Effects of mechanical activation and oxidation-reduction on hydrochloric acid leaching of Panxi ilmenite concentration

The effects of oxidation-reduction treatment and mechanical activation on the hydrochloric acid leaching performance of Panxi ilmenite concentration were investigated.The results show that both of oxidation-reduction treatment and mechanical activation significantly accelerate the extraction of Fe,Ca and Mg from Panxi ilmenite concentration;however,the CaO and MgO contents of the calcined residues obtained from oxidized-reduced ilmenite concentration are higher than the standard values required by chlorination process.The Ca and Mg in oxidized-reduced ilmenite concentration can be leached much faster after mechanical activation,yielding a synthetic rutile which meets the requirements of chlorination process containing 90.50% TiO2 and 1.37% total iron as well as combined CaO and MgO of 1.00%.The optimum oxidation and reduction conditions are as follows：oxidization at 900 ℃ in the presence of oxygen for 15 min and reduction at 750 ℃ by hydrogen for 30 min.

Extraction of molybdenum and nickel from roasted Ni-Mo ore by hydrochloric acid leaching, sulphation roasting and water leaching

To extract molybdenum and nickel from the roasted Ni-Mo ore, a process of hydrochloric acid leaching, sulphation roasting and water leaching was investigated. The results showed that this process could get a high leaching rate of Mo and Ni. Under the optimum conditions of hydrochloric acid leaching （roasted Ni-Mo ore leached with 0.219 mL/g hydrochloric acid addition at 65 ℃ for 30 min with a L/S ratio of 3 mL/g）, sulphation roasting （51.9% sulfiaric acid addition, roasting temperature 240 ℃ for 1 h）, followed by leaching with the first stage hydrochloric acid leaching solution at 95 ℃ for 2 h, the leaching rates of Mo and Ni reached 95.8% and 91.3%, respectively.

Effect of lactic acid bacteria and propionic acid on conservation characteristics,aerobic stability and in vitro gas production kinetics and digestibility of whole-crop corn based total mixed ration silage

This study was conducted to evaluate the effect of lactic acid bacteria and propionic acid on the fermentation quality, aer- obic stability and in vitro gas production kinetics and digestibility of whole-crop corn based totalmixed ration （TMR） silage. Total mixed ration was ensiled with four treatments： （1） no additives （control）; （2） an inoculant （Lactobacillus plantarum） （L）; （3） propionicacid （P）; （4） propionic acid＋lactic acid bacteria （PL）. All treatments were ensiled in laboratory-scale silos for 45 days, and then subjected to an aerobic stability test for12 days. Further, four TMR silages were incubated in vitro with buffered rumen fluid to study in vitro gas production kinetics and digestibility. The results indicated that all TMR silages had good fermentation characteristics with low pH （〈3.80） and ammonia nitrogen （NH3-N） contents, and high lactic acid contents as well as Flieg points. Addition of L further improved TMR silage quality with more lactic acid production. Addition of P and PL decreased lactic acid and NH3-N contents of TMR silage compared to the control （P〈0.05）. After 12 days aerobic exposure, P and PL silages remained stable, but L and the control silages deteriorated as indicated by a reduction in lactic acid and an increase in pH, and numbers of yeast. Compared to the control, addition of L had no effects on TMR silage in terms of 72 h cumulative gas production, in vitro dry matter digestibility, metabolizable energy, net energy for lactation and short chain fatty acids, whereas addition of PL significantly （P〈0.05） increased them. L silage had higher （P〈0.05） in vitro neutral detergent fiber digestibility than the control silage. The results of our study suggested that TMR silage prepared with whole-crop corn can be well preserved with or without additives. Furthermore, the findings of this study suggested that propionic acid is compatible with lactic acid bacteria inoculants, and when used together, although they reduced lactic acid production of TMR silage, they improved aerobic stability and in vitro nutrients digestibility of TMR silage.

