表面活性剂PEG3000强化铝酸钠溶液晶种分解的研究

研究了表面活性剂PEG3000对铝酸钠溶液晶种分解的影响,结果表明,当PEG3000加入量为140 mg.L-1时,PEG3000在Al(OH)3颗粒表面的吸附量最高,铝酸钠溶液的表面张力最低,其分解率可提高8%,有效地强化了铝酸钠溶液晶种的分解.     

无机盐杂质对铝酸钠溶液晶种分解率的影响

采用对比实验法, 研究了不同类型、不同浓度的无机盐杂质对铝酸钠溶液晶种分解的影响, 并探讨了其影响机理。结果表明, 铝酸钠溶液中氯化钠、碳酸钠、硫酸钠等杂质的存在对晶种分解会产生不利影响, 当NaCl浓度大于10 g/L、Na₂O_s浓度大于5 g/L、Na₂O_c浓度大于10 g/L时, 均将对铝酸钠溶液晶种分解产生明显的抑制作用。无机盐杂质的存在会影响铝酸钠溶液中氢氧化铝颗粒表面的Zeta电位值, 使Zeta电位变得更负, 不利于氢氧化铝晶体颗粒对铝酸根离子的吸附, 从而对铝酸钠溶液晶种分解产生抑制作用。无机盐杂质使铝酸钠溶液表面张力增大, 也阻碍铝酸根离子在晶体表面的吸附, 对晶种分解产生不利影响。     

高浓度铝酸钠溶液晶种分解获得高强度产物的机理讨论

<正> 本文对铝酸钠溶液中氢氧化铝颗粒的附聚的研究作了概述。在此基础上,根据实验结果,探讨了高浓度铝酸钠溶液一段法晶种分解使产物具有高强度镶嵌结构的机理。一、前言铝电解用氧化铝根据其物理性质的差异分为砂状和粉状氧化铝(有时还划分一种物理性质介于砂状和粉状之间的中间状氧化铝)。由于砂状氧化铝良好的流动性和对氟化氢气体优良的吸附性能,适应现代大型预     

超声强化铝酸钠溶液分解过程中的成核现象

在不同温度，不同苛性比以及不同品种量条件下，研究超声与未超声强化铝酸钠溶液分解过程的成核现象。结果表明，在45—65℃，苛性比1．28—1．90条件下，超声强化不能促使铝酸铀溶液在未加品种情况下发生一次成核。而温度低于60℃时，超声强化则可以促使次生晶核的生成。随晶种量的增加，超声强化生成次生晶核的时间可以大大缩短。     

表面活性剂强化喷雾用水润湿性能的实验研究

表面活性剂可提高喷雾用水的润湿性能,从而改善喷雾降尘效果.研究开展了4种表面活性剂溶液润湿不同类型煤尘性能的实验,并考察了表面活性剂种类、质量分数等因素的影响.表面张力实验显示,随着表面活性剂质量分数的增大,溶液的表面张力会不断减小,其中阴离子表面活性剂SDBS在降低表面张力的效率和效能方面最优.接触角实验表明,随着表面活性剂质量分数的提高,液滴在煤尘压片上的接触角不断减小,溶液润湿性能不断提高,其中OP-10溶液的润湿性能最优,在相同的质量分数下,能够获得最小的接触角.     

表面活性剂溶液降低爆破尘毒的研究

通过表面张力的测定和爆破对比实验，得到了降尘毒效果较优的两种表面活性剂溶液配方。对表面活性剂溶液的降生毒机理进行了研究。     

基于表面活性剂的煤尘润湿性研究

通过对4种不同浓度的表面活性剂单体溶液进行张力值的测定,并结合表面活性剂单体溶液对煤尘润湿接触角实验,对煤尘润湿性进行定量表征研究。研究表明,表面活性剂单体溶液对煤尘的润湿性不仅表现在溶液的表面张力的大小,而且体现在溶液与煤尘的接触角大小;通过煤尘接触角实验结果拟合分析,阐明了非离子表面活性剂和阴离子表面活性剂在润湿效果上明显好于阳离子和两性离子表面活性剂的机理。     

一种季铵盐双子表面活性剂的合成研究

以1,3-二溴丙烷和十二烷基二甲基叔胺为原料,以异丙醇为溶剂,合成出一种季铵盐双子表面活性剂二溴化-N,N′-二(二甲基十二烷基)丙二铵,使用丙酮/异丙醇混合溶剂对产物进行重结晶提纯.研究了反应时间、原料比、反应温度等因素对产物产率的影响,测定了产物的熔程并进行了红外光谱分析.在反应物配比n(十二烷基二甲基叔胺)∶n(1,3-二溴丙烷)=2.2∶1.0、反应时间为12 h、反应温度为85 ℃条件下,产物产率为48.2%、临界胶束浓度(CMC)为10.339×10-4 mol/L.     

