从某稀土尾矿中回收萤石和锶钡矿物工艺实验

这是一篇矿物加工工程领域的论文。某稀土矿矿石中伴生萤石和锶钡矿物,由于该样品成分和嵌布关系复杂,矿物嵌布粒度细,且萤石和锶钡矿物浮选性质相近,常规药剂和工艺无法实现样品中伴生萤石和锶钡矿物的富集和分离,影响当地生态环境,造成国家矿产资源的重大浪费。针对该样品,开展浮选药剂优选和工艺优化,形成适于该稀土尾矿资源化利用的混合浮选-分离再提纯选矿工艺。研究结果表明,针对SrO品位为8%,CaF₂品位为16%的稀土尾矿,经混合浮选-再分离提纯工艺可以得到品位为90%的萤石精矿和锶钡混合精矿纯度90%的锶钡精矿,研究结果可以为同类型尾矿资源化利用提供借鉴。     

白云鄂博深部稀土尾矿的工艺矿物学

为合理开发和利用白云鄂博的稀土尾矿中的萤石资源,对该矿的稀土尾矿进行工艺矿物学研究。通过化学分析、物相分析、扫描电子显微镜等检测手段对该矿石进行系统的工艺矿物学研究。结果表明,该矿石稀土尾矿中萤石含量为26.6%,铁矿物含量高达16.4%,硅酸盐矿物霓辉石、钠闪石和黑云母含量共计19.9%,碳酸盐矿物白云石、方解石含量共计15.7%,稀土矿物含量有3.9%。稀土尾矿原矿中萤石矿物的单体解离度为76.50%,萤石矿物与铁矿物、碳酸盐矿物、硅酸盐矿物以及稀土矿物大量连生,经过磨矿后稀土尾矿中萤石矿物的单体解离度92.38%。此研究结果为该矿的稀土尾矿中的萤石资源的合理开发利用提供重要依据。     

Effect of double doping on crystal structure and electrical conductivity of CaO and WO3-doped Bi2O3

The atomic arrangement of WO₃-doped Bi₂O₃ was found similar to that of the fluorite structure. However, the electrical conductivity of WO₃-doped Bi₂O₃ is significantly lower than that of commonly used Y₂O₃-doped Bi₂O₃. The structure and electrical conductivity of samples formulated as (Ca_xW_0.15Bi_0.85−x)₂O_3.45−x (x = 0, 0.1, 0.2 and 0.3) were investigated. The as-sintered (W_0.15Bi_0.85)₂O_3.45 and (Ca_0.1W_0.15Bi_0.75)₂O_3.35 exhibit similar single tetragonal structure that is isostructural with 7Bi₂O₃·2WO₃. Therefore, (W_0.15Bi_0.85)₂O_3.45 and (Ca_0.1W_0.15Bi_0.75)₂O_3.35 formed a superstructure consisting of 10 enlarged cubic fluorite subcells. However, the as-sintered samples consist of a tetragonal structure and tetragonal CaWO₄ for x = 0.2 and 0.3 because the oxygen vacancy concentration increases. The conductivities of (Ca_xW_0.15Bi_0.85−x)₂O_3.45−x (x = 0, 0.1, 0.2 and 0.3) did not exhibit linear dependence with x value. The best conductivity is 2.35 × 10⁻² S cm⁻¹ at 700 °C for x = 0.1 that is higher than that of Ca-free (W_0.15Bi_0.85)₂O_3.45. The higher conductivity of (Ca_0.1W_0.15Bi_0.75)₂O_3.35 than (W_0.15Bi_0.85)₂O_3.45 may result from the higher anion vacancy concentration and more symmetrical structure.     

Chemical and microstructural characterisation of HfO2-Y2O3 ceramics with high amount of Y2O3 (33, 40 and 50 mol. %) manufactured using spark plasma sintering

Hafnia based ceramics are potential promising candidates to be used as thermal barrier coatings (TBC) for applications in the field of propulsion. In this study, Spark Plasma Sintering (SPS) of fully stabilised hafnia with yttrium oxide (yttria) was investigated to provide a better understanding of the effect of manufacturing parameters, on the crystallography, chemistry and microstructure of the material. Several hafnia powders, containing different amounts of yttria (33 mol. %, 40 mol. % or 50 mol. %), were sintered by SPS at different temperature levels ranging from 1600 °C to 1850 °C. On these materials, X-ray diffraction patterns associated with scanning electron micrographs have highlighted the influence of both the sintering temperature and the amount of yttria on the final composition, the lattice parameter and the microstructure of hafnia-based materials. In the end, it is established that, for all quantities of yttrium employed, the main phase is Y₂Hf₂O₇ with very high densification levels.     

