DEVELOPMENT OF METHOD FOR REMOVAL THE NITRIC OXIDES FROM PROCESS OF PRECIOUS METALS RECOVERY FROM ANODE SLIME
Nitric compounds, especially nitric oxides, are extremely toxic with many unfavorable local effects, especially in the surrounding of great pollution sources. This work contains the results of laboratory research for involving of the best absorption parameters (temperature, type and concentration of absorption liquid), as well as a selection of absorption system for completely removal the nitric oxides from process of hydrometallurgical recovery of precious metals from anode slime in Plant for Anode Slime Treatment. The basic aim is decreasing of nitric oxides emission to the law approved concentration, both in working conditions and at gas emission point of the plant.
NOx suppression with hydrogen peroxide in the metals industry
Metal dissolution processes involving nitric acid are major sources of NOx. Technologies using hydrogen peroxide have been developed and proven on an industrial scale to suppress the emission of NOx from these processes. No changes are made to the dissolution process. Case histories are presented to illustrate the effectiveness of hydrogen peroxide with particular reference to the pickling of stainless steels.
Control of NOx in steel pickling
This paper describes the development of a simple, inexpensive, and efficient concept to meet the requirement of controlling NO/sub x/ emissions in full-scale pickling plants. Design data, operating experience and economics are presented. Other environmental aspects such as wastewater treatment are also discussed. The results revealed that NO/sub x/ emissions can be suppressed efficiently by adding hydrogen peroxide to the pickling bath; steel product quality is not affected. The method cuts NO/sub x/ peaks, improves working-space standard, simplifies spent-liquor disposal, and lowers HNO/sub 3/ consumption.