Mixture Compound Chalk

Agricola divides the minerals into 1. earths, such as clays, chalks, ochres, etc. 2. stones, properly so called, gems, semiprecious stones. 3. solidified juices, (succi concreti), salt, alum, vitriols, saltpeter, etc. This is an application of the theory of the ancients that these are derived from solidified waters. 4. rocks, such as marble, serpentine, alabaster, limestone, etc., hard and not friable like the earths. 5. metals. 6. compounds, or mixtures, under which head he classes various ores of the metals, from which he recognizes that simpler constituents, as the metals, may be obtained. The fundamental basis of this classification Agricola explains in the following manner.80... 

Patent literature reports also on halogen-free composition for PS foams, using phosphorus compound, such as RP, triphenyl phosphate, diphenyl cresyl phosphate, APP or diphenyl phosphate, and metal hydroxide such as magnesium or aluminum hydroxide.88 It is reported that PS foams containing a mixture of EG (6-10 wt%), inorganic compound (5-10 wt%) and RP, triphenyl phosphate (TPP) or 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOP)), and chalk compounds (5-10 wt%)89 or containing EG and phosphorus compounds such as RP, triphenylphosphate diphenyl cresyl phosphate, APP, melamine phosphate, resorcinol diphenyl phosphate, and dimethyl methylphosphonate in suitable amounts90 fulfills DIN 4102-B2 requirements. 

A process which has been used for silk-dyeing is similar to that of Messrs. Holliday. A diazo-compound in solution is neutralised by chalk, and a phenol (/3-naphthol) obtained in a fine state of division by precipitation is added. On working the goods in this mixture, the colour is gradually developed and is fixed on the fibre. 

Portland cement is a finely ground, powdered mixture of compounds produced by the high-temperature reaction of lime, silica, alumina, and iron oxide. The lime (CaO) may come from limestone or chalk deposits, and the silica (Si02) and alumina (AI2O3) are often obtained in clays or slags. The blast furnaces of steel mills are a common source of slag, which is a byproduct of the smelting of iron ore. 

To produce a terephtalate adipate copolyester, dimethyl terephthalate, adipic acid, 1,4-butanediol, and glycerol are mixed together with tetrabutyl orthotitanate as a catalyst (44). The reaction mixture is then heated to a temperature of 180°C for 6 h and at 240°C. The excess dihydroxy compound can be removed by distillation in vacuo. Then hexamethylene diisocyanate is slowly added to the mixture. The diisocyanate act as chain extenders. From this material, a biodegradable polyester film can be produced. In addition, the s mtheses of related copolyesters have been described in detail (45). It has been found that the addition of chalk can achieve an additional improvement in the biodegradability. 

The many forms of calcium carbonate described clockwise from top). An abalone shell is composed of thin overlapping layers of calcium carbonate, interspersed with a protein (a class of macromolecules described in Chapter 22). Limestone is a mixture of calcium carbonate and other compounds found in sedimentary rocks. Aragonite is one of the crystalline solid forms of calcium carbonate, characterized by the arrangement of carbonate ions in two planes that point in opposite directions. Blackboard chalk is often incorrectly believed to be made from the mineral chalk, which is a form of calcium carbonate, but, in fact, it is made from calcium sulfate. Iceland spar is the clear form of the mineral calcite, which is calcium carbonate arranged in a different crystal structure from that of aragonite. 

A recipe for Antwerp green is given by Fishwick, who was writing in the late eighteenth/early nineteenth centuries For lib of blue vitriol dissolved in [ ] of water, add immediately 11b of purified alkali, 4oz powdered white arsenic, dissolved previously in 1 gallon of boiling water the precipitate, from the mixture of these two solutions is to be well washed, and dry d on white paper spread on flat pieces of chalk [q.v.). This appears to be for the copper arsenite compound commonly known as Scheele s green. 

A compound material designed to imilate the colour of terracotta clay. According to Mayer (1991) terra cotta is a mixture of burnt umber, a natural red iron oxide and chalk in varying proportions further, baryte, zinc oxide or hthopone can replace flie chalk qq.v.). 

Flexible PVC compounds often contain 10-50 phr of fillers, normally calcium carbonate, which can be simply ground chalk or stearate coated precipitated calcium carbonate of finely controlled particle size. Examples are cable sheathing, footwear compounds and general extrusions. Other PVC compounds of a more specialised nature such as flooring compositions may contain from 100-500 phr of filler, often mixtures of calcium carbonate and asbestos flour. In this case the PVC compound is merely acting as a binder to hold the filler particles together. Electrical insulation... 

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