jimdoc said:
I was thinking of thiourea with the CLS.
Has anyone else tried using CLS from action mining,
or tried leaching with electro-precipitation?
The CLS manual also shows a zinc precipitation unit,
and ion exchange resins that look interesting.
And in his dvd he shows an activated carbon filter
that traps the metals, I was thinking if you would be
able to make something like that from a pool filter?
Thiourea is very toxic. Don't even think of using it.
http://www.scorecard.org/chemical-profiles/html/thiourea.html
HEALTH EFFECTS
Probable routes of human exposure to thiourea are inhalation, ingestion, and dermal contact.
Non-Cancer: Skin sensitivity in the form of eruptions may occur from repeated contact with thiourea. Thiourea may cause toxic effects on the blood system including bone marrow toxicity and reduction in red blood cells, white blood cells, and platelets. Enlargement of the thyroid (goiter) and spleen has also been reported from exposure to thiourea (HSDB, 1995; Sittig, 1991). The United States Environmental Protection Agency (U.S. EPA) has not established a Reference Concentration (RfC) or an oral Reference Dose (RfD) for thiourea (U.S. EPA, 1995a).
Cancer: There is evidence from studies in experimental animals that thiourea causes liver and thyroid tumors. The U.S. EPA has classified thiourea in Group B2: Probable human carcinogen (U.S. EPA, 1995a). The International Agency for Research on Cancer has classified thiourea in Group 2B: Possibly carcinogenic to humans, based upon sufficient evidence in animals and inadequate data in humans (IARC, 1987a).
The State of California has determined under Proposition 65 that thiourea is a carcinogen (CCR, 1996). The inhalation potency factor that has been used as a basis for regulatory action in California is 2.1 x 10-5 (microgram per cubic meter)-1 (OEHHA, 1994). In other words, the potential excess cancer risk for a person exposed over a lifetime to 1 microgram per cubic meter of thiourea is estimated to be no greater than 21 in 1 million. The oral potency factor that has been used as a basis for regulatory action in California is 7.2 x 10-2 (milligram per kilogram per day)-1 (OEHHA, 1994).