Extraction of Zr(IV) from hydrochloric acid with tri-octyl amine and Cyanex 921 in kerosene

This article reports the extraction of zirconium （IV） from aqueous HC1 solution by tri-octyl amine （TOA）, Cyanex 921, and their binary mixture using kerosene as the diluent. The effect of some parameters on the extraction of Zr（IV） was investigated such as equilibration time, aqueous phase acidity, extractant molarity, chloride ion concentration, nature of diluents, and temperature. The extraction of Zr（IV） was found to be 99% from 7.5 M HC1 using the mixture of extractants containing 0.1 M TOA and 0.02 M Cyanex 921 in kerosene. Kerosene was found to be the effective diluent for the extraction of Zr（IV） with the binary mixture of TOA and Cyanex 921. The positive enthalpy change and positive entropy change in the binary extraction system show the endothermic process with an increase in entropy. Stripping of Zr（IV） from the loaded organic phase containing the mixture of TOA （0.1 M） and Cyanex 921 （0.02 M） indicates that HNO3 and Na2CO3 are the best stripping agents.

Anodising of 2024-T3 aluminium alloy in electrolyte of sulphuric-boric-phosphoric mixed acid containing cerium salt as corrosion inhibitor

The effect of cerium salt as an inhibitor in anodising of the2024-T3aluminium alloy was studied.Scanning electronmicroscopy equipped with energy dispersive X-ray spectroscopy was used to study the surface composition of the alloy before andafter surface preparation.A mixed electrolyte of10%sulphuric acid,5%boric acid and2%phosphoric acid containing0.1mol/Lcerium sulphate salt was used as the anodising electrolyte.Sealing treatment was also done in boiling water and molten stearic acid.Electrochemical impedance spectroscopy and salt spray techniques were performed in order to investigate the corrosion behaviourand durability of the oxide films,respectively.It was concluded that the presence of cerium ions in anodising electrolyte resulted inthe increase in homogeneity,the rate of oxide film growth and also the thickness of the oxide layer,owing to the high oxidisingpower of cerium ion.

Leaching of iron concentrate separated from kiln slag in zinc hydrometallurgy with hydrochloric acid and its mechanism

It is taken as a novel prospective process to treat iron concentrate from hydrometallurgical zinc kiln slag forcomprehensive utilization of valuable metals by a hydrochloric acid leaching-spray pyrolysis method.The leaching mechanism ofdifferent valuable metals was studied.The results revealed that the leaching rates of Ag,Pb,Cu,Fe,As and Zn were99.91%,99.25%,95.12%,90.15%,87.58%and58.15%,respectively with6mol/L HCl and L/S ratio of10:1at60°C for120min.The actionof SiO2in leaching solution was also studied.The results showed that the precipitation and settlement of SiO2(amorphous)adsorbedpart of metal ions in solution,which greatly inhibited the leaching of Cu,Fe,As and Zn,so it is crucial to control the precipitation ofamorphous SiO2.

Preparation of Butyl Chloride from Butanol and Hydrochloric Acid Using Ionic Liquids as Catalyst

The catalytic performance of some quaternary ammonium salts for the liquid phase reaction of butanol and hydrochloric acid at different conditions was studied experimentally and compared with the traditional catalyst （ZnCl2）. The organic ammonium catalysts investigated include ionic liquids N-butyl-N-methyl imidazolium fluoborate （[BMIM][BF4]） and N-butyl-N-methylimidazolium chloride （[BMIM]Cl） as well as hydrochloric salts of N-methylimidazol （[HMIM]Cl）, pyridine （[HPy]Cl） and triethylamine （[HEt3N]Cl）. It is shown that the intrinsic catalytic performance of all organic ammonium salts except [HEt3N]Cl is slightly superior to ZnCl2, while the selectivity of butyl chloride is nearly at the same level around 96%. The conversion of butanol increases slightly with temperature and the catalyst amount added while the variation of selectivity is not obvious. Based on the recycle experiments, the ionic liquids as catalyst for the reaction of butanol and hydrochloric acid can be used more than 5 times, which suggests great potential of using ionic liquids as novel catalyst for such reactions.