表面活性剂抑尘性能的实验研究

表面活性剂作为改善防尘用水湿润性能的有效方法之一,广泛应用于煤矿粉尘治理工作中。通过对相同条件下不同表面活性剂及复配试剂进行接触角、表面张力测定实验,分析了其各自的湿润性能,得出复配试剂B、BS-12、快渗T、APG的湿润性能较好,且复配溶液的湿润性增益与否同表面活性剂单体的自身物理化学性质有较大关系。     

压注表面活性剂溶液防治煤与瓦斯突出的研究

煤层注水是一种有效防治煤与瓦斯突出的方法。建山矿煤层由于渗透性差，水很难注入。我们通过室研究试验，得取提高该矿煤层注水效果的最佳表面活性剂及配方，经过现场压注试验，取得了满意的效果。     

粒度分布信息在铝酸钠溶液加晶种分解动力学研究中的应用

阐述了在铝酸钠溶液加晶种分解的动力学研究中充分利用粒度分布信息的意义．通过分析铝酸钠溶液加晶种分解过程中固相产物的粒度分布情况，提出用(dN／dt)成核，(dN／dt)附聚和(dr／dt)径向长大 分别表示二次成核、附聚长大和晶粒径向长大的速率，并分别得到了其速率表达式．采用微分法研究了晶粒径向长大，结果表明通过控制适当的反应条件，能够突出晶粒径向长大这一基本过程．利用粒度分布信息求得的晶粒径向长大速率与实际长大速率基本一致．     

粒度分布信息在铝酸钠溶液加晶种分解动力学研究中的应用

阐述了在铝酸钠溶液加晶种分解的动力学研究中充分利用粒度分布信息的意义.通过分析铝酸钠溶液加晶种分解过程中固相产物的粒度分布情况,提出用(dN/dt)成核,(dN/dt)附聚和(dr/dt)径向长大分别表示二次成核、附聚长大和晶粒径向长大的速率,并分别得到了其速率表达式.采用微分法研究了晶粒径向长大,结果表明通过控制适当的反应条件,能够突出晶粒径向长大这一基本过程.利用粒度分布信息求得的晶粒径向长大速率与实际长大速率基本一致.     

中高浓度铝酸钠溶液一段脱硅工艺研究

硅是铝酸钠溶液中最难除去的杂质,若硅含量过高会造成氧化铝产品的损失。本文通过改变脱硅温度、脱硅时间、铝酸钠溶液浓度及脱硅剂用量来确定铝酸钠溶液一段脱硅的最优条件。实验表明最优条件是脱硅温度为100℃,时间为100 min,脱硅剂的用量为27g/ L ,搅拌速度为300 r/ min,铝酸钠溶液浓度从140g/L~200g/L脱硅指数可达1000以上。并通过测定表面张力随脱硅时间、脱硅温度变化,及通过钙硅渣XRD衍射实验,分析了铝酸钠溶液一段脱硅机理。且铝酸钠溶液一段脱硅后能够基本达到铝酸钠溶液二段脱硅的工艺要求。     

AUC沉淀废液除铀工艺研究

碳酸铵沉淀氟化铀酰制备二氧化铀的中间体原料三碳酸铀酰铵(AUC)的沉淀工艺中,AUC沉淀过滤后的废液中每L仍含有几十~几百mg的以UO2+2或以UO2+2配合离子存在的U。为了达到排放标准,研究了先用双氧水(H2O2)沉淀废液中的U,再用离子交换树脂将未沉淀完全的U吸附,使废液的ρ(U)0.05mg/L,达到排放标准。讨论了蒸煮液pH值对碳酸根离子浓度的影响;H2O2沉淀废液中的U的沉淀温度、沉淀剂用量和酸度对沉淀效果的影响;比较了大孔硅胶、201×7、D201、001×7、001×8、D418树脂对AUC废液中U的吸附影响。吸附条件试验结果表明,D418离子交换树脂对氧化铀酰离子吸附结果较好,使处理后的废液中ρ(U)0.05mg/L,满足废水处理工艺要求。     

Recovery of manganese from iron containing sulfate solutions by precipitation

Worldwide consumption of manganese is increasing, nevertheless huge amounts of manganese from hydrometallurgical processes still end up as waste since the recovery of manganese from multi-metal solutions at low concentrations is not considered feasible. Poor iron control typically prevents the production of high purity manganese. This work studies a number of precipitants in manganese recovery and iron separation from sulfate solutions. The precipitation reagents were compared from the point of view of selectivity and economy. Carbonate precipitation is a fast and effective method for the recovery of manganese from bulk solutions. Subsequent leaching of metal carbonate is also easier and consumes less acid than, for example, hydroxide or sulfide precipitates. In order to avoid gypsum formation, soda ash should be used instead of limestone. It was found that efficient selective iron removal from MnSO₄ solutions is achieved with combined O₂ or air oxidation and CaCO₃ precipitation at pH >5.8 and at a redox potential of >200 mV. Effective mixing and sufficient retention time are essential to make the method technically efficient and economically feasible.     

