低氧分压条件下CaO-SiO_2-P_2O_5(10%)-FeO体系热力学性质的研究

以促进2CaO·SiO_2-3CaO·P_2O_5固溶体生成的非均相脱磷工艺被视为未来实现转炉少渣冶炼的重要手段,但目前相关渣系热力学性质的研究较少,不能为合理解释非均相渣脱磷的机理提供理论依据.为此,本文利用FactSage热力学软件绘制了低氧分压(1mPa)条件下CaO-SiO_2-P_2O_5(10%)-FeO体系及其子体系的热力学相图,分析了不同温度下相平衡关系及液相线的变化规律.研究结果表明:升高温度可使体系中液相区及Ca_3(PO_4)_2初晶区的范围扩大,但会导致α'-Ca_2SiO_4的初晶区缩小以及Ca_2Fe_2O_5等物相的消失;降低氧分压可使体系的液相区缩小,并向高FeO的方向收缩;CaO-SiO_2-P_2O_5(10%)-FeO体系中存在较大的α'-Ca_2SiO_4与Ca_3(PO_4)_2共存区,尤其是α'-Ca_2SiO_4,Ca_3(PO_4)_2与Ca_2Fe_2O_5的三相共存区可极大地促进2CaO·SiO_2-3CaO·P_2O_5固溶体的生成.     

Prediction of Arsenic Removal by Electrocoagulation: Model Development by Factorial Design

Model was developed by two-level five-factor full-factorial designed-experiment to predict arsenic removal from contaminated water by electrocoagulation. Five factors, namely arsenic concentration (As), solution volume (V); current (I), electrode area (A), and current processing time (t) were investigated. Among the factors, arsenic concentration (As) and volume (V) have negative effect, and area (A), time (t), and current (I) have positive effect on arsenic removal. Within the studied levels of the factors, variance analysis at 5% significance level indicated that electrode area is not significant in arsenic removal by electrocoagulation. The model predicted reasonably good arsenic removal (error<2%) from low (0.288 mg/L) and high (0.882 mg/L) initial arsenic concentrations in presence of naturally cooccurring solutes in the groundwater. For the range of operating variables studied, optimum removal of arsenic (98.56%) is obtained at higher arsenic concentration (1.18 mg/L), lower volume (1 L), higher current (3 A), and higher current processing time (120 s).     

固态下SiO2对二元铁酸钙形成过程的影响

 铁酸钙作为高碱度烧结矿黏结相的主要组成,其形成受SiO2的影响,但到目前为止,其影响机理尚不是十分明确。通过XRD和矿相显微镜观察,并结合Rietveld法定量分析,研究了SiO2对二元铁酸钙形成过程的影响。结果表明：Fe2O3与CaO反应,700 ℃时形成Ca2Fe2O5,在800 ℃时出现CaFe2O4,随着温度升高,Ca2Fe2O5逐渐向CaFe2O4转变。SiO2存在时,在铁酸钙形成过程中有Ca2SiO4生成,温度低于900 ℃时,受动力学条件的影响,反应速率较低,Ca2SiO4的量相对较少,另外,SiO2的阻碍作用随其质量分数的增加而增强,进而导致已形成的Ca2Fe2O5与Fe2O3未能继续反应形成CaFe2O4而使其质量分数逐渐增多;高于900 ℃时,随着温度的升高,动力学条件改善,离子扩散能力增强,其中,Fe3+通过CaFe2O4层比Ca2+通过Ca2Fe2O5层更容易,进而促进了CaFe2O4形成反应的进行,Ca2Fe2O5向CaFe2O4转变,但随着SiO2质量分数增加,Ca2SiO4的生成量增多,CaO与Fe2O3的接触面积减小,抑制了CaFe2O4的生成。     

XRD and Unconfined Compressive Strength Study for a Qualitative Examination of Calcium–Arsenic Compounds Retardation of Cement Hydration in Solidified/Stabilized Arsenic–Iron Hydroxide Sludge

