An investigation of oxygen pressure acid leaching of Gacun complex Cu-Pb bulk concentrate

The treatment of the Gacun complex Cu-Pb bulk concentrate with high Zn,Ag,etc.,by oxygen pressure acid leaching was studied.The pri-mary copper and leadminerals in the concentrate are tetrahedrite and galena.The treatment of tetrahedrite was rarely studied,and most of silver occurred in themineral too.The optimum operating parameters of oxygen pressure acid leaching were established by conditional tests.Under these parameters,the result of pilot scale test showed that the leaching percentages of copper and zinc were separately as high as 98.9 wt.% and 94.9 wt.%,while lead and silver were transformed into sulfate and sulfide precipitations,respectively.The copper and zinc in lixivium were reclaimed by extraction-electrowinning and purification-electrowinning,respectively,and the lead and silver in the residue were reclaimed separately by carbonate transformation-silicofluoric acid leaching and thiourea leaching.

Selective depression mechanism of combination of lime and sodium humate on arsenopyrite in flotation separation of Zn-As bulk concentrate

Lime(CaO)and sodium humate(NaHA)were used as the combined depressant for arsenopyrite pre-treated by CuSO_(4) and butyl xanthate.Micro-flotation tests show that the combined depressant CaO and NaHA achieved the selective depression of arsenopyrite.Closed-circuit lab-scale test results indicate that the synergistic effect of CaO+NaHA achieved a satisfactory flotation separation of sphalerite and arsenopyrite,for which the Zn grade and recovery of Zn concentrate were 51.21%and 92.21%,respectively.Contact angle measurements,adsorption amount measurements and X-ray photoelectron spectroscopy analysis indicate that the dissolved calcium species(mainly as Ca(2+))were adsorbed on the mineral surfaces,thereby promoting NaHA adsorption.Moreover,the surface of the arsenopyrite absorbed more amount of calcium species and NaHA than that of the sphalerite,thereby accounting for the strong hydrophilic surface of arsenopyrite.The adsorption of NaHA on arsenopyrite was mainly chemical adsorption through its carboxyl groups and Ca atoms,whereas that on sphalerite surface was relatively weak.

Analysis of Sulfur Dioxide Concentration Around Bulk Curing Barn Group

This study was conducted to analyze the spatial distribution of SO2 mass concentration around baking barn groups. A bulk curing barn group was selected as monitoring object, and SO2 concentration around it was monitored for 2 years. The results showed that the SO2 mass concentration within 30-130 m from the baking barn group exceeded the standard, and with the ground as reference, the SO2 mass concentration at the position 0.9-2.1 m from the ground exceeded the stan- dard. According to the limit value of the SO2 mass concentration for sensitive crops, the SO2 mass concentrations over the standard were concentrated within the range of 200-300 m. On the basis of establishment of ＂sulfur control＂, ＂sulfur reduction＂ and ＂sulfur avoiding＂ system, the SO2 emission status of baking barn groups could be improved from the conversion of heat supply method, the utilization of clean en- ergy and adjustment of crop sensitive period and sensitive area.

云南某细粒铜钼混合精矿分离工艺优化及工业应用

云南某细粒硫化铜钼混合精矿中主要有价金属元素为铜和钼,矿石中主要矿物为黄铜矿和辉钼矿,脉石矿物主要是石英和云母,铜、钼矿物嵌布粒度较细,与脉石矿物复杂共生。针对混合精矿分离难度大、分离指标较差、药剂单耗用量大、药剂成本高的现状,结合混合精矿含钼品位的上升,在工艺矿物学研究基础上,开展了选矿试验研究。通过对原有工艺及药剂制度进行优化试验,研制了新型铜钼分离药剂D117和D118,其中D117为铜抑制剂,D118为调整剂。在原矿铜品位20.75%、钼品位0.47%的条件下,采用“抑铜浮钼”、一次粗选、四次精选、一次扫选浮选工艺,获得钼品位45.15%、铜品位1.03%、钼作业回收率85.65%的钼精矿及含钼0.069%、铜品位20.92%、铜作业回收率99.96%的铜精矿,取得了良好的实验室选别指标。将研究成果应用于工业生产后,浮选浓度由18%提升至33%,系统台效由17.4 t/h提高至25.9 t/h,钼作业回收率由66.11%提升至80.55%,年产钼金属由286 t提高至710 t。同时,D117、D118新型小分子药剂的使用取消了水玻璃的添加,并大幅降低了硫化钠用量,硫化钠粗选用量由设计之初125000 g/t降至6000 g/t,降幅达95.20%。通过药剂制度的持续优化,进一步压缩了硫化钠用量,硫化钠单耗由13.4 kg/t降至7.53 kg/t,D117单耗由6.18 kg/t降至3.98 kg/t,在药剂成本大幅度降低的前提下,实现了铜钼分离系统处理量及生产指标的双提升。

