Magnesia graphite Materials

Chemical composition silica-based and silica-alumina-based materials, chrome, magnesia, chrome-magnesia, spinel, SiC, materials containing carbon (more than 1% carbon or graphite), and special materials (containing other oxides or materials such as zircon, zirconia, Si3N4, etc.)... 

The cell which holds the molten salt and metal can be made of a variety of materials, such as iron, graphite, fire brick, alumina, magnesia, molybdenum or tantalum. The cathode is usually molybdenum, tantalum or tungsten and sometimes iron, cobalt or nickel. The choice of the cell and cathode materials will depend on the product desired. Graphite is almost always the choice for the anode because it is relatively inert to the halide gases (F2 or CI2) or oxygen liberated at this electrode. 

Refractories. Aluminosilicates, silica and aluminous material, basic materials such as magnesite, chrome-bearing materials such as magnesia-chrome bricks, zirconia-bearing materials, and silicon carbide. There are also raw materials such as fireclay, ferrosilicon, and graphite. 

The use of phosphates for ceramic bonding was patented in 1931 by Morgan [6]. Phosphoric acid [7] and its salts have since been used to bond numerous refractory materials, including kaolin, fireclay, alumina, magnesia, chromite, silica, sillimanite, zircon, silicon carbide and graphite. Bonding in these materials results, in part, from the formation of small quantities of phosphates of Al, Mg, Cr, Si, Zr and so on. 

Excessive reaction between the container material and the products or reactants must be avoided, and this may impose a limit upon the peak temperature which is allowable, or upon the materials of reactor construction. Reactors take different forms and are made from or lined with a variety of refractory materials. Lime, magnesia, electrically fused dolomite, calcium fluoride, nickel, stainless-steel, molybdenum, tantalum, niobium or graphite have all been used, for different purposes. 

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