This study investigates the adverse effects of synthesized arsenic–iron hydroxide sludge, the by-product of arsenic removal by coagulation with ferric chloride, on unconfined compressive strength (UCS) and cement hydration of solidified/stabilized matrices. The results from both UCS tests and X-ray diffraction (XRD) implied that synthesized arsenic–iron hydroxide sludge might not be chemically inert in a cementitious environment, which could account for the retardation of cement hydration. The culprit for this retardation is likely to be the multiphase formation of calcium arsenic compounds suggested by the strong peak at 7.90?? (11.2°?2θ). This peak appeared when more than 20 and 13% of arsenic–iron hydroxide sludge were added to the solidification/stabilization (S/S) process of cement–water and cement-hydrated lime–water systems, respectively. The proposed mechanisms for the retardation of cement hydration by calcium–arsenic compounds are calcium complexation and, subsequently, surface precipitation due to the interaction between desorbed arsenate and hydration by-products in a cement porewater environment. The extent of the hydration retardation is qualitatively determined by the semiquantitative comparison of Ca3SiO5 and Ca2SiO4 remaining after 28?days of hydration between the control S/S samples and that with various doses of the sludge added. When 20 and 33% of the sludge were added into the S/S matrices, the remaining Ca3SiO5 and Ca2SiO4 were more than that of the control sample by factors of 2 and 3.2, respectively.     

阳山矿区水文地球化学特征及成因分析

对阳山矿区内38件水样进行分析,结合区内地层岩石的地球化学特征,发现区内地下水组成以Ca^2＋、Mg^2＋、HCO3^-;、SO4^2-为主,其水化学类型则以HCO3-Ca为主,地下水化学特征与区内地层岩石化学特征相一致。研究还发现,区内地下水在空间分布上也有一定的特征,在地下水的补给区地表分水岭附近形成了以HCO3-Ca为主的地下水,而在径流区及排泄区地下水类型不一,总体而言,地下水水化学成分的形成以区内岩石的分解和水解等化学风化作用为主。区内含砷矿物及黄铁矿的溶解,导致水中SO4^2-及As元素含量的异常,也反映了矿区的2种金矿化蚀变现象,为下一步水化学异常圈定及水文地球化学找矿提供了依据。     

Effect of change of slag phase on dephosphorization of ��double- slag+slag- remaining�� steelmaking technology

The microstructure and phase constituent of dephosphorization slag of ??double- slag+slag- remaining?? steelmaking technology were observed and analyzed by SEM, part of the slag were heat treatment, and the effect of the change of slag phase on dephosphorization was studied. The research results show that the phase of dephosphorization slag A1-A3 with high dephosphorization rate are composed of calcium ferrite, complex liquid silicate phase (Ca3TiFeSi3O12, Ca54MgAl2Si16O9) and 2CaO??SiO2(C2S) solid phase solution with calcium phosphate (2Ca2SiO4??Ca3(PO4)2, Ca7(PO)4(SiO4)2), the main phase of dephosphorization slag A4 with low dephosphorization rate is liquid phase, the main phases of dephosphorization slag A5 are MnFe2O4, MnV2O4, Ca12Al14O33, little phosphorus rich calcium silicate solid phase is found in both dephosphorization slag A4 and A5; the phase of dephosphorization slag A3 changes little before and after heat treatment, but the phase of dephosphorization slag A4 changes greatly after heat treatment, which changing to liquid phase and white branches like RO phase; the dephosphorization slag of ??double- slag+slag- remaining?? steelmaking technology contain many un- dissolved CaO, but little is found in decarburization slag, the formation of C2S solid phase in dephosphorization slag plays an important role to accelerate the dephosphorization reaction.     

Oxidation of Fayalite in Molten Nickel Slag

This paper investigated the oxidation of fayalite (Fe2SiO4) in iron-rich nickel slag (INS) for iron recycling via an oxidation-magnetic separation method. A phase stability diagram of the FeO–SiO2–MgO–CaO–O2 system drawn by FactSage 7.1 illustrates that magnetite (Fe3O4) can be crystallized from liquid slag in an air atmosphere, but the further oxidation to Fe2O3 in molten slag was extremely hard. The mass content of divalent iron (w(Fe2+)) decreased and the ratio of trivalent iron to divalent iron (w(Fe3+)/w(Fe2+)) increased gradually with increasing oxidation time. The results show that an air flow rate of 300–500 mL/min, a basicity of 0.90–1.10, and a temperature of 1658–1728 K are conducive to the oxidation of Fe2SiO4 in INS. Fe3O4 is the main iron-bearing phase, and Fe2O3 is not observed in the X-ray diffraction (XRD) patterns. Silicates in the oxidized nickel slag (ONS) are mainly augite (Ca(Mg,Fe)Si2O6), forsterite ((Mg,Fe)2SiO4), and monticellite (CaMgSiO4), while akermanite (Ca2MgSi2O7) is observed only for a basicity up to 1.10. The oxidation kinetics of Fe2SiO4 in INS are first order with an apparent activation energy (Ea) of 315.16 kJ/mol.     

