摘要 |
A chemical method of removing thiourea from spent hydrochloric acid cleaning solutions comprising the steps of: adjusting the pH to not less than 12 by addition of base to remove metal hydroxides; oxidizing thiourea to urea by the addition of at least a stoichimetric amount of oxidant per mole of thiourea; and further oxidizing urea to nonregulated/nonhazardous compounds by the addition of at least 3 moles of a hypochlorite per mole of urea. UV analysis confirms a greater than 98% removal of thiourea from solutions containing 0.4 to 2.7 wt. % thiourea after as little as 3 hours with an exotherm, DELTA t, of less than 105 DEG F.
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