白云鄂博稀土混合精矿工艺矿物学研究

目前白云鄂博稀土元素的提取主要采用重污染和高能耗的高温浓硫酸焙烧法,“三废”问题至今没有得到合理的解决,且钍元素作为一种伴生组分难以得到再回收利用。采用自动矿物分析仪、X射线衍射分析、扫描电镜分析、配分分析、光学显微镜等分析方法对白云鄂博稀土混合精矿的化学成分、矿物组成、粒度及嵌布特征等进行了工艺矿物学研究,结果表明,该稀土混合精矿REO品位为59.25%,主要稀土矿物由氟碳铈矿、独居石和氟碳钙铈矿组成,主要脉石矿物为磷灰石、萤石、黄铁矿和磁/赤铁矿。在矿物中主要分布的稀土元素为La、Ce、Pr、Nd、Sm、Gd。矿样中矿石-38μm粒级含量占95.92%,氟碳铈矿和独居石单体解离度均在55%以上,矿石整体嵌布特征较为复杂,稀土矿物与萤石和磷灰石的连生关系最为密切。为简化冶金工艺,高效提取稀土元素,提出了采用矿相转化后“浮少抑多”的方法分离氟碳铈矿和独居石的展望,为白云鄂博稀土混合精矿的合理开发应用提供新思路。

Effect of surface roughness on plasticity of Zr_(52.5)Cu_(17.9)Ni_(14.6)Al_(10)Ti_5 bulk metallic glass

Zr52.5Cu17.9Ni14.6Al10Ti5 bulk metallic glass （BMG） rods were abraded to different surface roughnesses using different types of waterproof abrasive papers and sometimes polishing pastes, and the compressive deformation behavior was examined. The results show that the yield strength of the BMG is hardly affected while the compressive plasticity increases from 2.3% to 4.5% with decreasing the surface roughness. Observation of the fractured samples under a scanning electron microscope indicates that the rise in plasticity is accompanied with an increase in shear band density. The results suggest that it is necessary to reduce the surface roughness of BMGs for achieving a large plasticity.

铜铅混合精矿硫酸预氧化-浮选分离参数优化试验研究

方铅矿与黄铜矿的分离一直是选矿领域的难点,使用硫酸预氧化可选择性抑制方铅矿表面可浮性,使得两种矿物可浮性产生差异,实现浮选分离。针对铜铅混合精矿硫酸预氧化-浮选分离工艺进行了系统的参数优化。首先,利用单因素试验,分析了预氧化硫酸浓度、温度、时间等关键因素对铜铅混合精矿浮选分离效果的影响;其次,利用正交试验分析,建立了预氧化过程中各影响因素与浮选指标之间的数学模型;通过模型求解,得到最佳预氧化条件为硫酸浓度5 mol/L、时间40 min、温度100℃。最后在上述条件下进行了混合精矿预氧化-浮选闭路试验,获得了铜精矿Cu品位18.03%,Cu回收率94.52%;铅精矿Pb品位47.12%,Pb回收率为91.29%的良好指标,铜铅分离效果显著,对铜铅硫化混合精矿的浮选高效分离提供了一定的借鉴。

