Characteristic contaminant removal purification and high value ecological utilization technology of calcination modified manganese residue

Electrolytic manganese residue (EMR) is a general industrial solid waste which also contains some pollutants. So the accumulation of EMR causes severe land resource occupy and potential environmental risks. This study focuses on the new eco-friendly cement manufactured with EMR using the harmless treatment technology of calcination as a mineral admixture. Specifically, the particular pollutants, physical performance and environmental characterization were mainly investigated of cement mineral admixture made of recycled EMR. At the same time, the hydration process and mechanism of all products including EMR were studied to using XRD, FT-IR and SEM. The result showed that the ammonia nitrogen and manganese in the leaching solution EMR were 1134 mg/L and 8356 mg/L, respectively, both far exceed the Chinese standard requirements. The high-temperature (650celcius) harmless technology can minimize the pollutants in EMR, such as the leaching content of COD, ammonia nitrogen and manganese sulfate were all decreases up to 80%. As well as, the flue gas particular pollutants concentration of Mn, SO2 and NOx of EMR were all meet the China standard. And the heavy metals' results of single factor index method and potential ecological environment risk were all meet the relevant standard, and the contents of heavy metals in EMR are all under the level of national standard. In addition, the strength of cement mortar can be promoted when the content of modified EMR calcined at 650 degrees C is less than 3%, and its physical properties were all meet the standard requirement, and more ettringite AFt and C-S-H gel were formed in the hydration product system and filled in the pores, and the hydration products were more evenly distributed and the structure was denser, as well as, the environmental indicators of cement mixed with 3% calcined EMR met the requirements of the standard. This study can provide an effective way to safety and environmental protection dispose the electrolytic manganese residue.

Automated summary

This study focuses on the new eco-friendly cement manufactured with EMR using the harmless treatment technology of calcination as a mineral admixture. The high-temperature harmless technology can minimize the pollutants in EMR, such as the leaching content of COD, ammonia nitrogen and manganese sulfate were all decreases up to 80%. The study provides an effective way to safety and environmental protection dispose the electrolytic manganese residue.