Synthesis and thermal studies of mixed ligand complexes of Cu(II), Co(II), Ni(II) and Cd(II) with mercaptotriazoles and dehydroacetic acid

A series of new mixed ligand complexes of cobalt(II), nickel(II), copper(II) and cadmium(II) have been synthesized with 3benzyl1H4[(2 methoxybenzylidine) amino]1, 2, 4triazole5 thione (MBT), 3bezyl1H4[(4chlorobenzylidine) amino]1, 2, 4triazole5thione (CBT), 3benzyl 1H4[(4nitrobenzylidine)amino]1, 2, 4triazole 5thione (NBT) and dehydroacetic acid sodium salt (Nadha). The mixed ligand complexes have been characterized by elemental analysis, spec troscopic spectral measurements (IR, UVVis.), molar conductance, magnetic measurements and thermal studies. The stoichiometry of these com plexes is M:L1:L2 = 1:1:1, 1:2:1 or 1:1:2 where L1 = NBT, CBT and MBT and L2 = Nadha. Tetrahedral structure was proposed for all Cd(II) mixed ligand complexes while the square planar geometry was proposed for Cu(II) mixed ligand complex with NBT. Octahedral structure was proposed for Ni(II), Co(II) mixed ligand complexes and Cu(II) mixed ligand complexes with CBT and MBT ligands. The thermal decomposition study of the prepared complexes was monitored by TG, DTG and DTA analysis in dynamic nitrogen atmosphere. TG, DTG and DTA studies confirmed the chemical formulations of theses complexes. The kinetic parameters were determined from the the thermal decomposition data using the graphical methods of CoatsRedfern and HorwitzMetzger. Thermodynamic parameters were calculated using standard relations.

EFFECTS OF SIMVASTAIN COMBINED WITH OMEGA-3 FATTY ACIDS ON HIGH SENSITIVE C-REACTIVE PROTEIN, LIPIDEMIA, ANDFIBRINOLYSIS IN PATIENTS WITH MIXED DYSLIPIDEMIA

Objective To evaluate the effects of simvastatin combined with omega-3 fatty acids on high sensitive C-reactive protein(HsCRP), lipidemia, and fibrinolysis in coronary heart disease (CHD) and CHD risk equivalent patients with mixed dyslipi-demia. Methods A randomized, double-blind placebo controlled and parallel group trial was conducted. Patients with CHD and CHD risk equivalents with mixed dyslipidemia were treated with 10 or 20 mg simvastatin for 6-12 weeks. Following with the treatment of patients whose low-density lipoprotein cholesterol (LDL-ch) reaching goal level (< 100 mg/dL) or close to the goal (< 130 mg/dL), while triglyceride (TG) ≥200 mg/dL and < 500 mg/dL, was combined with omega-3 fatty acids (3 g/d) or a placebo for 2 months. The effects of the treatment on HsCRP, total cholesterol (TC), LDL-ch, high-density lipoprotein cholesterol (HDL-ch), TG, lipoprotein (a) [LP (a)], apolipoprotein A1 (apoA1), apolipoprotein B (apoB), plasminogen activator inhibitor-1 (PAI-1), and tissue plasminogen activator (tPA) were investigated. Forty patients finished the study with each group consisting of twenty patients. Results (1) There were significant reductions of HsCRP, TG, TC, and TC/HDL-ch, which decreased by 2.16 ±2.77 mg/L (38.5%), 94.0 ±65.4 mg/dL (31.1%), 13.3 ±22.3 mg/dL (6.3%), 0.78 ±1.60 respectively in the omega-3 fatty acids group (P< 0.01, < 0.001, < 0.05, < 0.05) compared to the baseline. HsCRP and triglyceride reduction were more significant in omega-3 fatty acids group compared to the placebo group (P=0.021 and 0.011 respectively). (2) In the omega-3 fatty acids group, the values and percentage of TG reduction had a significantly positive relation with HsCRP reduction (r=0.51 and 0.45, P=0.021 and 0.047 respectively). Conclusion In CHD and CHD risk equivalent patients with mixed dyslipidemia, dyslipidemia’s therapeutic effect using simvastatin and omega-3 fatty acids may result from not only the combination of lipid adjustment, but also enhancement of their own nonlipid influences.

