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In order to remove nitric oxide (NO) from flue gas, from small coal-fired boilers, it is necessary to exploit the cost-effective wet denitration technology. The absorption of NO with sodium chlorate solution was studied. The effects of experimental conditions, such as temperature, NaClO3 concentration, type of acid, mole ratio of NaClO3 to hydrogen ions, on NO removal rate were investigated, and the optimal conditions were established. As the effect of temperature on denitration was related to the type of acid used, the temperature required for sulfuric acid was high, and the temperature required for nitric acid was low. The optimal mole ratio between NaClO3 and the two types of acids was the same. The reaction products were analyzed by ion chromatography. The reacted solution could be recycled after the removal of sodium chloride. The reaction mechanism and the total chemical reaction equation of NaClO3 denitration were deduced. The thermodynamic derivations showed that this oxidation reaction could proceed spontaneously and the reaction was very thorough. NaClO3 exhibited high NO removal efficiency and its denitration cost was much lower than sodium chlorite. [ABSTRACT FROM AUTHOR]

The extraction behavior of Pr(III) has been investigated using four kinds of unsymmetrical diglycolamide (DGA) extractants having different alkyl chain lengths, namely N,N'-dimethyl-N,N'-didodecyldiglycolamide (DMDDdDGA), N,N'-diethyl-N,N'-didodecyldiglycolamide (DEDDdDGA), N,N'-dipropyl-N,N'-didodecyldiglycolamide (DPDDdDGA) and N,N'-dibutyl- N,N'-didodecyldiglycolamide (DBDDdDGA). The effect of the alkyl chain of amidic N atoms in DGAs on the extraction ability of Pr(III) is discussed. The extraction of hydrochloric acid and Pr(III) from hydrochloric acid medium by DGAs in sulfonated kerosene, toluene and octanol was studied. The effect of extractant concentration and diluents on the distribution ratio (D) of Pr(III) was investigated to understand the extraction mechanism. Pr(III) and Fe(III) can be separated very well by DMDDdDGA and DBDDdDGA diluted by toluene in hydrochloric acid solution. IR spectra of extracted species of DGA.HCl and DGA.Pr(III) were recorded to study the structure of the extracted species. [ABSTRACT FROM AUTHOR]

The behavior of Sm(III) and Nd(III) during extraction with N,N,N',N'-tetrabutyl-3-oxa-diglycolamide (TBDGA) in 70% kerosene--30 % n-octanol from hydrochloride acid was studied. The effects of temperature and the concentrations of hydrochloric acid and extractant on the distribution of the rare earth elements were investigated. The extraction mechanism was established and the stoichiometry of the main extracted species was confirm to be SmCl3•2TBDGA and NdCl3•2TBDGA for Sm(III) and Nd(III), respectively. The extraction distribution ratio decreased with increasing temperature, which demonstrates that the extraction reaction is exothermic. The IR spectra of the loaded organic phase and free extractant were recorded and are discussed. [ABSTRACT FROM AUTHOR]