采用压热氧化预处理—全泥氰化浸出工艺从硫砷金精矿中浸出金

研究了采用压热氧化预处理—全泥氰化浸出工艺从硫砷金精矿中浸出金,考察了影响金浸出率的主要因素。结果表明:在氧分压0.6 MPa、预处理温度160℃、矿浆液固体积质量比2/1、助浸剂硫酸20 g/L+Fe2(SO4)310 g/L条件下,88.24%硫和85.22%砷可转入压热氧化处理液中,渣相中的金、银可富集到75.46、1351.4 g/t;预处理渣再细磨至-20μm占71.29%,在氰化钠用量20 g/t、全泥氰化浸出条件下,金、银浸出率可达93.78%和98.64%。此工艺金、银浸出效果较好,相对能耗较低,环境污染小。

某难选冶金矿石压热氧化预处理工艺的碱性介质研究

系统地研究了压热氧化预处理贵州某难选冶金矿石工艺条件中碱性介质选取及用量对金浸出率的影响。研究结果表明 :NaOH与Ca(OH) 2 配合使用作为碱性介质 ,预处理效果较好。在NaOH初始浓度为 0 .1～ 0 .2mol/L(10～ 2 0kg/t矿石 )、矿石粒度 98% - 2 0 0目、矿浆浓度为 2 5 %、木质素磺酸钙用量 0 1kg/t、温度 2 2 0℃、操作压力 3 2MPa、氧化预处理 2h条件下 ,金的氰化浸出率能稳定在 90

高压釜内闪速氰化提金工艺研究

本文通过试验研究提出了在碱性压热氧化条件下，金精矿在高压釜内进行闪速氰化的新工艺。该工艺具有流程简单，操作方便，浸出时间短的特点。

生物氧化提金技术在京通过鉴定

据报道，辽宁天利生物氧化提金技术成果日前在北京通过鉴定。鉴定委员会认为，该项技术具有独立的自主知识产权，已达到国际先进水平。其中，生产使用菌种的氧化活性、温度适应范围已具有国际领先水平。我国的难处理金矿资源广泛分布于西南和东北等地区。采用常规选冶技术，其金的回收率只有10％～60％。

铜精矿中铜镍的浸出研究

采用五种体系进行了从铜精矿中浸出铜镍的研究 ,得出了最佳浸出体系及条件。在催化剂作用下压热氧化浸出 ,当催化剂浓度为 0 .2 mol/L、起始氧压为 0 .9～ 1 .0 MPa、温度为 1 60℃、浸出时间 2 .0～ 3 .0 h、固液质量体积比为 1∶ 6条件下 ,铜、镍的浸出率分别为 98.5%和 96.1 %。该方法对硫化矿中铜、镍浸出比较适用。

少硫化物微细粒浸染型难处理金矿石提金试验研究

陕西某金矿原生矿石为少硫化物微细粒浸染型矿石,金矿物的粒度细小,赋存状态以包裹金为主,且含有砷、碳等有害元素,常规选冶方法金回收率较低。采用强化浮选—精矿压热氧化—氰化浸出提金工艺,金的浮选回收率为82.73%,浮选精矿金的氰化浸出率可达97.27%,金总回收率为80.47%,取得了较好的技术指标。

微细粒浸染型金矿石选金试验研究

详细研究了矿石中金的赋存状态和载金矿物特征 ,进行了多方案选金试验研究。试验结果表明 :对含金黄铁矿精矿进行压热氧化—氰化浸出 ,是处理该微细粒浸染型金矿石较有效的方法。

难处理金矿石选冶技术现状及发展方向

我国难处理金矿资源分布较广 ,并且在已探明的地质储量中占有较大比例。合理、高效和环保地开发利用难处理金矿资源的关键在于难处理金矿石选冶技术的开发和工业化应用程度。从国内外金矿石选冶技术的应用和发展趋势分析 ,焙烧氧化、细菌氧化和热压氧化 3种预处理工艺将成为未来开发利用难处理金矿资源的基本工艺。针对国内难处理金矿资源的特点 ,进一步开展上述预处理工艺的工程化应用研究 ,是今后我国黄金生产工业发展的主要方向之一。

Formability of aluminum-silicon coated boron steel in hot stamping process

Flow behavior of the Al-Si coated boron steel was investigated with Gleeble-3500,in comparison with the uncoated one.Effect of deformation conditions on the coating integrity was characterized by optical microscopy.Facture surfaces of the coated steels were inspected under SEM.Experimental results indicate that the ultimate tensile strength and ductility of the Al-Si coated boron steel are lower than those of the uncoated steel under test conditions.Extensive cracks occur in the coating after tensile tests;the width and density of cracks are sensitive to the deformation temperatures and strain rates.The bare substrate exposed between the separate coating segments is oxidized.Appearance of the oxide degrades the Al-Si coating adhesion.Remarkable difference between formability of the coating layer and the substrate is confirmed.The formability of the Al-Si coating could be optimized by controlling the phase transformation of the ductile Fe-rich intermetallic compounds within it during the austenization.

