两段旋流电积法提纯粗铟

采用两段旋流电积工艺对粗铟进行提纯。根据线性扫描伏安法(LSV)研究结果及对扩散系数(D=6.15×10^(-11)cm^(2)·s^(-1))的评估可知,硫酸铟溶液中铟电沉积是受扩散控制的不可逆过程,可通过加强电解质流动强化液相传质。在第一段旋流电积提纯粗铟的最佳工艺条件下,电流效率达80.15%,单位能耗为2.11 kW·h/kg,平均槽电压为2.04 V,粗铟纯度由94.34%提升至99.95%。在第二段旋流电积提纯粗铟的最佳工艺条件下,电流效率为75.23%,单位能耗为2.23 kW·h/kg,平均槽电压为2.40 V,产品纯度为98.95%。经过二段旋流电积后,铟综合回收率高达98.22%。

硫化还原法协同回收铜冶炼渣中的铜、铅和锌

采用硫化还原法从铜冶炼渣中协同回收铜、铅和锌。以黄铁矿为硫化剂,在还原气氛下选择性硫化回收渣中有价金属。通过热力学分析和实验,确定该工艺的可行性和可靠性。确定了最佳的实验条件:硫化剂黄铁矿添加量为铜冶炼渣质量的26%,焦炭添加量为铜冶炼渣总质量的6%,温度1350℃,熔炼时间3h。在优化条件下,铜、铅和锌回收率分别为97.58%、89.91%和98.20%。清洁渣中铜、铅和锌含量分别为0.10%、0.01%和0.38%。铜锍相含铜7.28%,锌在气相、渣相和铜锍相中的分布比例分别为80.93%、10.09%和8.98%,铅在气相、渣相和铜锍相的分布比例分别为40.12%、1.79%和58.09%。铜锍相主要由Cu_(8)S_(5)、FeS和Cu、Pb、Fe等金属组成,渣中Fe_(3)O_(4)含量由19.50%降至2.97%。

熔渣中金属液滴沉降过程流体力学模拟

建立熔炼渣中金属液滴沉降过程的数学模型,研究不同粘性模型下金属/熔渣界面张力对液滴沉降速度以及拖曳力的影响。结果表明:对于较小直径的液滴,Laminar模型和RNG k-ε湍流模型能够准确预测液滴最终沉降速度;界面张力对液滴沉降速度有影响,且影响作用随着液滴尺寸增大而逐渐增大;“RNG+CSS”模型可以准确描述液滴沉降过程和液滴沉降速度的变化。结合数学模型和实验数据,推导出耦合界面张力作用下拖曳力系数计算公式。该模型揭示熔炼渣中金属液滴沉降过程机理,为实际生产中降低渣中有价金属含量提供理论指导。

Copper smelting mechanism in oxygen bottom-blown furnace

The SKS furnace is a horizontal cylindrical reactor similar to a Noranda furnace,however,the oxygen enriched air isblown into the furnace from the bottom.Mechanism model of the SKS process was developed by analyzing the smeltingcharacteristics deeply.In our model,the furnace section from top to bottom is divided into seven functional layers,i.e.,gas layer,mineral decomposition transitioning layer,slag layer,slag formation transitioning layer,matte formation transitioning layer,weakoxidizing layer and strong oxidizing layer.The furnace along the length direction is divided into three functional regions,that is,reaction region,separation transitioning region and liquid phase separation and settling region.These layers or regions play differentroles in the model in describing the mechanism of the smelting process.The SKS smelting is at a multiphase non-steady equilibriumstate,and the oxygen and sulfur potentials change gradually in the length and cross directions.The smelting capacity of the SKSprocess could be raised through reasonably controlling the potential values in different layers and regions.

