The combustion process of stoichiometric aluminium/copper(II)oxide thermite was experimentally investigated in an optical bomb under inert atmosphere (N2) and ambient pressure. The reaction zone was monitored with UV/VIS emission spectroscopy and a colour high‐speed camera. The emission spectra were analysed by modelling of the background radiation and the characteristic emission of all molecular emitters in the reaction of Al/CuO. Based on this, the particles′ surface and gas phase temperature, the emissivity and the radiation of energy was determined by a non‐linear least squares fit between experimental and modelled spectra. This work presents the first modelling of the diatomic band system of Cu2 and CuO. The results obtained can help to understand the underlying processes in thermite combustion and the influence of radiation processes in modelling the combustion of thermite mixtures.

Thermite type reactions are usually used when high quantities of heat should safely be produced with low gas release. Stoichiometric samples of aluminium, magnesium and titanium particles in mm-scale were mixed with iron(III) oxide and filled into small test tubes maintaining a constant bulk density. The metals were chosen regarding their heat release, melting and boiling point, the latter also important for the metal oxides. The samples were burnt in a window bomb pressurised from 0.1 to 13 MPa with nitrogen. The reaction was observed using a colour high-speed camera equipped with a macro object lens and different fast scanning emission spectrometers in UV/Vis and NIR to determine burning velocity, emitting species and reaction temperatures. The residues were analysed using scanning electron microscopy (SEM) including energy dispersive X-ray analysis (EDX) and X-ray diffractometry (XRD). The samples burnt in a reproducible way at a linear regression rate. A strong influence of pressure on the burning velocity and reaction zone temperatures was observed. The burning velocity varied by a factor of 3 forming a maximum at a certain pressure that is characteristic to the type of metal. In correlation, temperatures varied by several hundred Kelvin. Results were discussed regarding the decomposition, melting and boiling behaviour also including thermodynamic equilibrium calculations resulting in a qualitative two-step model of interacting and reacting droplets.

Iron oxide grain coatings in red sandstones contain trace metals that are released upon dissolution of the coatings. Analyses by ICP-MS following acid leaching of the grain coatings show that the dissolved metals can constitute an ore-forming fluid, as hypothesized in models for sandstone-hosted ore deposits. Median compositions of 37 samples, mostly of Triassic to Devonian age, from across Britain and Ireland are 6.3 ppm copper, 2.4 ppm cobalt, 10.1 ppm vanadium, and 0.3 ppm uranium. These contents at the basin scale are adequate to form the observed range of ore deposits in red beds. The migration of hydrocarbons or brines can cause the dissolution of grain coatings and contributes to controlling the distribution of ore deposits. Future measurements should test red beds derived from uplifted, mineralized plate margins, in which sandstones may be preloaded with ore metals.

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