无机磷酸盐抑制剂在含钙矿物浮选分离中的新见解

本文通过计算预测了焦磷酸四钠(TSPP)、三聚磷酸钠(STPP)和六偏磷酸钠(SHMP)对白钨矿、萤石和方解石的抑制能力,并通过微浮选试验进行了验证。亲水-亲脂性平衡(HLB)计算、基团电负性计算和微浮选试验结果表明,磷酸盐对三种矿物的抑制能力随着磷酸基团数量的增加而增强,三种无机磷酸盐的抑制能力顺序为SHMP>STPP>TSPP。STPP在萤石和方解石中浮选分离白钨矿具有很大的潜力。STPP对三种含钙矿物的抑制能力依次为方解石>萤石>白钨矿。接触角测量、吸附量测量、X射线光电子能谱(XPS)分析和原子力显微镜(AFM)成像结果表明,STPP在萤石和方解石表面的吸附量远大于在白钨矿表面的吸附。白钨矿对STPP的弱吸附几乎不影响油酸钠(NaOL)的捕收。STPP可与萤石和方解石表面的Ca^(2+)络合,阻碍后续NaOL的吸附。本研究结果对白钨矿的浮选和含钙脉石矿物抑制剂的筛选具有指导意义。

FR4环氧树脂覆铜板热解动力学及产物组成

采用TG、Py-GCMS、XRD、XRF等技术对FR4环氧树脂覆铜板的热解特性、热解动力学及热解产物组成进行研究。结果表明:FR4环氧树脂覆铜板的热解反应是由5个热解反应阶段叠加组成的吸热反应,不同升温速率下其初始分解温度为221.49~246.60℃,最大失重温度为281.99~317.10℃,终止温度为534.81~580.24℃,表观活化能Ea为139.67~273.56 kJ/mol。FR4环氧树脂覆铜板的热解反应主要是有机物的分解反应,产生固体、液体和气体产物,反应最终温度为500℃时热解反应基本完成。固体产物主要为铜、玻璃纤维和炭黑。液体产物主要是酚类化合物、含溴类化合物和其他化合物,热解温度升高使得溴元素向气相产物迁移。气体产物主要为CO_(x)、C_(1)-C_(4)和CH3Br,热解温度升高有利于烷烃等清洁能源的生成与回收。

全因子实验设计废弃光伏组件中铝和银的浸出

晶硅太阳能电池中铝和银的回收是废弃光伏组件资源化的重要内容,氧化-硫酸同步浸出是一种浸出铝和银的有效方式,浸出效率高,经济效益好。本文采用全因子实验设计的方法,以铝和银的浸出率为响应值,以浸出温度、浸出时间、液固比、过氧化氢浓度4个工艺条件为参数因子,通过建立回归模型,分析各参数因子之间的相互关系,得出优化方案,并对其进行验证。实验得到的最佳浸出条件如下:浸出温度为90℃,浸出时间为2 h,液固比为10∶1 (mL∶g),过氧化氢浓度为75 g/L,铝和银浸出率均在99%以上。结果表明:铝和银浸出率的拟合回归模型可信,精确度高,回归模型得出的优化方案经过平行实验验证,误差小,可信度高,全因子实验设计方案合理可靠。

废弃线路板的热解特性及其有价液体产物的分布规律

热解技术遵循减量化、无害化和资源化三大固体废弃物处理原则,是一种有前景的大批量废弃线路板处置方法。本论文针对废弃线路板热解产物成分复杂及利用价值低的问题,进行了废弃线路板热解特性、产物组成及其有价液体产物分布规律的研究,为后续工业应用提供理论支撑。结果表明,废弃线路板的热解温区为157~664℃,表观活化能为80.70~279.46 kJ/mol。废弃线路板在热解过程中转化为三种产物,其中固体和气体产物可应用于材料和能源领域。废弃线路板的液体产物组成复杂,并且对热解温度较为敏感。在600℃时热解液体产物中有价组分比例最高(82.94%),其中单环酚类化合物占52.87%,多环酚类化合物占4.39%,溴酚类化合物占3.07%,烃类化合物占22.61%。废弃线路板在热解过程中的有价液体产物可替代酚醛树脂和石化产品中的部分原料。