Selective removal of As from arsenic-bearing dust rich in Pb and Sb

The selective removal of arsenic from arsenic-bearing dust containing Pb and Sb in alkaline solution was studied. The influence of Na OH concentration, temperature, leaching time, liquid to solid ratio, and the presence of elemental sulfur on the dissolution of As, Sb and Pb in Na OH solution was investigated. The results indicate that the presence of elemental sulfur can effectively prevent leaching of lead and antimony from arsenic. The Sb2O3, As2O3 and Pb5(AsO4)3 OH in the raw material convert to NaSb(OH)6 and PbS in the leaching residue, while arsenic is leached out as As(Ⅲ) or As(Ⅴ) ions in the leaching solution. Arsenic leaching efficiency of 99.84% can be achieved under the optimized conditions, while 97.82% of Sb and 99.97% of Pb remain in the leach residue with the arsenic concentration of less than 0.1%. A novel route is presented for the selective removal of arsenic and potential recycle of lead and antimony from the arsenic-bearing dust leached by Na OH solutions with the addition of elemental sulfur.

Effects of acupuncturing Tsusanli (S_T36) on expression of nitric oxide synthase in hypothalamus and adrenal gland in rats with cold stress ulcer

AIM： To study the protective effect of acupuncturing Tsusanli （ST36） on cold stress ulcer, and the expression of nitric oxide synthase （NOS） in hypothalarnus and adrenal gland. METHODS： Ulcer index in rats and RT-PCR were used to study the protective effect of acupuncture on cold stress ulcer, and the expression of NOS in hypothalamus and adrenal gland. Images were analyzed with semi-quantitative method. RESULTS： The ulcer index significantly decreased in rats with stress ulcer. Plasma cortisol concentration was up regulated during cold stress, which could be depressed by pre-acupuncture. The expression of NOS1 in hypothallamus increased after acupuncture. The increased expression of NOS2 was related with stress ulcer, which could be decreased by acupuncture. The expression of NOS3 in hypothalamus was similar to NOS2, but the effect of acupuncture was limited. The expression of NOS2 and NOS3 in adrenal gland increased after cold stress, only the expression of NOS1 could be repressed with acupuncture. There was no NOS2 expression in adrenal gland in rats with stress ulcer. CONCLUSION： The protective effect of acupuncturing Tsusanli （ST36） on the expression of NOS in hypothalamus and adrenal gland can be achieved.

Relationship between copper content of slag and matte in the SKS copper smelting process

In the newly developed oxygen-enriched bottom-blowing copper smelting process(also known as the SKS copper smelting process), Cu loss in slag is one of the most concerning issues. This paper presents our research results concerning the relationship between the Cu content of the matte and slag in the SKS process; the results are based on actual industrial production in the Dongying Fangyuan copper smelter. The results show that the matte grade strongly influences Cu losses in slag. The dissolved and entrained losses account for 10%–20% and 80%–90% of the total SKS industrial Cu losses in slag, respectively. With increasing matte grade, the dissolved and entrained Cu losses in the SKS slag both increase continuously. When the matte grade is greater than 68%, the content of Cu in the smelting slag increases much more dramatically. To obtain a high direct recovery of copper, the matte grade should be less than 75% in industrial SKS copper production.

Multiphase equilibrium modeling of oxygen bottom-blown copper smelting process

A computational thermodynamics model for the oxygen bottom-blown copper smelting process(Shuikoushan,SKS process)was established,based on the SKS smelting characteristics and theory of Gibbs free energy minimization.The calculated results of the model show that,under the given stable production condition,the contents of Cu,Fe and S in matte are71.08%,7.15%and17.51%,and the contents of Fe,SiO2and Cu in slag are42.17%,25.05%and3.16%.The calculated fractional distributions of minor elements among gas,slag and matte phases are As82.69%,11.22%,6.09%,Sb16.57%,70.63%,12.80%,Bi68.93%,11.30%,19.77%,Pb19.70%,24.75%,55.55%and Zn17.94%,64.28%,17.79%,respectively.The calculated results of the multiphase equilibrium model agree well with the actual industrial production data,indicating that the credibility of the model is validated.Therefore,the model could be used to monitor and optimize the industrial operations of SKS process.

