Calcium oxides and hydroxides

Arsenic, phosphorus, fluorides, petroleum oils, calcium oxide and hydroxide, phenols... 

Following the original measurements of the surface energy of sodium chloride by heats of solution by Lipsett et al. 18), much more accurate determinations have been carried out recently by Benson and his co-workers 19-22). Other substances which have been investigated include magnesium oxide 23), calcium oxide and hydroxide 24), and silica, unhydrated and hydrated 25). 

Among the commonly observed spectral overlap problems due to molecular oxide and molecular hydroxide ions are those due to TiO+ (with 5 isotopes of Ti from mass 46 to 50) that result in overlaps with a minor isotope of nickel, 62Ni+ both isotopes of copper, 63Cu+ and 65Cu + and the two major isotopes of zinc, MZn+ and 66Zn+. Calcium oxide and hydroxide ions overlap with all five isotopes of nickel, both isotopes of zinc, and three of the four isotopes of iron. The analysis of rare earth elements is particularly complicated by molecular oxide and hydroxide ion spectral overlaps [141,142]. 

Typical fillers calcium carbonate, carbon black, zinc oxide, calcium oxide and hydroxide... 

Special considerations calcium oxide is used as acid scavenger and desiccant zinc oxide is a curing agent in vulcanization processes calcium oxide and hydroxide are used as acid scavengers... 

Vaughan MA and Templeton DM (1990) Determination of Ni by ICP-MS. Correction of calcium oxide and hydroxide interferences using principal components analysis. Appl Spectrosc 44 1685-1689. 

TABLE 11-2 Calcium Oxide and Hydroxide Species and Other Potential Interferences in the Mass Region for Ni Determination... 

Wastes from lime production and processing contain alkaline components such as calcium oxide and hydroxide. They may contain slightly soluble salts, such as calcium sulfate, as well as insoluble calcium carbonate, clay and fuel ash related products. Water draining through lime tips becomes alkaline and precipitates carbonate hardness in ground waters (33.1). 

Prepared calcium carbonates are purified forms of native material. Conversion of calcium oxide and hydroxide produced from the calcination of material such as limestone and the subsequent absorption of atmospheric carbon dioxide furttier accounts for the occurrence of pigments such as those sometimes called lime. 

Calcium group Calcium oxides and hydroxides group Lime Egyptian blue... 

The calcium oxides and hydroxides are primarily produced during the calcination of limestone (calciinn carbonate) to form hme (qq.v.), CaO, and its subsequent slaking with water to produce calcium hydroxide (Ca(OH)2), slaked time. Calciiun oxide is a very unstable compound and will readily combine with water to form calcium hydroxide. The reaction by which time cements form, tiie exchange of atmospheric carbon dioxide for the hydrous component of slaked lime, is a slow process, and unconverted Ca(OH)2 can linger for decades or even centuries. 

Calcium oxides and hydroxides group Feldspar group Calcite Calcium hydroxide Kaolin Orpiment Quartz FitzHugh (1997) Minguzzi (1937) Moropoulou et al. (1995) Peng eta/. (1995) Tilley (1934)... 

A known weight of the sample is slaked by boiling with water (reaction 8.2). Both calcium oxide and hydroxide are then extracted with sucrose solution and filtered. CaC03, MgO and other impurities are left behind. The base in filtrate is then titrated with standard acid using phenolphthalein indicator. 

The composition of the Hquid phase during the early hydration of Portiand cements is controlled mainly by the solution of calcium, sulfate, sodium, and potassium ions. Very Httie alumina, siHca, or iron are present in solution. Calcium hydroxide, as calcium oxide, and gypsum, as calcium sulfate, alone have solubihties of about 1.1 and 2.1 g/L at 25°C, respectively. In the presence of alkaHes released in the first 7 min, the composition tends to be governed by the equiHbrium ... 

A 5.025-g sample of calcium is burned in air to produce a mixture of two ionic compounds, calcium oxide and calcium nitride. Water is added to this mixture. It reacts with calcium oxide to form 4B32 g of calcium hydroxide. How many grams of calcium oxide are formed How many grams of calcium nitride ... 

Heating with the following solids, their fusions, or vapours (a) oxides, peroxides, hydroxides, nitrates, nitrites, sulphides, cyanides, hexacyano-ferrate(III), and hexacyanoferrate(II) of the alkali and alkaline-earth metals (except oxides and hydroxides of calcium and strontium) (b) molten lead, silver, copper, zinc, bismuth, tin, or gold, or mixtures which form these metals upon reduction (c) phosphorus, arsenic, antimony, or silicon, or mixtures which form these elements upon reduction, particularly phosphates, arsenates,... 

Now consider strong and weak bases. The common strong bases are oxide ions and hydroxide ions, which are provided by the alkali metal and alkaline earth metal oxides and hydroxides, such as calcium oxide (see Table J.l). As we have seen,... 

The low permittivity of these liquids compared with water inhibits dissociation of the acids so that cement formation demands much more reactive basic oxides. Oxides and hydroxides that are capable of cement formation are ZnO, CuO, MgO, CaO, Ca(OH)2, BaO, CdO, HgO, PbO and BiaOj (Brauer, White Moshonas, 1958 Nielsen, 1963). In practice these are confined to two calcium hydroxide and special reactive forms of zinc oxide. 

There is one disadvantage to having lime around, however. It must be kept completely dry wherever it is stored. The reaction between calcium oxide and water forms calcium hydroxide (or slaked lime ). 

Dry sorbents are also used to remove sulfur dioxide. Lime (calcium oxide) and slaked lime (calcium hydroxide) combine with sulfur dioxide to form calcium... 

The next major raw material for which we discuss the derived chemicals is calcium carbonate, common limestone. It is the source of some carbon dioxide, but, more importantly, it is used to make lime (calcium oxide) and slaked lime (calcium hydroxide). Limestone, together with salt and ammonia, are the ingredients for the Solvay manufacture of sodium carbonate, soda ash. Soda ash is also mined directly from trona ore. The Solvay process manufactures calcium chloride as an important by-product. Soda ash in turn is combined with sand to produce sodium silicates to complete the chemicals in the top 50 that are derived from limestone. Since lime is the highest-ranking derivative of limestone in terms of total amount produced, we discuss it first. Refer to Fig. 2.1, Chapter 2, Section 1, for a diagram of limestone derivatives. 

Calcium chloride is obtained as a by-product in the manufacture of sodium carbonate (soda ash) by ammonia-soda (Solvay) process. The process involves the reaction of sodium chloride with calcium carbonate and ammonia. Calcium chloride is currently produced in bulk amounts by evaporation of natural underground brines. In the laboratory, calcium chloride can be prepared by treating bmestone with hydrochloric acid followed by evaporation of solution to obtain crystals. The crystals are dehydrated to obtain anhydrous salt. Calcium oxide or hydroxide may be used instead of carbonate. 

In 1815, L. G. Gilbert1 noticed that thoroughly dried calcium oxide or hydroxide does not react chemically with dry chlorine, and similarly, in 1879, J. K. Weisherg showed that the same remark applies to dry barium or strontium oxide. The case is very different if moisture he present. With barium hydroxide two gram-atoms of chlorine are absorbed per gram-atom of the bivalent barium, and barium chloride and chlorate are produced so that if barium hypochlorite is formed as the first product of the reaction, it is immediately decomposed 3Ba(0Cl)2=Ba(C103)2 +2BaCl2 with calcium and strontium hydroxides, the reaction appears to he much... 

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