秸秆-污泥基活性炭的制备及其对吸附Pb2+的研究

基于实验室制备秸秆-污泥基活性炭和中小城镇生活垃圾双解技术的研究,开发了一套制备水稻秸秆-污泥基活性炭的成套装置,并在最佳条件下制备得到了秸秆-污泥基活性炭。实验结果表明,秸秆-污泥基活性炭主要官能团有—OH、—C=C—、C—O,比表面积为902.6 m2/g,总孔容为0.303 0 cm3/g,微孔容为0.205 0 cm3/g。考察了活性炭对Pb2+的吸附效果的影响,结果表明,在吸附时间为200 min、pH为6、活性炭投加量为6 g/L的条件下对Pb2+的吸附量为12.79 mg/g,吸附过程符合二级吸附动力学模型。     

Sb高效富集与As转化稳定化的砷碱渣清洁利用新技术工业试验

为了实现锑冶炼砷碱渣的清洁利用及无害化处置,设计了球磨浸出—重选收锑—废碱喷淋—氧化沉砷—砷稳定固化的砷碱渣清洁利用新工艺。结果表明:常温下液固比为4:1时,砷碱渣经球磨后水浸,球磨和浸出时间分别20 min和40 min,As浸出率为96.78%,碱浸出率为97.35%,实现Sb、As和碱高效分离;为提取回收浸出渣中锑资源,通过摇床高效富集回收Sb,回收率为40%~50%,且精矿中As < 1%,Sb≥10%,可通过冶炼系统回收;基于酸碱中和原理,浸出液（高砷废碱）进入锑冶炼中烟气脱硫喷淋系统与烟气中SO₂发生反应,烟气中SO₂和As含量达到排放标准,实现浸出碱液和烟气SO₂协同治理目的;向高砷废水加入H₂O₂对砷进行氧化,再加入脱砷剂（生物制剂）与砷发生沉淀反应而脱除,经两段脱砷后,废水中As含量降低至150 mg/m3, 脱砷效率分别为88.4%和92.5%;产生的脱砷渣采用铁盐稳定剂处理,在添加质量比为9%时固化体As毒性浸出浓度从348.67 mg/L降至0.65 mg/L,达到危险废物填埋场入场标准。工业扩大试验结果表明,新工艺可达到以废治废、清洁利用砷碱渣目的。      

Combustion behavior and influence mechanism of CO on iron ore sintering with flue gas recirculation

The properties of circulating gas have a significant effect on sintering with flue gas recirculation, and the influence of CO in sintering process was investigated. The results show that the post-combustion of CO conducts in sinter zone when flue gas passes through the sintering bed, which releases much heat and reduces the consumption of solid fuel. The ratio of coke breeze can be reduced from 5% to 4.7% with 2% CO in circulating flue gas. In addition, with the increase of CO content in circulating flue gas, the combustion efficiency of fuel is improved, and the flame front is increased slightly while still matches with the heat transfer front. These are beneficial to increasing the maximum temperature and prolonging the high temperature duration, especially in the upper layer of sintering bed. As a consequence, the productivity, vertical sintering velocity and quality of sinter are improved.     

Fundamental study on iron ore sintering new process of flue gas recirculation together with using biochar as fuel

It is of great significance for cleaner production to substitute bio-energy for fossil fuels in iron ore sintering. However, with the replacement ratio increasing, the consistency of heat front and flame front is broken, and the thermal utilizing efficiency of fuel is reduced, which results in the decrease of yield and tumble index of sinter. Circulating flue gas to sintering bed as biochar replacing 40% coke, CO in flue gas can be reused so as to increase the thermal utilizing efficiency of fuels, and the consistency of two fronts is recovered for the circulating flue gas containing certain CO2, H2 O and lower O2, which contributes to increasing the maximum temperature, extending the high temperature duration time of sintering bed, and results in improving the output and quality of sinter. In the condition of circulating 40% flue gas, the sintering with biomass fuels is strengthened, and the sintering indexes with biomass fuel replacing 40% coke breeze are comparative to those of using coke breeze completely.