Effect of inorganic salt impurities on seeded precipitation of silica hydrate from sodium silicate solution

To clarify the precipitation of silica hydrate from the real desilication solutions of aluminosilicate solid wastes by adding seeds and improve integrated waste utilization,the seeded precipitation was studied using synthesized sodium silicate solution containing different inorganic salt impurities.The results show that sodium chloride,sodium sulfate,sodium carbonate,or calcium chloride can change the siloxy group structure.The number of high-polymeric siloxy groups decreases with increasing sodium chloride or sodium sulfate concentration,which is detrimental to seeded precipitation.Calcium chloride favors the polymerization of silicate ions,and even the chain groups precipitate with the precipitation of high-polymeric sheet and cage-like siloxy groups.The introduced sodium cations in sodium carbonate render a more open network structure of high-polymeric siloxy groups,although the carbonate ions favor the polymerization of siloxy groups.No matter how the four impurities affect the siloxy group structure,the precipitates are always amorphous opal-A silica hydrate.

Adsorption of sodium polyacrylate at interface of dicalcium silicate-sodium aluminate solution

The adsorption isotherm of sodium polyacrylate on dicalcium silicate（2CaO-SiO2） in sodium aluminate solution at 80 ℃ was studied.The type of surface adsorption of sodium polyacrylate is saturated adsorption,and the adsorption behavior belongs to L-type,according with the monolayer adsorption model of Langmuir equation.The surface coverage of sodium polyacrylate is 1.06 mol/μm2.The relation curve between the surface pressure and the molecular area of adsorption film was obtained by Gibbs formula.The variation of interfacial energy caused by adsorption as well as the relationship between the relation curve and the type of adsorption was discussed.

Influence of silicate anions structure on desilication in silicate-bearing sodium aluminate solution

The structural changes of silicate anions in the desilication process with the addition of calcium hydrate alumino-carbonate were studied by measuring Raman spectra, infrared spectra and corresponding second derivative spectra. The results show that the desilication ratio in the solution prepared by the addition of sodium silicate(solution-SS) is much greater than that in the solution by the addition of green liquor(solution-GL), and low alumina concentration in the sodium aluminate solutions facilitates the desilication process. It is also shown that alumino-silicate anions in the solution-GL, and Q^3 polymeric silicate anions in solution-SS are predominant, respectively. In addition, increasing the concentration of silica favors respectively the formation of the alumino-silicate or the Q^3 silicate anions in the solution-GL or the solution-SS. Therefore, it can be inferred that the low desilication ratio in the silicate-bearing aluminate solution is mainly attributed to the existence of alumino-silicate anions.

Equilibrium concentration of lithium ion in sodium aluminate solution

Excess lithium in alumina is significantly bad for aluminum reduction.In this study,the concentration variation of lithium ion in sodium aluminate solution with addition of synthetic lithium aluminate was investigated.Elevating temperature,increasing caustic soda concentration,reducing alumina concentration or raising molar ratioαk improved equilibrium concentration of lithium ion in sodium aluminate solution.Agitation speed had a minimal effect on lithium ion concentration.Over 0.65 g/L lithium ion equilibrium concentration was observed in digestion process,whereas 35 mg/L lithium ion concentration remained in solution after precipitation time of 9 h.Moreover,equilibrium concentration decreased sharply from digestion of boehmite or diaspore to seed precipitation,about 95%lithium was precipitated into red mud(bauxite residue)and aluminum hydroxide.This study provides a valuable perspective in removal or extraction of lithium from sodium aluminate solution in alumina refineries.

Properties of low-modulus sodium silicate solution in alkali system

The properties of low-modulus(m≤1)sodium silicate and pre-desilication solutions in alkali systems were studied by measuring their electrical conductivity,viscosity,and surface tension.The results show that the property of high concentration pre-desilication solution is similar to that of sodium silicate solution.The electrical conductivity of sodium silicate solution increases with increasing the temperature and silica concentration but decreases with increasing the modulus.Further,the viscosity of the solution increases with increasing the silica concentration and linearly decreases with increasing the temperature,whereas its surface tension gradually decreases with increasing silica concentration and temperature,indicating that the sodium silicate solution is an oligomer with strong surface activity.At room temperature,the electrical conductivity and surface tension of sodium silicate solution are higher than those of pre-desilication solution,whereas its viscosity is smaller than that of pre-desilication solution.A turning point exists at a silica concentration of 44.7 g/L.When the silica concentration is less than 44.7 g/L,the ionic structure of the solution is dominated by monomeric silicate ions.In contrast,when the silica concentration changes from 44.7 to 50 g/L,the migration number of silicate anions significantly decreases.