Influence of vitamin E on preventive or therapeutic effect of MFA and DTPA in cadmium toxicity

Exposure to hypochlorous acid (HOCl), the main product of the reaction of neutrophil myeloperoxidase (MPO), H2O2, and Cl-, reportedly decreases apotransferrin's iron binding capacity. Optimal transferrin iron binding requires the coexistent binding of anions such as bicarbonate (HCO3-) near the protein's two iron binding sites. Recently, we found that if HCO3- was also present during HOCl exposure, apotransferrin retained its ability to inhibit iron-catalyzed hydroxyl radical generation. Therefore, we examined apotransferrin iron binding capacity after exposure to the MPO/H2O2/I- system in the presence and absence of several anions (HCO3-, H2PO4, SO4(2-), and ClO4-) known to bind to apotransferrin. Although the MPO system decreased apotransferrin iron uptake to only 46% of the untreated apotransferrin control, apotransferrin treated in the presence of 1 mM HCO3- or H2PO4- retained 84 and 74%, respectively, of its iron binding capacity. Similar results were seen when apotransferrin was treated with NaOCl. These results could not be explained on the basis of a loss of MPO activity or scavenging of HOCl. In contrast, SO4(2-) and ClO4- were unable to prevent the MPO-mediated loss of apotransferrin iron binding capacity. NaOCl had no effect on the ability of transferrin to bind any of these anions, as assessed by the anion-induced change in apotransferrin absorbance spectrum. HCO3- but not H2PO4-, SO4(2-), or ClO4- decreased MPO-mediated oxidation (iodination) of apotransferrin. Under some conditions H2PO4- actually increased apotransferrin iodination. HCO3- and H2PO4- may protect apotransferrin from MPO-mediated oxidative damage by preventing selective oxidation of one or both iron binding sites. This process may allow transferrin to retain its iron binding function during MPO exposure in vivo.     

渣系碱度对含碳球团渣相组成和渣铁分离的影响

采用煤基直接还原熔分技术和FactSage热力学分析软件以及XRD分析手段,研究了渣系碱度wCaO/wSiO2对高铁铝土矿含碳球团渣相组成和渣铁分离效果的影响。实验结果表明,渣系碱度对含碳球团的渣系组成和渣铁分离效果有重要影响。当碱度为1.0和1.5时,粒铁尺寸最大,渣铁的分离效果最好,粒铁收得率分别为91.55%和91.86%;当碱度为0.5时,粒铁尺寸较小,渣铁分离效果较差,粒铁收得率为65.43%。当碱度为2.0时;粒铁尺寸最小,渣铁分离效果最差,粒铁收得率只有44.53%。XRD分析结果表明,当渣系碱度分别为0.5、1.0、1.5和2.0时,熔分渣的主要组成分别为α-Al2O3-CaAl2Si2O8、α-Al2O3-CaO·6Al2O3-Ca2Al2SiO7、CaO·6Al2O3-Ca2SiO4-Ca2Al2SiO7、Ca2Al2SiO7-Fe2SiO4。FeAl4O7、CaAl4O7以及金属铁在熔分渣中的含量较少。     

Precipitative Removal of Fluoride from Electronics Wastewater

Synthetic wastewater was used for the investigation of main factors affecting F? removal performance. The existence of SiF2?6 or PO3?4, and a low initial F? concentration were the main causes of low and unstable F? removal. Lowering the pH reduced the adverse effects of SiF2?6 and PO3?4, and adding over 4 mg∕L?1 of freshly formed CaF2 precipitates as seed greatly enhanced F? removal during treatment of low concentration wastewater (50 mg∕L?1 F?). The seed-generation method, in which a small portion of wastewater was first mixed with the whole dose of Ca2+ and then mixed with the remaining portion of wastewater, greatly improved F? removal performance and could be used instead of the method of adding seed. The conclusions obtained from the treatment of synthetic wastewater were verified by using several kinds of actual electronics wastewater. The pH should be lower than 9 for efficiently removing F? from wastewater having a high ratio of SiO2 to F?, and an even lower pH was needed for treating wastewater with a relatively high PO3?4 concentration. The seed-generation method was also found to be effective for such wastewater with high concentrations of PO3?4.     

