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100℃下几种聚铝结晶的制备、表征及絮凝性能研究
A Research on Preparation of Several Kinds of Polyaluminum Chloride at 100℃, Characterization and Flocculating Property
【作者】 布林朝克;
【导师】 孙忠;
【作者基本信息】 内蒙古大学 , 物理化学, 2007, 硕士
【摘要】 本文采用湿渣法绘制了100℃下AlCl3—Al2O3—H2O三元体系的固液平衡相图,并在相图的指导下实现了对结晶水数目不同的两种五聚铝盐酸盐的制纯反应条件的有效控制,使其分别单独析出,制得产物一和二的纯度分别达到了84.58%和98.50%;通过化学分析、粉末XRD物相分析、红外光谱分析等分析及表征手段确定其主要物相分别为AlCl3·Al(OH)3·4H2O和AlCl3·Al(OH)3·7.5H2O。本文在制备聚合硫酸铝方面也取得了一定进展。在Al2(SO4)3·18H2O溶液中加Al粉调节碱化度,制成了一种六聚铝的硫酸盐—产物三,通过XRD分析,确定其主要物相为3Al2O3·4SO3·15H2O,经100℃下晶化,化学分析结果表明其纯度为93.7%。采用Al-Ferron法测定了三种产物的铝形态分布,测得产物一的Ala、Alb和Alc含量分别为:29.68%、34.56%和35.76%,形态分布较均匀,其中Ala含量较高是由于其含有15.42%的AlCl3·6H2O所致;产物二的三种形态含量分别为:0.77%、13.01%和86.22%,Alc含量占主导;产物三为:2.27%、4.02%和93.71%,Alc含量占绝对优势。产物二和三的Alc含量均较高,尤其是产物三,有一个原因可能是,产物二和三溶解性较差,尤其是产物三,其主要物相是硫酸盐,在常温下进行溶解并测定铝形态时可能有一部分没有溶解,其形态就被测成Alc,故其Alc含量较高。采用高岭土配制的模拟水样做了絮凝实验,其结果表明,产物一只在弱酸性条件下具有一定絮凝性能,在中性或弱碱性条件下无明显絮凝性能;产物二和三在中性或弱碱性条件下较大投加量(10-3.5mol/L)时具有较明显的絮凝性能。但在该投加量下出水样中残留铝含量过高,所以三种产物均不适合作絮凝剂。在100℃下结晶的聚铝品种的溶解度和Alb含量均较低,这可能是其絮凝性能差的主要原因。该实验事实支持了Alb是聚合氯化铝中关键絮凝成分的观点。虽然在100℃下结晶的聚铝产物的絮凝性能均不理想,但绘制出了该温度下AlCl3—Al2O3—H2O三元体系的固液平衡相图,找到了控制该温度下几种聚铝品种制纯反应的有效条件,为进一步纯化并培养这几种产物的单晶乃至解析其结构,从而深入揭示Al(Ⅲ)在100℃下水解聚合与形态转化规律,以及弄清聚阳离子的结构与其絮凝性能之间的联系打下了良好基础。
【Abstract】 In this paper, the solid-liquid balanced phase diagram of the system of AlCl3—Al2O3—H2O at 100℃was drawn with the method of wet dregs. With the guidance of the phase diagram, we controlled effectively the condition of preparing two kinds of 5-nuclear Al with 4 and 7.5 crystalline water, respectively. Let the two substances separated out solely from the solution one by one, got product one and two, their purity were up to 84.58% and 98.50%, respectively. Through chemical analysis, XRD and IR, the main phase of the two were confirmed as AlCl3·Al(OH)3·4H2O and AlCl3·Al(OH)3·7.5H2O.Some progress was made on the preparation of poly-Aluminum sulfate. Through adding Al powder into the aqueous solution of Al2(SO4)3·18H2O to modify the basicity, we got a sulfate of 6-nuclear Al—produc three. XRD identified it as 3Al2O3·4SO3·15H2O, after crystalization at 100℃, it’s purity improved to 93.7%, which was supported by chemical analysis.The aluminum species of the three products were studied using Al-Ferron time complex colorimetric method. The Ala、Alb、and Alc content of the product one are 29.68%, 34.56% and 35.76%, respectively, the species are distributed evevly. The relatively high content of Ala is duo to it’s 15.42% content of AlCl3·6H2O; The species distribution of product two are 0.77%, 13.01% and 86.22%, the main species is Alc; product three: 2.27%, 4.02% and 93.71%, Alc is the absolutely main species.Product two and three have high content of Alc, especially product three. These may because of the bad solubility of product two and three, especially, the main phase of product three is an aluminum sulfate, when be resolved at room temperature to measure the species distribution, one part was not resolved into water, it’s species was diagnosed as Alc, so their content of Alc is high. Prepared Kaolin suspending solution as simulated water sample, and treated this water sample with the three products. The result showed that, product oneexhibits certain extent of flocculating ability on only slight acidic condition, on neutral or slight alkaline condition exhibits no conspicuous flocculating ability; product two and three exhibits good flocculating ability on neutral or slight alkaline condition under the dose of 10-3.5mol/L, but the residue aluminum content in the post-treatment water sample was too high, so none of the three products can be used as flocculant.Those poly-aluminum species prepared at 100℃have low solubility and Ab content, which may can explain their bad flocculating ability. These facts can be a support to the viewpoint of Ab is the key flocculating component of the PAC.None of the aluminum species prepared under the temperature of 100℃has satisfactory flocculating ability, but drawn successfully the phase figure of the system of AlCl3—Al2O3—H2O at 100℃, found the effective condition of preparing several kinds of species at 100℃, which can be a solid basis for further purifying the products, get single crystals and analyse the structures to deeply reveal the rule of hydrolysis-polymerization, and species transformation of aluminum, clearify the relation between the structure of poly-cation and it’s flocculating property at 100℃.
【Key words】 Preparation; phase diagram; characterization; water treatment; flocculation;
- 【网络出版投稿人】 内蒙古大学 【网络出版年期】2007年 06期
- 【分类号】O631
- 【下载频次】142