Superficial performance and pore structure of palygorskite treated by hydrochloric acid

In order to amend the superficial performance of palygorskite and improve its application, the natural palygorskite(NP) was treated in the dipping and ionic exchanging experiments using 6mol/L hydrochloric acid treatment. The performance and pore structure of the treated palygorskite(TP) were investigated by means of microscope analyses, FT-IR, XRF, BET-SSA and full hole distribution analytical techniques. The results show that the hydrochloric acid treatment can make the gracile and aggregating compact crystal bundles inside palygorskite clay broken and dispersed, the roughness of microcrystalline surface increases, which not only can dissolve or remove dolomite but vary the superficial performance of palygorskite to some degree. The specific surface area and pore volume increase a lot, while the mean pore size decreases. The pore structure of TP changes remarkably compared with that of NP after 6mol/L hydrochloric acid treatment, and the relevant physicochemical performance can be improved.

Leaching behavior of heavy metals with hydrochloric acid fromfly ash generated in municipal waste incineration plants

The extraction behavior of heavy metals from municipal waste incineration （MWI） fly ash was investigated systematically. The extraction process includes two steps, namely, fly ash was firstly washed with water, and then subjected to hydrochloric acid leaching. The main parameters for water washing process were tested, and under the optimal conditions, about 86% Na, 70% K and 12% Ca were removed from fly ash, respectively. Hydrochloric acid was used for the extraction of valuable elements from the water-washed fly ash, and the optimal extraction was achieved for each heavy metal as follows： 86% for Pb, 98% for Zn, 82% for Fe, 96% for Cd, 62% for Cu, 80% for Al, respectively. And the main compositions of the finally obtained solid residue are Ca2PbO4, CaSi2Os, PbsSiO7, Ca3A12Si3012 and SiO2.

Syntheses,Structures and Properties of Lanthanide Coordination Polymers Constructed from Mixed Acid

Two new coordination polymers,[Ln（oba）（ox）0.5（H2O）2]n（Ln = Ho（1）,Eu（2）;H2oba = 4,4？-oxybis（benzoic acid）,H2ox = oxalic acid） have been synthesized under hydrothermal conditions.According to single-crystal X-ray diffraction analyses,complex 1 crystallizes in the monoclinic system,space group P21/c with a = 13.783（2）,b =10.0120（15）,c = 12.1974（18） ,β = 105.217（2）°,V = 1624.2（4） 3,C15H12O9Ho,Mr = 501.18,Z = 4,Dc = 2.050 g/cm3,F（000） = 964,μ = 4.919 mm-1,λ（MoKα） = 0.71073 ？,GOOF = 1.124,the final R = 0.0239 and wR = 0.0570 for 3310 independent reflections with Rint = 0.0298.Complexes 2 and 1 are isostructural.Oba and ox ligands bridge the Ln（III） ions into 2D layers with（4,4） topology,which are further interlinked into a 3D supramolecular network by hydrogen bonds.TG curves of the two complexes are studied to examine their thermal stabilities.Additionally,complex 2 shows red fluorescence in the solid state at room temperature.

Effects of Sustained-Release Calcium Hydroxide and Sustained-Release Hydrochloric Acid on Nutrient Di-gestion and Absorption of Rabbits

Rabbits with the body weight of （2.0 ± 0.5 ） kg were chosen, to study the effects of sustained-release calcium hydroxide and sustained-release hydro- chloric acid on nutrient digestion and absorption of rabbits. The results showed that sustained-release calcium hydroxide promoted digestion and absorption of nutri- ents, especially calcium and crude protein. The digestibility of calcium and crude protein was increased from 89.8% and 93.8% to 41.0% and 65.2%, respec- tively. Sustained-release hydrochloric acid was adverse to digestion and absorption of nutrients, especially calcium and crude protein. The digestibility of calcium and crude protein were decreased from 55.5% and 84.9% to 28.4% and 68.7%, respectively. The promotion effects of sustained-release hydrochloride on diges- tion lasted for 3 -4 d. Therefore, sustained-release calcium hydroxide promoted digestion and absorption of calcium and protein, while digestion and absorption of fat remained at a high level no matter what the condition was. Consequently, increasing the intake of fat would cause over nutrition. However, taking sustained-re- lease hydrochloric acid would reduce nutrient digestion and absorption.

