Huang Ke-long

LCA Case Study of zinc hydro and pyro-metallurgical process in China

Goal, Scope and BackgroundChina is one of the main producers of metallic zinc and its annual production has been becoming the largest in the world since the year 2000. To improve the environmental situation of zinc production in China, a life cycle assessment was performed for hydro and pyro-metallurgical processes, based on the case study of Zhuzhou Smelter and Shaoguan metallurgical plant, respectively.MethodsThe system is modeled into several sub-modules so as to identify the source of environmental impacts.Results and DiscussionThe main results of LCA study are summarized as follows: (1) Hydro-metallurgical process is superior to pyro-metallurgical process in GWP and inferior to pyro-metallurgical process in GER and ACP. (2) Compared with the advanced foreign zinc metallurgical process, the GWP, ACP and HME of the zinc metallurgical process in China are much higher. (3) In hydro-metallurgical processes, residue treatment and auxiliary processes are the main contributors of ACP and GWP, which are the key sub-modules, and should be improved. In pyro-metallurgical processes, the main sub-modules needing improvement are smelting, power and electricity generation. (4) Electricity is the main energy consumption in the hydro-metallurgical processes, accounting for 60% of GER. In pyro-metallurgical process, main energy sources are metallurgical coke and anthracite, both also accounting for 60% of GER.ConclusionsAccording to the discovery of LCA study, three main measures to improve the environmental performance of zinc products were proposed: 1) Regulating the structure of energy sources of Shaoguan Smelter, 2) removing SOb2 in low concentration from flue gas by absorption with zinc oxide, and 3) adjusting the material structure of Walze rotary furnace.

Chiral extraction of ketoprofen enantiomers with chiral selector tartaric esters

Distribution behavior of ketoprofen enantiomers was examined in methanol aqueous and organic solvent mixture containing tartaric esters. The influence of length of alkyl chain of tartaric esters, concentration of L-tartaric esters and methanol aqueous, kind of organic solvent on partition ratio and separation factors was investigated. The results show that L-tartaric and D-tartaric esters have different chiral recognition abilities. S-ketoprofen is easily extracted by L-tartaric esters, and R-ketoprofen is easily extracted by D-tartaric esters. L-tartaric esters form more stable diastereomeric complexes with S-enantiomer than that with R-enantiomer. This distribution behavior is consistent with chiral recognition mechanism. With the increase of the concentration of tartaric ester from 0 to 0.3 mol/L, partition coefficient K and separation factor α increase. Also, the kind of organic solvent and the concentration of the methanol aqueous have significant influence on K and α.

Determination of volatile components in cut tobacco with gas chromatography-mass spectrometry and chemometric resolution

Chromatography-mass spectrometry (GC-MS) was used to analyze the volatile components of cut tobacco samples with the help of heuristic evolving latent projections (HELP). After extracting with simultaneous distillation and extraction method, the volatile components in cut tobacco were detected by GC-MS. Then the obtained original two-dimensional data were resolved into pure mass spectra and chromatograms. The qualitative analysis was performed by similarity searches in the national institute of standards and technology (NIST) mass database with the obtained pure mass spectrum of each component and the quantitative results were obtained by calculating the volume of total two-way response. The accuracy of qualitative and quantitative results were greatly improved by using the two-dimensional comprehensive information of chromatograms and mass spectra. 107 of 141 separated constituents in the total ion chromatogram of the volatile components were identified and quantified, accounting for about 88.01% of the total content. The result proves that the developed method is powerful for the analysis of complex cut tobacco samples.

Synthesis of MnZn Ferrite Nanoscale Particles by Hydrothermal Method

Hydrothermal method was used to synthesize nanoscale particles of MnZn ferrites. The crystallites were characterized by XRD, TEM and SEM. The effects of the reaction time, temperature and additives on the product were investigated. Crystallization process would be carried out above 160 °C for 5 h or more, higher temperature can reduce the reaction time. Additives were used to remove impurities such as Fe2O3, ZnMnO3. 10–15 nm pure slightly agglomerated MnZn ferrite crystallites with a narrow grain size distribution were obtained.

Syntheses and applications of Eu(III) complexes of 2-thienyltrifluoroacetonate, terephthalic acid and phenanthroline as light conversion agents

A series of europium(III) complexes of 2-thienyltrifluoroacetonate (HTTA), terephthalic acid (TPA) and phenanthroline (Phen) were synthesized. The new complexes Eu(TPA)(TTA)Phen and Eu2(TPA)(TTA)4Phen2 were characterized by elemental analysis, IR spectrum, scanning electron microscope and thermal stability analysis. The results show that the thermal stability of the Eu(III) complexes increases in the following order: the mononuclear complex Eu(TTA)3Phen, the binuclear complex Eu2(TPA)(TTA)4Phen2, the chain polynuclear complex Eu(TPA)(TTA)Phen. And the formation of the binuclear/polynuclear structure of the new complexes appears to be responsible for the enhancement of their thermal and optical stability. In addition, The fluorescence excitation spectra of these new complexes show more broad excitation bands than that of the complex Eu(TTA)3Phen corresponding to their formation. The enhancement of Eu3+ fluorescence in the new complexes can be observed by the addition of Gd3+. The bright red luminescent plastics can be obtained when the complex EuGd(TPA)(TTA)4Phen2 is added above 0.5% (mass fraction).

