Introducing separate beneficiation technology for magnesites at the Magnezit Combine

Conclusions

The Magnezit Combine has completed measures to increase the throughput of existing ducts supplying the starting materials to the beneficiation section; installed a self-balancing, two-screen sieve unit GST-62A (heavy type) instead of the single screen unit; and put into operation a second conical separator SK-3.6 in the section that handles ore 70-8 mm in size; this has led to the use of a procedure for the separate beneficiation of magnesites in narrow fractions 70-40 (25) and 40 (25)-8 mm, and brought about improvements in the quality of the concentrate, as well as increasing the output of the beneficiation section by 30%.

When the technology was being developed using ordinary ores containing 4–6% CaO and contaminated with less than 15% dolomite we obtained up to 75% (of the original) of overall high-grade magnesite concentrate of coarse and fine fractions grade MIO (TU-14-200-350-89) with 1.07–1.35% CaO and 0.78–0.8% SiO₂ in place of the MI concentrate using the combined beneficiation method.

As a result of the development of the optimum schedules in heavy suspensions and preliminary separation of the starting ore into narrow fractions on a screen with 25 mm apertures, we established the possibility of processing balanced and nonstandard ores from special dumps containing more than 7% CaO and dolomite impurities of more than 18–20%, with the production from coarse fraction of 70-25 mm magnesite of up to 30% high-quality magnesite concentrate MIO, and from fine fraction 25-8 mm — a concentrate of MI quality. These concentrates are suitable for making bricks and powders used in refractory factories of the country on a level with those from ordinary ores, which is especially important where there is a scarcity of raw materials at the combine. The technology described above should improve the quality of magnesite concentrate. The savings from using it for reprocessing nonstandard raw materials tranported from special dumps was 128,8000 rubles a year.