Composition, Respirable Fraction and Dissolution Rate of 24 Stone Wool MMVF with their Binder

Table 4 SUMMARY of modern MMVF (#1 to #28) compared to IARC reference ranges: results on composition and dissolution. The compositional range of Rock (stone) wool (cancerogen classification, low biosolubility) is represented by the historical reference MMVF21. The compositional range of high-alumina, low-silica wool (synonymously HT stone wool or high biosolubility stone wool or CAS 287922-11-6) is represented by the historical reference MMVF34

	High-alumina, low-silica wool (exonerated from classif.)	MMVF34 (represents high biosolubility)	Rock (stone) wool, (cancerogen classification)	MMVF21 (represents low biosolubility)	This test set (excluding MMVF #17)
COMPOSITION	[10]	[19]	[10]	[19]	Average	Min	Max
SiO₂	33 – 43	39	43 – 50	46	42	40	44
Al₂O₃	18 – 24	23	6 – 15	13	19	15	24
CaO	23 – 33	15	10 – 25	17	28	16	33
MgO	23 – 33	10	6 – 16	9	28	16	33
Fe-oxides	3 – 9	7	3 – 8	6	7	1	10
Al/(Al+Si)		0.41		0.25	0.34	0.29	0.38
DISSOLUTION					Average	Min	Max
k_Si pH 4.5 in ng/cm²/h	> 400 ^‡	831 (620)*		47 (72)*	41	17	171
k_Si pH 7.4 in ng/cm²/h		58 (59)*		23 (20)*	20	6	35

*Note: Comparison of IARC Table 65 to Guldberg et al (1998) Table 4 clarifies that IARC chose to document for MMVF21 and MMVF34 the k_leach value, which reports Ca and Mg ions. The actual fibre disintegration is assessed by earlier and by the present studies via k_Si. Hence we compare materials based on k_Si and provide the values from the IARC table in brackets for transparency [10, 19]
‡The value of k > 400 ng/cm²/h for the exonerated CAS range is from [16]

ISSN: 1743-8977