Methods for quantitative analysis of asbestos in vermiculite-containing materials
View Patent ↗A method for quantitative analysis of asbestos in vermiculite-containing materials includes a first embodiment which includes washing the sample with water or treating the sample with a low concentration acid to digest gypsum and carbonates, ashing the sample at a low temperature to remove cellulose, therefrom and analyzing the sample. Digestion may be effected before or after ashing. Subsequently, a second subsample may be ashed at low temperature to remove cellulose and refluxed with a concentrated acid followed by refluxing with a base and rinsing with deionized water to wash away gypsum, vermiculite and other soluble components. This is followed by analysis to determine asbestos concentration. In a further embodiment, the residue of the first embodiment may be employed as the second subsample.
1. A method for quantitative analysis of asbestos in a vermiculite-containing material comprising,
providing a sample of said vermiculite-containing material,
placing said vermiculite-containing material in a filtering apparatus,
treating said sample with a material selected from the group consisting of water and an acid selected from the group consisting of HCl, HBr, HCrO 4 , H 2 SO 4 , HNO 3 , citric acid, acetic acid, and formic acid, in a concentration of about 0.1 N to 1.5 N,
washing the sample with water,
dry said washed sample,
determine weight loss of said sample from residue of said drying,
after determining said weight loss ash the residue of said sample at about 450° C. to 550° C. for about 1 to 3 hours,
cool said sample,
determine ash weight loss,
employing water to transfer the sample residue to a filter,
dry the residue,
calculate percentage weight loss, and
analyze the sample to determine the quantity of asbestos in said vermiculite-containing material, whereby cellulose, gypsum and carbonates have been removed from said sample prior to said analysis
subsequent to said ashing and calculation of the sample percent weight loss performing additional processing of said sample by refluxing said ash sample in an acid selected from the group consisting of HCl, HBr, HCrO 4 , HNO 3 citric acid, acetic acid, and formic acid at a temperature of about 200° C. to 250° C. for about 1 to 1.5 hours,
allow the sample to cool, water wash and filter the same,
reflux the sample with a base at about 200° C. to 400° C. for about 2 to 4 hours,
effecting by said acid refluxing a reduction in volume by washing away gypsum, vermiculite and other soluble components,
after said sample has cooled, dilute said sample with water and filter,
dry the sample,
weigh the sample, and
analyze the sample.
2. The method of claim 1 including,
effecting said analysis in said additional processing employing at least one process selected from the group consisting of polarized light microscopy, transmission electron microscopy, scanning electron microscopy and X-ray diffraction.
3. The method of claim 1 including,
if said analysis of said sample indicates that the vermiculite-containing material contains at least 1% asbestos concluding that the vermiculite-containing material is an asbestos-containing material.
4. The method of claim 1 including,
if said analysis of said sample indicates that the vermiculite-containing material contains at least 1% asbestos concluding that the vermiculite-containing material is an asbestos-containing material.
5. The method of claim 1 including,
employing said acid in a concentration below 1.2 N.
6. The method of claim 1 including,
in providing said sample reducing said vermiculite-containing material from bulk material to provide a portion in the form of released fiber material.
7. The method of claim 1 including,
employing a sample having a weight of about 0.1 to 1.0 grams.
8. The method of claim 1 including,
determining by said analysis whether amphibole asbestos is present by employing the polarized light microscopy.
9. The method of claim 1 employing,
determining by said additional processing whether naturally occurring amphibole asbestos is present.
10. The method of claim 1 including,
effecting by said method destruction of chrysotile present in said sample.
11. The method of claim 10 including,
effecting by said method freeing of amphibole trapped in said vermiculite.
12. A method for quantitative analysis of asbestos in a vermiculite-containing material comprising,
providing a sample of said vermiculite-containing material,
ashing said sample at a temperature of about 450° C. to 550° C. to create an ashed residue,
permitting the ashed residue to cool,
determining the ash weight loss,
calculating percent weight loss by weighing said ashed residue,
refluxing the ashed residue with an acid selected from the group consisting of HCl, HBr, HCrO 4 , H 2 SO 4 , HNO 3 , citric acid, acetic acid and formic acid at a temperature of about 200° C. to about 250° C. for about 1 to 1.5 hours,
allowing the sample to cool,
water washing and filtering the same,
refluxing the sample with a base at about 200° C. to 400° C. for about 2 to 4 hours,
effecting by said acid refluxing a reduction in volume by washing away gypsum, vermiculite and other soluble components,
after said sample is cooled, dilute said sample with water and filter,
dry the sample,
weigh the sample, and
analyze the same.
13. The method of claim 12 including,
effecting said analysis employing at least one process selected from the group consisting of polarized light microscopy, transmission electron microscopy, scanning electron microscopy and X-ray diffraction.
14. The method of claim 12 including,
if said analysis of said sample indicates that the vermiculite-containing material contains at least 1% asbestos concluding that the vermiculite-containing material is an asbestos-containing material.
15. The method of claim 12 including,
employing as said acid in a concentration below 1.2 N.
16. The method of claim 12 including,
in providing said sample reducing said vermiculite-containing material from bulk material to provide a portion in the form of released fiber material.
17. The method of claim 12 including,
employing a sample having a weight of about 0.1 to 1.0 grams.
18. The method of claim 12 including,
determining by said analysis amphibole asbestos is present by employing the polarized light microscopy.
19. The method of claim 12 employing,
determining whether naturally occurring amphibole asbestos is present.
20. The method of claim 12 including,
employing as said base a material selected from the group consisting of NaOH and KOH.
21. The method of claim 14 including,
effecting by said method destruction of chrysotile present in said sample.
22. The method of claim 12 including,
effecting by said method freeing of amphibole trapped in said vermiculite.