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This explains why some iron ores are rich in silica and may therefore be sensitive to the alkali-silica reaction. Very low level of reactive silica in heavy aggregates are sufficient to induce ASR. This is why heavy aggregates must be systematically tested for ASR before nuclear applications such as radiation shielding or immobilization of ...
Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula SiO 2, commonly found in nature as quartz. [5] [6] In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and abundant families of materials, existing as a compound of several minerals and as a
Microcrystalline silica consists of minute quartz crystals bonded together with amorphous silica. Examples include flint and chert . Amorphous silica consists of kieselgur ( diatomite ), from the skeletons of diatoms , and vitreous silica, produced by heating and then rapid cooling of crystalline silica.
Canisters are commonly filled with silica gel and other molecular sieves used as desiccant in drug containers to keep contents dry. Silica gel in a sachet or porous packet. A desiccant is a hygroscopic substance that is used to induce or sustain a state of dryness (desiccation) in its vicinity; it is the opposite of a humectant.
Colloidal silica gel with light opalescence. Silica gel is an amorphous and porous form of silicon dioxide (silica), consisting of an irregular tridimensional framework of alternating silicon and oxygen atoms with nanometer-scale voids and pores. The voids may contain water or some other liquids, or may be filled by gas or vacuum.
What: Shares of silica producer U.S. Silica jumped. Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they ...
What: Shares of U.S. Silica Holdings dropped as much. Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case ...
If alkali builds up due to ion exchange, and remains on the surface of the glass, the decay process will accelerate. The presence of sodium or potassium ions in the alkali build up will increase the pH on the surface of the glass, causing it to become basic. This will dissolve silica from the glass as well as releasing more alkali ions. [10] [7]