Structure characterization for the geopolymer of sodium silicate and metakaolin

Geopolymers of metakaolin and sodium silicate were synthesized respectively with the ratios of the amount of SiO2 in the sodium silica solution to that of Al2O3 in metakaolinite equal to 1.0, and 0.66. The geopolymeric structures of the products were investigated by 27Al and 29Si solid-state nuclear magnetic resonances with magic-angle spinning (MAS NMR), Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), differential scanning colorimetry (DSC) and scanning electron microscopy (SEM). The reaction of the Al-O sheet in meakaolinite with low-order polymerized Si-O tetrahedral units such as monomer of SiO4 yields three-dimensional structures with the Q3 Si-O tetrahedral structure and the coordination of Al(IV) in the Al-O tetrahedral structure. The geopolymers are essentially X-ray amorphous. The assays by 27Al and 29Si NMR, FTIR confirm that the active structure in the metakaolinite is the sheet of Al-O with three coordination states.

ANIONIC SPECIES OF SiO_2-CONTAINING SODIUM ALUMINATE SOLUTIONS

The anionic species of the SiO_2-containing sodium aluminate solutions prepared by different methods have been investigated by Raman spectra and ultraviolet spectra.It was found that these solutions have different SiO_2-containing anions.The solution prepared by leaching in- dustrial sinter of soda-lime sintering process contains polvsilicate ions with Si-O-Si radicals.

Concentration–discharge patterns of weathering products from global rivers

Quantifying the functional relationships relating river discharge and weathering products places key constraints on the negative feedback between the silicate weathering and climate. In this study we analyze the concentration–discharge relationships of weathering products from global rivers using previously compiled time-series datasets for concentrations and discharge from global rivers. To analyze the nature of the covariation between specific discharge and concentrations, we use both a power law equation and a recently developed solute production equation. The solute production equation allows us to quantify weathering efficiency, or the resistance to dilution at high runoff, via the Damkohler coefficient. These results are also compared to those derived using average concentration–discharge pairs.Both the power law exponent and the Damkohler coefficient increase and asymptote as catchments exhibit increasingly chemostatic behavior, resulting in an inverse relationship between the two parameters. We also show that using thedistribution of average concentration–discharge pairs from global rivers, rather than fitting concentration–discharge relationships for each individual river, underestimates global median weathering efficiency by up to a factor of ～10. This study demonstrates the utility of long time-series sampling of global rivers to elucidate controlling processes needed to quantify patterns in global silicate weathering rates.

Investigation on the Thermo-dynamics of Alkali-activated Carbonatite

The thermo-dynamics of reactions between carbonatite and sodium silicate solution at ordinary temperature （25℃） were investigated. The calculated results indicate that at ordinary temperature, the reactions between dolomite, calcite, Ca2＋ and Mg2＋ in carbonatite and H4SiO4, tl3SiO4- and H2SiO42- in sodium silicate solution to form the cementitious products of hydrated calcium silicate or hydrated magnesium silicate all possibly happen; among these reactions, the reactions to form gyrolite （2CaO.3SiO2.2.5H2O） and serpentine （3MgO.2SiO2-2H20） are the most possible to occur. Further, the dissociation degree of dolomite and calcite and the activity of H3SiO4 , H2SiO42- and H4SiO4 ions are the key factors to influence the reactions.

Synergistic Inhibition Effect of Sodium Silicate and Acrylamide on the Corrosion of Carbon Steel in a High-concentration KCI Solution

The corrosion inhibition performances of sodium silicate（Na2SiO3） and acrylamide（AM） for Q235 carbon steel in a high-concentration KCl solution（25%, mass fraction） were investigated via static mass loss method, elec- trochemical measurements, scanning electron microscopy（SEM）, X-ray photoelectron spectroscopy（XPS） and Auger electron spectroscopy（AES）. AM shows poor inhibition performance, while Na2SiO3 exhibits a better inhibition per- formance. Moreover, the steel gains mass instead of losing mass in the presence of 0.5% Na2SiO3 and 0.5% AM, in- dicating that the corrosion is completely inhibited~ SEM analysis indicates that a compact protective film is formed on the steel surface by the combined use of inhibitors. Our results demonstrate that Na2SiO3 and AM could have a synergistic effect on steel corrosion in high concentrations of KCl. The synergistic inhibition mechanism is further conjectured by the XPS and AES analysis.

