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Tao TIAN Chao-lan ZHANG Feng ZHU Shan-xin YUAN Ying GUO Sheng-guo XUE 《中国有色金属学会会刊》2021,31(5):1484-1495
A column experiment was conducted to investigate the effect of phosphogypsum (PG) on the saline- alkalinity, and aggregate stability of bauxite residue. Results showed that: with increasing leaching time, the concentrations of saline-alkali ions decreased while the concentration increased in bauxite residue leachate; compared with CK (control group) treatment, pH, electric conductivity (EC), exchangeable sodium percentage (ESP), sodium absorption ratio (SAR), and exchangeable Na+ content of bauxite residue were reduced following PG treatment; average particle sizes in aggregates following CK and PG treatments were determined to be 155 and 193 nm, respectively. SR-μCT test results also confirmed that bauxite residue following PG treatment acquired larger aggregates and larger pore diameter. These results indicate that the PG treatment could significantly modulate the saline-alkalinity, and simultaneously enhance aggregate stability of bauxite residue, which provides a facile approach to reclaim bauxite residue disposal areas. 相似文献
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《Ceramics International》2021,47(24):33956-33971
Ablative composites have been in use for thermal protection of space vehicles for decades. Carbon-phenolic composites have proven to perform exceptionally well in these applications. However with development in aerospace industry their performance needs improvement. In this field, different carbon-based and ceramic additives have been introduced into ablative composite systems. This review article gives a comparative analysis of researches done in this field in the recent past. Density, ablative, thermal and mechanical properties of ablative composites with different ultra-high temperature ceramic particles i.e. ZrSi2, Cenosphere, nano-SiO2, BN etc. and carbon-based nanoparticles i.e. CNTs, nano-Diamonds, Graphene oxide etc. used as additives, have been compared and discussed. Emphasis is put on carbon-phenolic composite systems although some epoxy matrix systems have also been discussed for comparison. 相似文献
4.
Xiang-feng KONG Xing-xing JIANG Sheng-guo XUE Ling HUANG William HARTLEY Chuan WU Xiao-fei LI 《中国有色金属学会会刊》2018,28(3):534-541
Bauxite residue, a highly saline solid waste produced from digestion of bauxite for alumina production, is hazardous to the environment and restricts vegetation establishment in bauxite residue disposal areas. A novel water leaching process proposed here was used to investigate the dynamic migration and vertical distribution of saline ions in bauxite residue. The results show that water leaching significantly reduced the salinity of bauxite residue, leaching both saline cations Na+, K+, Ca2+ and anions CO2?3, SO2?4, HCO?3. Na+ and K+ migrated from 40–50 to 20–30 cm of the column, presenting a high migration capacity. The migration capacity of Ca2+ was lower and accumulated at 30–40 cm of the column. CO2?3 initially distributed at 20–30 cm of the column, subsequently transported to 30–40 cm of the column, and finally returned to 20–30 cm of the column along with evaporation. SO2?4 was originally distributed at 40–50 cm, but finally migrated to 20–30 cm of the column. Nevertheless, HCO?3 remained at the bottom of the column, and its migratory was less affected by evaporation. 相似文献
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S. Karthikeyan A. Suganthi K. Bhuvaneswari J. S. Kennedy 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2019,36(2):270-277
An efficient analytical method was developed and validated using a modified QuEChERS method and LC-MS/MS for the detection and quantification of neonicotinoid insecticide residues in rice whole grain and rice straw. The samples were extracted using acetonitrile and cleaned up by dispersive solid-phase extraction. Validation based on five fortification levels showed good recoveries of neonicotinoids ranging from 75% to 116 % and 60% to 105 % for rice whole grain and straw, respectively. The precision ranged between 3% and 17 %, and 2% and 10 % for grain and straw, respectively. The limit of detection was from 0.007 to 0.0084 mg kg?1 and 0.005 to 0.15 mg kg?1 and the limit of quantification was in the range of 0.024–0.028 mg kg?1 and 0.016–0.051 mg kg?1 for rice whole grain and rice straw, respectively. Monitoring of farm gate samples indicated that, out of 24 samples, 1 rice whole grain sample was contaminated with thiamethoxam residues (0.07 mg kg?1). 相似文献
8.
Samira Lotfian Tommy Vikström Andreas Lennartsson Bo Björkman Hesham Ahmed Caisa Samuelsson 《Canadian Metallurgical Quarterly》2019,58(2):164-176
Shredder residue materials are produced after the removal of ferrous and non-ferrous fractions from end-of-life electronic equipment. Despite the high plastic content and metal value in the ash, high percentages of these materials are currently sent to landfills. In this study, the potential of utilising shredder residue material and other plastic-containing materials as reducing agents was studied. Plastic-containing materials were co-injected with coal into a zinc-fuming furnace in Boliden-Rönnskär smelter. The data obtained from the trial, such as the data from the chemical analysis of the slag and the steam production, are discussed. The observations indicate that plastic-containing material can replace up to 1?ton?h?1 of coal without a significant decrease in the zinc reduction rate. 相似文献
9.
采用元素分析、工业分析、热重、X射线衍射、扫描电镜、红外光谱等手段对煤油共炼残渣的组成、微观结构、官能团进行分析表征,并通过红外谱图的分峰拟合对官能团含量进行半定量计算。结果表明:残渣的有机物由具有片层堆积结构碳质颗粒组成,无机物由煤油共炼催化剂和煤中的无机矿物质组成;残渣颗粒粒径呈10 μm和2 μm的两级分布,颗粒呈整体无序、局部有序的分布状态。分别采用工业分析和热重分析得到挥发分、固定碳和灰分的含量,两组数据一致:残渣的氢键中羟基自缔合结构占到了47.95%;脂肪氢中亚甲基结构占64%左右;含氧官能团主要以碳氧键和羰基形式存在,含有微量的硅氧键,没有羧基;芳香结构中烷基侧链取代基较多,五取代氢的芳香结构只占约4.5%。 相似文献
10.
湿法炼锌流程中钴渣浸出液中含有高浓度的Fe2+和Mn2+,用分光光度法测定Co2+和Ni2+时,Fe2+-EDTA会严重干扰Co2+和Ni2+的测定;在用光度滴定法测定Zn2+和Co2+合量时,Ni2+对二甲酚橙指示剂具有封闭作用,Mn2+亦与EDTA螯合,导致滴定结果偏高。为消除Fe2+和Mn2+对Zn2+、Co2+和Ni2+测定的干扰,实验进行氧化分离Fe2+和Mn2+预处理,在NaAc/Hac缓冲体系下,以EDTA作显色剂用分光光度法测定Co2+、Ni2+。在波长466nm处,Co2+的线性范围为50~500mg/L时与吸光度呈线性,相关系数R2为0.9992;在384nm处,Ni2+的线性范围为50~500mg/L时与吸光度呈线性,相关系数R2为0.9998。根据分光光度法测出Ni2+物质的量,加入1.1倍的丁二酮肟以除去Ni2+,用二甲酚橙为指示剂,EDTA鳌合-光度滴定法测定Zn2+、Co2+合量,扣减Co2+含量得出Zn2+含量。选取4个锌湿法炼锌流程中钴渣浸出液实际样品,按照实验方法中的分光光度法测定Co2+和Ni2+,光度滴定法测定Zn2+、Co2+合量,Zn2+、Co2+和Ni2+测定结果的相对标准偏差(RSD,n=6)均不大于0.70%,加标回收率分别为99.59%~100.41%、99.69%~100.64%、99.92%~100.08%。 相似文献