Synthetic CaCO

Starting from limestone, a whole range of products can be obtained [6], First, by calcination of limestone, quicklime is produced, which chemical formula is CaO. Quicklime can then be reacted with water to produce hydrated lime, which chemical formula is Ca(OH)2. Depending on the quantity of water used for this reaction, the reaction is called either hydration or slaking and leads to the production of a dry powder (hydration) or a slurry called milk of lime (slaking). Once hydrated lime has been formed, it can be recarbonated by a reaction between gaseous CO2 and Ca(OH)2, and more specifically by a reaction between gaseous CO2 and a milk of lime to produce PCC (synthetic CaCOs). 

Calcium carbonate [471-34-1]—Cl Pigment White 18, Cl No. 77220, EEC No. E 170. A fine, white, synthetically prepared powder consisting essentially of precipitated calcium carbonate, CaCO. ... 

Calculations based on Stiff and Davies stability index (Ref. 11 indicated that under normal producing temperatures formation water 1s not expected to form scale. However, the high skin temperature (up to 150° C) of the crude heaters will cause severe CaCO-scaling. This expectation was confirmed by laboratory tests using synthetic formation water. The result indicates a requirement to Inject scale inhibitor upstream of the heaters. A polyphosphate scale inhibitor was found to be effective in the laboratory tests. 

The activities of Mg++ and Ca++ obtained from the model of sea water proposed by Garrels and Thompson have recently been confirmed by use of specific Ca++ and Mg++ ion electrodes, and for Mg++ by solubility techniques and ultrasonic absorption studies of synthetic and natural sea water. The importance of ion activities to the chemistry of sea water is amply demonstrated by consideration of CaC03 (calcite) in sea water. The total molality of Ca++ in surface sea water is about 10 and that of COf is 3.7 x 1C-4 therefore the ion product is 3.7 x 10 . This value is nearly 600 times greater than the equilibrium ion activity product of CaCO of 4.6 x 10-g at 25°C and one atmosphere total pressure. However, the activities of the free 10ns Ca++ and COj = in surface sea water are about 2.3 x 10-3 and 7.4 x 10-S, respectively thus the ion activity product is 17 x 10 which is only 3,7 rimes greater than the equilibrium ion activity product of calcite. Thus, by considering activities of sea water constituents rather than concentrations, we are better able to evaluate chemical equilibria in sea water an obvious restatement of simple chemical theory but an often neglected concept in sea water chemistry. 

Stevenson CL, Augustijns PF, Hendren RW (1995) Peremabil-ity screen for synthetic peptide combinatorial libraries using CACO-2 cell monolayers and LC-MS/MS. Pharm Res 12 94... 

The Tobermorite-like CSH samples were synthesized in hydrothermal conditions an aqueous reaction between CaO and silicic acid with different Ca/Si ratios. CaO was calcinated from CaCOs at 1100°C while silicic acid was calcinated at 150°C for 2 hours in order to remove adsorbed vapours. The water/solid ratio was fixed at 20. Plastic bottles containing the samples were placed in autoclave at 60°C with a permanent rotation system for 100 days. The samples were then rinsed with pure water and stored at 30% of relative humidity. Here, we report results for synthetic Tobermorite material with Ca/Si=0.9. 

However, much cheaper sources of ammonia gas are calcium cyanamide (which yields NHj and CaCO., when treated with superheated steam, Ca = N — RN + 3H.T) = CaCO.,+ 2NH3), and synthetic ammonia produced by the Badische Anilin- und Soda Fabrik by direct union of N and H (see p. 53). 

Rietveld structure refinements have also been undertaken on synthetic precipitated COsAps as model systems for biological apatites. The reduction in apparent PO4 volume, and P and Ca2 occupancies seen in dental enamel were also seen in Na-free precipitated COsAps with CO3 contents of 4 wt % produced by the reaction between CaCOs and CaHP04 at 100°C (Morgan et al. 2000). COsAps precipitated in the presence of Na ions... 

For the first trials, two laboratories (LHRSP and CRECEP) used natural mineral waters (Evian and Volvic) modified by adding hydrochloric acid to reduce alkalinity to 200 and 20 mg/1 CaCOs approximately. The three other labs (Kiwa, TZW and WRC) used synthetic waters prepared by dissolving calcium chloride and sodium biearbonate in deionized water. 

CRECEP and LHRSP used natural waters because they are more convenient for taste evaluation. Alkalinity of natmal waters has been corrected to obtain 20 ppm and 200 ppm CaCOs. The differences were alw s significant and very large with soft waters, but differences also appeared with medium mineralized waters. Almninimn leaehing is lower in natural waters than in synthetic waters. 

In this chapter, the study carried out on nanofillers reinforced natural/synthetic rubber has been discussed. After a description on the NR rubber and CaCOs as filler, the development of synthetic composites with the incorporation of micro and nano-CaC03 as a filler material has also been discussed for comparative study. In particular, the role of fillers on the property modification of rubber properties, such as surface properties, mechanical strength, thermal conductivity, and permittivity has been mentioned. The effectiveness of this coating was demonstrated. The importance of well-dispersed nanoparticles on the improvement of the mechanical and electrical properties of polymers is also emphasized. However, one of the problems encountered is that the nanoparticles agglomerate easily because of their high surface energy. 

In other cases, homemade matrix-matched standards have been prepared. For instance, Ulens et al. used CaCOs pellets doped with known amounts of the analytes for marble analysis [9]. Pereira et al. prepared synthetic obsidian standards based on the coprecipitation of trace elements in alumina and calcium carbonate, followed by the incorporation of the precipitates into a glass frit, for analysis of natural obsidian... 

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