Influence of Temperature and Water Vapour Pressure on Drying Kinetics and Colloidal Microstructure of Dried Sodium Water Glass

Industrially produced sodium water glasses were dried in climates with controlled temperature and humidity to transparent amorphous water containing sodium silicate materials. The water glasses had molar SiO2:Na2O ratios of 2.2, 3.3 and 3.9 and were dried up to 84 days at temperatures between 40&degC and 95&degC and water vapour pressures between 5 and 40 kPa. The materials approached final water concentrations which are equilibrium values and are controlled by the water vapour pressure of the atmosphere and the microstructure of the solids. The microstructure of the dried water glasses was characterized by atomic force microscopy. It has a nanosized substructure built up by the silicate colloids of the educts but deformed by capillary forces. In the final drying equilibrium, the water vapour pressure of the atmosphere in the drying cabinet is equal to the reduced vapour pressure of the capillary system built up by the silicate colloids. Their size scale can be explained by the deformation of colloidal aggregates due to capillary forces.

The Study of Method for Complex Processing Turgay Sub-Standard Aluminum-Containing Raw Materials

objects of the research are Kazakhstan’s Turgay clay, studied of method for alumina and potassium metasilicate obtaining from Turgay sub-standard aluminum raw materials. Concluded that optimal conditions for the process of Turgay clay: reaction temperature 100°C, original solution K2O concentration to 300 g/dm3, reaction time 120 min, liquid-solid ratio of 3:1;optimized the conditions of digestion alumina concentrate: original Na2O solution concentration of 400 g/dm3, temperature 280°C, molar ratio CaO : SiO2 = 1. Recovery is 99.6 % of alumina digestion under this condition;crystallized solid phase components as Na2O·Al2O3·6H2O sodium hydroaluminate crystals. Extracted of alumina from solution of sodium

黄铜矿粗选指标对水玻璃超声波改性的响应及其机理

为阐明黄铜矿粗选指标与水玻璃超声波改性的内在关系,以超声波预处理的水玻璃为调整剂,进行了黄铜矿实际矿物的浮选试验,并采用pH值、黏度及红外光谱等手段对超声波预处理水玻璃溶液及矿浆浊度进行了表征。结果表明,黄铜矿的粗选回收率对超声波改性的水玻璃较为敏感。铜的回收率在水玻璃预处理时间为15 min作用时的敏感性最强,为85.42%,与未改性水玻璃的回收率相比提高了9.19个百分点。超声波预处理可减小水玻璃溶液的pH值,并使其黏度降低0.36%,这有利于水玻璃在矿浆中的分散。此外,超声波预处理还可改变水玻璃溶液的中水分子的比例以及水玻璃官能团的组成,并使预处理后的水玻璃溶液中游离水羟基与H 2 SiO 3中的Si—OH的相对比例分别提高7.83个百分点和1.08个百分点。游离水组份的增加有利于改善黄铜矿的疏水性及浮选效果,水玻璃有效成分H 2 SiO 3中Si—OH的组份增加在一定程度上强化了对矿泥的分散作用,从而提高了粗选作业铜的回收率。研究对超声波技术在有色金属浮选领域的应用有一定参考意义。

封闭处理对超声波辅助制备的锌系磷化膜耐蚀性的影响

在Q345钢磷化过程中引入超声波以改善锌系磷化膜表面平整度和致密性,为进一步提高超声波辅助制备的锌系磷化膜耐蚀性,分别采用油性封闭剂、硝酸铈溶液、硅酸钠溶液进行封闭处理。结果表明:硅酸钠溶液的封闭效果好于油性封闭剂和硝酸铈溶液,封闭后超声锌系磷化膜的物相组成为Zn_(3)(PO_(4))_(2)·4H_(2)O、Zn_(2)Fe(PO_(4))_(2)·4H_(2)O、ZnSiO_(3)和Na_(2)Si O_(3),并且呈现良好的致密性和耐蚀性,其耐硫酸铜点滴时间超过150 s,腐蚀电流密度低至3.20×10^(-6)A/cm^(2),较未封闭超声锌系磷化膜的腐蚀电流密度降低幅度接近一个数量级。在硅酸钠溶液封闭过程中发生腐蚀整平现象,同时生成ZnSiO_(3)并析出Na_(2)Si O_(3)起到填补孔隙的作用,使超声锌系磷化膜的致密性得到更大程度改善,从而显著增强抗腐蚀能力。

