铬渣中铬,镍,锌,锰和铁的X射线荧光法测定

本文首次研究了用X射线荧光光谱法测定铬渣中Cr、Zn、Ni、Mn和Fe元素的模拟标样,样品直接压片不经化学处理。用稀释样品校正试样的基体效应。用人工模拟标样所建立的元素浓度与X射线强度间的线性函数关系令人满意,所试元素的线性相关系数均在0.99以上,测定结果与化学法基本一致。Cr的检测下限为0.036%;Fe为0.039%;Ni为35.33μg/g;Mn为498.18μg/g;Zn为55.61μg/g。各元素的相对标准偏差均低于2.48%。并首次用非线性方法研究了铬渣样品稀释比中Cr、Ni、Zn、Mn、Fe与X射线强度的线性关系。     

高钙高铁煤灰熔融及黏温特性研究

以金鸡滩煤为原料,沙子为添加剂,研究不同比例添加剂下高钙高铁煤灰熔融及黏温特性变化;通过XRD、高温热台显微镜与扫描电镜-能谱等分析方法研究矿物质转变对其灰熔融及黏温特性影响。结果表明,煤灰熔点随添加剂量的增加先降低后升高,辉石类低温共熔物生成是其降低的主要原因;原煤熔渣黏度波动与钙铝黄长石生成有关,而含铁矿物质析出导致其黏度迅速增加;添加沙子后,煤灰熔渣临界温度显著下降,熔渣由结晶渣向玻璃渣转变。原煤熔渣中Fe、Ca元素分布不均匀,添加沙子后均匀程度明显改善,与黏温曲线测试结果吻合。实验结果表明,沙子是改善高钙高铁煤黏温特性的一种有效添加剂。     

The mechanism of pristine steel slag for boosted performance of fly ash-based geopolymers

The high autogenous shrinkage of geopolymers hampers their application as building materials. In this study, pristine steel slag was used as an expansion material to mitigate shrinkage in geopolymers. The influence of pristine steel slag on the chemical deformation of alkali-activated fly ash-based geopolymers is investigated. The microstructure of the expanded system was studied by X-ray diffraction (XRD), FTIR measurement, thermogravimetric measurement (TGA), scanning electron microscopy with energy dispersive X-ray (SEM/EDS) and mercury intrusion porosimetry (MIP). Finally, the mechanisms of expansion were elucidated. The experimental results show that the shrinkage of the geopolymer is eliminated with the addition of steel slag. Fly ash was replaced by 0, 5, 10, and 15% of steel slag, and the expansion rate ranged from ?0.29% to 20.24%. Increased steel slag content reduced the bulk density of geopolymer. The incorporation of steel slag not only provided calcium for the information of C-A-S-H but also filled the pores. Steel slag produces different expansion effects in different porous media and thus refines the pore structure. Therefore, expansion by means of steel slag is an efficient approach for mitigating shrinkage in fly ash-based geopolymers.     

Ultrasound effects on restricted silica gelation during silica extraction from Pyro-Metallurgical copper slag under acidifying conditions

Pyro-metallurgical copper slag (CS) waste was used as the source material for ultrasound (US) silica extraction under acidification processes with 26 kHz with HCl, HNO₃, and H₂SO₄ at different concentrations at 100, 300, and 600 W. During acidifying extraction processes, US irradiation inhibited silica gel formation under acidic conditions, especially at lower acid concentrations of less than 6 M, whereas a lack of US irradiation led to enhanced gelation. When US stopped, gelation occurred to a considerable degree, suggesting that the gel particle size distribution was aggregated in the 3–400 µm size range. However, with US, the size was mainly in the 1–10 µm range. Results of elemental analysis indicated that US treatment decreased the co-precipitation of other metal ions such as Fe, Cu, and Al sourced from CS for lower acidic medium, whereas the higher concentration medium accelerated silica gelation and the co-precipitation of other metals. With acids of HCl and HNO₃, and H₂SO₄, the gelations were less likely to occur at 6 M and 3 M during US irradiation, but acidic extraction without US was efficient for silica gelation and co-precipitation of other metals in the purified silica. The silica extraction yield with H₂SO₄ concentration of 3 M was 80% with 0.04% of Fe, whereas the silica product from HCl 6 M had a 90% extraction yield with only 0.08% of Fe impurity. In contrast, even though the non-US system of HCl 6 M had a higher yield at 96%, the final product had 0.5% Fe impurity, which was much higher than the US system. Consequently, the US extraction process was quite noticeable for silica recovery from CS waste.     

Experimentally constrained atomic order probing of a Si–Al composite glass

High resolution X-ray diffraction (XRD), neutron diffraction (ND) and reverse Monte Carlo (RMC) modelling of a rapidly quenched multi-component oxide glass reveals a local atomic order largely made up by interactions between Si, Fe and Mg polyhedra, the stereochemistry of which is in close agreement with literature data. Overall, the glass was found to consist of a small number of basic Si–O, Fe–O and Mg–O clusters. A superposition of the ND dataset promotes an RMC supercell with a higher fraction of uncoordinated oxygens, more pronounced Fe–Al cluster interconnections and a markedly reduced Fe–Si–Mg cluster bridging, as compared to the RMC-generated environment restricted solely by XRD total scattering.     