普朗铜矿粗颗粒水力浮选实验研究

针对云南普朗斑岩型铜矿难磨难选的特点,在分析矿石性质的基础上进行粗颗粒水力浮选实验。矿石中的铜主要以黄铜矿形式赋存,钼主要以辉钼矿形式赋存,脉石矿物主要为石英及钠/钙长石。采用HydroFloat水力浮选机对粗颗粒铜钼矿进行混合浮选,达到抛尾目的,减少后续磨矿能耗。HydroFloat水力浮选机在传统流化床的基础上引入气泡,通过复合力场使粗颗粒悬浮后随气泡上升达到分选目的。经水力浮选后,可从铜品位0.39%和含钼0.009%的原矿浮选得到铜品位为0.73%、回收率为95.84%,钼品位为0.016%、回收率为92.05%的铜钼混合粗精矿,抛尾率可达48.80%。

Cycling performance of layered oxide cathode materials for sodium-ion batteries

Layered oxide is a promising cathode material for sodium-ion batteries because of its high-capacity,high operating voltage,and simple synthesis.Cycling performance is an important criterion for evaluating the application prospects of batteries.However,facing challenges,including phase transitions,ambient stability,side reactions,and irreversible anionic oxygen activity,the cycling performance of layered oxide cathode materials still cannot meet the application requirements.Therefore,this review proposes several strategies to address these challenges.First,bulk doping is introduced from three aspects:cationic single doping,anionic single doping,and multi-ion doping.Second,homogeneous surface coating and concentration gradient modification are reviewed.In addition,methods such as mixed structure design,particle engineering,high-entropy material construction,and integrated modification are proposed.Finally,a summary and outlook provide a new horizon for developing and modifying layered oxide cathode materials.

二氧化铀产品堆密度提升研究

为提升二氧化铀产品品质,分析了铀纯化新老生产线二氧化铀产品的堆密度,发现铀纯化老生产线产品堆密度均高于新生产线产品的堆密度。分析其主要原因是新生产线结晶剂浓度波动较大,导致三碳酸铀酰铵的结晶效果变差,晶体粒径变小,进而影响了晶体煅烧效果和二氧化铀产品堆密度。通过将新老生产线碳酸铵配制岗位合并,统一、就近供应结晶剂,对回收的碳酸铵溶液进行增浓,并用蒸汽冲洗输送管道,解决了新生产线结晶效果波动问题,使新生产线二氧化铀产品平均堆密度提升了5.71%,平均每桶产品净重提升了4.73%,并提升了二氧化铀的产品品质。

某混合精矿铜钼分离浮选试验研究

针对云南某铜钼混合精矿特点,在矿石工艺矿物学研究的基础上,开展单因素条件试验研究。探索优化浮选工艺、药剂制度、筛选出对辉钼矿捕收效果较煤油更优的新型钼捕收剂M1。试验结果表明:在最佳药剂条件下,使用新型钼捕收剂M1,可获得精矿钼品位46.330%,钼作业回收率87.69%,铜精矿作业回收率99.83%的较好指标。

Bulk metallic glasses formed by alloying the Cu_6Zr_5 cluster

The bulk metallic glass formation in the Cu-Zr-M ternary systems by alloying of a binary basic Cu6Zr5 cluster was inves- tigated, where M stands for Sn, Mo, Ta, Nb, Ag, Al and Ti. The Cu6Zr5 cluster is a capped Archimedean antiprism that characterizes the local structure of the Cu10Zr7 crystalline phase. This cluster composition almost superposes with Cu-Zr eutectic Cu0.56Zr0.44. A se- ries of alloys along the cluster line (Cu6Zr5)1-xMx were examined for their glass forming abilities. Alloy rods with a diameter of 3 mm were prepared by copper mould suction casting method and analyzed by XRD and thermal analysis. The Cu-Zr based bulk metallic glasses were discovered with minor Nb, Sn, Mo, Ta additions (≤2at%) and Al, Ti, Ag (8at%≤concentration≤9at%). The alloying mechanism was discussed in the light of atomic size, cluster-linking structure and electron concentration factors.

