Effect of Different Kinetic Factors on the Thermochemistry of Sulfophosphoric Attack Reaction of Natural Phosphate Tunisian by DRC

Mixture of phosphoric and sulfuric acid solutions has been used to investigate the dissolution of natural phosphates (PN) by DRC. The effect of concentration, particle size and stirring speed reaction is examined. Thermochimique properties of each kinetic parameters reaction are determined. It was found that these parameters have a considerable effect on the thermochemical aspect of the attack reaction. It is known that the process of PN sulphophosphoric acid attack leads to the formation of dihydrate (CaSO4.2H2O: DH). The present work shows the precipitation of other residues their formula depends on factors studied. The increase in concentration leads to the formation of hemihydrate (CaSO4v1/2H2O:HH) beside DH for the low values of% H2SO4 due to the solubility of dihydrate on the etching solution and the precipitation of (Ca (H2PO4)2.2H2O) next of DH for low agitation values because of the lack of turbulence between the liquid phase and the solid phase which favors the precipitation of this latter compound.

铁尾矿制备介孔硅酸锌复合材料及其对亚甲基蓝的高效吸附

铁尾矿转化为高附加值产品的功能化利用越来越受关注和期待。本文以铁尾矿为原料,引入锌离子水热合成了介孔硅酸锌复合材料,包括由层状纳米片组装而成的花瓣状硅酸锌类物质(zincsilite)和异晶锌(hemimorphite)复合材料,以及由短棒组装而成的椭球状硅锌矿(willemite)复合材料。其中,花瓣状异晶锌复合材料具有典型的片状粒子聚集形成的狭缝孔结构,孔隙宽度约为3.385 nm,比表面积为96.15 m^(2)/g。该复合材料对染料亚甲基蓝(MB)有高效吸附效应,10 min内去除率接近100%,在染料废水处理领域具有潜在的应用前景。

La^(3+)/NH_(4)^(+)在双电层内交换过程中铵的吸附规律

离子交换反应过程中铵的吸附规律是浸矿剂用量计算的基础。以化学纯高岭土为吸附剂,以镧离子为吸附质,制备高岭土饱和镧矿样,采用不同浓度铵离子浸取矿样中的镧离子。结果表明:当铵离子浓度为1~5 mg/L时,铵只出现物理吸附;当铵离子浓度大于300 mg/L时,铵开始出现化学吸附;离子交换吸附开始时,铵离子吸附量为0.012 mg/g,双电层内ζ电势趋于0,滑动面与扩散层最外层几乎重合。通过铵的解吸实验,得到镧离子交换完全后,物理吸附态、离子交换态和固定态的所占比例分别为30%、65%和5%;铵的总吸附量与镧离子浸出量之间的摩尔比接近5∶1。此结果为高岭土作为主要黏土矿物的离子型稀土矿浸矿剂的用量计算提供理论依据。

普通/ORS模式-ICP-MS法测定动物血液和组织中硒的比较

采用ICP-MS法测定动物血液和组织中硒,方法简便、快速、准确、检出限低。实验比较了样品消解方法、同位素的选择以及普通模式和ORS模式的差异,为同类样品的测定提供了参考。普通模式通过采用干扰方程,有效消除了^82Kr＋对^82Se产生的干扰,选用^82Se测定,测定结果准确可靠;ORS模式通过H2-碰撞反应池有效地消除了分子离子干扰,选用^78Se测定,大大降低了检出限。普通模式的检出限为0.024ng·g^-1,ORS模式的检出限为0.0046ng·g^-1。两种方法的相对标准偏差均在1.8%～5.5%范围内,回收率为90.8%～107.2%。

ORS-ICP-MS测定工业废水中La系稀土元素

用 ORS- ICP- MS法测定工业废水中的 L a系稀土元素 ,优化了 ICP- MS测定条件 ,利用动态反应池技术 ,可降低基体干扰 ,提高灵敏度。分析方法的检出限为 0 .8— 8.2 5 ng/ L,加标回收率为 92 %— 99%。