自动电位滴定法测定铜冶炼分银渣中的银量刘秋波

铜冶炼分银渣是铜阳极泥冶炼过程的副产品,但其还有一定量的银等贵金属,准备测定银的含量具有重要的意义。由于分银渣中除含有大量的银外,还含有铅、碲、铋、金、铂等元素,造成后续的处理比较复杂。本实验采用自动电位滴定法直接测定分银渣中的银量,避免了处理合粒复杂过程。实验讨论了硅酸度、氧化铅用量、杂志干扰等因素对银含量测定结果的影响。银的加标回收率在98.4%～99.3%之间,方法精密高,可满足分析检测的需要。     

电感耦合等离子体发射光谱法测定富铼渣中的铼

建立了电感耦合等离子体发射光谱法测定富铼渣中铼含量的方法。对样品的酸密闭消解、碱熔解和测定铼的条件进行了研究。结果表明：于10%盐酸介质、227.525 nm分析线,铼测定浓度在0.20～50.00 μg/ mL线性良好;两种样品分解方法测得铼结果吻合,用于富铼渣样品中1.85%～3.66%铼含量的测定,检出限、相对标准偏差(RSD,n=22)和回收率分别为酸密闭消解法6.46×10-10 μg/mL、0.689%～1.065%和99.95%～100.06%,碱熔解法6.49×10-10 μg/mL、0.691%～1.059%和99.96%～100.31%。     

电感耦合等离子体原子发射光谱测定钒钛高炉渣中钪镓铬镍钴

建立电感耦合等离子体原子发射光谱法(ICP-AES)同时测定钒钛高炉渣中0005%～0.3%的贵金属元素钪、镓、钴和0.0005%～0.6%铬、镍的检测方法。样品前处理方法采用氢氟酸、盐酸、硝酸和硫酸消解钒钛高炉渣,高温加热至硫酸分解产生三氧化硫浓白烟为此,直接以水稀释定容制备样品溶液,不仅快速完全消解高钛基样品,而且通过挥发除去高含量二氧化硅基体和反应残余的氢氟酸,减少溶液共存组分有效降低基体效应影响以及避免腐蚀检测仪器;而且依靠残余硫酸根与高钛基体络合生成硫酸氧钛离子,解决了高浓度钛基体在低酸度介质中易水解问题,无需补充加入大剂量酸以限制钛水解,直接以水稀释制备样品溶液,从而降低溶液酸度减少酸度效应影响。方法重点试验考察了钒钛高炉渣中钒钛铁钙镁铝等共存介质下基体效应、光谱干扰等干扰影响因素,优选了元素的分析谱线、背景校正区域以及光谱仪工作参数等检测条件,采用基体匹配和同步背景校正法消除基体效应影响。验证表明方法的技术性能指标：校准曲线相关系数>0.999,背景等效浓度0.0001%～0.0002%,元素检出限0.0001%～0.0002%,检测范围内RSD＜15%,回收率90%～114%     

添加剂对燃煤电石渣固硫的促进作用

在煤的燃烧过程中采用钙基固硫技术脱除SO2等气体污染物,是实现煤高效清洁燃烧的有效措施之一。传统钙基固硫剂价格低廉,但普遍存在固硫剂利用率低,固硫反应速率与硫析出速率不一致,以及高温下形成的固硫产物易于分解等缺点。研究表明,在钙基固硫剂中掺入微量添加剂可以有效提高钙基固硫剂的固硫率。添加剂主要起两大作用,一是对煤的燃烧过程有助燃和促进作用,提高钙基利用率;二是在燃烧过程中形成耐热稳定的物相或熔融物相包裹固硫物相,从而抑制固硫物相的分解,阻止SO2的排放。     

生物质气化发电厂灰渣中微量元素的分布与富集规律

采用电感耦合等离子体发射光谱仪,研究了生物质气化发电厂灰渣中元素As、Al、Br、Ca、Cd、Cl、Cr、Cu、F、Fe、Ga、K、Mg、Mn、Na、Ni、P、Pb、S、Si、Sr、Ti、Zn在气化器底灰、淋洗器灰和旋风分离器灰中的质量分数,并分析了这些元素在不同粒径3种灰渣中的分布规律。结果表明,大部分极易挥发的元素,如卤族元素、碱金属元素主要在淋洗器中存在,表明了它们在飞灰颗粒中的富集。旋风分离器灰在灰渣中所占比例为10%左右,以粗灰为主,灰中Fe、Si、Ni、Pb、Zn、Cr、Cd为多;表明了此灰中重金属元素积累。在气化炉底灰中以K、S、Mn、Cu为主。元素随颗粒物粒径大小和元素性质的不同,呈现不同的富集规律。