Oyster shell flour is a kind of animalized mineral feedstuff with higher calcium content, widely used in producing mixed feed.
贝壳粉是一种含钙量极高的动物性矿物质饲料，被广泛应用于配合饲料的配方当中。
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If air is used as a carrier for transporting the powdered substances (such as the coal dust, the metal mineral powder and the flour), explosions are easy to cause.