Solid-Liquid Equilibria of Succinic Acid in Cyclohexanone,Cyclohexanol and Their Mixed Solvents

Solubilities were measured for succinic acid dissolved in cyclohexanone, cyclohexanol and 5 of their mixed solvents at the temperature range from 291. 85 K to 358.37 K using a dynamic method. The solubility data were regressed by λh equation, with,the average absolute relative deviation 3.47%. The binary interaction parameter is 0.306 7 for the mixed solvent of oyolohexanone and cyclohexanol was determined by correlating the experimental solubilities with the modified λh equation. When the binary interaction parameter was determined it can be used to extrapolate the solubilities of succinic acid in mixed solvents of cyclohexanone and cyclohexanol at any proportion.The average absolute relative deviation was 7. 69% by using the modified λh equation to correlate the solubility data, however, the average absolute relative deviation was 8.89% by using NRTL equation to correlate the solubility data. The results show that the accuracy of the modified λh equation is better than that of the NRTL equation for the solubility of succinic acid in the 5 mixed solvents of cyclohexanone and cyclohexanol.

Modeling and Optimization of Galena Dissolution in Hydrochloric Acid: Comparison of Central Composite Design and Artificial Neural Network

Response surface methodology (RSM) and Artificial neural network (ANN) were used for the simulation and optimization of galena dissolution in hydrochloric acid. The galena ore was characterized for structure elucidation using FTIR, SEM and X-ray diffraction spectroscopic techniques and the results indicate that the galena ore exists mainly as lead sulphide (PbS). A feed-forward neural network model with Leverberg-Marquardt back propagating training algorithm was used to predict the response (lead yield). The leaching temperature, acid concentration, solid/liquid ratio, stirring rate and leaching time were defined as input variables, while the percentage yield of lead was labelled as output variable. The multilayer perceptron with architecture of 5-9-1 provided the best performance. All the process variables were found to have significant impact on the response with p-values of 2 of 0.991 and 1.00, respectively. A non-dominated optimal response of 85.25% yield of lead at 343.96 K leaching temperature, 3.11 M hydrochloric acid concentration, 0.021 g/ml solid/liquid ratio, 362.27 rpm stirring speed and 87.37 min leaching time was established as a viable route for reduced material and operating cost using RSM.

Electro-physical Properties of Super-thin Basalt Fiber Chemically Modified by Hydrochloric or Sulphuric Acid

The influence of hydrochloric or sulphuric acid treatment on the electro-physical properties of superthin basalt fiber (STBF) made from Armenian basalt rocks was studied. Specific electric resistance for direct and alternating currents, dielectric parameters of ε, and ε,, were measured. It is shown that specific resistance and dielectric parameters of super-thin basalt fiber change essentially after hydrochloric or sulphuric acid treatment. The temperature dependences of these parameters were studied, too, and their non–monotonic behavior was observed. The probable variation of mentioned STBF parameters is explained by different water absorption capacity of pores as a result of acid treatment.

Syntheses of Coordination Compounds of 2-Amino-3-Methylbutanoic Acid Their Mixed Ligand Complexes and Antibacterial Activities

Coordination compounds of 2-amino-3-methylbutanoic acid were synthesized with chromium(III) and oxovanadium(IV) ions. M:L;1:2. Adducts of these complexes using 1,10-phenantroline and ethylenediamine were further synthesized, M:L, (1:2). These compounds were characterized using electronic, infra-red spectrophotometry, magnetic susceptibility measurement and percentage metal analyses. The zones of inhibition and minimum inhibitory concentrations of the compounds against eight microbes were studied. The results obtained indicated an octahedral geometry for the Cr(III) complexes, indicative of additional coordination of two water molecules. On the other hand a square pyramid geometry was obtained for the binary oxovanadium complex and its 1,10-phenantroline adduct. However, for the oxovanadium ethylenediamine adduct a distorted octahedral geometry was proposed. The result for the antibacterial studies indicated that both mixed ligand complexes of 1,10-phenantroline exhibited good antibacterial activity, and in some cases better activity than the standard, streptomycin.

