Limestone samples, compositions

The principles of sampling slaked lime products are similar to those described in section 6.2 for limestone and section 18.3 for quicklime products. Definitions of the terms increment, sample, spot sample, composite sample and laboratory sample are given in the Glossary and Fig. 6.1 illustrates how they are related. 

The surface composition of the limestone samples has been investigated using XP8 which probes to a depth of about 3 nm. Figure 6 shows broad scan spectra for the Portland samples. Whilst the pristine sample shows only calcium, carbon and oxygen peaks, associated with the matrix calcium carbonate, the sheltered and exposed samples also give prominent sulphur peaks. These are most striking in the spectrum for the sheltered sample. Integration of the peak areas for the elements present in the spectra recorded for both the Portland and monks Park... 

Table 1, Surface composition (atom %) of limestone samples from XPS experiments. 

Table 5.4 Olivine major element compositions (in weight %). Samples occur in different types of rocks (1) = forsterite from a metamorphosed limestone (2) = hortonolite from an olivine gabbro (3) = fayalite from a pantelleritic obsidian (4) = fayalite from an Fe-gabbro (5) = forsterite from a cumulitic peridotite (6) = forsterite from a tectonitic peridotite. Samples (1) to (4) from Deer et al. (1983) sample (5) from Ottonello et al. (1979) sample (6) from Piccardo and Ottonello (1978). ...

A number of environmental applications [3] have been performed in order to size characterize colloids collected in rivers (riverbome particles, SPM, and sediments), clay samples and ground limestone (from soils), coal particles, diesel soot particles (from combustion processes), or airborne particles in urban areas (from waste incinerators, vehicles, household-heating systems, and manufacturing). In many of these cases, not only the size but also the particle size distribution was important and thus, in conjunction with the traditional UV detector, specific detectors such as ETAAS, ICP-MS, ICP-AES were used [40] in order to obtain more detailed, more specific compositional information. 

Figure 8.24. Summary of composition of nonstoichiometric dolomite. A. Data for 246 samples from continental exposures of dolostones and dolomitic limestones. B. Data for 153 samples from continental exposures of dolomites related and not related to evaporite sequences. C. Ranges of Holocene dolomite compositions. D. Data for 35 samples of deep-marine dolomite from DSDP cores. E. Histogram of 245 samples of deep-marine dolomite E evaporite-associated, O organic origin, L samples of Lumsden (1988) above, D detrital, and U uncertain. (After Lumsden, 1988.)...

According to Krolopp, the mollusc material indicates deposition in warm water. Also according to him, samples collected from various sites of the lime mud are almost identical in chemical composition with the limestone, hence the name lime mud is appropriate. 

Figure 33 Oxygen isotopic composition of limestones and calcitic shells during geologic history. Triangles and circles represent samples with good and poor age assignment, respectively (after Shields and Veizer, 2002).

Most speleothem crystals are translucent rather than transparent. This is because of the presence of myriad tiny bubbles trapped in the growing calcite. The bubbles provide a sample of the water from which a particular bit of calcite grew. Measurements can also be made on the drip water from actively growing speleothems. The calibration is important because of the complicated pathway taken by the infiltration water from its origin as rainfall, through soil water, to water dissolving limestone at the bedrock interface, to drip water and finally to incorporation in the speleothem. If speleothem isotope ratios are to provide useful climatic information, it must be shown that the isotope record incorporated in the speleothem accurately reflects the isotope composition of the original rainfall. 

Barba and his colleagues sampled the three outcrops of limestone to determine their distinctive signatures. This information was compared to lumps of calcium carbonate found in the finished plaster in the city. The group of scientists used several different techniques to examine the samples. The major element composition of the geological samples was determined by XRF. The major element composition of the lumps was determined by SEM-EDS. Trace element composition was determined by LA-ICP-MS (laser ablation inductively coupled plasma mass spectrometry) to measure the elemental composition of the plaster and the limestone. This methodology is well suited for analyses of very small lumps with microscopic spot sizes. The LA-ICP-MS method is able to analyze a large number of trace and rare earth elements with speed, precision, and high resolution, especially in cases where the major chemical composition does not appear to be particularly distinctive. The instrument worked extremely well for the characterization and determination of the provenance of the Ume plaster source material. 

The limestone reactivity test procedure calls for the samples to be ground and screened to produce material in narrow particle size ranges for testing. Solution composition and pH are maintained constant throughout the measurement period (up to 20 hours) at preselected values. The selection of pH and solution compositions is based upon several design criteria including ... 

Lime (CaO), gypsum (CaS04), limestone (CaC03), and calcite (another form of CaC03) were all known to, and used by, ancient people. However, the chemical compositions of these substances were not known until the 19th century. By 1808, English chemist Sir Humphrey Davy had already produced by electrolysis pure samples of sodium and potassium. It was only natural that in that year he would apply the same electrolytic technique to the isolation and identification of strontium, barium, calcium, and magnesium—the major alkaline earth metals. 

The minimum size and number of increments of granular limestone, required to produce representative spot and composite samples, are specified in BS 6463 and are reproduced in Table 6.2. 

Most of the samples collected over this interval and from certain other regions represent only non-transformed micrite carbonates. XRD analyses and microscopic observations only reveal very poorly crystallized limestones, the carbon isotope composition of which corresponds to that of carbonate rocks of marine origin. Even here,... 

There being several varieties of limestone, the limes prepared from them show corresponding variations in composition. The type of analysis required on a given sample depends to some extent on the use for which the sample is intended. Though routine analysis includes the same determinations as are canied out on limestone, there are certain specific uses which depend on the caustic value of lime (CaO content), and the impurities including CaC03 are not available for reaction. It is therefore often desirable that available CaO content of lime be determined. 

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