Hydrogen-Rich Gas Produced by the Chemical Neutralization of Reactive By-Products from the Screening Processes of the Secondary Aluminum Industry

In the framework of the industry of secondary aluminum, the chemical neutralization of highly reactive materials that come from the pre-treatment screening processes of scraps (beverage cans and domestic appliances) was investigated through experiments in aqueous alkaline solutions. Metallic aluminum-rich by-products are classified, according to EU law, as dangerous waste, as they can potentially develop flammable gases capable of forming explosive mixtures with air. In this way they cannot be disposed of in landfills for non-hazardous wastes if chemical neutralization is not planned and performed beforehand. In this way, these experiments were mainly aimed at unraveling the oxidation rate and at quantifying the production of hydrogen-rich gases from the reactions of the metallic aluminum-rich by-products in a water-rich alkaline (liquid or vapor) environment. Reactions were carried out in a stainless-steel batch mini-reactor with metering and sampling valves, with the resulting gases analyzed by gas-chromatography (GC). The experimental setup was planned to avoid the following issues: (i) the corrosion of the reactor by the alkaline solution and (ii) the permeability of the system to hydrogen (i.e., possible leaks of H2), related to the fast kinetics and short duration of the reactions (which may hinder a pile-up-effect) between the solid by-products and the liquid. The procedure was defined by a controlled interaction process between metals and liquid, using NaOH to increase reaction rates. The experimental runs performed in the mini-reactor proved to be effective for eliminating the reactive metallic aluminum, reaching a maximum hydrogen production of 96% of the total gases produced in the experiments. The relations between gas generation (up to 55 bar of H2 in the experiments, which lasted for four days) and each specific parameter variation are discussed. All the obtained results can be transferred and applied to (i) the possible industrialization of the method for the chemical neutralization of these dangerous by-products, increasing sustainability and workplace safety, (ii) the use of the resulting hydrogen as a source of energy for the furnaces of the secondary aluminum industry itself, and (iii) new technological materials (e.g., “foamed geopolymers”), by using hydrogen as a foaming agent, coupled with aluminosilicate materials, during geopolymeric reactions.

MODIFIED CARBON-CONTAINING ALUMINUM CHLORIDE CATALYSTS

Catalytic systems based on metallic aluminum Al and carbon tetrachloride CCl4, modified by Mg, CuCl2, NiCl2, MgCl2, have been developed. EPR and IR spectroskopiya studies of synthesized samples of catalysts were carried out. Based on the EPR spectrum, the presence of a Cu-C -bond was revealed in the Al + CCl4 catalyst with the modifying additive CuCl2. Using IR spectra, it was determined that catalysts without modifiers and with modifiers are a mixture of two complexes based on Corbin-type structures. In this case, the catalysts differ in the ratio of the main structures with double C=C and triple C≡C bonds. Catalysts with modifying additives NiCl2 and Mg have significantly fewer of these structures than a catalyst without modifiers, and a catalyst with Mg is characterized by the smallest number of structures containing C=C bonds. It is shown that the catalysts obtained on the basis of Al and CCl4 and its various modifications are complexes, the carbon-containing part of which is represented by polycumulene and polyine structures containing ethylene and acetylene bonds.

Novel green manufacture of metallic aluminum coatings on carbon steel by sol–gel method

The novel double-layer specimen of Al coating had the ability to resist simulated seawater corrosion for 30 days and air oxidation at 500 °C for 15 h.

Nickel-Palladium Alloy Nanoparticles Supported on the Reduced Graphene Oxide Decorated with Metallic Aluminum Nanoparticles (Al-rGO/NiPd): a multifunctional catalyst for the transfer hydrogenation of nitroarenes and olefines using water as hydrogen source

We report herein an innovative design and synthesis of a novel multifunctional nanocatalyst for the transfer hydrogenation (TH) of nitroarenes and olefines using water as hydrogen source and solvent. The...

Application of Response Surface Method to Copper Cementation by Metallic Aluminum Particles

In the present study, the interactive effects of the process variables containing copper concentration, temperature, and time on the efficiency of copper cementation by metallic aluminum particles were examined by using response surface methodology (RSM). It was observed that the efficiency of cementation increased with an increase in the initial concentration of copper, temperature and time. The multiple regression analysis to the experimental data was applied to see the interactive effects of process variables. The second-order polynomial equation was obtained. The optimal values were found to be 0.075 mol/l, 303 K, and 90 min to maximize the amount of the deposited copper.