The aim of this study was comparative analysis of catalysts with 5 and 20 wt.% Ni loading, with and without Pd additive, and it included: determination of reduction degrees, investigation on microstructure by scanning electron microscopy and chemical analysis by energy-dispersive spectroscopy. Ni/Al 2 O 3 and Ni-Pd/Al 2 O 3 catalysts supported on α-Al 2 O 3-based foams were synthesized by aerosol assisted impregnation. Impregnation of the foams by ultrasonically aerosolized chlorides was followed by drying at 473 K and hydrogen reduction at 533 and 633 K. Lower Ni loading resulted in higher reduction degrees. Ni loading of 20 wt.% enabled relatively uniform coverage of the foam with a metallic coating. Nearly complete reduction was achieved at both temperatures with activity modifier (Pd). Reduction degrees reached 99.4 and 98.2 wt.% at 533 K for 5 and 20 wt.% of Ni, respectively.
Primena hidrometalurških procesa omogućava proizvodnju metala iz ruda i koncentrata koji, zbog kompleksne mineralogije i/ili niskog sadržaja metala, nisu pogodni za pirometaluršku preradu. Pored toga, manja potrošnja energije i manji uticaj na životnu sredinu su važne prednosti hidrometalurgije u odnosu na konvencionalne pirometalurške procese. Prilikom luženja sulfidnih minerala sumpornom kiselinom rastvor za luženje mora sadržati oksidaciono sredstvo za oksidaciju sulfidnog sumpora. U ovom radu je ispitivan uticaj temperature na stepen izluženja bakra iz halkopiritnog koncentrata u prisustvu vodonik-peroksida kao oksidansa pri atmosferskom pritisku. Hemijska i rendgenska difrakciona analiza polaznog koncentrata i čvrstog ostatka nakon luženja su korišćene za određivanje mehanizma procesa luženja bakra iz ispitivanog koncentrata.
Fires are an accompanying manifestation in modern weaponry use and in various accidents in peacetime. The standard military uniform is a primary barrier in protection of a soldier's body from all external influences, including the thermal ones which can cause burns. The minimum thermal resistance to the effect of burning napalm mixture (BNM) in individual uniform garment materials was determined, and found to be higher for simultaneous use of more materials one over another (the so-called sandwich materials), where the best thermal protection was exhibited by sandwich materials with an air interspace. The requirement for the thermal resistance of the material of the filtrating protective suit (FPS) to the effect of BNM (≥ 15 s) was fully met. The highest thermal resistance was demonstrated by the FPS whose inner layer was made of polyurethane foam with active carbon. The FPS thermal resistance to the effect of BNM was found to be proportional to water vapor permeability through this garment mean, and inversely proportional to air permeability.
This paper aims to consider the treatment of jarosite residue using a different reducing agents, aluminum, magnesium, and carbon. The jarosite residue is not standard-it contains higher amounts of Pb and Ag, as well as In, Ga and Ge. We show thermodynamical conditions of gas phase equilibrium for the given experiments and predominance diagrams that show potential for obtaining critical metals in the metallic phase. Using a mixture of aluminum and magnesium, as reducing agents, showed proper fuming of Zn and Pb at a temperature of 1200 °C. However, magnesium alone, and carbon in the mixture of reducing agents cause poor results for zinc fuming, which is explained by the modeling of the given compositions.
Paper presents a thermodynamic analysis of chemical reactions occurring during chlorination with and without additives for both nickel oxides and nickel ferrites, which are component parts of nickel ore. The experimental research investigated the influence of temperature in the range from 600 up to 1000 °C and time (up to 3 h) on the chlorination degree of nickel ores with and without additives. It was found that the introduction of additives such as C, S, BaS and NaCl intensified the chlorination of nickel ore. The results can be applied and may help determine the optimal conditions for the chlorination of low-grade ferrous nickel ores
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