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Usage: As a rare mineral in the nature, hercynite is generally artificially synthesized by the process of mixing the material at accurate proportion, briquetting, fusing at high temperature in special furnace (proper paper pulp as addition agent), and natural cooling. It should maintain the tiny reduction to avoid FeO being oxidated to Fe2O3, and the generation of Fe during the fusing process.It shows even big crystal with none crystal boundary,re-sum-bling to viyreous material under the microscope.Without pollution by hexavalent chrome,mainly used in large-sized cement convertor,Fe-Al Spinel brick replaces present chromite brick in cement rotary kil-n,lengthens the working life of lining brick(10-12 months for Chrome Magnesia Brick,17-18 months for Spinel Brick),highly reduces the chromite-free production in cement kiln,resolves social effects of chrome pollution.