form insoluble aluminum hydroxide (Lopez-Delgado et al., 2020). It can then be reacted with hot water to produce pure hydrogen gas at 373 K. The hydrogen can be separated from the dross by condensation to produce aluminate cement, which is also useful for construction.
Another way to use the generated gas is to react it with ammonia or nitrogen gas to form aluminum nitride powder. This is a very useful process, because it allows the production of high-purity aluminum nitride for use in electrical applications. In addition, it can be produced at a lower temperature than direct metal reduction, making it more economical.