Carbon dioxide mineralisation

Fig. 4-1. Relation between carbon dioxide in soil and copper mineralisation at Huaitongshan, Gansu province, China.

Carbon dioxide, probably introduced at the time of emplacement of mineralisation, occurs in a form that is easily released at 100°C as halo around and above many mineral deposits. Along soil traverses over nine mineral deposits in China, determination of this CO2 yields good-contrast anomalies, even when the mineralisation is deeply buried. There is also an elevated CO2 expression in soils over faults in mineralised areas. 

Fig. 14-9. Oxygen and carbon dioxide in soil air over sedimentary copper mineralisation at Witviei, Namibia (from Lovell et al., 1983).

Fig. 14-11. Carbon dioxide in soil air (sample sites and contours in %) over mineralised breccia pipe, northern Arizona (from Lovell and Reid, 1989).

Lovell, J.S. and Reid, A.R., 1989. Carbon dioxide / oxygen in the exploration for sulphide mineralisation. In G.G. Garland (ed.), Proc. Exploration 87. Ontario Geol. Survey, Spec. Vol., 3, pp45 7-470. 

Lovell, J.S., Hale, M. and Webb, J.S., 1983. Soil air carbon dioxide and oxygen measurements as a guide to concealed mineralisation in semi-arid and regions. J. Geochem. Explor., 19 305-317. 

Mineralisation half-life states the amount of time required for degradation to carbon dioxide and water. 

The evolution of carbon dioxide or methane from a substrate rqpresents a direct parameter for mineralisation. Therefore, gas evolution tests can be... 

Some materials tend to degrade very slowly under stringent test conditions without an additional source of carbon. However, if readily available sources of carbon are added, it becomes impossible to tell how much of the evolved carbon dioxide can be attributed to decomposition of the plastic. The incorporation of radioactive V in synthetic polymers gives a means of distinguishing between CO2 or CH4 produced by the metabolism of the polymer, and that generated by other carbon sources in the test environment. By comparison of the amount of radioactive COa or CH4 to the original radioactivity of the labelled polymer, it is possible to determine the percent by weight of carbon in the polymer which was mineralised... 

Saturated solutions of calcium carbonate under atmospheric carbon dioxide have been shown to contain 80 per cent Ca with the other 20 per cent dissolved calcium being CaCOa and CaHCOa species [422]. Of rather more significance in the dental and mineralised tissue field is the complexation of calcium ions with various inorganic phosphates where results for tetrapolyphos-phates, trimetaphosphate, and tetrametaphosphate obtained with calcium ion-selective electrodes match those of pH titrations [423,424],... 

Determination of the degradability caused by microbial activity and quantification by either oxygen (O2) demand, carbon dioxide (CO2) release or methane (CH4) production, considering the time needed for full mineralisation. 

The second step is known as mineralisation and occurs inside the cell. Small-sized oligomeric fragments are converted into biomass, minerals, salts, water, and gases such as carbon dioxide (CO2) and methane (CH4). 

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