SiO2对CaO-Fe2O3熔体结晶矿物组成及显微结构的影响

摘要：由于近年来低品位铁矿石的使用量增加,导致烧结过程中SiO2含量升高。SiO2是烧结矿中主要的脉石成分,其含量的变化与烧结矿最终质量密切相关。运用X射线衍射、光学显微镜和SEM-EDS方法研究了SiO2对CaO-Fe2O3熔体结晶矿物组成及显微结构的影响。研究结果表明,随着SiO2含量的增加,CaO-Fe2O3-SiO2熔体结晶产物中CaFe2O4(CF)含量减少而富铁铁酸钙(SFC)含量增加,CaFe2O4和SFC分别以块状和板条状析出,SFC的晶体结构随着SiO2含量的增加从Ca36Fe144O25-2向SFCA-I转变;当SiO2的质量分数超过3.0%时,椭圆状的Ca2SiO4（C2S）从熔体中结晶,其含量随SiO2含量的增加而增加,另有大量圆点状玻璃相分布于铁酸钙基体表面。     

Removal of impurities from scandium chloride solution using 732-type resin

The deep removal of Al, Fe(Ⅱ/Ⅲ), Ca, Zr, Ti and Si from scandium chloride solution was carried out by using 732-type strong acid cation exchange resin. The effects of pH value, contact time and complexing agents(EDTA) on the purification process are investigated. The results indicate that the 732-type resin have a good scandium selectivity and the adsorption order is Sc Fe(Ⅲ)Al Ca Zr Ti Si in the pH range of 1-3. The separation of Sc and Zr, Si, Ti can be directly carried out because the resin have a good adsorption effect on Sc, AI and Fe(Ⅲ) but poor adsorption effect on Zr, Si and Ti under the condition of pH = 2.5 and contact time 180 min. The Fe(Ⅱ), Ca and Al are selectively adsorbed on the resin by adding reducing agent ascorbic acid and EDTA into the solution for reducing Fe(Ⅲ) to Fe(Ⅱ) and complexing Sc.By using two-step ion exchange adsorption separation method, the removal rates of Fe(Ⅲ), Ti, Al, Ca, Zr and Si are 95.5%,99.8%,100%,98.2%,98.6% and 100%,respectively.     

磷酸二氢钙淋洗修复矿区周边镉污染土壤

以磷酸二氢钙（Ca(H2PO4)2）为原料配制淋洗剂,对某矿区周边镉（Cd）污染土壤进行淋洗修复。分析了不同配制条件下淋洗剂中Ca2+、总磷含量及其对Cd污染土壤的淋洗效果,并在此基础上进一步分析了液固比、淋洗时间对修复效果的影响。对淋洗过程进行动力学分析,分析了淋洗前后土壤Cd形态分布。结果表明：淋洗剂中Ca2+、总磷含量与Ca(H2PO4)2投加量呈正相关,且未加热条件下配制的淋洗剂中Ca2+、总磷含量、pH更高。采用投加量为0.07 mol的Ca(H2PO4)2与去离子水混合加热配制的淋洗剂,在液固比5、淋洗时间3 h的条件下,淋洗效果最优,土壤Cd去除率高达70.83%。Elovich方程可以较好地拟合淋洗过程,解吸过程为非均相扩散过程。淋洗后,弱酸提取态及可还原态Cd得到有效去除。淋洗修复方法可行,为去除土壤中的Cd提供新思路。     

