Topics CoveredIntroductionDiscussionCalibrationSensitivityPrecisionConclusionAcknowledgmentReferencesAbout PANalytical IntroductionAirborne silica particles pose a carcinogenic threat at concentrations as low as 50 μg/m3. mineral material grinding mill in mining industry Standard methods such as NIOSH7500, OSHA ID-142, and MDHS 51/2 use XRD to quantify the mass of SiO2 phases per volume of air sampled directly on the polymer collection filter or on samples ashed and deposited on silver membranes. The maximum allowed concentration of respirable silica in the atmosphere at a workplace is under constant review, with lower maxima proposed worldwide, so low limits of detection are of utmost importance. PANalytical’s diffraction systems, equipped with the X’Celerator detector, offer advances in both speed of measurement and sensitivity compared to conventional point detectors.PANalytical’s X’Celerator detectorSiO2 loaded silver membrane mounted on a standard sample holderTable 1. Typical instrument setupInstrumentX’Pert Powder or CubiX3Incident beam optics StageProgrammable divergence slit, 10 mm irradiated length StageSpinner stage, 2 revs/sDiffracted opticsProgrammable anti-scatter slit, 10 mm observed lengthDetectorX’Celerator, scanning mode 2.2 –2.5 deg. LengthScan parameters20 – 33 degrees 2theta,0.03 deg step,100 s per stepTotal sample analysis time4 minutes or higher, depending on number of peaks measured, number of phases of interest, and precision level requiredDiscussionIndustry software greatly simplifies the practice of quantitative X-ray diffraction because all programming and measurement commands, calibration mathematics, mine mill machine for grinding gypsum, limestone, phosphate, clay, coal, cinder, chalk, ore minerals and customizable reporting are conveniently available in one software package.Calibration standards with loads ranging from 3 to 210 μg SiO2 were utilized to construct the calibration curve below. The calibration curve demonstrates the linear relationship between intensity (peak area) and weight of quartz on the filter, up to about 200 μg SiO2. These specimens were prepared at the INSHT in Spain compliant with their standard methods - MTA/MA-036/A00 and MTA/ MA-056/A05.The deconvolution of interfering peaks from other minerals with reflections near quartz (101) at 26.6 degrees can be perfectly done by using the Industry software from PANalytical.CalibrationAnalysis programQz2528ModelStraight linePhaseQuartzRMS2.07Slope6.611K0.61Offset-5.367SampleUseInt (cps)Conc (μg)Calc. conc (μg)Abs. diff (μg)Rel. diff (%)120Use18.68120118.1-1.879-1.612aUse 2.9741214.292.29319150Use23.74150151.51.5441180Use 27.96180179.5-0.5021-0.28210Show36.76210237.727.651330Use5.7433032.62.5998.73aUse1.1932.501-0.4993-1760Use9.9346060.310.30650.516aUse1.21662.672-3.328-5590Use14.349089.47-0.5334-0.59SensitivityThe X’Celerator detector brings increased sensitivity and accuracy to the application of respirable silica analysis by two mechanisms.First, the X’Celerator detector is a solid-state linear array of more than 100 detector elements measuring more than 2 degrees simultaneously. Crystallites slightly inclined from being parallel to the surface can also participate in the diffraction signal with cone crusher manufacturer price the X’Celerator detector, improving the particle statistics as compared to a point detector that only receives diffracted X-rays from parallel crystal planes. This leads to greater sensitivity for low levels of respirable silica phases. Secondly, the design of the X’Celerator also leads to an increase in the speed of a measurement by up to 100 times over a conventional point detector. This speed of measurement can allow for a reduction in the counting statistical error, thus in the same amount of time as a conventional XRD measurement, the counting statistical error can be improved by a factor of 10.