Multi-element analysis of iron ore pellets by Laser-induced Breakdown Spectroscopy and Principal Components Regression

Laser-induced Breakdown Spectroscopy (LIBS) in combination with Principal Components Regression (PCR) has been applied to determine the elemental composition of a series of run-of-mine (ROM) iron ore samples. The samples were presented for measurement both as compressed pellets and as loose chipped material. The present paper details the results of the measurements of the compressed pellets. Results from ore chips will be reported separately. LIBS spectral data was recorded in three separate spectral regions to measure major, minor and trace components of the iron ore sample pellets. Background stripping, normalization and spectral cleaning were applied to minimize the relative standard deviations of the LIBS data. PCR analysis was then applied to produce calibration models for iron, aluminum, silicon, manganese, potassium and phosphorous. These calibration models were then validated using independent LIBS measurements. Robust calibration models were determined for iron, aluminum, silicon and potassium, whilst the results for manganese were encouraging. Phosphorous, present at low levels in the ores measured, remained the most difficult element to determine accurately. The combination of LIBS and PCR shows potential for in-situ on-line determination of ore composition.     

The application of a mathematical model of sustainability to the results of a semi-quantitative Environmental Impact Assessment of two iron ore opencast mines in Iran

The paper outlines the application of a mathematical model of sustainability to an Environmental Impact Assessment (EIA) of two opencast iron ore mines in Iran. The model’s application to the EIA, which used the Folchi method, was undertaken for the purpose of indicating the potential level and nature of sustainability (if appropriate) of the two mines.The results indicated that both Chogart and Gol-e-Gohar iron ore mine were deemed to be potentially unsustainable. The results suggests the delicate balance and failure of achieving some form of sustainability in regards to mining in Iran, due to the impacts it has upon the local environment and community affected. The paper concludes as to the potential significance of the model’s application in the attainment of the goal of sustainable mining.     

X-Ray Fluorescence Analysis of Iron in Ore Dressing Processes

The investigation of iron using off - line energy dispersive X-ray fluorescence, in iron ore dressing process, is presented. Techniques have been developed to determine the quality control of grinding, homogenization, separation, classification processes and residue material in dry basis of iron deposit. The laboratory trials on a wide variety of iron ores indicated that the range of ore grades is from 28–40 % Fe and maximum value is to be found 70 % Fe for processed ore. The results obtained increased the knowledge and performance of the dressing process which is of basic importance for its improvement and future automation.     

Spectrophotometric Determination of Osmium at the PPB Level Using Pyrocatechol and Hydroxyamidine

Abstract

A sensitive method for the spectrophotometric determination of osmium at the ppb level is described. The method is based on the formation of a brown-coloured complex by heating the reaction mixture containing Os(VIII), pyrocatechol and a hydroxyamidine at pH 8.5 over a boiling water bath, with subsequent extraction of the coloured species into chloroform. The molar absorptivity of the coloured species with N-hydroxy-N,N′-diphenylbenzamidine is 3.95 × 10⁶ 1 mol^?1 cm^?1 at λ_max = 410 nm. The method is free from interferences for almost all ions tested.     

还原焙烧红土矿的硫酸浸出动力学

研究了选择性还原焙烧红土矿的硫酸浸出动力学.实验考察了浸出温度(30 ℃～70 ℃)和硫酸浓度(0.01～0.5 mol·l-1)对Ni、Fe浸出率的影响.结果表明:红土矿的选择性还原焙烧可增快Ni的浸出而抑止Fe的溶解.Ni的浸出动力学可用Avrami方程描述,其浸出反应的表观活化能为(15.40±0.18) kJ·moL-1.Fe的浸出受内扩散过程控制,浸出的表观活化能为(55.16±1.37) kJ·moL-1.     

微波密闭消解-ICP-MS－标准加入法测定矿石中金和银

建立了微波密闭消解-电感耦合等离子体质谱法(ICP-MS)采用标准加入法测定矿石中痕量元素金和银。考察了微波试样消解、基体效应、质谱干扰,并进行了ICP离子源以及质谱仪检测条件和微波消解参数的最优化。以标准加入法消除复杂多变的矿石基体对分析信号的影响,干扰校正方程消除多原子离子等质谱重叠影响。本法测定矿石中金银结果表明:回收率为197Au 106%～113%、107Ag 95%～105%、 109Ag 93%～103%,相对标准偏差RSD <6%（n=8）,检测限197Au为10 ng/g、107Ag为3 ng/g、109Ag为6 ng/g。方法适用性强,可满足不同类型矿石中超痕量金银的测定,分析步骤少,操作简便,快捷准确     

黑龙江多金属矿区植物胁迫光谱及其与金属元素含量关系研究

以黑龙江多宝山和铜山矿区为例,通过采集矿区典型植物的光谱,以及岩石、土壤、植物中14种金属元素和植物叶片生化参数的测试分析,表明不同植物选择性吸收富集的金属元素不同,分别与岩石、土壤不同层中金属元素含量的相关性不同。由于植物叶片对金属元素富集,植物胁迫光谱的变异体现在光谱的‘红边’和吸收深度不同,而植物光谱的变异特征与其粗蛋白和叶绿素(a、b)含量相关,与叶绿素a的相关性更强。通过叶片内重金属元素含量和550～760nm之间波段吸收深度的多元回归分析,表明叶片中Co,Cu,Ni,Mo,Ag,Sb,W,Pb和As的含量与其光谱吸收深度的复相关系数都在0.75以上,相关性强。通过此研究,为植被覆盖区利用高光谱遥感调查评价金属元素的分布和富集奠定基础。     

红色黏土型金矿中金与其伴生元素的关系

红色黏土型金矿是近年来发现的金矿新类型。利用中子活化分析方法研究了As、Sb等元素与Au的相关关系,为红色黏土型金矿勘探提供了一种新的思路,并通过分析含与其它微量元素的关系,可以看出,该金矿床为一种除金以外的多金属金矿,可以综合利用。