信江流域水化学与同位素地球化学特征

为探究信江流域水化学特征,揭示流域内主要离子来源及其影响因素,共采集了82个地表水、地下水样,运用数理统计方法分析水化学组分特征,Piper三线图和舒卡列夫分类法划分水化学类型,Gibbs图法和岩石风化端元模型分析离子来源和影响因素,氢氧同位素特征判别水体补给来源及影响因素。结果表明,信江流域地表水和地下水中优势阳离子为Ca2+,优势阴离子为HCO3-、SO42-,pH呈中性(7.32)和弱碱性(8.88)。水化学类型均以HCO3?SO4-Ca、HCO3-Ca型为主,地下水的水化学类型更丰富。水化学成因分析表明,地表水和地下水的主要控制因素是岩石风化作用,少量点位受人为因素影响。岩石风化端元模型进一步确定碳酸盐岩风化是研究区岩石风化的主导类型。氢氧同位素特征表明,信江流域地表水地下水均接受大气降水补给,地表水受蒸发作用影响最强,氢氧同位素分馏效应明显。地表水线和地下水线偏移明显,表明两者水力联系差。海洋性气团是信江流域水体的主要降水控制气团。     

Competitive Effects of Trichloroethylene on Cr(VI) Removal by Zero-Valent Iron

Eleven columns were set up under various groundwater geochemistry conditions to investigate the competitive effect of trichloroethylene (TCE) on hexavalent chromium [Cr(VI)] removal by zero-valent iron (Fe0). They were found to be electron competitors in the redox reactions. In the presence of TCE, the Cr(VI) removal capacities of Fe0 were decreased by about 40% when compared with their respective Cr(VI) removal capacities with identical groundwater geochemistry but without TCE. The specific reaction rate constant (kSA) of TCE was decreased by about 50% when Cr(VI) was singly applied. The kSA of TCE was further decreased by 75% in the presence of both Cr(VI) and carbonate. However, there was no apparent effect on the kSA of TCE when Cr(VI), hardness and carbonate were all present. It revealed that TCE was a stronger electron competitor of Cr(VI) and the degradation of TCE became more favorable when both hardness and carbonate were present. This suggests that the passivated precipitates formed on the Fe0 surface in the presence of both hardness and carbonate may significantly affect the Cr(VI) removal by Fe0 but has insignificant effect on the TCE removal.     

焦家断裂带深部地下水水化学特征及其变化规律研究

焦家断裂带位于龙（口）莱（州）断裂带的南段,为胶西北地区三大著名的金成矿带之一,分布有新城、焦家、寺庄和马塘等多个大中型金矿。为研究焦家断裂带深部水化学特征及其变化规律,选取了焦家断裂带上多个矿区的抽水试验孔的深部地下水水样13个,对这13个水样进行常规阴阳离子含量统计分析,并对焦家断裂带走向和倾向上深部地下水水化学变化规律进行分析。结果表明：焦家断裂带深部地下水水化学类型以Cl-Na型和Cl·HCO3-Ca·Na型为主,矿化度（TDS）在0.77~9.66 g/L之间,多数为微咸水和咸水,部分为淡水。焦家断裂带深部地下水的强酸大于弱酸。TDS与Cl-存在显著的线性正相关关系,与Na+、Mg2+之间存在较好的正相关关系,而与HCO3-、SO42-、Ca2+之间的相关关系不明显。对比分析表明,在焦家断裂带走向上,由南至北,Cl-、Ca2+含量和矿化度基本呈上升趋势。在焦家断裂带倾向上,由东至西,由浅部至深部,Cl-含量和矿化度呈上升趋势,且下盘含水层的Cl-浓度随深度变化较上盘含水层Cl-浓度随深度变化快。该研究成果为区域内深部地下水的合理开发利用提供了指导。     

