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How about the physicochemical characteristics of perlite after expansion ? Release:2014-12-12 16:13:09 Back>>

Perlite is the vitreous rock made of acidic lavas which arise from volcanic eruption and rapidly cool after meeting surface water (lakes, large rivers, rivers and sea), which is named for its pearl fissure structure. Perlite ore includes perlite, obsidian and pitchstone. The difference between the three is that perlite has circular cracks called perlite structure arising from condensation, and the moisture content is 2 ~ 6%; pitchstone has unique resinous luster, and the moisture content is 6 ~ 10%; obsidian has vitreous luster and conchoidal fracture, and the moisture content is generally less than 2%.

When the acidic lava erupts to the surface, due to the strong viscosity of magma quenching, a lot of water vapor can not escape from the magma but store in the glassiness with a lower softening point, such as SiO2, Al2O3, Na2O, etc. When roasting, the bound water in the glassiness will produce great pressure in vaporization when it reaches the softening point (about 1000 ℃) due to rapid heating, and the volume will rapidly swell to 10-40 times that of its original volume. When the glassiness cools to below the softening temperature, it will congeal into cavity structure and form expanded perlite with cellular structure, low density and excellent cold insulation properties. Therefore the glassiness is a basic condition for ore expansion, and water is the internal cause for ore expansion.

Expanded perlite becomes a very light white particle with honeycomb micropores inside, and has non-toxic, odorlessness, non-flammation, imputrescibility, acid resistance, alkali resistance and other characteristics. PH value is neutral (6.5-7.5). Because of its special cellular structure, it has strong adsorption and thermal insulation, and it is commonly used as the material for heat insulation and absorption filtration.

1 、Physicochemical properties:
(1 ) The transparency of glassiness and structure development: the glassiness is from transparency, translucency to opacity; perlite structure is from extreme development, relative development to non-development, and expansion times become small accordingly.
(2 ) The content of sanidine and quartz phenocryst: the sanidine and quartz phenocryst in the glassiness is unfavorable to ore expansion. After the expansion of perlite with phenocryst, its pores are interconnected with each other, resulting in too large porosity and the impact on thermal insulation property.
(3 ) Iron content: if the ore has too high iron content, the color of the products will be impacted, and there is a tendency to reduce expansion effect.
(4 ) Moisture content: the moisture content of the ore is one of the factors affecting the quality of products.

2 、Production process conditions:
(1) Granularity of the raw ore sand
(2) Preheating temperature and time
(3) Expansion temperature and time

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