Fabrication of ferrocenyl glutathione modified electrode and its application for detection of cadmium ions

Abstract1′-cysteaminecarbonyl-1-glutathionecarbonyl-ferrocene (Fc-GSH) was synthesized from ferrocene dicarboxylic acid and reduced glutathione (GSH) with 4 steps. IR and 1H-NMR were used to characterize the products. Then Fc-GSH was immobilized on the surface of gold electrode. Cyclic votammetry (CV) was adopted to investigate the electrochemical properties of this Fc-GSH modified electrode in the absence and presence of Cd2+ aqueous solutions. The peak oxidation potential (Ea) and reduction potential (Ec) of Fc-GSH modified electrode were observed at Ea = 0.74 V and Ec = 0.64 V (vs Ag/AgCl) before the accumulation of Cd2+. This redox process is a monoelectron chemical reaction. The anodic shift is about 80 mV in the presence of 20 nmol/L of Cd2+ aqueous solution. Moreover, this shift is in proportion to the concentration of Cd2+ when the concentration of Cd2+ is lower than 20 nmol/L. So the modified electrode can be used as probes to detect cadmium ions with the limit of 0.1 nmol/L by cyclic voltammetry.

First-principle investigation on stability of Co-doped spinel λ-Mn4−x CoxO8

The mechanism of stability of Co-doped spinel λ-MnO2 that is referred to as spinel LixMn2O4 (x=0) was studied by using the first-principle calculation method. The total energy and formation enthalpy can be decreased remarkably due to the Co substation, resulting in a more stable structure of λ-MnxCr2−xO4. The bond order and DOS analysis were given in detail to explain the nature of stability improvement. The calculated results show that as the content of Co dopant increases, the bond order of Mn—O becomes larger and the peak of density of states around Fermi level shifts toward lower energy. The charge density distribution illustrates that the Mn—O bonding is ionic and partially covalent, and the covalent Mn—O bonding becomes stronger with the increase of Co dopant content. The results confirm that the Co-doping will enhance the stability of λ-MnO2 and hence improve the electrochemistry performance of LixMn2O4.

Synthesis of calixarenes and their extraction performance for ester catechins

A series of extractants (tert-butylcalix[6]arene, tert-butylcalix[8]arene and octeacetate of tert-butylcalix[8]arene) were synthesized, and their structures were identified by IR and 1H-NMR. The distribution behavior of ester catechins monomer in the aqueous and chloroform two-phase system containing one of calixarene was studied. The influences of different extractants, concentration of tert-butylcalix[8]arene and extraction temperature on the partition coefficients and the separation factors were investigated. The experiment results show that tert-butylcalix[8]arene is the best extractant that forms a more stable supramolecular compound with gallocatechin gallate (GCG) than with epigallocathechin gallate (EGCG) or epicatechin gallate (ECG). When the concentration of p-tert-butylcalix[8]arene is 3.79 mmol/L, the extraction temperature is 4 °C, the partition coefficients of KGCG, KECG, KEGCG are 0.987, 0.629, 0.449, the separation factors of a1 and a2 are 1.450 and 1.596, respectively. The important factors influencing the extraction properties of calixarene are discovered to be its cavity size and hydrogen bonding.

Synthesis, property and heat stability for polyvinyl chlorids of antimony tris (mercaptoacid ester)

Antimony mercapide heat stabilizer for polyvinyl chloride is synthesized from antimony trioxide and mercaptocarboxylic acid esters, HS(CH2)nCOOi-C8H17(n=1–2) at 100–115°C in the presence of 0.5%–1% an organic acid catalyst. Some physicochemical constants of the compounds, such as density and refractive index, are determined. The complexes are hydrolabil in aqueous solutions and the bond of Sb-S is weaker than that of Sb-O. The forming bond property of antimony tris (mercaptoacid ester) has been elucidated by measurement of infrared spectra in comparison with mercapto carboxylic acid esters. The polyvinyl chloride resins containing antimony mercaptide heat stabilizers, do not darken at elevated temperatures and exhibit a high degree of stability. It is proposed that mercaptocarboxylic acid ester free radicals can esterify PVC microradicals at carbon atoms with upaired electrons.

Effects of Oxalic Acid Addition on the Hydrothermal Synthesis of Kaolinite

Kaolinite was hydrothermally synthesized from alumina gel and silicate by dissolving alumina gel in oxalic acid before it was mixed with silicate, effects of the amount of addition on the species of synthetic products were discussed. The reaction product was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that analcite is the only phase of the reaction solution without oxalic acid, the proportion of kaolinite in product increases with the amount of addition, and kaolinite is the main species when the molar ratio of oxalic acid to alumina reaches 0.6:1.0. This is because oxalic acid addition is beneficial to the formation of kaolinite through changing the coordination number of aluminium from four to six, while the mixture of alumina gel, before it was dissolved in oxalic acid with silicate interfered with the crystallization of kaolinite.