氧压酸浸工艺从烧结镍合金中选择性浸出镍和钴

本研究采用氧压酸浸工艺来提高烧结镍合金中有价金属的浸出率。技术分析表明,样品中的NiO和被Ni_(2)O_(3)包裹的NiO阻碍了常压酸浸过程中镍的进一步溶解。氧压酸浸工艺可将镍的氧化物转化为可溶性的硫酸镍。热力学分析表明,在pH<6.26、温度>146℃和电位>0.20 V的体系中,烧结镍合金中的大部分镍和钴能以离子的形式溶解在溶液中,而大部分铁则水解形成Fe_(2)O_(3)进入浸出渣。优化浸出条件为:H_(2)SO_(4)浓度150 g/L,温度180℃,氧分压2 MPa,液固比10 mL/g,搅拌速度400 r/min,时间150 min。在此条件下,Ni、Co和Fe的浸出率分别为97.42%、96.30%和10.05%。反应动力学研究表明,镍的浸出过程受表面化学控制模型支配,表观活化能为43.73 kJ/mol。这项工作为从烧结镍合金中高效浸出镍提供了一种可行且环保的方法。

废旧镍钴锰电池回收工艺及污染控制概述

系统介绍了废旧镍钴锰电池回收利用的工艺路线,包括放电、预处理、火法与湿法回收工艺以及电解液的回收等。通过对比各回收方法的优缺点,认为火法-湿法联合处理工艺具有较好的应用前景;关注每项工艺中产生的二次污染,对污染控制方法进行了总结概括。旨在为废旧镍钴锰电池的绿色回收提供借鉴。

硫砷铜矿、蓝辉铜矿与铜蓝表面选择性氧化浮选分离研究

针对蓝辉铜矿、铜蓝和硫砷铜矿开展了表面选择性氧化浮选分离研究,并通过矿物表面接触角变化及XPS表面分析,阐明了3种矿物表面选择性氧化反应机制。结果显示,氧化剂次氯酸钙和高锰酸钾均可有效抑制蓝辉铜矿和铜蓝上浮,但对硫砷铜矿可浮性无影响;在丁铵黑药作用下,硫砷铜矿和蓝辉铜矿接触角均达到90°,经次氯酸钙氧化后,蓝辉铜矿接触角降至15°~30°,硫砷铜矿接触角仍高于86°;XPS分析结果表明,次氯酸促进了蓝辉铜矿表面的氧化,硫元素被氧化为SO_(4)^(2-),以CuSO_(4)形式覆盖在矿物表面,增加了表面亲水性,而硫砷铜矿表面As、Cu和S元素并未发生明显的氧化反应,矿物表面维持较高的疏水性。次氯酸钙实现了蓝辉铜矿与硫砷铜矿表面选择性氧化,强化了两者的浮选分离。

铜电解液含铋复盐沉淀法脱砷新工艺研究

针对目前诱导法脱砷产能不足、脱除率低的问题,开发了电解液含铋复盐沉淀法脱砷新工艺,优化沉淀条件为:含铋复盐沉淀剂用量Bi/As摩尔比1∶1、温度55℃、时间30 min,此时电解液中铜、砷、锑沉淀率分别为4.75%、63.62%和91.30%;在NaOH浓度50 g/L、液固比5∶1、温度80℃,时间0.5 h条件下,碱浸砷浸出率可达78.98%;沉淀剂再生性能良好,可循环使用;碱浸液经苛化再生循环利用,经过一次碱浸-苛化,NaOH损失率仅为2.7%。