应用ICP-MS的ORS技术进行人体铁稳定同位素代谢示踪研究的初探

目的应用四极杆型电感耦合等离子体质谱仪(ICP-MS)配合最新的八极杆碰撞/反应池(ORS)消干扰技术进行Fe的同位素比测定研究。方法于现场进行人体代谢试验,受试者口服57Fe稳定性同位素示踪剂,以卡红为标志,粪便监测法收集试验期内的所有粪样,测定粪样中57Fe/56Fe的比值。结果运用ICP-MS的ORS技术可消除由Ar等离子体本身以及样品中存在的Ca等产生的多原子离子对Fe带来的干扰;稀释实际样品到一定范围,基体干扰可忽略不计;标准样品和实际样品短期及长期精密度均小于0.3%;测定两组受试者粪样中的57Fe/56Fe的比值,发现代谢后排泄出的57Fe遵循一定的变化趋势,从而可以测定人体对Fe的代谢吸收比率。结论该技术可准确测定粪样中57Fe/56Fe的比值,可以用来计算评价膳食中铁吸收率的情况,追踪铁在人体中的代谢过程。

ORS-ICP-MS测定食用植物油中的多种微量元素

研究电感耦合等离子体质谱（ICP-MS）法测定植物油中Na、Mg、Si、P、K、Ca、Ti、V、Cr、Mn、Fe、Co、Ni、Cu、Zn、As、Mo、Cd、Sn、Sb、Hg、Pb等22种元素的分析方法。样品经乙醇稀释后直接进入ICP—MS进行分析，在等离子气中引入少量氧气，使样品溶液中的高碳有机物燃烧可防止碳在采样锥锥口沉积导致分析元素的灵敏度降低，应用ORS技术消除了多原子离子对待测元素产生的质谱干扰，采用Sc、In、Bi为内标元素校正了质谱分析中的基体效应。22种待测元素的检出限在0．060-72．61ng／L之间，加标回收率在93．37％。106．20％之间，相对标准偏差（RSD）为1．36％-3．50％。

量子化学在氧化锌矿浮选中的应用研究进展

锌矿资源的高效利用对于保障我国资源安全和高质量发展具有重要意义。随着优质硫化锌矿资源的开发殆尽,低品位的复杂氧化锌矿资源高效利用越来越受到重视。浮选是复杂氧化锌矿加工利用的重要方法。然而传统的浮选方式存在分离效率低且环境污染严重等问题,亟需从更精细化角度针对性开发新的理论和方法。量子化学是量子力学在电子、原子和分子层面研究化学问题的有效工具,能够从微观上深层次地解释浮选作用的本质,从而为高效浮选新技术的开发和高精度浮选新药剂的筛选设计提供有效的理论和方法支撑。本文主要介绍了近年来量子化学在氧化锌矿浮选中应用研究的发展情况,并总结了该领域的优势以及存在的挑战和未来发展的方向。

膏盐层在矽卡岩型铁矿成矿过程中的作用:以邯邢地区矽卡岩型铁矿床为例

矽卡岩型铁矿床是中国富铁矿床的重要类型,其储量占全部富铁矿的60%左右。膏盐层在矽卡岩型铁矿成矿过程中的作用一直是广大学者所关注的重点。研究表明,邯邢地区矽卡岩型铁矿层中硫酸盐、硫化物的δ^(34)S值分别为24‰~29‰、11‰~20‰,具有海相沉积岩的S同位素组成特征,沉积膏盐层物质参与矽卡岩型铁矿的成矿过程。以邯邢地区矽卡岩型铁矿床为例,系统地分析了矿床中硫化物、硬石膏等含硫矿物的δ^(34)S的主要组成,阐述了膏盐层在矽卡岩型铁矿成矿过程中的作用。(1)膏盐层中的Na^(+)、Cl^(-)等物质作为矿化剂加入气水热液,富碱的气水热液令接触区附近的闪长岩体出现钠长石化现象,析出Fe,并以铁氯酸钠络合物和铁卤化物的形式随热液运移。(2)膏盐层中的硫酸盐在高温条件下具有高氧化活性,与还原性的富铁热液发生氧化还原反应,提高热液氧逸度,热液中的Fe^(2+)被氧化成Fe^(3+),从而产生Fe_(3)O_(4),磁铁矿在围岩层间富集、沉淀,形成富铁矿床。(3)膏盐层物质溶解后在碳酸盐岩层间形成各种溶(熔)蚀空隙,为岩浆侵入和矿体就位提供有利的成矿空间,是矽卡岩磁铁矿矿床形成的重要地质条件之一。膏盐层在矽卡岩型铁矿成矿过程中具有提供矿化剂、氧化剂和储矿空间的作用。

