Diatomite, flux-calcined

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. 

Extracts from all samples were analyzed by gas chromatography as described by Hindin, May, and Dunstan (5). After the residue had been taken up in a measured volume (0.1 or 1.0 ml.) of petroleum naphtha, a 10-/Jiter aliquot was injected into a Beckman temperature programmer coupled with a Dohramann microcoulometric titration detector. The column-packing material used for the separation of the insecticides was 5% by weight of EPON 1001 on 60/80-mesh acid-washed, flux-calcined diatomite (Chromosorb P). This material was packed in aluminum tubing % inch in o.d. by 3 feet. 

Figure 2.24 shows the method of processing of diatomite to different grades of fillers. The natural grades are uncalcinated powders which are crushed and classified according to particle size distribution. In this process moisture is also removed. Natural diatomite contains 40% moisture. In the production of the calcinated and the flux-calcinated products, large kilns are used. The high... 

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. 

Kenite, White flux-calcined diatomite, antiblock additive, CeUte Corp., do World Minerals Inc. 

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