Growth of spinel crystals in vanadium slag and their characterization

Morphology of vanadium slags were investigated by scanning electron microscopy (SEM). The mineralogical phases were characterized by energy disperse X‐ray spectrometry (EDS) and powder X‐ray diffraction (XRD). The obtained results show that spinels and silicates are the major phases in the vanadium slag, and V is concentrated in Fe_xV_3‐xO₄ and Mg_x(V, Ti)_3‐xO₄. Both the spinel grain size and volume fraction in the slag with higher V₂O₃ content are much larger than that with lower V₂O₃ content. (Fe, Mn)₂SiO₄ and (Fe, Mn)SiO₃ have a higher proportion in the slag with lower V₂O₃ and higher SiO₂ content. The relation among cooling conditions and grain size and volume fraction of spinels is also discussed. It is found that low cooling rate and long holding time benefit spinel crystal growth, especially for the interval of 1200‐1250 °C. Both mean diameter and volume fraction of spinels could achieve or exceed the industry vanadium slag when holding more than 45 min. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

烧结法制备高炉渣CMAS系统微晶玻璃的研究

利用高炉渣及其它辅助原料制备基础玻璃,采用一步烧结法制备主晶相为辉石的CaO-MgO-Al2O3-SiO2(CMAS)微晶玻璃.综合运用DSC,XRD以及场发射扫描电子显微镜等测试手段,分析热处理制度对高炉渣CMAS微晶玻璃的析晶行为及性能的影响.结果表明:随着热处理温度上升,微晶玻璃的主晶相均为辉石,次晶相均为长石,晶相析出量增加,微晶玻璃的体积密度及抗折强度均呈现先增后减趋势.随着热处理时间增加,微晶玻璃的体积密度及抗折强度均呈现下降趋势.当热处理温度为1020 ℃,晶化时间30 min时,样品的机械性能最好,体积密度为2.690 g·cm-3,抗折强度为67.00 MPa.     

Utilization of blast furnace slag nano-fluids in two-phase closed thermos-syphon heat pipes for enhancing heat transfer

This article deals with utilization of blast furnace slag nano-fluids in two-phase closed thermo-syphon heat pipes for enhancing heat transfer at various states of operation. The utilization of nano-fluids obtained from X₂O₃-, XO-, XO₂-, and X₂O-type oxides, such as Al₂O₃, Fe₂O₃, CaO, SiO₂, MgO, MnO, K₂O, and Na₂O, on the improvement of heat pipe performance has been separately reported in a number of studies in the literature. The present study experimentally demonstrated the effect of using a nano-fluid obtained from blast furnace slag comprised of various types of metal oxides in varying ratios on improving the performance of a heat pipe. The slag was obtained from the iron blast furnace of Karabük Iron Steel Workings (Turkey). Triton X-100 (Dow Chemical Company) dispersant was used in the study to produce the blast furnace slag/water nano-fluid via direct-synthesis. The 2 wt% concentration of blast furnace slag/water nano-fluid was used as the working fluid in heat pipes. A straight copper tube with an inner diameter of 13 mm, outer diameter of 15 mm, and length of 1 m was used as the heat pipe in the present experimental study. The nano-fluid filled 33.3% (44.2 ml) of the volume of the two-phase closed thermo-syphon. Three heating power levels (200, 300, and 400 W) were used in the experiments with three different flow rates of cooling water (5, 7.5, and 10 g/s) used in the condenser for cooling the system. An increase of 22% was achieved in thermal performance of the two-phase closed thermo-syphon when 2 wt% blast furnace slag containing nano-fluid was used to replace pure water at a heat load of 200 W with a cooling water flow rate of 5 g/s.     

碱熔试样-原子吸收光谱法测定铜阳极泥预处理渣料中的Sb

铜阳极泥是一种重要的冶金工业副产品,因其中含有多种贵金属和有价金属元素,铜阳极泥的综合回收利用日益受到关注。铜阳极泥预处理富集渣中富含的Sb难以用常规方法溶解,有必要建立一种准确、简便的测试方法实现Sb的定量分析。采用X射线荧光光谱、X射线衍射光谱和场发射扫描电镜能谱分析等多种光谱学分析手段对富集渣的化学成分、物相和微观结构做了全面分析,结果表明,富集渣的化学组成和物理结构复杂,组分化学性质稳定且共生紧密。Sb以高锑酸金属化合物的形式存在,结构稳定化学惰性强。采用Na₂O₂熔融法消解试样,合成标准样品做标准系列,用火焰原子吸收光谱法测定了富集渣中Sb的含量值为8.23%,相对标准偏差为0.97%。该方法的检出限为0.072%,加标回收率为94.9%~99.2%。本方法溶样彻底,不需贵重试剂和仪器,方法简单易行。采用与样品基体相近的合成标准样品,消除了样品化学成分复杂所造成的共存物质干扰。通过标准样品测试验证和其他仪器方法比对,证明本方法灵敏度高,准确性好,可用于铜阳极泥预处理渣料中Sb的定量测定。     

