Microwave-Assisted Oxidative Recovery of Cyanide From the Thiocyanate-Containing Solutions

EPA Contract Number: 68D99034
Title: Microwave-Assisted Oxidative Recovery of Cyanide From the Thiocyanate-Containing Solutions
Investigators: Milosavljevic, Emil
Small Business: BioQuest
EPA Contact: Manager, SBIR Program
Phase: I
Project Period: September 1, 1999 through March 1, 2000
Project Amount: $69,480
RFA: Small Business Innovation Research (SBIR) - Phase I (1999) RFA Text |  Recipients Lists
Research Category: Water and Watersheds , SBIR - Water and Wastewater , Small Business Innovation Research (SBIR)


Precious metal operations use a large excess of cyanide to extract gold and silver from the ore. Cyanide consumption is often the most important component of the total operating cost. Currently, there are no commercially available processes for recovering cyanide from thiocyanate and thermodynamically stable cyano complexes. Hence, in many operations, expensive cyanide detoxification processes are necessary. The innovative approach of using microwave-assisted oxidate recovery of cyanide from thiocyanate solutions may fill the void. An additional benefit of the proposed microwave-assisted cyanide recovery and recycling procedure is that it will be able to recover cyanide from thermodynamically stable cyanide complexes such as [Fe(CN)6]4-/[Fe(CN)6]3-, Hg(CN)2, and [Ni(CN)4]2-. This Phase I project will concentrate on identifying the most promising oxidation system that will achieve the highest cyanide yield at the lowest cost. If the proposed microwave-assisted cyanide recovery and recycling process is successfully developed, it will reduce cyanide consumption and thereby reduce cyanide production. This in turn will substantially lower the environmental impact of various cyanide species.

BioQuest anticipates that the data gathered through the proposed research project will produce an optimized microwave-assisted cyanide recovery and recycling process. Although this process is primarily intended for the precious metals industry, it can find application wherever the cyanide-based commercial processes produce the thiocyanate ion and/or thermodynamically stable metal cyano complexes. The potential candidates are such varied industries as electroplating, metal finishing, mining and steel, petroleum, semiconductor, and chemical manufacturing.

Supplemental Keywords:

small business, SBIR, wastewater treatment, engineering, chemistry, EPA., Scientific Discipline, Toxics, Waste, Sustainable Industry/Business, Chemical Engineering, cleaner production/pollution prevention, Remediation, Chemistry, Technology for Sustainable Environment, New/Innovative technologies, Engineering, Hazardous, 33/50, steel production, oxidation, detoxification, recovery, semiconductor industry, microwave-assisted oxidative recovery, electroplating, cyanide compounds, recycling, metal finishing , chemical manufacturing, mining, treatment, innovative technology, semiconductor manufacturing, innovative technologies

Progress and Final Reports:

  • Final Report