Osteoid osteoma of the proximal humerus: two misleading cases

OBJECTIVES: To investigate how often the ED ordering of stat serum calcium (Ca+2), magnesium (Mg+2), and phosphorus (PO4(-3)) levels affected clinical treatment; to define the diagnoses of patients for whom Ca+2, Mg+2, and PO4(-3) measurements did affect clinical therapy; and to suggest guidelines for more appropriate ordering of these laboratory tests. METHODS: A retrospective chart review was performed in an academic teaching hospital. All adult ED patients who had Ca+2, Mg+2, or PO4(-3) laboratory testing during the 9-month study period were included and evaluated for potential clinical impact of an abnormal Ca+2, Mg+2, or PO4(-3) laboratory test. RESULTS: 1.477 patients had Ca+2, Mg+2, or PO4(-3) measured while in the ED during the study period. Of these, 260 patients (17.6%) had a total of 312 abnormal Ca+2, Mg+2, or PO4(-3) values as defined by results exceeding +/- 15% of normal reference values. Of these, only 5 patients (0.3%) received treatment for abnormal values in the ED, while 75 patients (5.1%) were treated once admitted to the hospital. In this study, the only diagnostic groups to whom significant treatment was administered were diabetic patients (Ca+2 and PO4(-3); alcoholic patients (Mg+2); and renal failure patients (Ca+2, Mg+2, and PO4(-3). CONCLUSION: These results suggest that stat Ca+2, Mg+2, and PO4(-3) levels seldom affect clinical treatment in the ED. The frequency of ordering these tests may be reduced by obtaining Ca+2, Mg+2, or PO4(-3) measurements only for patients known to be at risk for such abnormalities, based on their existing or suspected diagnoses. The authors suggest obtaining these tests, when indicated, on a "non-stat" basis, with the subsequent laboratory results becoming available in-hospital, where treatment is more likely to occur.     

Intense blue-emitting Ca₂PO₄Cl:Eu²⁺ phosphor for near-ultraviolet converting white light-emitting diodes

A blue phosphor Ca2PO4Cl:Eu2+(CAP:Eu2+) was synthesized by solid state reaction.The Ca2PO4Cl:Eu2+ exhibited high quantum efficiency and excellent thermal stability.The luminescent intensity of Ca2PO4Cl:Eu2+ was found to be 128% under excitation at 380 nm,149% under 400 nm,and 247% under 420 nm as high as that of BaMgAl10O17:Eu2+.The optimal doping concentration was observed to 11 mol.% of CAP:Eu2+.The energy transfer between Eu2+ ions in CAP were occurred via electric multipolar interaction,and the critical transfer distance was estimated to be 1.26 nm.A mixture of blue-emitting Ca2PO4Cl:Eu2+,green-emitting(Ba,Sr)2SiO4:Eu2+ and red-emitting CaAlSiN3:Eu2+ phosphors were selected in conjunction with 400 nm chip to fabricate white LED devices.The average color-rendering index Ra and correlated color temperature(Tc) of the white LEDs were found to be 93.4 and 4590 K,respectively.The results indicated that it was a promising candidate as a blue-emitting phosphor for the near-UV white light-emitting diodes.     

CaF_2及碱度变化对中间包覆盖剂黏度的影响

采用二次正交组合设计法,对以高炉渣为主料的不同碱性中间包覆盖剂的黏度进行了测试研究,得出CaF2及碱度变化对覆盖剂黏度的影响规律及程度,得到回归方程,采用XRD和TG-DSC热分析法对熔融覆盖剂的矿物相进行分析,研究黏度变化机理,优化配方。结果表明:覆盖剂的黏度随CaF2含量的增加呈现先增大后减小趋势;随碱度的增大而逐渐增大。XRD图谱和TG-DSC曲线表明:碱度由1.75增大到1.95时,熔融覆盖剂低熔点的黄长石区域等进入较高的尖晶石区域,生成物由Ca4Al2SiO7F2、Ca3(Mg2Si2O4)、CaAlO4等高熔点化合物,向Ca4Al2SiO7F2、(Mg,Fe)2SiO4、CaMgSi2O4等低熔点化合物转变,流动性逐渐加强。     

钼精矿真空冶炼过程中主要杂质元素分布的研究

为提高钼精矿真空分解产品的质量,降低产品中Si、Ca、Mg、Al等杂质的含量,在冶炼过程中加入了碳粉。对钼精矿中主要杂质元素Si、Ca、Mg、Al在真空分解过程中的分布进行了研究。结果表明,在钼精矿中加入碳粉,有利于杂质SiO_2、Al_2O_3、MgO、CaO的去除。在研究的温度范围内,硅脱除率~100%,镁脱除率~99.7%,铝脱除率~78.44%,随着碳含量的增加及时间的延长,其脱除率可能会进一步提高。钙脱除率~9.8%。采用品位为48%的低品位钼精矿为原料,在加入碳粉真空冶炼的条件下,得到的金属钼中钼含量达到了92%,S含量降至0.69%,主要杂质SiO_2降至0.0021%,Cu0.005%,P0.005%,Mg降至0.001%,Al降至0.64%,Ca含量为0.51%。铁含量为4.44%,基本没有去除。