Glass formation of ternary Sm-based Sm-Al-Co bulk metallic glasses

Ternary Sm-based Sm-Al-Co alloys at specific compositions designed using an e/a- and cluster-related criteria exhibit high glass forming abilities and form bulk glassy rods of 3 mm in diameter by a copper mold suction-casting method. Four composi- tions of bulk metallic glasses (BMGs) are Sm50Al25Co25, Sm52Al24Co24, Sm54Al23Co23 and Sm56Al22Co22, which all satisfy a constant conduction electron concentration of 1.5. Among them, the BMG exhibiting the largest reduced glass transition temperature (Trg) is Sm50Al25Co25, which reaches 0.648. The glass transition temperature Tg and the onset crystallization temperature Tx of this alloy are respectively 579 and 640 K at a heating rate of 20 K/min.

Determination of elastic moduli of composite medium containing bimaterial matrix and non-uniform inclusion concentrations

Reservoir porous rocks usually consist of more than two types of matrix materials, forming a randomly heterogeneous material. The determination of the bulk modulus of such a medium is critical to the elastic wave dispersion and attenuation. The elastic moduli for a simple matrix-inclusion model are theoretically analyzed. Most of the efforts assume a uniform inclusion concentration throughout the whole single-material matrix. However, the assumption is too strict in real-world rocks. A model is developed to estimate the moduli of a heterogeneous bimaterial skeleton, i.e., the host matrix and the patchy matrix. The elastic moduli, density, and permeability of the patchy matrix differ from those of the surrounding host matrix material. Both the matrices contain dispersed particle inclusions with different concentrations. By setting the elastic constant and density of the particles to be zero, a double-porosity medium is obtained. The bulk moduli for the whole system are derived with a multi-level effective modulus method based on Hashin＇s work. The proposed model improves the elastic modulus calculation of reservoir rocks, and is used to predict the kerogen content based on the wave velocity measured in laboratory. The results show pretty good consistency between the inversed total organic carbon and the measured total organic carbon for two sets of rock samples.

铜钼混合精矿预处理强化铜钼分离研究进展

铜钼硫化矿常常紧密共生且可浮性相近,二者的浮选分离一直是选矿研究的重点。铜钼矿石一般采用浮选方法进行分离,铜钼混合浮选—铜钼分离是目前工业上应用最为广泛的工艺,在混合浮选之后,通常先进行预处理,尽可能脱除铜钼混合精矿中的浮选药剂以及矿物表面残余的药剂,为铜钼分离提供条件。本文将铜钼分离预处理工艺分为三大类:一是解吸脱药法,二是机械脱药法,三是矿物表面的氧化处理。前两种是目前比较常用的预处理脱药方法,但仍存在着流程复杂、有污染等特点,而矿物表面的氧化处理除了可以达到脱药的目的,还可以实现铜矿物的表面氧化,增大铜钼的可浮性差异。铜钼混合精矿浮选分离预处理工艺研究对改善铜钼混合精矿的分选效果具有重要意义。

Low-strain Co-free Li-rich layered cathode with excellent voltage and capacity stability

Owing to the inherent advantages of low cost and high capacity,cobalt(Co)-free lithium(Li)-rich layered oxides have become one of the most promising cathodes for next-generation high-energy lithium-ion batteries.However,these familial cathodes suffer from serious voltage decay due to many reasons,such as oxygen release and transition metal(TM)migration,which are closely related to nanoscale strain evolution.Here,by combining the synergistic effects of surface integration,bulk doping,and concentration gradient,we successfully construct a Co-free Li-rich layered cathode with a very small volumetric strain(1.05%)between 2.0 and 4.8 V,approaching the critical value of zero strain.Various characterizations indicate that the constructed zero-strain cathode can significantly suppress the TM migration,interfacial reactions,and structural degradation including cracks,lattice defects,phase evolution,and nanovoids,leading to improved voltage stability of Co-free Li-rich layered oxides during the prolonged cycles.This work provides a strategy to eliminate the lattice strain of Li-rich layered cathodes and facilitates the up-scaled application of the as-prepared cathode materials.