我国金属矿山废石资源化综合利用现状与发展

随着社会的发展,我国对矿产资源的需求日益增加,矿山废石的大量堆积不仅造成矿产资源的严重浪费,而且占据大量土地,还会带来严重的安全问题和环境污染。针对我国矿山废石堆存量大、增长快、废石种类及成分复杂、废石资源化综合利用率低等特点,本文总结了矿山废石的危害和现行的处理及利用方式,详述矿山废石用于回收有价金属及进一步的废石回填、覆土造田、制造建筑材料等主要处理方式的特点、发展及应用情况,并归纳展望矿山废石未来可能研究发展的重点方向,提出矿山废石资源化利用的可行性建议。指出矿山废石的资源化综合利用的跨区域集聚处理、多领域多产业协同处理和分类分段处理是日后研究的关键。确定矿山废石堆存量以及成分、粒度、有价金属的含量是矿山废石综合利用的重要前提。制定合理方案对矿山废石进行分类分段处理是提高矿山废石综合利用率的重要步骤。

阳离子-阴离子组合捕收剂浮选分离白钨矿和方解石

通过纯矿物浮选试验、红外光谱分析、表面张力测定以及动电位测试研究了阳离子捕收剂十二胺(DDA)和阴离子捕收剂油酸钠(Na OL)及其组合捕收剂在白钨矿和方解石浮选分离中的作用及机理。结果表明,当p H值为7左右,DDA和Na OL组合捕收剂总用量为1.5×10-4mol/L、组合比为9∶1时,白钨矿回收率达到95%,比单独使用DDA、Na OL以及DDA和Na OL组合比为1∶9时明显提高;在该比例下预先加入2.0×10-3mol/L的酸化水玻璃,白钨矿回收率仍然达到90%,而方解石回收率由80%下降到了40%,这可以实现白钨矿和方解石的浮选分离。

Cu^2+、Fe^2+和Fe^3+对中等嗜热混合菌浸出黄铜矿的影响

在50℃、pH 1.6的条件下,研究了Fe^2+、Fe^3+和Cu^2+对中等嗜热混合菌浸出黄铜矿的影响。结果表明:添加低质量浓度Fe^2+时,在浸出前期能够促进黄铜矿的浸出;而添加较高质量浓度Fe^2+时,铜的浸出率反而降低;当添加不同质量浓度Fe^3+时,由于形成黄钾铁矾而导致总铁质量浓度降低,但铜的浸出率并没有明显变化;添加不同质量浓度Cu^2+对黄铜矿的浸出没有显著的影响。同时,添加Fe^2+和Cu^2+与单独添加Fe^2+对黄铜矿的浸出影响是相似的。因此,在生物浸出过程中,可以通过调节浸矿微生物组成降低微生物的亚铁氧化活性,提高硫氧化能力来控制溶液电位,从而强化黄铜矿的生物浸出。

烟气脱硫石膏与冶炼行业石膏渣综合利用研究进展

燃煤电厂烟气脱硫过程和冶炼污酸的中和过程均产生以二水硫酸钙为主要成分的固体废物,前者称为烟气脱硫石膏,后者通常称为石膏渣。烟气脱硫石膏在建筑材料、生产化工原料、固定二氧化碳、环境治理和土壤修复等方面得到了有益的应用,但冶金行业石膏渣因含有砷、铜、铅、铬等有害元素而利用困难,通常其处置方法有固化/稳定化处置、高温熔融处置、回收有价金属和作为熔剂造渣等。结合国内外烟气脱硫石膏及冶炼石膏渣综合处置的最新研究成果,全面阐述两者的综合利用现状。分析了两类石膏渣处置与利用技术的优缺点,探讨了应用中存在的一些问题与不足,并提出了建议与展望。未来烟气脱硫石膏的研究重点是以减量化、高值化、扩大脱硫石膏高值化利用规模为主,以开发高附加值产品为辅,提高综合利用率;冶炼行业石膏渣的无害化、资源化利用技术,如污酸中和过程中硫酸钙晶型调控、火法−湿法协同处理以及熔炼造渣等是未来的发展方向。

