Table 2.

Chemical composition, expressed as an atomic percentage, of the starting chrysotile together with the materials obtained after acid treatment at 8, 12, 16 and 20 min

	Atomic %
	Mg	Al	Si	Ca		Mg + Al	(Mg + Al)/Si
Natural	19.74	0.91	14.1	0.78		20.65	1.46
8 min	8.74	2.16	21.47	0.00		10.90	0.51
12 min	7.31	1.94	24.08	0.00		9.25	0.38
16 min	6.03	1.12	25.33	0.00		7.15	0.28
20 min	2.76	0.34	25.98	0.00		3.10	0.12