Viscosity of copper slags from chalcocite concentrate smelting

The viscosity of smelting slags from the Glogow copper plant in Poland was measured using a concentric cylinder viscometer. These slags contain typically 45 pct SiO₂, 16 pct CaO, 8 pct MgO, 11 pct Al₂O₃, and only 5 to 7 pct total iron. The viscosity was measured as a function of the CaO, MgO, SiO₂, Cu₂O, Cr₂O₃, and Fe₃O₄ contents in the temperature range from 1473 to 1623 K. Silica and chromium oxide additions increased the viscosity, while small additions of the other oxides decreased the viscosity. However, at large additions of CaO or MgO, cooling resulted in a rapid increase in the viscosity upon reaching the transition temperature. This critical transition temperature increased with increasing additions of CaO and MgO. This was explained by the precipitation of solid particles upon reaching the saturation limit. Depending on the slag composition, the activation energy for viscous flow was found to be in the range from 200 to 370 kJ/mol.     

闪速吹炼技术的实践与改进

介绍了闪速吹炼技术在阳谷祥光铜业有限公司的应用实践及改进。     

Kinetics of biochemical leaching of sphalerite concentrate

The paper deals with bacterial leaching of sphalerite. The data include progress curves for leaching of the concentrate in terms of Zn, Cu, and Cd solubilization. Plots of the Zn and Cu data followed a relationship predicted by a chemical rate equation. Reaction rates for Zn and Cu were inversely related to initial particle size of the concentrate. A pulp density in excess of 2 pct caused a decrease in percent Zn leached in 31 days, presumably due to oxygen limitation. The leaching of Zn and Cu followed first order kinetics.     

Mathematical modeling of minor-element behavior in flash smelting of copper concentrates and flash converting of copper mattes

A mathematical model has been developed to describe the behavior of minor elements during flash smelting and flash converting. The model incorporates equations describing volatilization of minor elements from the molten particles and distribution of these elements between the molten phases in the settler. The basic premise of the volatilization model is that at the surface of the molten particle, the partial pressures of the minor-element species are those at equilibrium. Transport of the minor-element species to the gas then is described by external mass transfer. Good agreement has been obtained between observed and predicted behaviors. The effects of oxygen enrichment, matte grade, and wall temperature, as well as the bath temperature, on minor-element behavior have been elucidated. Formerly Assistant Professor, Department of Metallurgy and Metallurgical EngineeringUniversity of Utah, Salt Lake City, UT Formerly Metallurgical Engineer Kennecott, Salt Lake City, UT     

铁精粉氧化过程的动力学研究

通过恒温和均匀升温实验,采用大载荷热重分析仪研究了铁精粉氧化过程动力学.结果表明:均匀升温过程中,铁精粉氧化的主要控制环节变化是外扩散型→内扩散型→外扩散型,氧化结束后,部分Fe₂O₃发生分解反应生成Fe₃O₄和O₂,使得TG曲线质量变化率减小;等温实验也证明了氧化主体部分的控制环节是内扩散,其表观活化能为26.193kJ·mol^-1;铁精粉氧化过程促进了钛元素富集,改变了产物的微观结构.     

Investigation of the phase composition of accretions formed into WHB under flash smelting of copper concentrate

The phase composition of the depositions formed in the radiation section of the waste heat boiler utilizer (RS of WHB) after injecting sulphatizing flow in the volume of the off-gases from the uptake of flash smelting furnace for copper sulphide concentrate smelting was studied. With the help of X-ray diffraction (XRD), Reflected-light microscopy and Electron probe microanalysis (EPMA) of samples from the accretions, it was established that the main crystalline phases in the accretions were spinel, delafossite, cuprite and tenorite. The results from EPMA have shown that the spinel phase is with variable composition from cuprospinel to solid solution into the system Fe₃O₄-CuFe₂O₄-ZnFe₂O₄ (magnetite-cuprospinel-franklinite). Calculated on the basis of XRD and EPMA approximate formulae for the phases, identified in the samples from the accretions were the following: of the cuprospinel-(Cu_0.85²⁺Zn_0.09²⁺Fe_0.06²⁺)(Fe_1.87³⁺Al_0.10³⁺Si_0.03⁴⁺)O₄; of the spinel solid solution—(Cu_0.32²⁺Zn_0.36²⁺Fe_0.32²⁺)(Fe_1.81³⁺Al_0.19³⁺)O₄; Delafossite—Cu_1.07Fe_0.93O₂; cuprite—Cu_1.99Fe_0.02Si_0.01O and tenorite—Cu_0.993Fe_0.008O. The influence of the temperature on the sulphate formation processes of copper and iron oxides in the dust-gas flow was evaluated, based on experimental data and thermodynamic analysis of phase equilibriums in the systems Cu-S-O and Fe-S-O for the conditions, typical of the radiation section of the waste heat boiler (RS of WHB).     