矿焦耦合反应中焦炭显微气孔结构的演变

为了研究焦炭在高炉中的溶损行为,选取冶金焦炭与烧结矿、球团矿,进行不同时间的矿焦耦合反应试验,采用显微图像法分析反应后的焦炭气孔结构,探究其演变规律。结果表明:①随着矿焦耦合反应的进行,焦炭小孔溶并形成中大孔,焦炭的溶蚀深度增加,相较于球团矿,烧结矿耦合反应的扩孔作用稍弱;②焦炭与球团矿耦合反应中气孔结构的溶蚀更剧烈,气孔溶并作用更强,焦炭气孔结构演变速度较快;③焦炭与烧结矿的耦合反应中,深度反应层较厚,缩核程度较小,而焦炭在球团矿环境下,气孔壁溶蚀剧烈,深度反应层较薄,缩核程度较大。

Extracting reaction mechanism analysis of Zn and Si from zinc oxide ore by NaOH roasting method

The orthogonal test was used to optimize the reaction conditions of roasting zinc oxide ore with NaOH aiming to comprehensively utilize zinc oxide ore.The optimized reaction conditions were molar ratio of NaOH to zinc oxide ore 6:1,roasting temperature 450°C,holding time 150 min.The molar ratio of NaOH to zinc oxide ore was the most predominant factor affecting the extraction ratios of zinc oxide and silica.The mineral phase transformations were investigated by testing the phases of specimens obtained at different temperatures.The process was that silica reacted with molten NaOH to form Na_2SiO_3 at first,then transformed into Na_4SiO_4 with temperature rising.ZnCO_3 and its decomposing product ZnO reacted with NaOH to form Na_2ZnO_2.Na_2ZnSiO_4was also obtained.The reaction rate was investigated using unreacted shrinking core model.Two models used were chemical reaction at the particle surface and diffusion through the product layer.The results indicated that the reaction rate was combine-controlled by two models.The activation energy and frequency factor were obtained as 24.12 k J/mol and 0.0682,respectively.

Acting mechanism of F,K,and Na in the solid phase sintering reaction of the Baiyunebo iron ore

The effect of F,K,and Na on the solid phase reaction of the Baiyunebo iron ore was investigated by differential thermal analysis （DTA） and X-ray diffraction（XRD）.It has been identified that alkaline elements K and Na in the Baiyunebo ore instigate the formation of low melting point compounds Na2SiO3 and Na2O·Fe2O3 and the generation of molten state in the solid phase sintering.Element F in the Baiyunebo ore facilitates the formation of cuspidine compound 3CaO·2SiO2·CaF2 in the solid phase reaction.The cuspidine compound is kept in solid as one of the final products through the entire sintering process due to its high melting point.In the sintering process,CaF2and SiO2 react with CaO first and form 3CaO·2SiO2·CaF2 and 3CaO·2SiO2,so the formation of ferrites,Na2O·Fe2O3,and 2CaO·Fe2O3 is inhibited.

