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Text Size<< Back to Sampling and Analysis of Crystalline Silica - X-ray Diffraction (XRD)
This questionnaire has been prepared to determine how accredited analytical laboratories test samples and report results involving the family of crystalline cristobalite minerals and the family of non-crystalline opal minerals, opal-CT and opal-C. Please answer the questions as presented and add any supportive remarks in the space available or on a separate sheet keyed to the question code. All answers will remain confidential with respect to individual laboratories. Only cumulative results will be published in any report. 1. Method of analysis for crystalline silica phases A. How many analyses for crystalline silica do you do in an average year __1_ 0-10, _13__ 11-100, _19_101-1000, __4_ 1001-10000 B. What type of samples do you analyze __11_ Air filter ____ Bulk _26_ Both C. What method of analysis is your primary technique for quantifying crystalline silica _22_ X-ray Diffraction _14_ Infrared __3_Chemical _1__ Optical __2_ Other _Colorimetric__ D. What is the average level of silica in analyzed samples _23_0-10 wt.% _10__10-50 wt.% ____ 50-100wt.% E. Indicate the percentage of analyzed samples that are dominantly ____ quartz ____ cristobalite/tridymite ____opal 30 labs do >95% quartz F. Problems encountered with silica analyses _12_ Insufficient sample _9__ Difficult samples _17_ Interferences among the silica phases _24_ Interferences from other phases in sample _7__ Difficulties with identification of silica phases _13_ Limitations on accuracy in the methods of analysis _0__ Other G. Which of the following methods do you employ for the detection of crystalline silica _23_ X-ray diffraction _14_ Infrared Analysis _7__ Chemical (e.g. Phosphoric acid digestion) ____ Differential Thermal Analysis _1__ Scanning electron microscopy _1__ Transmission electron microscopy _6__ Optical microscopy __2_Other __Colorimetric_________________ H. Which of the following methods do you employ for the quantification of crystalline silica _22_ X-ray diffraction _14_ Infrared Analysis __4_ Chemical (e.g. Phosphoric acid digestion) ____ Differential Thermal Analysis ____ Scanning electron microscopy ____ Transmission electron microscopy __4_ Optical microscopy __2_Other ___Colorimetric________________ I. General questions Can you quantify crystalline silica phases at the 0.10% level _18_ Yes _15_ No Do you employ preconcentration methods _11_ Yes _23_ No What standards do you use for sample and instrument calibration Sample______AIHA PAT (7)________________Internal Ag (2)__________ ____________MinUSil (11)_______________Pre-spiked Stds. (2)_____ ____________NIST (17)_______________CanMet (1)_____________ ____________NIOSH (7)________________In-House (3+)____________ ____________Arkansas (3)_________________________________________ ____________Outside suppliers (6)_____________________________________ Instrument______This question was misinterpreted to mean instrument type________ _______not instrument calibration. Calibration standards are listed above.______ ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ 2. Distinguishing cristobalite and opal A. Do you recognize cristobalite and opal as distinct silica phases _7__ Yes _30_ No (If answer is “No”, go to section 3) B. Which of the following criteria do you use to distinguish the two phases. _6__ Value of d-spacing of peak at 22 2 (d = 4.04 - 4.20A) _5__ Full width at half maximum of peak at 22 2 (FWHM = 0.12 - 3.5) _3__ Presence of double peak at 22 2 (d = 4.08, 4.20A) _4__ Asymmetry of peak at 22 2 _4__ Presence of peak at 36 2 (d = 2.50A) _2__ Recognition of more than two diffraction peaks _1__ Recognition of more than four diffraction peaks ____ Recognition of more than seven diffraction peaks ____ Tests for presence of water in the phase _3__ Changes in diffraction pattern with heating _3__ Confirmation with IR measurements or optical microscopy ____ Confirmation of analysis beyond computer produced values _1__ TEM _2__ Other ___Opal removed by H3PO4__________________ 3. Reporting of silica results A. Do you recognize quartz, tridymite, cristobalite and opal as distinct minerals in reports _19_ Yes (Except for opal where indicated) _17_ No B. How do you report final results. _16_ Percent abundance by individual silica mineral species _2__ Mass Loading _12_ Total abundance of all crystalline silica species as one number ____ Do you supply copies of the analytical data to requestors _1__ Yes _7_ No _24_ Only if specifically requested 4. Please complete the following information and return in the supplied envelope Name and address of analytical laboratory ______All but one respondend identified lab____ _______________________________________________ _______________________________________________ _______________________________________________ Name of person responding to questionnaire _______________________________________________ 5. Use this section for further comments on any answer. (Indicate the section by number and letter.) ___________Does IR. Where XRD required contracts with another AIHA lab______________________ ___________Never have considered opal. Never has been requested_____________________ ___________Only analyzing AIHA PAT samples___________________________________________ ___________Reports respirable dust and respirable silica_____________________________ ___________Employs XRD when quartz is found__________________________________________ ___________Opal determination requires multiple tests________________________________ ___________Several never see opal____Others comment on never seeing tridymite__________________ ___________Some samples have low crystallinity.______________________________________ ___________Only reports quartz based on IR___________________________________________ ___________Only do in-house analyses_________________________________________________ Please return the questionnaire to Deane K. Smith 1652 Princeton Drive State College, PA 16803 FAX number is 1-814-238-4069 or 1-814-863-7845 Thank you for your time responding to this important survey |
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