Assay Laboratory Standards & Quality
It is important to have Assay Laboratory standards over a range of grades. This alone may preclude the material being sampled from serving exclusively for the preparation of standard material. One of the standards must have as close to an absolute zero value as possible. At least three and if possible five other standards should […]
Cryogenic Plant at Mining Metallurgical Processing Plants
In the 1940’s a top blown water-cooled oxygen lance was developed to inject oxygen into liquid iron. This process, the LD or BOF process technique, today is used in 65% of the world’s steel production, and represents the largest oxygen market for temperature enhancement in steel and non-ferrous smelting applications. There are three major approaches […]
Zirconium Crucibles
Zirconium crucibles are rapidly becoming a standard piece of equipment, particularly in laboratories where fusions using strongly alkaline fluxes are common. This Center has found no better material to use for the thousands of sodium peroxide fusions that are done here every year. Zirconium crucibles usually arrive from their suppliers in a polished, silvery state. […]
Acid Digestion of Ferrochrome Metal
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 ferrochrome samples. The […]
Manganese in Chromite, and Ferrochrome
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 […]
Gravimetric Silica in Chromite and Ferrochrome Slag
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 […]
Calcium in Mineral Chromite and Ferrochrome Slags
Calcium is rarely found in chromite ores in amounts greater than a few tenths of a percent, and calcium analysis is rarely requested on ore samples. Calcium compounds are, however, used as slag conditioners for ferrochrome smelting. Most of the chromite-related samples received for calcium analysis at this Center have been slag samples. The data […]
Aluminum and Magnesium in Chromite and Ferrochrome
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 […]
Metallic Iron in Ferrochrome Slags
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 […]
Ferrous Iron in Mineral Chromite and Ferrochrome Slags
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 […]