Reaction condition optimization and kinetic investigation of roasting zinc oxide ore using (NH_4)_2SO_4

An orthogonal test was used to optimize the reaction conditions of roasting zinc oxide ore using（NH_4）_2SO_4. The optimized reaction conditions are defined as an（NH_4）_2SO_4/zinc molar ratio of 1.4：1, a roasting temperature of 440°C, and a thermostatic time of 60 min. The molar ratio of（NH_4）_2SO_4/zinc is the most predominant factor and the roasting temperature is the second significant factor that governs the zinc extraction. Thermogravimetric-differential thermal analysis was used for（NH_4）_2SO_4 and zinc mixed in a molar ratio of 1.4：1 at the heating rates of 5, 10, 15, and 20 K·min-1. Two strong endothermic peaks indicate that the complex chemical reactions occur at approximately 290°C and 400°C. XRD analysis was employed to examine the transformations of mineral phases during roasting process. Kinetic parameters, including reaction apparent activation energy, reaction order, and frequency factor, were calculated by the Doyle-Ozawa and Kissinger methods. Corresponding to the two endothermic peaks, the kinetic equations were obtained.

Simulating Some Complex Phenomena in Hydrothermal Ore-Forming Processes by Reaction-Diffusion CNN

Complexity phenomena like dynamic and static patterns, order from disorder, chaos and catastrophe were simulated by the application of 2-D reaction-diffusion CNN of two state variables and two diffusion coefficients transformed from Zhabotinksii model. They revealed somehow the mechanism of hydrothermal ore-forming processes, and answered several questions about the onset of ore forming.

Extraction and Reaction Mechanism of Potassium from Associated Phosphorus and Potassium Ore

Potassium and phosphate were extracted at low temperature by acid hydrolysis process to decompose a new type of associated phosphorus and potassium ore. The main factors affecting the dissolution rate were investigated, such as grinding fineness, the amount of sulfuric acid and fluoride salt, reaction time and temperature, etc. Meanwhile, the effects of various factors on the formation of soluble potassium and phosphate were also discussed. The reaction products and residues were determined by X-ray diffraction（XRD）, scanning electron microscopic（SEM） analysis and other means. The results showed that the dissolution rates of potassium and phosphorus were 70wt% and 93.7wt%, respectively, under the conditions of a grain size of 95.64wt% lessthan 0.074 mm, 9.78 g·g^（-1） sulfuric acid, 0.5 g·g^（-1） ammonium fluoride, 160 ℃ and a reaction time of 2h. The thermodynamic and chemical reaction mechanism was revealed that the primary reaction could be completed spontaneously in a temperature range of 298-433 K. The increase of reaction temperature had an important influence on ion exchange reaction, which was more conducive to the spontaneous process. The research will open up a new way for efficient use of potassium ore resources.

Optimization of reaction conditions for the electroleaching of manganese from low-grade pyrolusite

In the present study, a response surface methodology was used to optimize the electroleaching of Mn from low-grade pyrolusite. Ferrous sulfate heptahydrate was used in this reaction as a reducing agent in sulfuric acid solutions. The effect of six process variables, including the mass ratio of ferrous sulfate heptahydrate to pyrolusite, mass ratio of sulfuric acid to pyrolusite, liquid-to-solid ratio, current density, leaching temperature, and leaching time, as well as their binary interactions, were modeled. The results revealed that the order of these factors with respect to their effects on the leaching efficiency were mass ratio of ferrous sulfate heptahydrate to pyrolusite 〉 leaching time 〉 mass ratio of sulfuric acid to pyrolusite 〉 liquid-to-solid ratio 〉 leaching temperature 〉 current density. The optimum conditions were as follows： 1.10：1 mass ratio of ferrous sulfate heptahydrate to pyrolusite, 0.9：1 mass ratio of sulfuric acid to pyrolusite, liquid-to-solid ratio of 0.7：1, current density of 947 A/m^2, leaching time of 180 min, and leaching temperature of 73°C. Under these conditions, the predicted leaching efficiency for Mn was 94.1%; the obtained experimental result was 95.7%, which confirmed the validity of the model.

