do as you please, and post back so others know.. nevertheless, when people with chemical knowledge and experience in the exact question you are asking tell you why it doesnt work (inf's answer was pretty thorough), dont you think it would be time better spent if you made experiments in other areas where we are still not sure about and increase the knowledge of the community? I mean, whether it says on the label that the CaOH is pure or whatever, it makes no difference as inf said, CaOH is CaOH.
For example, why dont you make two small side-by-side extractions, half with sodium carbonate and half with lye, and keep all other variables the same? Then you can tell us how well each one worked. Or whatever other comparisons and tests..
But again, do as you please, we can only tell you what we think and what we know from our own experiments