Pumice stone is a type of volcanic rock formed by an eruption of ultra-high temperature and high-pressure volcanoes. Its powder is called pumicite. The pumice foam structure is due to simultaneous rapid cooling and rapid decompression. Depressurization generates bubbles by reducing the solubility of gases (including water and CO2) dissolved in lava, leading to rapid gas evolution. At the same time cooling and depressurization freezes the bubbles in the matrix. Because of its amorphous structure, pumice is considered glass. Pumice is usually pale in color from white, cream, blue or gray to greenish brown or black.
The method of treating pumice makes it suitable for lightweight concrete:
It is characterized in that the pumice stone is crushed, and the separated pieces are subjected to a temperature of about 1000° C. or more until the melting point, whereby shrinkage occurs in each individual piece, the contraction shrinks with the height of the temperature, thereby increasing the hardness at the glass hardness all the time. And the external pores thus reaching the melting point are completely closed by surface melting while each individual component remains internally porous.
Pumice is used to make lightweight concrete or insulating low density cinder blocks. When used as a cement additive, a fine-grained version of pumice called pozzolan is mixed with lime to form a lightweight, smooth gypsum-like concrete.
It is used in beauty salons to remove dry skin and calluses from the bottom of the foot. It is added to toothpaste and hand wash liquids as a mild abrasive.
Drinking water treatment
Pumice's foamy structure and near-white purity can capture cyanobacterial toxins and other impurities found in contaminated drinking water. It can also be used to purify grease and remove odors from water, with excellent filtration and absorption properties.
It is used in horticulture mixed with soil to provide good aeration for plants. Due to its highly porous nature, pumice stones can retain moisture and air, both of which are critical for well-conditioned aerated soils. This makes pumice stone an excellent soil conditioner. It is also used in soaps, detergents, erasers, dental polishes and stoned jeans.