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.

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％。

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

Baiyunebo 铁矿石的稳固的阶段反应上的 F， K，和 Na 的效果被微分热分析 DTA 调查， X 光检查 diffractionXRD.It 被识别了在 Baiyunebo 矿石的那碱的元素 K 和 Na 怂恿低融化的点混合物 Na2SiO3 和 Na2O 的形成吗？？

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。

甲烷气氛中铁精矿粉闪速还原行为研究

高炉炼铁工艺存在流程长、能耗高以及强烈依赖冶金焦等问题,发展绿色低碳的非高炉炼铁工艺对钢铁生产具有重大意义。本文采用超级铁精矿粉进行了甲烷闪速还原试验,考察还原温度及甲烷体积分数对金属化率的影响,研究铁精矿粉在试验条件下的闪速还原行为,并对还原产物微观形貌进行观察,分析闪速还原机理。结果表明:还原温度为1550 K、甲烷体积分数7.5%、还原时间为5.49 s时,矿粉金属化率可达90.0%;还原温度的升高及甲烷体积分数的增加提高了矿粉的金属化率;甲烷在还原过程中发生裂解,生成的固体碳在还原产物表面沉积,促进铁氧化物的还原和金属铁的渗碳;渗碳过程降低了金属铁的熔点,还原产物由不规则形状向球型转变;矿粉内部为致密的铁层包裹着未反应的铁氧化物的结构,在FeO/Fe界面处FeO的还原主要是由铁中的固溶碳[C]完成。

硫化矿内现场混装乳化炸药自燃自爆影响因素分析

针对硫化矿内存在现场混装乳化炸药自燃自爆的问题,通过化学反应机理分析、组分接触性试验以及装药实践,研究了影响现场混装乳化炸药在含硫矿内装药自燃自爆的因素及原因,主要针对炮孔环境特性、硝铵组分与矿岩接触、敏化组分与矿岩接触等进行深入研究。结果表明:酸性潮湿环境对孔内装药自燃自爆影响较大,游离的硝酸铵组分以及敏化组分在该环境下极易发生放热反应造成热积累。在试验研究的基础上提出了通过优化乳化基质配方、精确调节快速敏化组分的浓度及添加量、改善乳化基质W/O结构等解决问题措施,研究结果可为硫化矿爆破工程提供理论依据。

电感耦合等离子体质谱法测定甜味剂中重金属元素

采用微波消解-八极杆碰撞/反应池(ORS)-电感耦合等离子体质谱仪(ICP-MS)测定甜味剂中Cr,Co,Ni,Cu,As,Cd,Sn,Sb,Hg,Pb等十种重金属元素的含量。样品用硝酸+双氧水消解后,试液直接用ICP-MS法进行测定。应用ORS技术,有效地消除了多原子离子对待测元素的干扰,选用45Sc,89 Y,115In和209 Bi等元素为内标混合液校正基体效应和信号漂移,确定了实验的最佳测定条件。结果表明,该方法对十种待测元素的检出限在0.003～0.038μg.L-1之间,加标回收率在93.0%～106.6%之间,相对标准偏差(RSD)≤3.4%。方法简便、快速、准确,可以用于食品甜味剂质量控制和安全评价。

八极杆碰撞/反应池-ICP-MS测定纯铜中的磷

利用ORS—ICP-MS测定纯铜中的磷。对ICP-MS测定条件进行了最佳化的选择，利用动态反应池技术（ORS）和在线内标加入技术，可降低基体干扰，提高灵敏度。分析方法的检出限为0．33ng／mL，加标回收率为94％～97％。

微波消解-电感耦合等离子体质谱法同时测定水产品中28种微量元素

建立了微波消解-电感耦合等离子体质谱仪（ICP-MS）测定水产品中微量元素的分析方法。采用HNO3-HClH2O体系消解样品,通过在溶液中加入Au标准溶液消除系统的Hg记忆,普通/ORS混合模式-电感耦合等离子体质谱仪（ICP-MS）测定水产品中Li、Be、Al、Ti、V、Cr、Mn、Fe、Co、Ni、Cu、Zn、Ga、As、Se、Sr、Mo、Ag、Cd、Sn、Sb、Te、Ba、Tm、Hg、Tl、Pb、U等28种微量元素。经标准物质和加标样品检测验证,测定结果与推荐值（或加标值）基本相符,回收率85.3%-110%,相对标准偏差RSD〈10%。28种元素的检测限（LOD）为0.001-0.022mg·kg-1。本方法适用于实验室开展水产品中28种微量元素的同步检测。