Attack of Tunisian Phosphate Ore by a Mixture of Sulfuric and Phosphoric Acid: Thermochemical Study by Means of Differential Reaction Calorimetry

A calorimetric, Differential Reaction Calorimetry (DRC), study of the thermochemical of the attack of a phosphate ore from Gafsa region (Tunisia) by a mixture of sulfuric and phosphoric acid is undertaken at different solid-liquid ratio and different temperature. The plot of the quantity of heat measured by integrating the raw signal as a function of the dissolved mass in the same volume solution at 25℃ presents three straight segments attributed at the formation of the hemihydrate (CaSO4·1/2H2O:HH), the dihydrate (CaSO4·2H2O:DH) or a mixture of these two products checked by X-ray diffraction, infrared spectroscopy and thermal analysis (Differential Scanning Calorimeter: DSC). The attack by the acid mixture was performed at higher temperature and showed in addition the formation of another form of calcium sulfate:anhydrous (CaSO4:AH). Moreover, the variation of mass enthalpy versus temperature presents a break at the T = 45℃. According to our results, it seems that the effect of the temperature on the sulfo-phosphoric attack reaction on the natural phosphate (NP) generates a change of mechanism at around 45℃.

Ore Zoning as Self-Organization of Geochemical Dynamic Systems

Zoning in ore bodies, ore deposits and ore regions are recognized as temporal-spatial structures generated by the dynamics of ore- forming processes. Viewed from the theory of dissipative structures, ore zoning is a kind of self-organization phenomenon occurring in far from-equilibrium geochemical dynamic systems. Therefore,kinetic and dynamic approaches must be taken to reveal the mechanisms of ore zoning. Two dominant coupling processes leading to ore zoning——reaction-transport feedbacks and double-diffusive convection——are discussed.

粉煤灰地质聚合法团聚细粒级铜矿石及其耐酸机理研究

为了解决低品位铜矿石经高压辊磨机破碎后细粒级含量增加对后续直接堆浸产生的偏析问题,提出了粉煤灰地质聚合细粒级铜矿石的方法。该方法利用自制转鼓对高压辊磨机破碎后的细粒级(-1.7mm)铜矿石在粉煤灰地质聚合反应的基础上进行制团,进而考察粉煤灰添加量、水添加量、碱激发剂用量及其中硅酸钠含量对团聚体粒度和耐酸性质的影响。采用XRD、FTIR分析测试技术对矿石团聚和耐酸机理进行了分析。结果表明:通过加入粉煤灰可以提高团聚体的耐酸性,且增加粉煤灰添加量可使团聚体的耐酸性得到提升,在粉煤灰添加量为6%时耐酸性最好;增加碱激发剂用量以及水添加量都有利于团聚体的成团粒度,并提高其耐酸性;碱激发剂中硅酸钠含量越高团聚体的耐酸性越好。

电感耦合等离子体质谱(ICP-MS)法测定锰矿冶炼烟尘中多种重金属元素

为了准确测定锰矿冶炼烟尘中重金属元素的含量,为锰矿冶炼过程中监测和评价环境影响提供有力的数据支撑,采用HCl+HNO_(3)+HClO_(4)+HF消解体系对试样进行前处理,通过选用合适的内标溶液消除测定中的非质谱干扰,采用碰撞池模式和编辑校正方程消除质谱干扰,从而建立了电感耦合等离子体质谱法测定锰矿冶炼烟尘中的Cr、Ni、Cd、Tl、Pb等多种重金属元素的方法。实验结果表明,各元素标准曲线的线性相关系数均大于0.9999,方法检出限为0.007~0.094 mg/kg,样品测定的相对标准偏差(RSD,n=11)在0.43%~4.9%,样品加标回收率为93.8%~107%。方法具有操作简便、线性范围宽、检出限低、精密度高等优点,满足锰矿冶炼烟尘中Cr、Ni、Cd、Tl、Pb等多种重金属元素同时测定的要求。