新型捕收剂SCA在河南某白钨选矿厂的应用研究

针对白钨矿在低温高碱条件下粗选回收率低的难题,开发了一种新型捕收剂SCA,并在河南某白钨选矿厂进行了工业应用。结果表明,SCA比现场用捕收剂FX⁃6具有更优的白钨捕收性能和更强的耐低温、耐高碱性能;在抑制剂Y1用量30 g/t、温度10℃、pH值11.0、SCA用量220 g/t条件下,经一粗两扫闭路浮选,可获得WO3回收率79.95%的白钨粗精矿,相比FX⁃6,回收率提高了4.53个百分点;工业应用中,在捕收剂用量降低20.37 g/t条件下,使用SCA时的WO3回收率比使用FX⁃6时提高了2.76个百分点。SCA在低温高碱条件下对白钨矿的浮选指标较好,具有广阔的工业应用前景。

Water leaching of arsenic trioxide from metallurgical dust with emphasis on its kinetics

Water leaching of As2O3 from metallurgical dust containing various metals was investigated,serving the purpose of dearsenization and simultaneous metal enrichment especially for indium.Effects of leaching temperature,liquid/solid ratio(LSR)and leaching time were studied.It was found that the initial dissolution was very fast but was then so inhibited by the increasingly dissolved As2O3,which makes it difficult to saturate enough arsenic in the leaching solution or in leaching out all the soluble arsenic with excess dosage of water within acceptable time(120 min).Only about 73%of As2O3 was extracted under the optimal conditions investigated.Two-step leaching showed similar trends and was thus unnecessary for improving As2O3 extraction.These observations could reasonably be accounted for the reversibility of the dissolution reaction.Kinetically,the leaching was described satisfactorily by the semi-empirical Avrami model with the apparent activation energy of 36.08 kJ/mol.The purity of the obtained product As2O3 could reach 98.7%,while the indium could be enriched in the leaching residue without loss.

Collecting performance of vegetable oils in scheelite flotation and differential analysis

The composition of a collector directly affects its collecting performance in mineral flotation.In this study,three vegetable oils were used as the collectors,the flotation performance of scheelite and the differential analysis were studied through flotation experiments,zeta potential,contact angle measurement and Fourier transform infrared spectrum(FTIR)analysis.Flotation results show that the recovery of scheelite increases in the order of oleic acid<rapeseed oil<rice bran oil<soybean oil,especially in the pH range of 5-8.The distinction in the scheelite recovery is due to the different compositions of these collectors.The addition of LA,LNA and PA(<5%)can increase the recovery of scheelite with OA,but the addition of SA deteriorates the scheelite flotation.Results of zeta potential,contact angle measurement and FTIR analysis indicate that the collector adsorption on scheelite surface is enhanced when using the three vegetable oils.For the raw ore with 0.086%WO3,a rough concentrate containing 1.423%WO3 with the recovery of 84.22%is obtained using soybean oil as the collector.

Leaching of chalcopyrite: An emphasis on effect of copper and iron ions

Many researchers found that the Fe2+together with less amount of Cu2+can accelerate the leaching of chalcopyrite.In this work,the leaching of chalcopyrite with Cu2+was investigated.The leaching residuals were examined by Raman spectroscopy.Based on the leaching experiments,the chemical equilibrium in solution was calculated using Visual MINTEQ.The results showed that the Fe in chalcopyrite lattice was replaced by Cu2+;therefore,the chalcopyrite transformed into covellite.Furthermore,the formation of chalcocite occurred when Fe2+and Fe3+were added to the solution containing Cu2+.The copper extraction increased with a decrease of the initial redox potential(or the ratio of Fe3+/Fe2+).