Effects of ageing on defect structure in the Bi3NbO7–Bi3YO6 system

Ageing effects in the defect fluorite structure of Bi₃Nb_1−xY_xO_7−x have been studied using powder neutron diffraction. Two compositions at x = 0.4 and x = 0.6 were studied after annealing for prolonged times (400–500 h) at 410 and 550 °C. The results show that significant changes in oxide ion distribution occur at 550 °C, but that at 410 °C only the lower x-value composition exhibited such a change. A comparison of lattice parameter variation with temperature for annealed and unannealed samples suggests that at higher temperatures the oxide ion distribution is independent of thermal history.     

萤石浮选捕收剂研究进展

萤石捕收剂可分羧酸类、生物脂类、两性捕收剂 、复合捕收剂、烷基膦酸和烷基硫酸(烷基磺酸)等五类,其中绝大部分属化工厂副产品。羧酸类(油酸或油酸盐)仍然是萤石浮选的主要捕收剂。使用两性捕收剂能改善萤石-方解石分离的选择性,而生物脂类则可有效排除萤石精矿小的二氧化硅。     

柠檬酸对萤石和方解石的抑制效果研究

通过单矿物浮选试验、人工混合矿试验、Zeta电位测定、接触角测试及X射线光电子能谱(XPS)测试分析,考察了柠檬酸对萤石和方解石在浮选中的作用机理。结果表明,在油酸钠体系下,柠檬酸对萤石的抑制效果强于方解石,柠檬酸抑制两种矿物受pH值的影响较小。对于萤石和方解石的混合矿,随着pH值的升高,萤石精矿的品位和回收率开始下降。Zeta电位、接触角测试及XPS分析结果表明,萤石比方解石表面电位高,Ca 2p轨道的电子结合能大,更容易与柠檬酸结合。柠檬酸作用后,萤石比方解石电位负移大,接触角降低明显,Ca 2p轨道中Ca-COOR的相对含量占比多。萤石与方解石混合时,随着矿浆pH值的升高,Ca 2p轨道中Ca-CO₃的相对含量占比逐渐升高。     

钢水钙基脱硫剂的应用探讨

在钢铁市场面临激烈竞争的形势下,用户对产品质量,品种的要求不断提高。深脱硫已经成为提高钢质量、扩大品种和开拓钢材市场的重要手段。针对钢水钙基脱硫剂的文献研究中,并对其学者的文献和观点进行归纳和总结,找出提高钢水快速脱硫的途径。     

柿竹园多金属矿资源综合利用选矿流程研究

根据柿竹园多金属矿矿石性质,从综合利用矿产资源的角度研究并提出采用浮—磁—浮主干流程。对黑白钨矿、萤石、石榴石的选矿工艺研究分别获得质量符合ＧＢ２８５１－８１ 一级Ⅰ类品标准的黑、白钨精矿;达到ＧＢ５６９０－８５ 二级品质量要求的萤石精矿和纯度为９２．３１％ 的石榴石精矿。回收率均超过国家“八五”科技攻关提出的要求。     

化学发光法测定铅的研究及其应用

本文研究了痕量Ｐｂ（１１）对Ｈ２Ｏ２氧经鲁米诺－邻菲罗啉产生强的化学发光反应,以邻菲较啉为增强剂,Ｐｂ（１１）的检出限为２．８×１０＾－６ｍｇ／ｍＬ,工作曲线响应浓度范围在１×１０＾－５－１×１０＾３ｍｇ／ｍＬ测定５×１０＾－４ｍｇ／ｍＬＰｂ（１１）离子相对标准偏差为３．２％,化学发光法检测萤石中微量铅可获得满意结果。