苛碱体系低模数硅酸钠溶液的结构

通过红外光谱测试技术,研究二氧化硅质量浓度、模数以及放置时间对苛碱体系低模数m(m≤1)硅酸钠溶液结构的影响,比较纯硅酸钠溶液和预脱硅溶液在结构上的差异。研究结果表明:苛碱体系预脱硅溶液结构与纯硅酸钠溶液结构相似,模数0.75≤m≤1.00,ρ(SiO2)≤20 g/L的硅酸钠溶液主要含有硅氧环状和三元环状这2种复杂阴离子;模数m≤0.50、30≤ρ(SiO2)≤50 g/L的硅酸钠溶液以单体和线型这2种简单形态出现;钠硅渣形成过程主要消耗单体硅酸根离子,ρ(SiO2)=50 g/L左右的预脱硅溶液结构稳定,溶液中的铝酸根离子不会影响硅酸根离子结构。

脂血对血常规红细胞参数测定结果的干扰及处理方法

目的:探讨脂血对血常规红细胞参数测定结果的干扰及处理方法。方法:选取2021年9月—2023年8月在广西壮族自治区脑科医院行血常规检测且血脂异常增高的脂血标本128份,分析采用等量0.9%氯化钠溶液置换血浆处理前后血常规参数变化。结果:处理后,血红蛋白(HGB)、平均血红蛋白量(MCH)、平均血红蛋白浓度(MCHC)、血小板(PLT)水平低于处理前,差异有统计学意义(P<0.05);处理前后,白细胞(WBC)、红细胞(RBC)、红细胞压积(HCT)、红细胞平均体积(MCV)比较,差异无统计学意义(P>0.05);在128份脂血标本中,23份MCHC≥380g/L,占17.97%,105份MCHC<380g/L,占82.03%。处理后,350g/L≤MCHC<380g/L和MCHC≥380g/L组的HGB水平均低于处理前,差异有统计学意义(P<0.05);处理前后,MCHC<350g/L组的HGB水平比较,差异无统计学意义(P>0.05)。结论:当MCHC≥350g/L时,建议检查标本性状,若是脂血影响,可通过等量0.9%氯化钠溶液置换血浆法进行纠正,0.9%氯化钠溶液置换血浆法能有效降低脂血对血常规红细胞参数测定结果的干扰,为临床和患者提供准确的检验报告。

响应曲面法优化PAC深度净化高浓度硫酸钠溶液中F-的研究

提出了以聚氯化铝(PAC,下同)深度净化高浓度硫酸钠溶液中F-,研究了铝氟物质的量比、反应终点pH和絮凝时间对F-去除率的影响。通过响应曲面法得到的回归方程模型来预测F-深度净化得到最佳的实验条件参数,同时用得到的响应曲面图和等高线图来直观反应各因素对F-去除率的影响及交互作用强弱。影响F-去除率的显著性因素从高到低依次为反应终点pH、铝氟物质的量比、絮凝时间。响应曲面法优化PAC去除高浓度硫酸钠溶液中F-建立的数学模型,其拟合值与验证实验结果的吻合度较高,絮凝沉淀前溶液含盐质量浓度为292.85 g/L、含F-质量浓度为70.58 mg/L,模型优化后最佳工艺参数:铝氟物质的量比为15.6,反应终点pH为7.6,絮凝时间为50 min,此时F-去除率为94.03%。经过多次实验验证得到,实际F-去除率均值为93.56%,F-去除率与模型预测值相差0.47%,净化后溶液中F-质量浓度可由70.58 mg/L降低至4.55 mg/L,说明模型优化条件准确性与可靠性高。

Diclofenac sodium aqueous systems at low concentrations: Interconnection between physicochemical properties and action on hydrobionts

