Recovery of vanadium pentaoxide and potassium sulfate from spent catalyst using ammonium sulfate

The aim of the present work was directed to investigate thoroughly, the effectiveness of extraction of vanadium oxides as well as potassium sulfate from the spent vanadium pentaoxide catalyst using ammonium sulfate as an attacking reagent, in order to avoid the use of corrosive acids. The investigation was also aimed to utilize the accumulated amounts of spent catalyst in production of vanadium pentaoxide and potassium sulfate which help in minimization of environmental pollutions arised from accumulation of the former one by times. The chemical reactions between the reactive species, resulted from thermal decomposition of ammonium sulfate and various species forming the spent catalyst at different temperatures ranged between 200-450[degree sign] C were investigated in detail the different reaction products were characterized by means of x-ray diffraction patterns as well as by electronic absorption spectra, whereas the contents of tetra-and pentavalent vanadium species were determined by volumetric methods of chemical analysis. Depending on the different results, samples of vanadium pentaoxide and potassium sulfate were prepared in pure forms from the spent catalyst

Studies on reaction between KHSO4-VOSO4 system at different temperatures

The present study deals with some industrially important vanadium compounds produced as a result of solid-solid interactions between potassium hydrogen sulfate and vanadyl sulfate at different temperatures. The reaction products have been characterized by chemical and thermal analysis, X-ray diffraction patterns, electronic absorption spectra and electrical conductivity. The results of XRD revealed that the reaction products are composed of a mixture of vanadium compounds which possess different valences of tn [KV[SO 4] 2], tetra [K 2VO[SO 4] 2] and pentavalent vanadium [K 3VO 2 [SO 4] 2, K 4[VO 2] 2[SO 4] 2[S 2O 7], KVO 2SO 4, K 2V 2S 2O 12], in addition to some potassium bronze and polyvanadate [KV 6O 15, K 2V 8O 21]. The reactions that lead to the formation of these compounds were suggested and discussed. The identity of these products depends essentially on the temperature as will as the molar ratios of the reactants. The optimum conditions for the formation of soluble vanadium compounds are molar ratio 1:1 of KHSO 4 and VOSO 4 at 450°C. Under these conditions, up to 78% of vanadium was leached with 0.5 M H 2SO 4 The electrical conductivity was measured over a temperature range of 298 to 590 K at frequency 1y00kHz/s. The reaction products exhibited semiconductor character. The electrical conductivity is proportional to reaction temperature and vanadium ions content. The temperature dependence of electrical conductivity has been discussed on the basis of electronic and ionic conduction mechanism

Study of the preparation and characterization of copper ferrite including ferritization of copper scraps

Samples of copper ferrite, CuFe2O4, were prepared using both dry and wet processes, either from powders of iron oxide or from interaction of copper and iron sulfates, or co-precipitation of copper and iron hydroxides from homogeneous sulphate solutions at different pH values. Also, a sample of copper ferrite was prepared in optimum conditions from copper scraps. The effects of temperature and time of ferritization were studied. The prepared samples were investigated by X-ray diffraction analysis, differential thermal analysis, DTA, and scanning electron microscopy, SEM. Optimum conditions were found to depend on the input materials, the pH values, time and temperature

Colorimetric determination of some hydrazone derivatives

A simple and rapid colorimetric method was described for the determination of isocarboxazid, iproniazid phosphate and phenylhydrazine hydrochloride. The method depended on the use of 2-iodoxybenzoic acid, as an oxidant in 50% w/v orthophosphoric acid to oxidize chlorpromazine HCl to chlorpromazine free radical, which absorbs at 530 mm. This red free radical was rapidly and quantitatively reduced by the investigated compounds to the colorless chlorpromazine. The decrease in absorbance was found to be directly proportional to the quantity of each compound studied, and this forms the basis for the quantitative estimation of micro-quantities of the investigated compounds