有色金属钨矿和铅锌矿尾矿资源化利用工艺技术研究

Study on resource utilization technology of nonferrous metals tungsten and lead-zinc tailings

以有色金属钨矿和铅锌矿尾矿为原料,分别采取酸浸后高温碱熔和无酸浸低温碱溶两种活化预处理,并以常规水热法(CH)和微波水热法(MH)合成ZSM-5分子筛,采用XRF、ICP-AES、FT-IR、XRD、SEM、BET和催化剂活性评价对所得产物进行表征分析。结果表明:合成产物为ZSM-5分子筛,其总比表面积在273.21~350.51 m^(2)/g之间,MH法产物孔径较小;低温碱溶可以得到更高硅铝摩尔比n(SiO_(2))/n(Al_(2)O_(3))的前驱液,导致产物形貌由类球形转变为六方棱柱形,并且产物粒径减小;高温碱熔合成产物对干化尾矿SiO_(2)利用率更高,不过工艺复杂,能耗高;活化过程SiO_(2)溶出率的影响因素程度由高到低的顺序为CaO、其他杂质、Fe_(2)O_(3);合成相同结晶度的ZSM-5分子筛时,MH法所需时间仅为CH法的四分之一左右,并且合成产物粒径更小,表面更洁净,SiO_(2)利用率更高;1 L反应釜工艺放大效应小,搅拌条件有利于合成体系的传质和传热,导致产物粒径减小,产物应用于脱硝反应的NO转化率可达94.31%。

The ZSM-5 molecular sieve was synthesized by conventional hydrothermal method(CH)and microwave hydrothermal method(MH),using non-ferrous metal tungsten ore and lead-zinc ore tailings as materials which were activated pretreatment by high-temperature alkali fusing after acid leaching and low-temperature alkali dissolving without acid leaching,respectively.The obtained products were characterizated by XRF,ICP-AES,FT-IR,XRD,SEM,BET and catalyst activity evaluation.The results show that,the synthesized product is ZSM-5 molecular sieve.BET shows that the total specific surface area of the product is between 273.21−350.51 m^(2)/g,and the pore diameter of the product by the MH is small.Low-temperature alkali dissolution activate pretreatment can obtain higher n(SiO_(2))/n(Al_(2)O_(3))liquid precursors,which leads to the transformation of the morphology of the product from a spherical shape to a hexagonal prism shape,and the particle size of the product decreases.The product synthesis by activation pretreatment with high-temperature alkali fusion has a higher utilization of the SiO_(2) of dried tailings,but the process is complicated and the energy consumption is high.The sequence of influence factors of SiO_(2) dissolution rate during activation from high to low are:CaO,Others,Fe_(2)O_(3).The required time to synthesize ZSM-5 with the same crystallinity by MH method is only about a quarter of the that of CH method,and the product size by the MH method is smaller,the surface is cleaner,and the SiO_(2) utilization rate is also higher.The 1 L reactor has a small amplification effect,and the stirring conditions are conducive to the mass and heat transfer of the synthesis system,resulting in a decrease in the particle size of the product,and the NO conversion rate of the product applied to the denitration reaction can reach 94.31%.