粉煤灰焙烧-酸浸提取氧化铝工艺

采用酸浸法提取淮南某电厂粉煤灰中的Al2O3,通过单因素实验研究了Na2CO3混合焙烧活化工艺和H2SO4酸浸工艺中的各种因素对Al2O3浸出率的影响,确定了工艺最佳条件:焙烧灰碱比为1∶0.9,焙烧时间为2h,焙烧温度为875℃;酸浸H2SO4浓度为3mol/L,酸浸温度为90℃,酸浸时间为2h,液固比为4∶1,Al2O3浸出率可达95%。     

蔗髓低温还原焙烧-浸出低品位软锰矿工艺

以蔗渣造纸工业废弃物蔗髓为还原剂,研究了低温焙烧还原浸出软锰矿的新工艺. 考察了蔗髓与软锰矿中锰的质量比、焙烧时间、焙烧温度、搅拌速率、浸出温度、浸出时间、H2SO4浓度和液固比对锰浸出率的影响,并分析还原焙烧过程. 结果表明,锰浸出率随蔗髓用量、焙烧时间、焙烧温度、搅拌速率、浸出温度、浸出时间、H2SO4浓度和液固比增加先增加然后基本保持不变. 蔗髓热解生成还原性气体有机物将软锰矿中高价锰氧化物MnO2还原为低价MnO. 适宜的焙烧还原浸出条件为：蔗髓/锰质量比0.62:1、还原焙烧温度350℃、还原焙烧时间60 min、浸出搅拌速率200 r/min、浸出温度60℃、浸出时间40 min、H2SO4浓度3.0 mol/L、液固比6 mL/g. 在此条件下,软锰矿的浸出率可达97%.     

粉煤灰酸浸提铝及其动力学

对KF为助剂焙烧活化粉煤灰酸浸提铝过程进行了研究,考察了粉煤灰焙烧活化和盐酸浸出条件对粉煤灰中铝浸出率的影响及其浸出过程动力学. 结果表明,焙烧活化优化条件为：时间1 h、温度800℃、粉煤灰与KF质量比为20:4. 浸出温度90℃、浸出时间2 h、盐酸浓度4 mol/L、液固比4 mL/g的条件下,铝提取率达到92.46%. 粉煤灰烧结产物加热酸浸过程符合收缩未反应核模型,反应级数为0.3718,反应活化能为43.49 kJ/mol,过程速率为化学反应速率控制.     

Ga2(SO4)3/凹凸棒固体酸催化剂的制备及催化合成丁酸己酯

采用凹凸棒负载Ga2(SO4)3制备了Ga2(SO4)3/凹凸棒固体酸催化剂,用红外光谱、X射线衍射等对催化剂结构进行了表征,通过丁酸己酯的酯化反应考察了催化剂的制备条件、催化活性、重复使用性以及反应动力学。催化剂较优制备条件是:凹凸棒经1.1 mol/L硫酸溶液酸化处理,Ga2(SO4)3负载量占催化剂总质量的25%,焙烧温度350℃,焙烧时间2.0 h,在该条件下平均酯化率为98.1%。催化剂经5次重复使用后,酯化率仍不低于85%。反应动力学研究表明:反应级数为2,表观活化能为76.17 kJ/mol。     

硫酸镓/凹凸棒石黏土固体酸催化剂的制备及其催化性能

采用凹凸棒石黏土负载硫酸镓(Ga2(SO4)3)制备了Ga2(SO4)3/凹凸棒石黏土固体酸催化剂,采用红外光谱及X衍射光谱等对催化剂结构进行了表征。通过乳酸丁酯的合成考察了催化剂的较优制备条件和催化性能,并对相应催化反应进行了动力学研究。结果表明催化剂的较优制备条件是:凹凸棒石黏土经1.2mol/L硫酸溶液酸化处理,Ga2(SO4)3负载量为5.7%,焙烧温度350℃,焙烧时间2.5h。在较优酯化反应条件下,平均酯化率为95.5%。动力学研究表明反应为准一级反应,表观活化能为45.072kJ/mol,378K时反应速率常数为2.35×10--2 min--1。     

银铟在复杂硫化锌精矿加压酸浸中的行为

实验研究了银铟在复杂硫化锌精矿加压酸浸过程中的行为,考察了浸出温度、浸出时间、硫酸浓度、氧压、精矿粒度及液固比对铟浸出率和银入渣率的影响,分析了铟在浸出初期的动力学. 结果表明,在浸出温度150℃、浸出时间90 min、硫酸浓度152 g/L、氧分压1.2 MPa、精矿粒度<45 mm及液固比5 mL/g的条件下,铟浸出率达76%以上,银入渣率达98%以上. In的初期浸出符合核收缩模型,受界面化学反应控制,表观活化能为70.67 kJ/mol.     