Preparation of ultrafine silver powders with controllable size and morphology

The ultrafine silver powders were prepared by liquid reduction method using Arabic gum as dispersant.The effects of different dispersants,pH values,and temperature on the morphology and particle size of silver powders were investigated.It is found that Arabic gum can better adsorb on silver particles via chemical adsorption,and it shows the best dispersive effect among all the selected dispersants.The particle size of silver powders can be finely tuned from 0.34 to 4.09μm by adjusting pH values,while the morphology of silver powders can be tuned by changing the temperature.The silver powders with high tap density higher than 4.0 g/cm3 were successfully prepared in a wide temperature range of 21.8-70°C.Especially,the tap density is higher than 5.0 g/cm3 when the temperature is optimized to be 50°C.The facile process and high silver concentration of this method make it a promising way to prepare high quality silver powders for electronic paste.

Thermodynamic analysis and process optimization of zinc and lead recovery from copper smelting slag with chlorination roasting

An efficient chlorination roasting process for recovering zinc(Zn)and lead(Pb)from copper smelting slag was proposed.Thermodynamic models were established,illustrating that Zn and Pb in copper smelting slag can be efficiently recycled during the chlorination roasting process.By decreasing the partial pressure of the gaseous products,chlorination was promoted.The Box−Behnken design was applied to assessing the interactive effects of the process variables and optimizing the chlorination roasting process.CaCl_(2) dosage and roasting temperature and time were used as variables,and metal recovery efficiencies were used as responses.When the roasting temperature was 1172℃ with a CaCl_(2) addition amount of 30 wt.%and a roasting time of 100 min,the predicted optimal recovery efficiencies of Zn and Pb were 87.85%and 99.26%,respectively,and the results were validated by experiments under the same conditions.The residual Zn-and Pb-containing phases in the roasting slags were ZnFe_(2)O_(4),Zn_(2)SiO_(4),and PbS.

Copper and arsenic substance flow analysis of pyrometallurgical process for copper production

The metabolism of copper and arsenic in a copper pyrometallurgy process was studied through substance flow analysis method.The mass balance accounts and substance flow charts of copper and arsenic were established,indicators including direct recovery,waste recycle ratio,and resource efficiency were used to evaluate the metabolism efficiency of the system.The results showed that,the resource efficiency of copper was 97.58%,the direct recovery of copper in smelting,converting,and refining processes was 91.96%,97.13%and 99.47%,respectively.Meanwhile,for producing 1 t of copper,10 kg of arsenic was carried into the system,with the generation of 1.07 kg of arsenic in flotation tailing,8.50 kg of arsenic in arsenic waste residue,and 0.05 kg of arsenic in waste water.The distribution and transformation behaviors of arsenic in the smelting,converting,and refining processes were also analyzed,and some recommendations for improving copper resource efficiency and pollution control were proposed based on substance flow analysis.

Percutaneous vertebroplasty in the treatment of malignant vertebral compression fractures with epidural involvement

Purpose: To evaluate the safety and the clinical efficacy of percutaneous vertebroplasty(PVP) in treating malignant spinal tumors and malignant vertebral compression fractures with epidural involvement. Materials and methods: 43 patients with spinal metastatic tumors and malignant vertebral compression fractures with epidural involvement were treated using PVP. American Spinal Injury Association(ASIA) impairment scale results at presentation were used to divide patients into 2 groups. Patients in group A had no symptoms of neurological compression(n = 25); and patients in group B had symptoms of neurological compression(n = 28). A 13 G bone puncture needle was placed across the pedicle of the fractured vertebra, and polymethyl methacrylate(PMMA) was injected into the fractured vertebral body under fluoroscopic control. Patients were seen in follow-up at 1, 3, and 6 months after the procedure and every six months thereafter. Results: PVP was technically successful and well-tolerated in all patients. Clinical assessment at the final follow-up found complete pain relief(n = 19) or good pain relief(n = 14) in 33 patients(62.3%, 95% CI: 49%, 76%). ASIA impairment scale assessment at the final follow-up demonstrated symptoms of neurologic compression in 31 patients and no symptoms of neurologic compression in 22 patients. Symptoms of neurologic compression were found in five group A patients and eight group B patients. Conclusions: PVP was a safe and moderately effective procedure in the treatment of malignant vertebral compression fractures with epidural involvement.

