What is silica
What is silica
Silica, chemistry, pure silica is colorless, is solid at normal temperature, chemical formula SiO, insoluble in water. Insoluble in acid, but soluble in hot concentrated hydrofluoric acid and phosphoric acid, and melt alkali works. There are two kinds of crystalline silica and amorphous silica in nature. Silica is so widely used, mainly used for glass, water glass, pottery, ceramic, refractory material, gas gel mat, ferrosilicon, sand, elemental silicon, cement and other, in ancient times. Silica is used to making porcelain glazed and carcass. The general stone is mainly composed of silica and calcium carbonate.
Silica is widely found in nature, and other minerals together constitute the rock. Natural silica called silica, accounting for about 12% of the mass of the crust, the existing forms of crystalline and amorphous two. Quartz crystal is crystalline silica, with different crystal forms and colors. A colorless and transparent crystal in a quartz crystal is often said to be a crystal. A colored ring or layered, called agate (containing impurities).
Silica minerals is refers to the same chemical formula (SIO), but the structural differences of minerals. These minerals are collectively referred to as a matter of different body image, mainly consists of quartz, cristobalite and tridymite. The minerals in the earth deposit in granite, sandstone and black siliceous rocks, and the moon almost devoid of, main reason is: evolution of chemical composition, the moon formed a low silicon, high aluminum shell, high silicon granitic rocks are extremely rare; the moon in evolution lack like ball as a crystallization of silica mineral water and hot water system. Although the silica minerals are extremely rare on the moon rocks, it is important to study the classification and genesis of the lunar rocks.
Quartz minerals on the moon the first is found in a few pieces of Granitoids in the broken place, in the felsite also filled with many quartz minerals, from the micro structure and composition analysis showed that the quartz is actually by cristobalite change over. Later in the coarse crystalline lunar granites fragments also found minerals such as quartz, according to the results of the analysis of the isotope, the mineral is 41 million years or so, in the deep environment for crystal formation, indicating that the quartz is not in magmatic rocks formed during the crystallization of the formation of.
Silica minerals in the mare Wu Yanzhong most is the cristobalite, volume percentage of up to 5%, almost no minerals such as quartz, only in fine crystalline mare basalts exist only for small amounts of minerals such as quartz. The quartz with typical twin structure showed that in magma cold but process, from high temperature to formed under low temperature conditions of quartz. In addition, in some coarse crystalline mare basalt also exist cristobalite and tridymite, but from the structural feature, cristobalite is transition from tridymite, because tridymite is generally embedded in between the irregular particles.
Preparation of macroporous mesoporous silica composites
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