Researched on the low carbon steel by mineral component ore phase structure of mould powder and its slag film under optical microscope. The result shows that the glass phase, quartz, and pyroxene in the mould powder helped to the slag film turn into glass. The melilite and wollastonite in the mould powder can promote the formation of melilite, and wollastonite can promote the formation of cuspidine in the slag film. The structure of the slag film is even and the main structure is glass phrase, the rate of crystallization is low, the crystallized mineralogical phases was melilite, the cuspidine did not appeared, which is good for lubrication. The content of glass phase, quartz and pyroxene in the mould powder of the low carbon steel should be increased, the content of wollastonite and fluorite should be reduced.

The microstructe of mold fluxes of low-carbon steel and mould powders were researched by means of polarizing microscope. The result shows that the mineral compositions of the mould fluxes primarily are glass phase, wollastonite, quartz, melilite, pyroxene and feldspar. The main mineral compositions of mould powders is melilite. The quartz, pyroxene and glass phase are helpful to reduce the crystalline portion of mould powder, but the melilite, wollastonite help to improve the crystalline portion and promote crystallization of melilite. It is good for the crystalline portion when the casting speed droop.

The characteristics of the texture, dissemination grain size, mineral composition and content of the refractory hematite ore are researched systematically. The result shows that: the ore is be of colloidal texture, complex mineral contents, fine dissemination grain size, so the ore is difficult to be separated. In order to get the idea result of processing, the ore must be ginded and concentrated stagely.