Kieselguhr, diatomite

Diatomaceous earth is known as kieselguhr, diatomite, or filtration sand. Diatomaceous earth is a nonmetallic mineral composed of the skeletal remains of microscopic single-celled aquatic plants called diatoms. These microorganisms have the unique ability to absorb water-soluble silica present in water and... 

The first commercial shipment of diatomite ia the United States was made ia 1893 and consisted of material from a small quarry operation ia the vast deposit near Lompoc, California. It went to San Francisco to be used for pipe iasulation. Small-scale operation of parts of the Lompoc deposit continued until it was acquired by the Kieselguhr Co. of America, which later became the CeHte Co. (4). Siace that first work, the iadustry has grown immensely, and diatomite products are used ia almost every country. 

The most common inorganic adsorbents used in TLC are silica gel, alumina and kieselguhr silica gel being by far the most important. Kieselguhrs are made from natural diatomites and are an impure form of silica, being about 90% or so silica with the... 

There are some exceptions. The diatoms are unicellular microorganisms that protect themselves with a filigree skeleton of silicon dioxide (silicic acid). The sometimes major fossil deposits of kieselguhr (diatomaceous earth or diatomite)... 

The silica carrier of a sulphuric acid catalyst, which has a relatively low surface area, serves as an inert support for the melt. It must be chemically resistant to the very corrosive pyrosulphate melt and the pore structure of the carrier should be designed for optimum melt distribution and minimum pore diffusion restriction. Diatomaceous earth or synthetic silica may be used as the silica raw material for carrier production. The diatomaceous earth, which is also referred to as diatomite or kieselguhr, is a siliceous, sedimentary rock consisting principally of the fossilised skeletal remains of the diatom, which is a unicellular aquatic plant related to the algae. The supports made from diatomaceous earth, which may be pretreated by calcination or flux-calcination, exhibit bimodal pore size distributions due to the microstructure of the skeletons, cf. Fig. 5. 

Packed columns contain an inert and stable porous support on which the stationary phase can be impregnated or bound (varying between 3 to 25%). The solid support is made of spheres of approximately 0.2 mm in diameter, obtained from diatomites, silicate fossils (such as kieselguhr, tripoli) whose skeleton is chemically comparable to amorphous silica. These materials, which have a specific surface area ranging from 2 to 8 m2/g, have been commercialised by several companies such as Johns Manville, under the name of Chromosorb , and are used universally. Other synthetic materials have been developed such as Spherosil , made of small silica beads. All of these supports have a chemical reactivity comparable to silica gel because of the presence of silanol groups. 

These are prepared from flux-calcined diatomaceous earth, also called diatomite, diatomaceous silica, or kieselguhr. This earth is composed of the skeletons of diatoms, which are single-celled algae. It is excavated from deposits found in various parts of the world. The calcining is carried out by mixing the earth with a little sodium carbonate (called the flux), and raising the temperature to above 900°C. Various white diatomaceous earths are available commercially. The more common of these are Anak-rom U, Celite 545, Chromosorb G (very robust material), Chromosorb W, Gas-Chrom CL, Gas-Chrom P, and Gas-Chrom S. 

Evidence has recently been provided by the work of de Lange and Visser (10) on nickel catalysts deposited on kieselguhr. This has established that the normal lattice of metallic nickel does not occur in materials prepared in this way, and that the reduced active catalyst is obtained as a result of the attack of hydrogen on a nickel hydrosilicate. By interaction of the diatomite and the nickel hydroxide deposited on it, an entirely new lattice is produced which provides a greatly increased total surface of catalyst, and which leads in the finished state to a widely dispersed and very stable arrangement of nickel atoms. It will be of great interest to obtain further evidence as to the exact distance between pairs of nickel atoms in this catalyst, which is of exceptionally high activity. 

Synonyms cas 61790-53-2 d.e. diatomaceous silica diatomite infusorial earth kieselguhr... 

CAS 6067-86-0 7631-86-9 68855-54-9 EINECS/ELINCS 231-545-4 Synonyms Diatomaceous silica Diatomite Fossil flour Infusorial earth Kieselguhr Siliceous earth Silicon dioxide, diatomaceous Solum diatomeae... 

Synonyms Amorphous silica Diatomaceous earth, natural Diatomaceous silica Diatomite Infusorial earth Kieselguhr... 

Diatomite (Kieselguhr). Diatomaceous earth (as it is also called) is chemically ineit, but it has high adsorptive power. This can account for adsorption of curing ingredients that interfere with accelerated-sulfur vulcanization. However, diatomite is used as a filler in silicone rubber. Because of its high adsorptive capacity, it is used as a process aid in high-oU rubber compounds. 

Diatomite di- a-t9- mlt (1887) (diatomaceous earth, DE, kieselguhr, infusorial earth, siliceous earth, and tripolite) n. The naturally occurring deposit of skeletons of small unicellular algae called diatoms, consisting of from 83 to 89% silica. Its many uses include fillers for plastics. 

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