Biologically enhanced degassing and precipitation of magnesium carbonates derived from bicarbonate solutions

This contribution reports the results of batch and semibatch experiments involving bubbling of nitrogen in aqueous solutions of magnesium bicarbonate, with and without the addition of either carbonic anhydrase (CA) or Scenedesmus alga to the solution. Precipitation of nesquehonite occurred during both an accelerated degassing of CO₂ induced by sparging small nitrogen bubbles (representative diameter of 20 μm), and during slow degassing engendered by introducing large nitrogen bubbles (representative diameter of 5 mm). The response of the system during low rates of degassing closely approached quasi-thermodynamic predictions, which permitted an estimation of the level of supersaturation of nesquehonite, prior to the onset of precipitation. Small bubbles and CA significantly increased rates of degassing and indirectly the production of nesquehonite, as the rate of degassing can limit the precipitation process. The response of the system during rapid rates of degassing, prior to precipitation, was not entirely consistent with quasi-thermodynamic predictions. During precipitation, higher rates of degassing produced similar alkalisation and precipitation trends to that observed for lower rates of degassing. Our results agree with the formation of travertine deposits in nature, where the degassing of solutions enriched with inorganic carbon, and enhanced alkalisation by microorganisms, have been shown to influence carbonate formation. The results demonstrate a catalytic effect of CA on the rate limiting carbonate reactions, increasing CO₂ exchange between nitrogen and water, and indirectly accelerating the precipitation of carbonates for a system controlled by rate of degassing. The results of this study have applications to large-scale storage of CO₂ by mineralisation.     

Recovery of dissolved platinum group metals from copper sulphate leach solutions by precipitation

The pregnant leach solution produced in the final leaching stage of base metal refineries (BMRs) operated by platinum producers contains impurities such as selenium and tellurium as well as other precious metals (OPMs, which include Rh, Ru and Ir). The aim of this project was to propose operating conditions for a thio-urea precipitation process that would allow maximum OPM recovery and impurity precipitation from the leach solution with minimal copper and nickel co-precipitation. Experimental results illustrating the effects that operating temperature (80 °C and 160 °C), pressure (atmospheric pressure and seven bar), stirring rate (250 rpm and 500 rpm) and thio-urea quantity (200% and 320% excess) have on the precipitation behaviour are presented.Virtually all of the Rh contained in the solution was precipitated irrespective of the values of the process variables studied. The maximum percentage Ru and Ir precipitation achieved were 87% and 60%, respectively. Complete Se precipitation was observed at all process conditions, while Te precipitation increased as the operating temperature was increased. Increasing the reagent quantity and temperature did, however, also result in increased copper and nickel co-precipitation.Regression models were used to perform numerical analyses to determine suitable operating conditions. Predictions with this numerical approach suggested that precipitation with 200% excess thio-urea at a temperature of 80 °C and a pressure of 7 bar would yield 98% Rh, 75% Ru, and 48% Ir precipitation with less than 5% Cu and Ni co-precipitation; these results could be experimentally validated.     

Extraction of zinc from zinc ferrites by fusion with caustic soda

Zinc ferrites are one of the major forms of zinc in some wastes, such as steel mill EAF dusts and the leaching residues of roasted zinc sulfide concentrates. These ferrites can be very difficult to chemically decompose so that the zinc can be recovered. This decomposition is the key to the recovery of zinc in these solid wastes. In this work, the recovery of zinc from synthetic zinc ferrite was investigated. It was found that around 75–80% of the zinc in zinc ferrite can be extracted after being fused directly with NaOH pellets and dissolved in an alkaline leaching solution. The recovery increased to over 90% when the ferrite was hydrolyzed with water or dilute NaOH solution prior to the fusion step.     

利用湿法炼锌赤铁矿法沉铁渣制备铁红

湿法炼锌工业中产生的沉铁渣的资源化利用,长期以来是备受关注的问题,渣的堆积容易对环境产生污染。目前主流的三种沉铁方法中的赤铁矿法所产生的赤铁矿渣具有较高的利用回收价值,对其的资源化利用,具有较高的研究价值。本文以湿法炼锌赤铁矿渣为实验对象,探究其在一定条件下使用酸洗浸出的方法制备高纯度铁红颜料的可行性,针对其中主要的杂质硫、锌等,以及不同含铁物相的去除与转化,研究了温度、时间、酸度、液固比对杂质脱除效果的影响。结果表明,在酸度8 g/L硫酸、温度220 ℃、时间3 h、液固比为6 mL/g工艺条件下可获得较好的脱杂提纯效果,可将沉铁渣铁含量由58%提高至66.5%以上,渣中主要杂质硫脱杂率在70%以上,锌等其余杂质脱除率在90%以上。