Calcium hydroxide behaviour

Lime is made by heating limestone, including chalk, to a temperature between 1100°C and 1200°C in a current of air, at which point carbon dioxide is driven off to produce quicklime (CaO). Approximately 56 kg of lime can be obtained from 100 kg of pure limestone. Slaking and hydration of quicklime take place when water is added, giving calcium hydroxide. Carbonate rocks vary from place to place both in chemical composition and physical properties so that the lime produced in different districts varies somewhat in its behaviour. Dolostones also produce lime however, the resultant product slakes more slowly than does that derived from limestones. 

Alite (tricalcium silicate) reacts with water to form calcium silicate hydrates (CSH phases) containing less lime, while calcium hydroxide is split off. Belite (dicalcium silicate) shows similar behaviour. The hydration reaction is, for example ... 

A study of this carbonylation reaction catalysed by tetracarbonylnickel in polar aprotic solvents, e.g. dimethyl sulphoxide or iVA-dimethylformamide, in the presence of calcium hydroxide reveals that the reaction can proceed at one atmosphere pressure of carbon monoxide and at 100 °C. The reaction probably involves oxidation-addition of aryl halide to the nickel followed by carbon monoxide insertion. Rates decrease in the order I > Br > Cl > F, Chloride ions and bromide ions enhance the reaction and this explains the autocatalytic behaviour observed as these ions are released from the aryl halide during reaction. ... 

When sodium gluconate was used in place of calcium gluconate, copper was always remaining in solution at the end of the reaction. Such a difference of behaviour let to think that the precipitation of calcium carbonate led the precipitation of copper hydroxide when calcium gluconate was used. ... 

The principal exception to this pattern of behaviour is trimethyltin hydroxide [v(OH) 3620, 8(OH) 920 cm-1] which sublimes unchanged above 80 °C it can be dehydrated with sodium in benzene13 or with calcium hydride14 to give the oxide [vas(SnOSn) 740 cm4], but this fumes in air as it is hydrolysed back to the hydroxide. 

Ca, Sr, and Ba r and for Na and K F for Rb and Cs. In the presence of Na20 or NaOH, iodate ion undergoes disproportionation according to reaction (20). Calcium oxide or hydroxide caused some disproportionation to occur. Thus this behaviour of iodates in the presence of good oxide-ion donors is similar to that of chlorates. The reaction between IO3 and Br" ions in the LiBr-KBr eutectic melt (temperature range 420—483 °C) proceeds according to reaction (21), and lithium orthoperiodate separates out from solution. The initial rate of consumption of IO3 is first-order in [IO3]. 

The effectiveness of intumescent flame retardants is frequently reduced when fillers are added. Interactions can be either chemical or physical. Materials which are basic in character such as aluminium and magnesium hydroxides and calcium carbonate tend to interfere chemically with the phosphoric acid precursor in the intumescent system, presumably forming inorganic phosphates. Such antagonistic behaviour can be easily recognized by an almost complete lack of char formation. 

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