Sulfide mineral bioleaching:Understanding of microbe-chemistry assisted hydrometallurgy technology and acid mine drainage environment protection

Bioleaching is regarded as an essential technology to treat low grade minerals,with the distinctive superiorities of lower-cost and environment-friendly compared with traditional pyrometallurgy method.However,the bioleaching efficiency is unsatisfactory owing to the passivation film formed on the minerals surface.It is of particular interest to know the dissolution and passivation mechanism of sulfide minerals in the presence of microorganism.Although bioleaching can be useful in extracting metals,it is a double-edged sword.Metallurgical activities have caused serious environmental problems such as acid mine drainage(AMD).The understanding of some common sulfide minerals bioleaching processes and protection of AMD environment is reviewed in this article.

Comparison of leaching of bornite from different regions mediated by mixed moderately thermophilic bacteria

Bioleaching experiments combined with X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XRD)and scanning electron microscopy(SEM)were conducted to investigate three kinds of bornites from different regions leached by moderately thermophilic mixed bacteria of Leptospirillum ferriphilum YSK,Acidithiobacillus caldus D1 and Sulfobacillus thermosulfidooxidans ST.The results of bioleaching experiments showed that the leaching efficiency and the redox potential were significantly increased.The copper extraction efficiencies of three kinds of bornite maintained rapid growth until around the 12th day and no longer increased after the 18th,reaching 83.7%,96.5%and 86.6%,respectively.The XRD results of the leaching residue indicated that three kinds of bornites all produced jarosite in the late stage of leaching,and the leaching residues from of Daye Museum and Yunnan Geological Museum contained a mass of elemental sulfur.XPS analysis and scanning electron microscopy experiments showed that the surface of mineral particles was jarosite and the copper in the leaching residue was almost dissolved.

A promising method for recovery of LiMn_(2)O_(4) and graphite from waste lithium-ion batteries: Roasting enhanced flotation

In this study,a roasting enhanced flotation process was proposed to recover LiMn_(2)O_(4) and grapite from waste lithium-ion batteries(LIBs).The effects of roasting temperature and time on the surface modification was investigated,and a series of analytical technologies were used to reveal process mechanism.The results indicate that LiMn_(2)O_(4) can be effectively separated from graphite via flotation after the roasting.The flotation grade of LiMn_(2)O_(4) was significantly increased from 63.10%to 91.36%after roasting at 550℃for 2 h.The TG-DTG analysis demonstrates that the difficulty in flotation separation of LiMn_(2)O_(4) from graphite is caused by the organic binder and electrolytes coating on their surfaces.The XRD,SEM,XPS,and contact angle analyses confirm that the organic films on the surfaces of those materials can be effectively removed by roasting,after which the wettability of LiMn_(2)O_(4) is regained and thus the surface wettability difference between the cathode and anode materials is increased significantly.The closed-circuit flotation test indicates that a LiMn_(2)O_(4) sample with high grade of 99.81%is obtained,while the recovery of LiMn_(2)O_(4) is as high as 99.40%.This study provides an economical and eco-friendly way to recycling waste LIBs.

Improving collecting performance of sodium oleate using a polyoxyethylene ether in scheelite flotation

In order to improve the scheelite flotation with sodium oleate(NaOL),the effect of a non-ionic polyoxyethylene ether(JFC-5)on the floatability of scheelite was investigated through flotation experiments at10°C,compared with60mg/L NaOL alone,the recovery of scheelite is improved from22%to85%in the presence of JFC-5with a mass ratio of20%at pH10.Moreover,the resistance to Ca2+of NaOL is increased.The adsorption mechanism was analyzed by zeta potential measurement,contact angle measurement and X-ray photoelectron spectroscopy(XPS)analysis.The results show that the adsorption of NaOL on scheelite surface is enhanced after adding JFC-5due to the more negative zeta potentials and larger contact angles of scheelite.And the co-adsorption of NaOL and JFC-5is confirmed by XPS analysis,so it is indicated that the adsorption of JFC-5decreases the electrostatic repulsion between the oleate ions,resulting in the stronger adsorption of NaOL on scheelite surface.In short,the mixed NaOL/JFC-5collector can effectively improve scheelite flotation.