Evaluation of the use of a sequential extraction procedure for the characterization and treatment of metal containing solid waste

Metal containing wastes like MSWI fly ashes and blast furnace sludge form a major environmental problem as they are polluted with heavy metals. The ash has to be landfilled or can be used as a construction material, but a pretreatment is in general necessary. Washing of the ashes with water in order to dissolve soluble salts or extracting the heavy metals with chemicals are possibilities. Blast furnace sludge contains large quantities of iron and carbon and could be recycled in the blast furnace, if the zinc content were not that high. Using a hydrometallurgical process the zinc can be removed from the sludge particles. In order to evaluate such treatment methods knowledge of the leaching behaviour of the studied material is very important. One of the factors influencing the leaching behaviour is the composition and mineralogy of the solids. A sequential extraction procedure, whereby the material is sequentially leached with different leaching solutions, can be used as an aid to characterize the material and to determine which chemical conditions are needed to obtain a sufficient extraction efficiency. To verify the accuracy of the sequential extraction procedure, a method is tested on MSWI fly ash and evaluated by comparing the results with those of leaching experiments whereby the final pH of the leaching solutions is varied over a wide range. Based upon this evaluation some suggestions for the use of the sequential extraction procedure are made and an adapted procedure is suggested, and applied to a blast furnace sludge.     

包钢高炉出铁场烟尘的治理

包头钢铁集团公司共有六座高炉,这里出铁场高浓度的烟尘对厂区大气环境造成严重污染,直接危害职工的身体健康,同时影响周边的环境。六座高炉全部实现干法除尘,成为国内大型钢铁企业中首家实现高炉全干法除尘的企业,对出铁场烟尘进行净化处理,净化后的气体可直接排入大气,改善了钢铁生产污染严重的现状。出铁场烟尘控制的关键处为出铁口、撇渣器、摆动流嘴三处。抓住了出铁场烟尘控制的关键环节,就加强了对出铁口烟尘的控制。     

烧结脱硫灰制备胶凝材料强度影响因素研究

通过正交及单因素试验方法研究了烧结烟气半干法脱硫灰复掺矿渣、钢渣,辅之外加剂,制备生态胶凝材料的可行性。结果表明采用分别预磨钢渣、矿渣及水泥熟料再与经低温煅烧的改性脱硫灰混磨制备的复合生态胶凝材料,具有良好的安定性、水化性能和力学性能;初凝时间、终凝时间合格。正交试验确定了一定比例和掺量的矿渣和钢渣复掺15%改性脱硫灰、15%水泥熟料和0.5%激发剂时胶凝材料的各项性能较好,通过单因素试验对方案进行了优化,用SEM对两组配方的水泥净浆体进行晶形微观分析,验证了不同水化产物在不同龄期对水泥体的强度影响。     

生活垃圾焚烧飞灰的污染特性

对我国两种占主导地位的焚烧炉炉型-炉排炉和流化床产生的焚烧飞灰进行分析,包括16个采用炉排炉的主要生活垃圾焚烧厂和部分使用流化床的生活垃圾焚烧厂,对焚烧飞灰从重金属含量,氯、硫、碱含量,二英含量方面对我国生活垃圾焚烧飞灰的性质做比较全面的归纳和总结。统计结果表明炉排炉焚烧飞灰重金属含量要高于流化床焚烧飞灰,Zn的最高含量在10倍以上,均值也在7倍左右,Cu的最高值为7倍,均值为3倍,Cd,Pb,Cr,Ni的均值为7倍,4倍,4倍和1.5倍。Hg的差别最小,高出30%;炉排炉焚烧飞灰的氯、硫、碱含量全面高于流化床焚烧飞灰,炉排炉焚烧飞灰和流化床焚烧飞灰的平均氯含量分别为15.41%,1.71%,SO3的平均含量分别为10.67%,2.875%,焚烧飞灰的K2O和Na2O含量接近,炉排炉焚烧飞灰的平均含量为6.06%,5.325%,流化床焚烧飞灰的平均含量为2.43%,2.63%,两种类型的焚烧飞灰在碱含量上差别没有氯、硫大;焚烧飞灰的二英含量差别巨大,炉排炉和流化床焚烧飞灰二英含量低值比较接近,而高值炉排炉焚烧飞灰要高出流化床焚烧飞灰很多。     

