Titanium dioxide is widely used in the manufacturing of paints, varnishes, lacquer, paper, paperboard, printing inks, rubber, floor covering, and ceramics and so on. White titanium dioxide pigment has been produced by two main processes. The sulfate and the chloride processes. Each of these two routes requires different feedstocks. However, economic and environmental pressures are shifting ...

Application of selective non-catalytic reduction systems at municipal solid waste incinerators (MSWIs) often involves over-stoichiometric injection of ammonia into flue gases. Un-reacted ammonia may be deposited on fly ash particles and can ultimately influence the leaching behaviour of air-pollution-control (APC) residues. Batch tests were conducted to investigate the impacts of ammonia levels...

A method was developed to assess leaching of several poly(vinyl chloride) (PVC) plasticizers in aqueous media using gas chromatography (GC), and compared to a gravimetric standard test method (ASTM Method D1239). The GC method was a more direct measurement of plasticizer concentration in the aqueous phase. The leaching of commercial plasticizers, as well as several series of "green" candidate p...

This paper presents an experimental study on the nature of permeation properties and pore structure of concrete surface layers containing fly ash. Concretes containing different dosages of fly ash as a replacement for cement (15% and 30% by weight of total cement materials, respectively) were investigated. Concrete without any fly ash added was also employed as the reference specimen. Laborator...

Au-Ag noble metal wastes represent a wide range of waste types and forms, with various accompanying metallic elements. The presented leaching strategy for Au-Ag contained in circuit boards (PCBs) aims at gaining gold and silver in the metallic form. Application of the proposed ammonium thiosulphate leaching process for the treatment of the above mentioned Au-Ag containing wastes represents a pr...

In this paper, the leaching behavior of the major metals present in printed circuit boards waste is evaluated, aiming at its recycling by hydrometallurgy. Several leachants were compared (sulfuric, hydrochloric and nitric acids, at 2 M H concentration), at temperatures of 25oC and 90oC and 4 hours of reaction time. Sulfuric acid leaching was not very promising concerning metals dissolution bein...

Military small arms shooting range (SASR) soils are heavily polluted by metals like copper, lead, antimony, and zinc. This study was carried out to define efficient operating conditions to solubilize these metals by a chemical leaching technique. The comparison of different leaching reagents (HCl, H2SO4, CH3COOH, and EDTA) has revealed that sulfuric acid leaching coupled with the addition of so...

In this work, various 3-cyano-4-aryl-4H-pyran derivatives were prepared efficiently through a one-pot,multicomponent synthesis between aromatic aldehyde, malononitrile and acetophenone derivativesor ethyl acetoacetate using Fe3O4/EDTA magnetic nanocatalyst and ethanol as solvent. The reactionswere completed at room temperature in 10 min using 5 mg of catalyst and 2 mL of solvent to prepare1 mmo...