Acupuncture therapy for experimental stomach ulcer and c-Fos expression in rats

AIM: To determine the role of acupuncture therapy in treating experimental gastric ulcer in rats.METHODS: Twenty-eight adult male Sprague-Dawley rats were randomly divided into four groups (pre-acupuncture group; acupuncture group; paradistance-acupuncture group;and control group), and pre-acupuncture, paradistanceacupuncture, and control groups received 5 μL acetic acid (200 mL/L HAc) injection after a same course of electroacupuncture (EA) treatment (4 Hz, 0.6 mA, 0.45 ms,45 min for 4 d). The rats in these three groups recovered within 4 d. The acupuncture group received EA therapy for 4 d, after HAc injection. The stomach was dissected to compare the pathological structures of ulcer. Also c-Fos activation in the nuclei of solitary tract (NTS) was observed under microscope after regular immunohistochemistry staining of brain stem sections.RESULTS: The number of ulcers was different among the four groups, especially between control group and paradistance-acupuncture group or pre-acupuncture group. In the latter group, the number of ulcers was much less. The gastric ulcer area was consistent with the histopathological results, indicating that pre-acupuncture had an obvious therapeutic effect on gastric ulcers.Acupuncture had a very modest effect and paradistanceacupuncture had no effect on gastric ulcers. No therapeutic effect was found in the control group. Fos-Li neurons in NTS induced by noxious gastric ulcer showed a significant difference between pre-acupuncture and control groups.CONCLUSION: Acupuncture before ulceration can obviously alleviate ulcer. The production of c-Fos proves that the vagus nerve mediates the induction of c-Fos in nuclei of solitary tract following experimental ulceration,suggesting that parasympathetic afferents promote the process of noxious visceral stimulation.

Application of response surface methodology in optimizaing thesulfation-roasting-leaching process of nickel laterite

Nickel was recovered from nickel laterite using a sulfation-roasting-leaching process and the effects of operation parameters in- cluding acid addition, roasting temperature, and roasting time on nickel extraction and iron dissolution were investigated using response sur- face methodology （RSM）. Two second-order polynomial models of high significance were presented to show the relationship between the responses and the variables. The analysis of variance （ANOVA） showed high coefficients of determination （R2） of 0.894 and 0.980 for the two models, respectively. Optimum areas of 〉-80% Ni extraction and 〈5% Fe dissolution were obtained by the overlaid contours. Verification experiments in the optimum areas were conducted and the results indicate a close agreement with the predicted values obtained from the models.

One-step and selective extraction of nickel from nickel-based superalloy by molten zinc

Nickel-based superalloy was treated with molten zinc for the selective extraction of nickel.The effects of heating temperature,heating time,and the mass ratio of zinc to superalloy on the extraction of metals in the superalloy were investigated.An extraction rate of 95.2%for nickel,55.4%for iron and 30.4%for chromium,but low extraction rates of the refractory metals(titanium(Ti),molybdenum(Mo),and niobium(Nb))were obtained under the optimal conditions of the heating temperature of 850℃,the heating time of 4 h,and the zinc/superalloy mass ratio of 10:1.In the subsequent vacuum distillation process,the obtained nickel alloy contained nickel with a purity of 73.5 wt.%after zinc removal.Moreover,the recovered zinc after the distillation process had a purity of 99.9 wt.%.The results of the investigated process indicated the possibility of extracting nickel directly from nickel-based superalloy scraps.

Mineralogical characterization and pretreatment for antimony extraction by ozone of antimony-bearing refractory gold concentrates

The mineralogical characterization of antimony-bearing refractory gold concentrates and the antimony extraction by ozonein HCl solution were investigated.The mineralogical study shows that there exist stibnite(Sb2S3),arsenopyrite(FeAsS),pyrite(FeS2)and quartz in the concentrates,and the gold is mainly(67.42%)encapsulated in sulfides.The antimony extraction by ozone inhydrochloric acid was employed and the influences of temperature,liquid/solid ratio,HCl concentration and stirring speed on theextraction of antimony were investigated.High antimony extraction(93.75%)is achieved under the optimized conditions.After thepretreatment by ozone,the antimony is recovered efficiently and the gold is enriched in the leaching residue.