饱和磁性分析法快速测定闪速吹炼炉渣中磁性四氧化三铁含量

探讨了饱和磁性分析仪快速测定闪速吹炼炉渣中磁性四氧化三铁含量的方法。通过选择试验发现了采用自制四氧化三铁合成标准物质绘制校准曲线时适用的局限性,改用实际闪速吹炼炉渣标准样品系列绘制校准曲线,得到了很好的应用。研究了试样量、试样粒度、共存磁性物质等各种因素的影响,确定了最佳实验条件。方法测定闪速吹炼炉渣中磁性四氧化三铁的含量范围为2409%～6662%,方法检出限为014%,相对标准偏差（RSD,n=12）在064%～079%之间,样品的分析结果与X射线衍射分析法（XRD）结果吻合较好,能完全满足生产控制快速分析的需要。     

Kinetics and mechanism of the oxidative dissolution of a zinc sulphide concentrate in ferric sulphate solutions

The kinetics of the oxidative dissolution of a zinc sulphide (sphalerite) concentrate was studied. It was observed that the dissolution of the concentrate continued beyond 90% conversion in two hours at 80°C. The kinetics of dissolution are successfully described by an electrochemical mechanism in which the charge transfer from the solid to the oxidant is rate-limiting. The rate of reaction is proportional to the sum of the concentrations of the Fe³⁺ (aq) and FeHSO₄²⁺ complexes with a reaction order of one-half. The addition of Fe (II) to the solution had an indirect effect on the reaction rate, by decreasing the concentrations of the electro-active ions. Addition of ZnSO₄ did not affect the reaction rate.     

The kinetics of the dissolution of chalcocite in alkaline cyanide solution

A kinetic study of the dissolution of chalcocite in an alkaline cyanide solution indicates that the reaction is first order with respect to surface area and free cyanide ion concentration, and inversely proportional to the sulfide ion concentration to approximately the 0.1 power. The experimental rate constant is approximately 7.5 × 10⁻⁵ (mole Cu¹⁺/ min) ([S⁻²]^0.1/[CN¹⁻]/cm²/l at 25°C. The activation energy of 2.5 kcal/mole indicates rate control by diffusion through a limiting boundary layer. The concentrations of the important ions in the cyanide solutions are obtained by solving the ionic equilibria and mass balance equations for the system.     

有菌和无菌体系下辉铜矿氧化电化学

运用循环伏安曲线、稳态极化曲线和Tafel曲线等电化学手段以及X射线光电能谱（XPS）法研究了辉铜矿在有菌和无菌体系下氧化过程的电化学行为.研究结果验证了辉铜矿在有菌体系和无菌体系下的两步氧化溶解机理,第一步氧化反应为辉铜矿不断氧化生成缺铜的中间产物Cu_xS（1≤x<2）,直至生成CuS,在较低电位下即可进行;第二步反应为中间产物CuS的氧化,需要在较高电位下才可进行,反应速率较慢,是整个氧化反应的限制性步骤.循环伏安实验显示有菌体系电流密度明显大于无菌体系,表明细菌加快了辉铜矿的氧化速率.稳态极化实验显示辉铜矿点蚀电位较低,无菌体系第一段反应活化区电位范围小于有菌体系,表明辉铜矿氧化过程生成的中间产物硫膜具有钝化效应,细菌可以通过自身氧化作用破坏硫膜,减弱辉铜矿表面的钝化效果,加快辉铜矿的氧化溶解速率.X射线光电子能谱分析显示电极表面钝化层物质组成复杂,包含了CuS、多硫化物（S_n^2-）、（S⁰）和含（SO₄^2-）的氧化中间产物等多种物质,其中主要的钝化物为CuS,表明辉铜矿的氧化遵循多硫化物途径.     