Chemoselective Reduction of Fenofibric Acid to Alcohol in the Presence of Ketone by Mixed Anhydride and Sodium Borohydride

A highly efficient and facile protocol for the selective reduction of carboxylic acid of Fenofibric acid to corresponding alcohol was developed. The selective reduction was carried out by activation of carboxylic acid by mixed anhydride followed by the reaction of sodium borohydride in presence of methanol. This is the first example of chemoselective reduction of carboxylic acid to alcohol in presence of a ketone without any external catalyst or ligand in a single step. The reaction offers wide applicability for the selective carboxylic group reduction methodology. The chemoselective reduction was demonstrated by the reduction of Fenofibric acid, an active metabolite of the drug Fenofibrate, to corresponding alcohol in excellent selectivity, yield, and purity.

Optimization of Ilmenite Dissolution by Synergistic Effect of Oxalic Acid and Hydrochloric Acid for Preparing Synthetic Rutile

This study was carried out to investigate the interaction of oxalic acid with hydrochloric acid to attain the better performance for iron dissolution in comparison to absence of oxalic acid. The effects of oxalic acid on ratio of hydrochloric acid, acid concentration, ratio of liquid to solid, temperature and dissolution time are investigated for the dissolution of Fe and Ti from ilmenite to produce synthetic rutile. The DX7 software basing on an experimental design method with the central composite of response surface design is applied to specify the effects of the parameters and to optimize the leaching process. The optimum condition was determined by analysis of variance (ANOVA), indicating that the ratio of oxalic acid to hydrochloric acid for Fe dissolution and acid concentration for Ti dissolution were the most effective parameters. The results showed that the dissolution of Fe and Ti in 30% (w/w) hydrochloric acid solution was only 48.65% and 5.14%, respectively, while at the same condition and in the presence of oxalic acid with twice the ratio, these values are increased to 78.65% and 12.06%, respectively. The optimum values of parameters were as follows: oxalic acid to hydrochloric acid ratio (2:1), acid concentration (30%), ratio of liquid to solid (10), temperature (160 °C), and dissolution time (3 h). By applying the optimized parameters, Fe and Ti dissolution of 97.15% and 2.8% were predicted by the software with a desirability of 0.745. The results of leaching tests indicated that the Fe and Ti dissolution of 97.58% and 2.43%, were achieved, respectively, which are very close to the predicted value.

Study on Addition Amount of Lactic Acid Bacteria and Cellulase in Mixed Silage of Potato Plants

[Objectives]This study was conducted to investigate the appropriate addition amounts of lactic acid bacteria and cellulase in the mixed silage of potato plants,so as to provide a basis for the rational use of potato plants.[Methods]Fresh potato(Solanum tuberosum)seedling plants,watermelon(Citrullus lanatus)plants,and melon(Cucumis melo)plants were selected as raw materials for silage,each of which was added at a ratio of 32%,and 4%of brown flour was added additionally.On this basis,an L 9(32)orthogonal experiment was designed to investigate the effects of the amount of lactic acid bacteria(10,20,30 g/kg)and the amount of cellulase(5,10,15 g/kg)on the experimental results with sensory evaluation score as an investigation index.[Results]With the increase of the amount of lactic acid bacteria and the amount of cellulase,the sensory evaluation score of silage increased,and it was the highest when the amount of lactic acid bacteria added was 20 g/kg and the amount of cellulose was 10 g/kg.With the increase of the amounts of lactic acid bacteria and cellulase added,ammonia nitrogen showed a decreasing trend,and the pH and ammonia nitrogen were the lowest when the amount of lactic acid bacteria added was 20 g/kg and the amount of cellulose was 10 g/kg.[Conclusions]This study provides a theoretical basis for the rational use of effective ingredients and nutrients in potato plants and the development of new feed resources.