The roasting of hematite is one of the election do hematite. When the mineral composition of the complex and other beneficiation methods are difficult to obtain good sorting indicators, often using magnetic roasting method of selection. Vertical furnace in the reduction of 75-20mm lump ore roasting process is mature, long-term practical experience in production, 20-0mm rotary kiln magnetic roasting production practice less. The common high intensity magnetic separation of iron ore fines, the re-election, flotation method and the joint process for sorting.
1924, China built the first hematite Kennedy furnace roasting plant, which appeared in the "Anshan roasting shaft furnace, more than 40 years be a number of transformation. Former 50m3 vertical furnace in the 1960s to expand to 100m3, used in JISCO concentrator, thereby enhancing Taiwan when the capacity of the shaft furnace. 50m3 vertical furnace transformed into the 1970s the original across the beam vertical furnace, in conditions that do not expand the Dimensions, change the furnace structure, so that the furnace volume expanded to 70m3, the Taiwan when capacity is increased by 74% and heat consumption reduced by 18%. The roasting process ore grading people furnace roasting and magnetic pulley to constitute a semi-closed roasting process enables concentrate recovery rate. (Hematite mineralogical properties)
For Anshan hematite - quartz, shaft furnace 75-20mm hematite mixture of coke oven and blast furnace gas heating and reduction, to generate artificial magnetite ore, and then the magnetic iron concentrate grade of 65.82% and the recovery rate target of 78.41%.
Concentrator two election workshops Qidashan has used the roasting process, after a magnetic roasting, ore dressing processes by continuous grinding, magnetic separation, and stages of grinding, magnetic separation - re-election of two parts. Which continuous grinding, magnetic separation process is relatively simple, for two consecutive grinding, a period of drier, a magnetic separator for some fine sieve operations, fine sieve out the concentrate return Sec grinding fine sieve and then grinding re-election; stage grinding, magnetic separation - the re-election process is more complex, for a period of grinding, magnetic tailing in magnetic concentrate grade flow classification thickness, the cyclone overflow period of drier, a permanent magnet machines, do not for some fine screening, sieve and cyclone grit merger for a period of roughing spiral chute for the concentrate, the period of selection of the spiral chute election do not have to concentrate, rougher spiral chute, Featured spiral chute, tailings grade flow into the secondary merge to secondary classification by cyclone and Sec mill to constitute a closed circuit grinding. Continuous grinding, magnetic separation, and stages of grinding, magnetic separation - concentrate merged to re-election into the Sec drier, resulting in the final concentrate of the workshop. Integrated technical indicators: ore grade of 29.26%, the concentrate grade of 63.26%, 10.44% of the tailings grade, recovery rate of 77.03%. (Hematite ore type)
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