Angiotensin converting enzyme (ACE) inhibitor-induced cough and substance P

BACKGROUND: Angiotensin converting enzyme (ACE) inhibitors cause coughing in 5-10% of patients, but the exact mechanisms of this effect are still unclear. In the airways ACE degrades substance P so the cough mechanism may be related to this peptide. METHODS: Nine patients who developed a cough and five patients who did not develop a cough when taking the ACE inhibitor enalapril (2.5 or 5.0 mg/day) for hypertension were enrolled in the study. No subjects had respiratory disease and the respiratory function of all subjects was normal. One month after stopping enalapril, inhalation of hypertonic saline (4%) was performed using an ultrasonic nebuliser for 15-30 minutes to induce sputum. The concentration of substance P in the sputum sample was measured by radioimmunoassay. In four of the nine cases with a cough enalapril was given again for 1-2 weeks and the concentration of substance P in the induced sputum was again measured. RESULTS: One month after stopping enalapril the mean (SE) concentration of substance P in the sputum of the group with a cough was 16.6 (3.0) fmol/ml, significantly higher than that in the subjects without a cough (0.9 (0.5) fmol/ml). All four subjects in the group with a cough who were given a repeat dose of enalapril developed a cough again, but the concentrations of substance P in the induced sputum while taking enalapril (17.9 (3.2) fmol/ml) were similar to the values whilst off enalapril (20.0 (2.5) fmol/ml). CONCLUSIONS: The mechanisms of ACE inhibitor-induced coughing may involve substance P mediated airway priming. However, the final triggering of the ACE inhibitor-induced coughing is unlikely to be due to this peptide.     

Kinetics of carbochlorination of chromium (III) oxide

Kinetics of the carbochlorination of Cr₂O₃ has been studied with Cl₂+CO gas mixtures between 500 °C to 900 °C using thermogravimetric analysis. The apparent activation energy is about 100 kJ/mol. Mathematical fitting of the experimental data suggests that the shrinking sphere model is the most adequate to describe the carbochlorination mechanism of chromium oxide and that is controlled by the chemical reaction. In the temperature range of 550 °C to 800 °C, the reaction order is about 1.34 and is independent of temperature. Changing the Cl₂+CO content from 15 to 100 pct increases the reaction rate and does not affect the reaction mechanism. Similarly, changing the ratio of Cl₂/(Cl₂+CO) from 0.125 to 0.857 does not modify the carbochlorination mechanism of Cr₂O₃. In these conditions, the reaction rate passes through a maximum when using a chlorinating gas mixture having a Cl₂/(Cl₂+CO) ratio of about 0.5.     

Kinetics of nitric acid leaching of cerium from oxidation roasted Baotou mixed rare earth concentrate

The kinetics of nitric acid leaching of cerium was investigated for the oxidation roasted Baotou mixed rare earth concentrate. The effects of leaching temperature, HNO₃ concentration, liquid–solid ratio (L/S) and stirring rate on rare earth extraction were studied. The XRD and SEM mapping analysis of the samples before and after acid leaching shows that the roasted bastnaesite is completely leached. Besides, the decomposition process of oxidizing roasting was also obtained by TG–MS and XRD. Different kinetics models were applied in this leaching process. The results of dynamic fitting show that the leaching process can be described by a new variant of the shrinking-core model. And the leaching rate is controlled by both the interfacial transfer and diffusion through the product layer. The apparent activation energy is calculated as 76.78 kJ/mol and the reaction orders with respect to HNO₃ concentrations and liquid–solid ratio are determined to be 7.609 and 2.516, respectively. Besides, an empirical rate equation is obtained to describe the process.     

Antagonist effects of seglitide (MK 678) at somatostatin receptors in guinea-pig isolated right atria

Somatostatin (SS) exerts a negative inotropic effect in isolated atria. Here we report that in guinea-pig isolated right atria, seglitide, a potent cyclic hexapeptide somatostatin agonist, behaves as a competitive somatostatin receptor antagonist with pA2 values against SS14, SS25 and SS28, of 6.50 +/- 0.40, 6.24 +/- 0.08 and 6.09 +/- 0.06, respectively. Seglitide had little or no effect on the negative inotropic action of carbachol or N6-cyclohexyladenosine. Our findings indicate that the receptor-response coupling characteristics of guinea-pig atria are such that in this preparation seglitide has low intrinsic activity and behaves specifically as a somatostatin receptor antagonist.     

三烷基氧膦萃取铱的动力学研究

利用恒界面池法研究三烷基氧膦(TAPO)-煤油从盐酸介质中萃取Ir(Ⅳ)的动力学。测定了水相金属浓度，水相氢离子浓度，三烷基氧膦浓度，温度，搅拌速度等对萃取速率的影响，并得出萃取速率规律。