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Behaviour of mercury from hazardous solid waste generated by chlor-alkali Cuban industry. Remediation proposal at pilot scale

Abstract:

One of the major concerns from the chlor-alkali industry is the mercury solid waste generated by the process. A pilot-scale thermal treatment technology to treat high mercury containing waste generated by the chlor-alkali Cuban process was designed. Mass and energy balances at steady-state, the upscaling methods as well as the mercury reaction scheme were used for the design of the plant. Two operating alternatives have been analyzed. In the first alternative, the plant operates to achieve the maximum mercury removal. In the second alternative, the waste is treated to a point where it meets the TCLP leaching limit. The proposed pilot plant with 960 t of waste/y of processing capacity is able to recover 639 kg of metallic Hg/y and 479 t/y of treated waste (arid) that can be sold. "Arid" is a Cuban term referring to aggregate materials that are used as a component of construction material. The second alternative is most advantageous from the techno-economic point of view if an integrated economic analysis with the chloralkali Cuban plant is done. An annual gross profit of US$ 166,450, a return on investment of 10.6 %/y and net present value of US$ 12,157 could be realized.