Oxidation behavior of C/C composites with SiC/ZrSiO_4-SiO_2 coating

A SiC/ZrSiO4？SiO2 （SZS） coating was successfully fabricated on the carbon/carbon （C/C） composites by pack cementation, slurry painting and sintering to improve the anti-oxidation property and thermal shock resistance. The anti-oxidation properties under different oxygen partial pressures （OPP） and thermal shock resistance of the SZS coating were investigated. The results show that the SZS coated sample under low OPP, corresponding to the ambient air, during isothermal oxidation was 0.54% in mass gain after 111 h oxidation at 1500 ° C and less than 0.03% in mass loss after 50 h oxidation in high OPP, corresponding to the air flow rate of 36 L/h. Additionally, the residual compressive strengths （RCS） of the SZS coated samples after oxidation for 50 h in high OPP and 80 h in low OPP remain about 70% and 72.5% of those of original C/C samples, respectively. Moreover, the mass loss of SZS coated samples subjected to the thermal cycle from 1500 ° C in high OPP to boiling water for 30 times was merely 1.61%.

Mechanism of high pressure roll grinding on compression strength of oxidized hematite pellets

The mechanism of high pressure roll grinding on improvement of compression strength of oxidized hematite pellets was researched by considering their roasting properties. The results indicate that oxidized hematite pellets require higher preheating temperature and longer preheating time to attain required compression strength of pellets compared with the common magnetite oxidized pellets. It is found that when the hematite concentrates are pretreated by high pressure roll grinding （HPRG）, the compression strengths of preheated and roasted oxidized hematite pellets get improved even with lower preheating and roasting temperatures and shorter preheating and roasting time. The mechanism for HPRG to improve roasting properties of oxidized pellets were investigated and the cause mainly lies in the increase of micro-sized particles and the decrease of dispersion degree for hematite concentrates, which promotes the hematite concentrate particles to be compacted, the solid-phase crystallization, and finally the formation of Fe203 bonding bridges during subsequent high temperature roasting process.

Pressure distribution inside oscillating heat pipe charged with aqueous Al_2O_3 nanoparticles,MWCNTs and their hybrid

Effective thermal performance of oscillating heat pipe(OHP)is driven by inside pressure distribution.Heat transfer phenomena were reported in terms of pressure and frequency of pressure fluctuation in multi loop OHP charged with aqueous Al2O3 and MWCNTs/Al2O3 nanoparticles.The influences on thermal resistance of aqueous Al2O3,MWCNTs as well as the hybrid of them in OHP having 3 mm in inner diameter were investigated at 60% filling ratio.Experimental results show that thermal characteristics are significantly inter-related with pressure distribution and strongly depend upon the number of pressure fluctuations with time.Frequency of pressure depends upon the power input in evaporative section.A little inclusion of MWCNTs into aqueous Al2O3 at 60% filling ratio achieves the highest fluctuation frequency and the lowest thermal resistance at any evaporator power input though different nanofluids cause different thermal performances of OHPs.

Cooling of Superheated Refrigerants Flowing inside Tubes Filled with Porous Media： Study of Heat Transfer and Pressure Drop, Carbon Dioxide Case Study

In this work an experimental study combined with an analytical investigation for cooling superheated Carbon Dioxide （CO2） gas were carried out. This work is intended to be part of the super critical Gustav Lorentzen refrigeration cycle of CO2. Experimental and analytical works concentrated on heat transfer and pressure drop for single phase flow during gas cooling inside tubes filled with porous media. Analytical empirical correlations were formulated for the coefficient of convectional heat transfer and for the pressure drop. A comparison between experimental results and that obtained by developed correlations were carried out, and a comparison between these results and literature published ones were carried out too. The results of this research showed that for cooling process the proposed correlations were proved to be acceptably accurate for pressure drop with difference from experimental results of 2%, while for convective heat transfer the difference from experimental results reached about 3%. More than 90% agreement with literature results was obtained. This work can enhance the calculations of heat flux and pressure drop of gases flow inside porous media filled tubes, and can help in the design procedure of heat exchangers and cooling processes.

Use of Magnesium Oxide-cement Binder in Composites Based on Hemp Shives

In this paper, it presented the results of experimental study of utilization of MgO cement as calcium hydrate replacement in lightweight composites based on hemp shives. The results of selected characteristics （compressive strength and coefficient of thermal conductivity） of hardened composites show that MgO cement based on the milled caustic magnesite is suitable alternative in comparison to conventional binders used in hemp concrete. This material leads to new environmentally products as non-load bearing building materials.