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Table of ContentsMethod AEquipment MaterialsMaterialsProcedureProcedure NotesMethod BEquipmentMaterialsProcedureProcedure Notes At times it may be necessary or desirable to dissolve a ferrochrome sample in acid rather than fusing it in sodium peroxide. Acid digestion methods are slow, but require little in the way of attention. Two alternative methods are described here. The A method is the basic method to use for most

Table of ContentsEquipmentMaterialsProcedureProcedure Notes Manganese commonly occurs in mineral chromite as an impurity, and the amount can range from trace quantities to a few percent. In ferrochrome smelting operations, the manganese should find its way into the slag rather than the metal. Data from these analyses have most often been used to trace the partitioning of the manganese through the

Table of ContentsEquipmentMaterialsProcedureProcedure Notes Silica is present in chromite ores as a basic silicate. In characterization and beneficiation studies performed on chromites at this Center, the chromium-silica ratio determines the purity of the gangue material being analyzed. Accurate characterization of the original ore material and the further feasibility of smelting to ferrochrome are identified by using this ratio. The method

Table of ContentsEquipmentMaterialsProcedureProcedure Notes Aluminum and magnesium occur as gangue components in chromite ores and ferrochrome slags. At this Center, ores from many different sites and of many varieties are examined for commercial feasibility. The beneficiation of these ores is a continuing activity that produces most of the samples that are analyzed with this method. Data from this method are

Table of ContentsMaterialsProcedureProcedure Notes It would truly be unusual to find a sample of mineral chromite with metallic iron in it. However, (his Center has handled many samples of prereduced smelter charges with several percent of metallic iron and ferrochrome slags with measurable quantities of metallic iron. Therefore, this method finds its use in the later stages of mineral chromite

Table of ContentsEquipmentMaterialsProcedureProcedure Notes The determination of ferrous iron in mineral chromites and other chromite-bearing samples is limited by the difficult solubility of the chromite lattice. Reaction of the ferrous iron immediately upon release from the crystal seems to be the preferred way of measurement. Attempts to dissolve chromite by other methods depend on strong oxidizing agents that leave no

Table of ContentsEquipmentMaterialsProcedureProcedure Notes Iron is the second major element in chromite. In smelting operations where ferrochrome is the product, a specific range in the chromium-to-iron ratio is desired. Where pure metallic chromium is the product, the iron concentration is not as important. In both cases, it is important to have a good value for the chromium-to-iron ratio. A typical

Table of ContentsEquipmentMaterialsProcedureProcedure Notes At this Center, results from this method have been used almost exclusively as data for the calculation of the total degree of reduction in a smelter batch, rather than as an indicator for the metallization of chromium. When a charge of chromite material is smelted or prereduced, the crystal structure is changed, and once the chromite

Table of ContentsEquipmentMaterialsProcedureProcedure Notes The total chromium content in mineral chromite and ferrochrome slags can range from a fraction of a percent in the slags to greater than 30 pct in the ore concentrates. Because of this variation and because of the difficulty in dissolving chromite-containing samples, the method of choice at this Center has been fusion with sodium peroxide,