石煤灰渣二次焙烧稀酸浸出提钒工艺条件

为获得石煤灰渣二次焙烧稀酸浸出提钒工艺的优化条件,对该工艺钒浸出率的影响因素进行了实验研究.结果表明,二次焙烧温度、二次焙烧时间、熟料粒径、酸浸温度、硫酸浓度5种因素对钒浸出率的影响较大,酸浸液固体积质量比、酸浸时间的影响较小.最佳工艺条件为:二次焙烧温度850℃,二次焙烧时间1h,熟料粒径180μm以下,常温(18℃)酸浸,硫酸浓度0.36mol/L,液固比2~2.5mL/g,浸出时间0.25h.在此条件下,石煤灰渣钒浸出率可达81%以上.     

钒铬还原渣碱浸提钒工艺及其动力学

采用常压下空气氧化-碱浸工艺,对钒冶炼的钒铬还原渣进行提钒. 通过正交实验考察了碱浓度、浸出温度、液固比对钒浸出率的影响,研究了钒的浸出动力学. 结果表明,最佳条件为碱浓度100 g/L、浸出温度100℃、液固比4 mL/g、浸出时间1 h. 该条件下钒浸出率最高达98%. 钒的浸出过程符合核收缩模型,受扩散步骤控制,表观活化能为11.04 kJ/mol.     

杂卤石生产硫酸钾工艺研究北大核心

本文以渠县农乐杂卤石为原料,研究K2SO4的制备工艺。在反应温度70 0C,反应时间2 h的条件下,考查了不同溶浸剂和固液比对杂卤石中K+浸出率的影响。结果表明:以CaO为溶浸剂,反应温度70℃,固液比1∶4时,K+浸出率为78.8%,将浸出液进行蒸发结晶制备K2SO4,产品纯度达到94.3%。杂卤石矿焙烧后以水为溶浸剂、反应温度70℃、固液比1∶6时,K+浸出率为73.0%,在浸出液中加入KOH和K2CO3混合溶液以除去Ca2+、Mg2+等杂质,固液分离后蒸发结晶制得K2SO4产品的纯度可达99.5%。最后得出由杂卤石生产硫酸钾的工艺路线。     

基于硫酸减量化从钕铁硼废料中选择性转型分离稀土

针对现阶段钕铁硼废料中稀土难于经济有效提取的现状,开展了钕铁硼废料硫酸化焙烧选择性分离稀土的研究。结果表明,Fe2(SO4)3亦可使稀土氧化物发生硫酸盐转型,这使硫酸用量显著减少,在硫酸用量为理论量的2.0倍、焙烧温度750℃、焙烧时间1.5 h条件下,近98%的稀土氧化物在H2SO4, Fe2(SO4)3的共同作用下转化为易分离的硫酸稀土,而铁的浸出率小于0.1%,主要以易于冶炼的赤铁矿(Fe2O3)物相存在于渣中,该工艺实现了硫酸的减量化与钕铁硼废料的综合利用。     

酸浸渣综合回收浸铅工艺研究

针对氰化提金工艺酸浸渣中低品位金属铅的综合回收,采用盐浸法对金属铅进行了浸出实验研究,通过正交试验详细考察了浸出液固质量比、浸出温度、氯化钠浓度、浸出pH和浸出时间等因素对浸铅率的影响。结果表明,浸出液固质量比为5、浸出温度为333.15 K、氯化钠质量分数为30%、pH=0、浸出时间为4 h的实验条件下,最佳平均浸铅率为92.05%,相对标准偏差RSD=4.3‰;室温下最佳平均浸铅率为90.20%,RSD=4.1‰。因此,酸浸渣常温盐浸提铅是综合利用矿产资源回收铅及提高金、银回收率的有效途径。     

Recycling of GaN,a Refractory eWaste Material: Understanding the Chemical Thermodynamics

South Korea is a major producer of light‐emitting diode (LED) material, contributing 31% of total LED demand worldwide, and also a major consumer of electronic devices. During manufacturing and after end of life (EOL) of the consumer electronics, significant amount of GaN‐bearing waste is being generated. As the Republic of Korea depends upon the import of all mineral commodities, under the national policy of securing a stable supply, much attention has been paid to the notion of “urban mining.” The stringent international environmental directive for recycling of waste electrical and electronic equipment (WEEE), United Nations Environment Programme (UNEP) E‐Waste Management goal, restriction of the use of hazardous substances in EEE (RoHS), and extended producer responsibility (EPR) have made recycling an important responsibility. Recovery of the gallium from GaN‐bearing waste can be a promising feasible option; simultaneously from the waste, the wealth can be generated. As GaN is a refractory material, which is hard to leach in the recovery process, hence, needs a chemical pretreatment. In this study, thermodynamics of GaN oxidation and oxidative roasting using Na₂CO₃ has been studied. Thermodynamic feasibility for leaching of oxidized GaN either through acidic leaching or through alkali leaching has been explored.     

