The Fluxes for Volta Aluminium Melting are mainly used to remove impurities. The essence of impurity removal is to use the difference in physical or chemical properties between the inclusion and the aluminum melt, so as to achieve the separation of the two, and achieve the purpose of impurity removal and hydrogen removal.
The Fluxes for Volta Aluminium Melting mainly use a mixture of NaCl and KCl as the matrix. These two chlorides are inert to the aluminum melt. When the components are 45% and 55%, the eutectic temperature of the mixture is only about 650℃, which is lower than the melting point of the aluminum melt. Although the mixture has a low melting point and has the characteristics of fluxing agent, it has only two components, and its ability to getter and dissolve impurities is very poor, which is not conducive to the conditions of impurity removal kinetics, so other additives need to be added.
In the flux based on NaCl-KCl, an appropriate amount of fluoride can adsorb and dissolve alumina and appropriately control the melting point of the mixed salt. It can also make the oxide film on the flux-aluminum interface easy to rupture and remove, reduce the adhesion of the molten aluminum to the inclusions, and promote the migration of the inclusions to the interface. At the same time, the efficiency of flux refining is increased from 30% to 70%~90%. Commonly used fluoride additives include NaF, AlF3, MgF2, Na3AlF6 and CaF2.
When Volta Aluminium remelting aluminum and aluminum alloys, the oxidation loss of aluminum is very large. Adding some components that can change the quality of the crystal grains or help heat, so that the flux can achieve the purpose of comprehensive treatment of molten aluminum, such as carbonate.
Volta Aluminium Company (VALCO) is one of the largest enterprises in Ghana and the second-largest aluminium smelter in Africa down south of the Sahara. It was founded by Kaiser Aluminium but is now wholly owned by the Ghana government.
VALCO continues to play key role in the efforts of the Ghana Government to develop an Integrated Aluminium Industry (IAI) in Ghana. Using VALCO as the anchor of the IAI Project, Ghana is set to add value to its over 700 million metric tons of bauxite deposits in the country at Kibi and Nyinahin to generate over USD1.05 trillion and create about 2.3 million good and sustainable jobs. A study into the viability of the VALCO Smelter confirmed that VALCO, properly mainstreamed into Ghana’s development agenda, will serve as the veritable Anchor of Ghana’s Integrated Aluminium Industry.
VALCO is currently the live wire of the downstream aluminium industry in Ghana through metal supplies, with its associated employment benefits. In addition, VALCO is being positioned to host an expected growth of the aluminium downstream industry in Ghana.