硅铁炉生产工艺及烟气处理

硅铁电炉目前应用比较广泛,分析硅铁的生产工艺和烟气处理不仅是完成节能减排的需要,也是保护环境的重要手段。     

电捕法在炭素焙烧炉烟气净化中的应用

针对炭素焙烧炉的烟气特点,采用雾化水预处理和电捕焦油技术,对炭素厂焙烧炉烟气进行治理,达到高效净化有害气体—沥青烟的目的。     

钢铁渣粉对混凝土中钢筋的保护作用

钢渣和矿渣是冶炼钢、铁过程中产生的固体废物.由于其矿物组成与水泥熟料相似,具有水硬胶凝性能,所以被用作混凝土掺合料.钢铁渣粉是钢渣粉和矿渣粉接一定的比例混合而成的.试验表明,钢铁渣粉的使用能够保留钢渣粉和矿渣粉单掺时的优点,弥补单掺时的缺点,对钢筋起到很好的保护作用.     

高炉风口漏损分析与控制措施探讨

本文通过分析高炉风口损坏的形式和原因,探讨了目前常用的风口检漏技术和方法;根据高炉运行管理实践,介绍了风口漏损的主要表现形式,并针对风口的漏损程度提出了应采取的处理和维护措施,以及延长高炉风口寿命的建议性措施.     

Development of novel absorbents for CO2 capture from blast furnace gas

In order to establish energy-saving technology for CO₂ capture from blast furnace gas, novel absorbents were developed in the laboratory and evaluated at a 1 t_CO2/d test plant. At first, CO₂ absorption and desorption behaviors of single-component amine solvents for simulated blast furnace gas (CO₂/N₂ = 20%/80%) were investigated through a screening test using a small scrubbing bottle. These amine solvents were additionally analyzed using nuclear magnetic resonance (¹³C NMR) spectroscopy and reaction calorimetry. The results of the laboratory experiments showed that there was a trade-off between absorption rate and enthalpy of absorption but some absorbents had unique features. For example, 2-isopropylaminoethanol (IPAE) had high absorption rate and small enthalpy of absorption. Then, new IPAE-based amine solvents (RITE solvents: RITE-A and RITE-B) were formulated and evaluated at the 1 t_CO2/d test plant. CO₂ regeneration energies of the RITE solvents were 3.3 and 3.1 GJ/t_CO2, respectively. With certain process conditions and plant specifications optimized, RITE-B was estimated to have the potential to achieve 2.5 GJ/t_CO2.     

高炉矿渣对铝电解废旧阴极炭焚烧中氟化物的迁移转化行为影响

废旧阴极炭（Spent potlining）是铝电解行业产生的一种高无机氟含量危险废物.本研究以高炉矿渣（Blast furnace slag）为添加剂与废旧阴极炭混合焚烧,模拟计算有关反应的吉布斯自由能,研究焚烧过程中氟化物的转化和稳定化行为.结果表明,高炉矿渣中的钙基化合物可促进废旧阴极炭中的NaF和Na₃AlF₆转化为稳定的CaF₂. 在850 ℃、焚烧1 h的条件下,废旧阴极炭和高炉矿渣混合样（4/6,质量比）水溶性氟浸出率降低42.27%;同时,减少HF释放可使氟化物保留率提高3.85%.高炉矿渣的掺入将其中93.50%的氟化物固定于底渣中,显著降低了废旧阴极炭的浸出毒性.高炉矿渣中的SiO₂和Al₂O₃促进了NaF向CaF₂的热转化行为,高炉矿渣参与焚烧使得焚烧底渣颗粒更加疏松、分散,底渣的 氟化物主要以Ca₄Si₂O₇F₂形态存在,表明高炉矿渣具有协同处置废旧阴极炭的良好性能.