钒矿石活化焙烧-酸浸新工艺的研究

对河南某钒矿进行了活化焙烧-酸浸实验,系统考察了添加剂种类与用量、焙烧温度、焙烧时间、浸取酸度、液固比、浸取温度及时间对钒浸取率的影响。实验结果表明:焙烧过程中,采用氧化钙为添加剂,控制添加量为10%,850～900℃下焙烧3h,矿样的活化效果较好;酸浸过程中,硫酸酸度为5%,液固比为2.5∶1,70～80℃,浸出3h的条件下,钒的浸出率最高,可达80%以上。     

煤矸石酸浸除铁及废液利用的实验研究

对六盘水矿区高铁的煤矸石采用低温焙烧后,进行酸浸除铁,获得的优化除铁条件是:用18%的硫酸,固液比为1∶8,在350℃焙烧2 h,在90℃酸浸2.5 h,除铁率达到95%以上,并利用酸浸废液制备了氧化铁红。     

太阳能级多晶硅切割废料的酸洗除杂研究

为获得一种制备高纯硅的高纯原料,在分析太阳能级多晶硅切割废料(CLW)物性的基础上,详细研究了CLW的酸浸除杂,超声酸浸除杂,考察了盐酸浓度、酸浸时间、酸浸温度、酸浸液固比和搅拌对除杂效果的影响,并分析了超声酸洗过程动力学,得到的最适宜工艺条件为:w(盐酸)为19％,反应时间3 h,水浴温度为60aC,浸出液固比4:1...     

Removal of strontium from aqueous solutions by adsorption onto activated carbon: kinetic and thermodynamic studies

This work reports the adsorption of strontium from aqueous solutions onto activated carbon. Various factors such as pH, initial concentration of strontium, particle size and temperature were considered. The optimum conditions obtained were: pH value = 4.0, contact time = 8 h, initial concentration of Sr(II) = 100 mg/l, particle size = 270 μm and temperature of 293.15 K. The adsorption of strontium(II) on activated carbon follows pseudo-first order kinetics and the energy of activation E_a calculated using the Arrehenius equation was found to be 3.042 kJ/mol.The adsorption isotherms could be fitted by the Langmuir model with the maximum adsorption capacity Q_o being 5.07×10^–4 mol/g at 293.15 K. A dimensionless separation factor R_L was used to judge the favourable adsorption. The values of the mass transfer coefficient β_L (cm/s) at different temperatures indicated that the velocity of mass transfer of Sr(II) ions onto activated carbon was slow. The intraparticle diffusion mechanism is of great importance in determining the overall rate of removal and the negative entropy of activation ΔS^# value 145.13 J/mol K, reflects that no significant change occurs in the internal structure of activated carbon during adsorption of strontium(II). The Gibbs free energy ΔG°_ads values range from –36.61 kJ/mol to –41.75 kJ/mol at 293.15–333.15 K, which show the physical adsorption properties of activated carbon and indicate the feasibility of the process.     

废铅蓄电池铅膏湿法回收制取氯化铅技术的研究

研究了一种由废铅蓄电池铅膏湿法制取氯化铅的工艺技术。采用HCl-NaCl混合溶液将铅膏中的铅浸出制备氯化铅，考查了冷析滤液的处理方法及循环使用效果。结果表明：采用该工艺技术，铅浸出率达99．3％以上，冷析滤液循环使用4次，铅回收率达到98．2％，制取的氯化铅产品纯度达到了试剂化学纯的要求。     

A novel technique for microcrystalline graphite beneficiation based on alkali-acid leaching process

Purification of microcrystalline graphite concentrate with alkali-acid leaching process was studied in this paper. The influences of alkali leaching temperature, NaOH concentration, alkali leaching time, HCl consumption, liquid-solid ratio, and acid leaching times were investigated respectively. Final refined products with carbon content in the range of 90.88%–98.36% were prepared from flotation concentrate with carbon content of 84.27%. In addition, the volatile content in the end product was reduced from 2.7% to 1.17%. X-ray diffraction (XRD) and scanning electron microscope equipped with energy-dispersive X-ray spectroscopy (SEM-EDS) analysis revealed that the crystal structure and morphology of graphite had no obvious change when impurities composed of Si, Al, and O were almost completely removed. Alkali-acid leaching process could enhance the carbon content of microcrystalline graphite to a higher level than the traditional method of alkali roasting-acid leaching process.     

硫脲法浸出废弃电脑线路板中金的研究

废弃电脑线路板是一种典型的电子废弃物,其中含有丰富的贵金属资源,而金的回收是废弃电脑线路板资源化研究的热点。研究了用硫脲浸出废弃电脑线路板中的金,考察了硫脲质量浓度、反应时间、反应温度、三价铁离子质量分数、溶液pH对金浸出率的影响。结果表明,在硫脲质量浓度为12 g/L、反应时间为60 min、反应温度为30 ℃、三价铁离子质量分数为0.45%、溶液pH为1.5条件下,金的浸出率达到90.93%。硫脲法浸金因具有浸出速率快、浸出时无毒、对环境污染小、试剂易再生、干扰离子少等优点而具有广泛的应用前景。