Processing Magnesite

The processing of magnesite can be divided into the following operations crushing, sizing, and beneficiation, and most of these operations are 

Blasted Rock — Primary Crusher — Screen Secondary Crusher 

Finished Product Storage Beneficiated Magnesite Pile HMS 

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The decomposition of MgC03 (magnesite) is an interface process [734] between 813—873 K and E = 150 kJ mole-1. In the presence of C02, E was increased to 234 kJ mole-1 but was reduced slightly on the addition of ZnO or NiO. Admixture with CaO reduced the value of E to 54 kJ mole-1. This is a surprising result since the value of E for decomposition [734,753] of the mixed carbonate (Ca, Mg)C03, dolomite, is 220 kJ mole-1, larger than the value for each constituent. The influence of PCOz and of alkali metals on MgC03 decomposition has been the subject of a DTA study [404]. 

The nucleation of these decomposition processes was studied by means of thermomicroscopy on single crystal cleavage plates of calcite, magnesite, dolomite and smithsonite (Fig. 59). The shape of the nuclei was found to be different for these carbonates, which might be also of importance for the decomposition mechanism. The partial pressure of water vapor has a pronounced effect on the decomposition of transition metal carbonates such as ZnC03 and CdC03. The evolution of C02 is probably catalyzed in the presence of water vapor and shifted to considerably... 

Magnesium occurs in many igneous rocks and in dolomite. It is usually obtained from seawater (1300 mg kg-1) or from the minerals magnesite (MgCC>3) or carnallite (KCl-MgCl2-6H20). The metal is used in lightweight alloys, MgO is employed as a refractory material and as an adsorbent for water treatment, and other Mg compounds find applications in the pharmaceutical and chemical process industries. 

Magnesite - [METALLURGY-EXTRACTIVEMETALLURGY] (Vol 16) - [MAGNESIUMCOMPOUNDS] (Vol 15) - [CARBON-NATURALGRAPHITE] (Vol4) -annual production of [MINERALS RECOVERY AND PROCESSING] (Vol 16) -refiactones from [REFRACTORIES] (Vol 21)... 

Carbon pitch is used for carbon electrodes in electrolytic reduction processes, such as aluminum reduction or the production of electro-steels in arc furnaces. Refractory pitch is used in the manufacture of refractory brick, usually burned magnesite or dolomite, the pores of which are filled with pitch by hot impregnation. Upon firing, the pitch in the brick is converted to carbon by carbonization. The remaining pitch coke within the refractory product retards penetration of molten metals and slags, thus prolonging the life of the brick furnace lining. Coke pitch is used in the production of foundry cores. 

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