不同处理工艺钢渣的X射线衍射和X射线荧光光谱分析及其活性指数预测模型

以不同处理工艺钢渣,即转炉热泼渣、转炉滚筒渣、铸余渣、铁水脱硫渣、电炉热泼渣和电炉滚筒渣作为研究对象。利用X射线衍射仪和X射线荧光光谱分析仪研究钢渣的化学成分与物相组成。利用BP神经网络模型建立钢渣活性指数预测模型,研究化学成分、物相组成与活性的关系。结果表明： 钢渣的处理工艺不同,其化学成分与物相组成存在明显差异;钢渣活性指数预测模型具有良好的符合性,即相对误差为2.42%和-2.54%,能充分反映输入层与输出层之间的映射关系。     

基于电石渣的硬硅钙石晶须的制备与表征

利用水热合成工艺,以电石渣作钙源合成了硬硅钙石晶须.用HCl对电石渣进行酸洗除杂,采用控制电石渣浆pH值,Ca(OH)2选择性溶解的方法去除电石渣中的其它杂质.采用ICP、XRD、SEM和DSC-TG分析了电石渣酸洗后的杂质含量及产品的晶相组成、微观形貌和耐温性.结果表明:控制pH值让电石渣中的化学组分选择性溶出,可使电石渣得以净化,成为制备硬硅钙石晶须的钙源;不同酸洗pH值、水热合成温度及保温时间对电石渣钙回收率、杂质去除率及合成的硬硅钙石晶须形貌具有很大的影响.比较适宜的制备条件是:电石渣酸洗pH=8、水热合成工艺参数220 ℃保温20 h.制备出的硬硅钙石晶须长径比为100～400,最高使用温度可达1000 ℃.     

Synthesis of Porous Material from Coal Gasification Fine Slag Residual Carbon and Its Application in Removal of Methylene Blue

A large amount of coal gasification slag is produced every year in China. However, most of the current disposal is into landfills, which causes serious harm to the environment. In this research, coal gasification fine slag residual carbon porous material (GFSA) was prepared using gasification fine slag foam flotation obtained carbon residue (GFSF) as raw material and an adsorbent to carry out an adsorption test on waste liquid containing methylene blue (MB). The effects of activation parameters (GFSF/KOH ratio mass ratio, activation temperature, and activation time) on the cation exchange capacity (CEC) of GFSA were investigated. The total specific surface area and pore volume of GSFA with the highest CEC were 574.02 m²/g and 0.467 cm³/g, respectively. The degree of pore formation had an important effect on CEC. The maximum adsorption capacity of GFSA on MB was 19.18 mg/g in the MB adsorption test. The effects of pH, adsorption time, amount of adsorbent, and initial MB concentration on adsorption efficiency were studied. Langmuir isotherm and quasi second-order kinetic model have a good fitting effect on the adsorption isotherm and kinetic model of MB.     

电石渣在煅烧/氯化反应中的HCl脱除特性研究

采用钙基废弃物———电石渣煅烧后脱除HCl。在煅烧/氯化反应器上研究脱氯反应温度、HCl体积分数、颗粒粒径和煅烧温度对电石渣脱氯性能的影响。结果表明,电石渣在700℃时取得最高氯化转化率;脱氯反应温度高于650℃后,电石渣氯化转化率均高于石灰石,电石渣高温脱氯更有优势。电石渣氯化转化率随反应气氛中HCl体积分数提高呈线性增长。随电石渣颗粒粒径增大,氯化转化率缓慢降低。高于900℃的煅烧温度不利于电石渣脱除HCl。煅烧后电石渣分布在2~10 nm的孔隙较多,氯化后分布在此孔径范围内的孔容和孔面积分别降低了56.2%和62.2%,2~10 nm孔隙是煅烧后电石渣吸收HCl的主要区域。     

超声提取-离子选择电极法测定铝渣中的氟化物

目前铝渣中的氟化物对环境的影响已经成为人们关注重点之一。为了能够准确测定铝渣中的氟化物含量,实验对超声时间、固液比以及Al~(3+)和Ca~(2+)同时存在下的干扰进行了研究。确定了最佳超声时间为20min,以固液比为1∶20进行超声提取,提取液移取体积为5mL,加入总离子强度溶液15mL的方法来消除质量浓度不大于25mg/L Al~(3+)和Ca~(2+)的干扰,运用离子选择电极法准确测定铝渣中的氟化物,得到标准曲线线性相关系数为0.999 9,方法检出限为0.3mg/kg,相对标准偏差(n=6)小于2%,加标回收率在90.8%～108%。同时用超声提取法对样品进行前处理,分别运用离子选择电极法和离子色谱法对铝渣中的氟化物进行测定,两者测定结果一致,方法的准确度良好。     

含铁有色金属矿渣的除砷方法

用ICP-AES法初步研究了含铁的有色金属矿渣除砷的方法.采用以硝酸为主的低浓度浸取液,在不损失铁含量的前提下,除砷效果好,且成本较低、周期短、工艺简单.