The mineral crystalline morphology of foundry natural silica sands has been investigated, which can be divided into two groups:single crystal and polycrystalline gather.

考查了铸造用天然硅砂的矿物晶体形态， 可将其大致分为单晶体和多晶集合体两类。

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The silica bricks of high refractoriness, high loading and heavy melting point made of large crystalline quartz have already increased the life to 5 times.

用大结晶脉石英制成高耐火度、高荷重软化点硅砖，使用寿命提高5倍以上。

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For example, both crystalline and glassy forms of silica (SiO,) have structures with each si surrounded by four oxygen atoms, and each o by two si.

例如，晶体二氧化硅和石英结构的二氧化硅是每个硅原子被四个氧原子所包围，每个氧原子周围有两个硅原子。

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