Diclofenac sodium(DS) is a widely used nonsteroidal anti-inflammatory drug(NSAIDs).NSAIDs are poorly removed during standard wastewater treatment.The consequences of the presence of NSAIDs in rivers and lakes at 10-11–10-8 mol/L are not yet established;therefore, ecotoxicologists have focused their efforts on studying the effect of lowconcentration NSAIDs on fish and hydrobionts, and also on predicting the potential risks to humans.Literature provides some information about the bioeffects of some NSAID solutions in low concentrations but there is no physicochemical explanation for these phenomena.Studying the physicochemical patterns of DS solutions in the low range of concentrations and establishing an interconnection between the solutions’ physicochemical properties and bioeffects can provide a conceptually new and important source of information regarding the unknown effects of DS.The physicochemical properties and action of DS solutions on Ceriodaphnia affinis cladocerans,Paramecium caudatum infusoria, Chlorella vulgaris unicellular green algae, as well as on the growth of the roots of Triticum vulgare wheat seeds, were studied in the calculated concentration range of 1 × 10-3–1 × 10-18 mol/L.The relationship between these phenomena was established using the certified procedures for monitoring the toxicity of natural water and wastewater.It was shown for the first time that water solutions of DS are dispersed systems in which the dispersed phase undergoes a rearrangement with dilution, accompanied by changes in its size and properties, which affects the nonmonotonic dependences of the system’s physicochemical properties and could cause nonmonotonic changes in action on hydrobionts in the low concentration range.

工业铝酸钠溶液中腐殖酸的检测分析及降解规律研究

铝酸钠溶液中的有机物对氧化铝生产危害较大,目前铝酸钠溶液中腐殖酸浓度测定操作流程繁琐、测定结果准确度低,本文创新性提出了以“萃取-沉淀法”测定的腐殖酸浓度为基础,采用“吸光光度法”快速测定腐殖酸浓度的方法,并探讨进入工业铝酸钠溶液中的腐殖酸在高温循环过程中的降解规律,得到以下主要结论。萃取-沉淀法测定的原理是在反萃溶液中加入钡盐溶液沉淀腐殖酸,然后焙烧沉淀物,通过焙烧产物的质量推算腐殖酸浓度,试验用工业铝酸钠溶液中的腐殖酸浓度为1.80 g/L;吸光光度法测定的原理是先通过试验测定吸光度曲线方程Y=1.6298X-0.1628,再测定待测溶液吸光度,吸光度测量值应在0.2~2.0之间,代入方程即可计算出待测溶液中的腐殖酸浓度。温度和时间对腐殖酸的去除影响较大,温度越高,保温时间越长腐殖酸的去除率越高,280℃保温1 h后,腐殖酸去除率为68.30%;温度和时间对铝酸钠溶液中的总有机碳,以及丙二酸根、甲酸根、乙酸根、丁二酸根和草酸等小分子酸的质量浓度影响不大,但是草酸根质量浓度在长时间保温后则有较大幅度的增加,工业生产中需关注草酸钠质量浓度的变化。

复方聚乙二醇电解质散与硫酸镁钠钾口服用浓溶液在肠道准备中的应用效果比较

目的 比较复方聚乙二醇电解质散与硫酸镁钠钾口服用浓溶液在肠道准备中的应用效果。方法 56例行肠道疾病检查患者,采用抽签法分为比照组和试验组,每组28例。比照组采用复方聚乙二醇电解质散进行检查前的肠道准备,试验组采用硫酸镁钠钾口服用浓溶液进行检查前的肠道准备。比较两组肠道清洁合格率、不良反应发生率、电解质丢失率、肝肾功能异常情况、满意度。结果 试验组肠道清洁合格率92.86%高于比照组的64.29%,差异具有统计学意义(P<0.05)。试验组不良反应发生率10.71%低于比照组的42.86%,差异具有统计学意义(P<0.05)。试验组钠离子、钾离子、氯离子丢失率分别为7.14%、3.57%、10.71%,低于比照组的32.14%、25.00%、46.43%,差异具有统计学意义(P<0.05)试验组谷丙转氨酶、谷草转氨酶、血清尿素氮、血肌酐异常率均低于比照组,但差异无统计学意义(P>0.05)。试验组总满意率89.29%高于比照组的60.71%,差异具有统计学意义(P<0.05)。结论 复方聚乙二醇电解质散与硫酸镁钠钾口服用浓溶液均可进行肠道清洁,且不会对患者的肝肾功能造成影响,但硫酸镁钠钾口服用浓溶液的肠道清洁效果更显著,安全性更高,能够减少因过度腹泻造成的电解质丢失情况,值得推广应用。