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Here we report on a single-step, eco-friendly, and facile approach to combustion-assisted reprocessing of oily copper waste into copper powder without preliminary cleaning. Complete reduction of copper from oily copper waste in the combustion wave was reached in the presence of ammonium nitrate and without introducing any reducing agent. The optimal conditions for obtaining >99 % copper powder were reached for green [Cu2O + m(oil)] + xNt mixtures with m = 7–11 wt % and x = 0.35–0.55, were m stands in wt % and x in mole fractions, both in relation to 1 g-mol of Cu2O. In scale-up experiments (up to 10 kg of green mixture), the copper powder with oxygen content below 0.5 wt % and free carbon content below 0.25 wt % was successfully produced. Our approach was also successfully applied to combustion-assisted reduction of copper oxide oily waste mixed with nickel oxide to yield composite powders and Cu–Ni alloys.

The combustion synthesis process activated by organic polymers (Teflon and polystyrene) in the SiO2/Al/C system is investigated under the counter-current and co-current degassing conditions. It is found that the combustion parameters, i.e. wave velocity and temperature, and final product microstructure are influenced by the degassing mode considered as well as the type and amount of promoters added to the starting mixture. In particular, the combustion wave results to accelerate during its propagation when adopting the forward infiltration configuration and in absence of polystyrene. In addition, under the same degassing condition, the produced gases are found to provide a specific orientation on the growth direction of thread-like SiC crystals during final product formation.

The mechanism of initiation and combustion of the 3SiO2-4Al-3C system is studied under conditions of activation of the combustion reaction by a high-energy additive of Al+αKNO3. It is shown that combustion of this system is possible only when a certain quantity of the additive is introduced into the starting mixture. The mechanism of activation of the reaction is established, and the processes involved in the reduction stage of the combustion are shown to play a leading role in the reaction. Optimal conditions for synthesis of a SiC/Al2O3 composite powder containing SiC fibers are determined.