水耕历史对稻田-田埂过渡区土壤物理性质与水-氮分布的影响

选取水耕年限分别为2年、19年和>100年稻田,通过野外样品采集与室内分析相结合的方法,对比了稻田田内和田埂土壤物理性质与水-氮分布差异,揭示了水耕历史对稻田-田埂过渡区土壤物理性质与水-氮流失过程的影响机制。结果表明,耕作活动影响了稻田-田埂过渡区土壤容重、孔隙、土壤水分特征曲线和饱和导水率(Ks)等物理性质。随着水耕年限的增加,田内耕作层与田埂表土层、田内犁底层与田埂硬质层的容重差异增大;耕作层的中小孔隙(直径<0.03 mm)含量增加,其他土层的总孔隙和大孔隙(直径>0.3 mm和>0.03 mm)含量降低;田内土壤的Ks下降速度较田埂更快。在测定的吸力范围内(0~100 kPa),2年和19年的耕作层与表土层持水能力相近,而100年耕作层持水能力高于表土层;2年和100年的硬质层与犁底层持水能力相近,而19年硬质层持水能力更强;19年和100年田埂底土层持水能力较田内强。随着水耕年限增加,耕作层与表土层Ks差异减小,硬质层与犁底层Ks差异增加,2年、19年和100年硬质层的Ks分别是对应犁底层的1.10倍、6.90倍和6.32倍,100年田埂底土层的Ks明显高于田内。土壤物理性质的变化影响稻田-田埂过渡区的水-氮分布特征,主要表现为2年稻田的水-氮含量明显低于19年和100年稻田,且19年和100年稻田的水-氮在耕作层聚集。当水耕年限较短时,水-氮同时通过田内和田埂区域快速流失;随着水耕年限的增加,水-氮更易通过田埂发生渗漏。老稻田新修田埂的硬质层土壤会发生退化,再次成为水-氮快速流失位点。因此,对于耕作年限长的稻田,其田埂区域的水-氮渗漏更应引起重视。

钼铋混合精矿盐酸浸出分离并制备海绵铋工艺研究

针对钼铋混合精矿进一步分选流程长、成本高以及传统火法炼铋工艺冗长、能耗高、铋回收率偏低等问题,采用通氧盐酸浸出新工艺,考察了盐酸浓度、浸出时间、温度等因素对钼铋浸出的影响,在盐酸浓度3 mol/L、液固比3∶1、温度80℃、搅拌转速500 r/min优化条件下通氧气浸出6.0 h,铋浸出率达99.13%,钼不浸出富集于浸出渣中,实现了铋和钼的高效分离;浸出液经净化除杂及铁板置换后得到了纯度99%以上的海绵铋。

云南某硫精矿二次回收铅锌工艺研究

为了实现硫精矿中铅锌金属资源的二次回收,同时提高硫精矿的品质,采用工艺矿物学研究了矿物的嵌布特征和赋存状态,拟定了铅锌混浮的原则流程。硫酸铜作为闪锌矿活化剂、石灰作为黄铁矿抑制剂,丁基黄药、乙硫氮、丁铵黑药作为组合捕收剂。通过试验确定药剂制度,在一粗三精一扫的闭路试验中获得铅品位为5.49%(回收率为13.52%)、锌品位为38.11%(回收率为57.12%)的混合精矿。硫精矿经过提质后铅锌品位之和降至0.98%。

小麦粮堆中玉米象和黄曲霉发生与二氧化碳浓度变化关系研究

构建4种模拟小麦粮堆(模拟自然带菌、模拟害虫发生、模拟霉菌发生、模拟虫霉发生),研究了25℃下不同水分(12.5%和15.0%)小麦粮堆CO_(2)浓度变化情况。结果显示,水质量分数为12.5%的自然带菌粮堆二氧化硕(CO_(2))浓度30 d内未出现显著变化(P>0.05);害虫发生粮堆第2天CO_(2)体积分数即超过0.5%,第15~17天后快速增长,于第23天达到4.5%;霉菌发生粮堆第30天时CO_(2)体积分数也未超过0.04%;虫霉共同发生粮堆第2天CO_(2)体积分数即超过0.6%,第13~17天后快速增长,于第26天达到4.5%。水质量分数15.0%的小麦的4种模拟粮堆中霉菌发生粮堆、虫霉共同发生粮堆的CO_(2)浓度增加更快、幅度更大。研究初步明确了虫霉发生与粮堆CO_(2)浓度变化的关系,为利用粮堆CO_(2)浓度变化来监测粮堆虫霉发生提供参考。