利用低品位菱锰矿矿石热处理制备纳米材料

A Nanomineral Material from Thermally Treated Low Grade Natural Rhodochrosite

通过热处理低品位菱锰矿矿石制备高活性纳米材料,并探究其催化去除NOx、吸附重金属性能.利用X射线荧光光谱仪、透射电子显微镜等研究菱锰矿矿石组成;利用X射线粉末衍射仪、扫描电子显微镜、比表面积分析仪、烟气分析仪、原子吸收分光光度计等研究菱锰矿矿石空气中热处理后结构变化及其NH3-SCR脱硝、重金属吸附效果.菱锰矿矿石主要组分为菱锰矿,含有少量黄铁矿、石英、白云石及硫酸盐.在空气中550℃煅烧1h后,菱锰矿分解完全,产物以黑锰矿为主晶相,同时含有其他低结晶态锰氧化物;样品表面出现大量3~7nm气孔,比表面积达到最大(31.5 m2/g).脱硝实验显示R550在170℃时脱硝效率可达到90%;吸附实验表明R550对Cd2+、Pb2+、Cu2+均有较好的吸附作用,表明低品位菱锰矿矿石在空气中550℃煅烧可获得高比表面积、高活性的纳米结构化材料,在环境污染物去除方面有潜在的利用价值.

A nanomineral material was prepared from thermally treated low grade natural rhodochrosite in this study.The composition of natural rhodochrosite was investigated by combining XRF,TEM and chemical method.The substance and structure after calcination were characterized by TG-MS,XRD,SEM,BET,and XPS.The results show that the mineral constituents of the rhodochrosite ore are rhodochrosite,quartz,pyrite and sulfate oxidized from pyrite.When the temperature increases to550℃,the rhodochrosite calcines gradually,releasing agreat amount of CO2,forming hausmannite and other species of MnOx.As a result,the porous structure（massive accumulation）occurs on the surface of rhodochrosite,which has the pore sizes in 3-7 nanometer,in particular,the maximum specific surface area is 31.5 m2/g.NH3-SCR results show that the sample R550 exhibited a high denitration performance.R550 also has a good removal efficiency of cadmium,lead and copper ions.It is indicated that the nano-porous material with better specific surface area can be prepared through calcining rhodochrosite ore at 550℃.