Preparation of low-oxygen-containing Ti-48Al-2Cr-2Nb alloy powder by direct reduction of oxides

A high-purity Ti-48Al-2Nb-2Cr alloy powder with an oxygen content as low as 0.0572 wt.%and a particle size of<150μm was produced from a mixture of TiO_(2),Al_(2)O_(3),Nb_(2)O_(5),and Cr_(2)O_(3)powders through reduction with magnesium and deoxidation with calcium.The phase and composition of the products were analyzed.The final product mainly includedγ-TiAl and minorα_(2)-Ti_(3)Al phases,and Ti,Al,Cr,and Nb were homogenously distributed in the powder with a mole ratio of 49.73:43.51:2.05:1.98.The reduction and deoxidation mechanisms were investigated by thermodynamic modeling using the HSC Chemistry software and Pandat software based on the Ti alloy database.

Thermodynamic modeling of antimony removal from complex resources in copper smelting process

This work investigated the reaction mechanism of Sb in copper smelting process. The difference of multi-phase distribution of Sb in four typical copper smelting processes was analyzed. A multi-phase equilibrium model of the oxygen-enriched bottom-blow copper smelting process was developed. The impacts of Cu, S, and Sb concentrations in raw materials on Sb distribution in multiphases were researched. This model was also used to investigate the effect of process factors such as copper matte grade, oxygen-enriched concentration, smelting temperature, and oxygen/ore ratio(ratio of oxygen flow rate under standard conditions to concentrate charge rate) on Sb distribution behavior. The results showed that calculation data were in good agreement with the actual production results and literature data. Increasing the Cu content and decreasing the S and Sb contents in the concentrate, increasing the copper matte grade, oxygen/enriched concentration, and oxygen-ore ratio, and at the same time appropriately reducing the smelting temperature are conducive to the targeted enrichment of Sb into the slag. Modeling results can provide theoretical guidance for the clean and efficient treatment of complex resources and the comprehensive recycling of associated elements.

Leaching kinetics of antimony-bearing complex sulfides ore in hydrochloric acid solution with ozone

The leaching kinetics of Sb and Fe from antimony-bearing complex sulfides ore was investigated in HCl solution by oxidation?leaching with ozone.The effects of temperature,HCl concentration,stirring speed and particle size on the process were explored.It is found that the recoveries of Sb and Fe reach86.1%and28.8%,respectively,when the reaction conditions are4.0mol/L HCl,900r/min stirring speed at85°C with<0.074mm particle size after50min leaching.XRD analysis indicates that no new solid product forms in the leaching residue and the leaching process can be described by shrinking core model.The leaching of Sb corresponds to diffusion-controlled model at low temperature(15?45°C)and mixed-controlled model at high temperature(45?85°C),and the apparent activation energies are6.91and17.93kJ/mol,respectively.The leaching of Fe corresponds to diffusion-controlled model,and the apparent activation energy is1.99kJ/mol.Three semi-empirical rate equations are obtained to describe the leaching process.

Employing magnesium−lead melt for synergetic and selective extraction of copper from copper−cobalt alloy

This research aims to extract Cu from Cu-Co alloy with high efficiency and selectivity by employing binary Mg-Pb melt. The optimal conditions for the extraction of Cu were determined. The results showed under optimal conditions, 96.5% of Cu in the Cu-Co alloy could be selectively extracted after treatment at 800 ℃ for 1 h, with the extraction rates of only 0.2% Fe, 0.6% Co, and 1.4% Si. The dissolution mechanism involved the counter diffusion of Mg/Pb and Cu across the diffusion zone of the Cu-Co alloy, and Mg in the binary Mg-Pb melt played a major role in the selective dissolution of Cu, especially at the dissolution forefront. The rate-controlling step of the extraction was dominated by the interfacial reaction.