Radioactive tracer such as a cell or tissue, or as a flow tracer to track fluid flow. Radioactive tracers are also used to determine the location of fractures created by hydraulic fracturing in natural gas production. Radioactive tracers form the basis of a variety of imaging systems, such as, PET scans, SPECT scans and technetium scans. Radiocarbon dating uses the naturally occurring carbon-14 isotope as an isotopic label. Isotopes of a chemical element differ only in the mass number. For example, the isotopes of hydrogen can be written as H, H and H, with the mass number at top left. When the
Hydrochloric acid regeneration on pyrohydrolysis and adiabatic absorption of hydrogen chloride in water, a process invented in the 1960s. However tightening environmental standards and stringent air permit policies render it increasingly difficult to establish new pyrohydrolysis-based acid regeneration plants. The following processes for the regeneration of HCl from spent pickle liquors have been adopted by the ferrous metals processing industry: Hydrothermal hydrolysis of hydrochloric SPL from carbon-steel pickling lines is a hydrometallurgical reaction, which takes place according to the following chemical formulae: 12 FeCl + 3 O → 8 FeCl + 2 FeO 2 FeCl + 3 HO → 6 HCl + FeO