含钙添加剂强化─水硬铝石矿拜耳法溶出过程的作用分析

一水硬铝石型铝土矿在拜耳法过程中很难溶出,加入石灰等添加剂可以改善其溶出性能．本文评述了石灰、其它含钙化合物、合成铁－水化石榴石以及ＣａＯ＋（Ｍｎ／Ｆｅ）等添加剂的作用效果,并对其作用机理进行了分析．     

含钙添加剂强化一水硬铝石矿拜耳法溶出过程的作用分析

一水硬铝石型铝土矿在拜耳法过程中很难溶出,加入石灰等添加剂可以改善其溶出性能.本文评述了石灰、其它含钙化合物、合成铁-水化石榴石以及CaO+(Mn/Fe)等添加剂的作用效果,并对其作用机理进行了分析.     

净水剂用铝酸钙粉中氧化铝溶出率的测定

介绍生产净水剂聚合铝反所用原料中的氧化铝溶出率的测定方法,此法适合多种含铝原料氧化铝溶出率的测定。     

铝土矿高温溶出过程的性能研究

评述在高压溶出铝土矿过程中,加入石灰等添加剂可以改善氧化铝溶出的工艺过程,同时论述石灰添加量、溶出时间、溶出温度对氧化铝溶出率的影响,并对其作用机理进行了分析.     

亚熔盐溶出一水硬铝石型铝土矿过程中赤泥的铝硅行为

对NaOH亚熔盐溶出一水硬铝石型铝土矿过程中赤泥的Al, Si行为进行了研究,通过实验研究了溶出过程的反应温度、碱矿比、添加CaO等主要因素对赤泥成分和物相结构的影响. 结果表明,在相同碱矿比下,温度越高越有利于Al2O3的溶出. 在碱矿比为2、反应温度为180℃、反应时间为2 h的条件下,一水硬铝石完全溶出,赤泥中硅主要以Na8Al6Si6O24(OH)2(H2O)2和Na9Al9Si15O48(H2O)27的钠铝硅酸盐形式存在. 亚熔盐溶出过程中添加CaO并不能抑制Si进入溶出液中,甚至会降低Al2O3的溶出率. 但添加CaO可以减少碱的损耗,适于处理中等品位的铝土矿.     

硬铝石矿拜耳法溶出液生产砂状氧化铝

本文介绍了对某厂处理－水硬铝石矿的拜耳法高浓度溶出液,经引进、消化、设计了一段分解生产砂状氧化铝新工艺。通过对该工艺技术条件的分析研讨,总结其生产实践,认为一段分解工艺,具有流程简短平稳、易于操作控制、分解出的氧化铝产出率高、产品为１００％砂状、能满足电解制铝要求等优点。具有较好的工业生产实用价值。     

低温磁化焙烧对高铁铝土矿溶出及磁选性能的影响

为实现高铁铝土矿铝铁元素的高效利用,采用“低温磁化焙烧-拜耳溶出-赤泥磁选”的方式处理高铁铝土矿,考察了焙烧温度、H₂浓度及通入时间对高铁铝土矿溶出及磁选性能的影响。结果表明,焙烧过程中一水硬铝石脱水转变为过渡态Al₂O₃,矿物发生热破裂现象,比表面积增大,氧化铝溶出活性增加,在焙烧条件为焙烧温度530℃、H₂浓度20vol%、H₂通入时间5 min时,氧化铝相对溶出率可达97.65%。磁化焙烧过程中,针铁矿转变为赤铁矿,再由赤铁矿转变为磁铁矿,通过溶出解除了铝铁元素之间的嵌布关系,对焙烧矿的赤泥进行磁选,其铁精矿品位达62.05wt%,铁回收率为86.36%。     

腐植酸在氧化铝生产溶出 沉降工艺中的影响

笔者曾在《腐植酸》1991年第2期,对烧结法生产氧化铝工艺中,添加腐植酸对提高碳分蒸发母液浓度及改善料浆流动性,已作了简单叙述。本文就腐植酸在烧结法生产氧化铝溶出、沉降工艺过程的影响再予以介绍,以供商讨。     

硫铝酸钙的氧化铝溶出性能

使用分析纯CaCO₃、Al₂O₃与CaSO₄·2H₂O配料,在1375℃、保温2 h的条件下合成了纯物相硫铝酸钙3CaO·3Al₂O₃·CaSO₄（C₄A₃S）,对其物相组成和微观形貌进行了表征。并探究了碳碱浓度、苛碱浓度、溶出温度、溶出时间、粒度等因素对C₄A₃S氧化铝溶出性能的影响。结果表明：C₄A₃S的氧化铝溶出性能随着碳碱与苛碱浓度的增加先提高,之后趋于稳定。粒度越小,溶出率越高。与七铝酸十二钙12CaO·7Al₂O₃（C₁₂A₇）相比,C₄A₃S的孔洞状结构使其氧化铝更易溶出,在10 min时氧化铝溶出率即达到98%以上,且溶出所需的碳碱浓度与溶出温度均低于C₁₂A₇。在最佳条件：碳碱80 g·L^-1、苛碱10 g·L^-1、溶出温度80℃、溶出时间10 min下,C₄A₃S的氧化铝溶出率为98.76%。     

拜耳法生产氧化铝的分解工艺

种子分解是拜耳法生产砂状氧化铝工艺中一个十分重要的生产单元,它直接影响氧化铝产品的质量.目前国内外生产砂状氧化铝的种子分解工艺共分为一段分解工艺和二段分解工艺.本文根据我国一水硬铝石生产砂状氧化铝的实际情况对一段分解及二段分解进行介绍并完成技术经济评估工作.     

Recovery of Gallium and Aluminum from Electrofilter Dust of Alumina Calcination Plant in Bayer Process

In this study, the recovery of gallium (Ga) and aluminum (Al) from the by-product of Bayer process, the electrofilter dust of a calcination plant, was studied. Factorial leaching tests were also designed based on the results of the preliminary tests. Effects of factors and their interactions on the extraction of Ga and Al were demonstrated using Analysis of Variance of the findings. In the factorial design, nitric acid (HNO₃) leaching tests up to 43.4% Ga and 35.2% Al were leached from the electrofilter dust. The addition of oxalic acid (H₂C₂O₄) significantly enhanced the sulphuric acid (H₂SO₄) leaching of the dust with up to 48.3% Ga and 39.6% Al extractions.     

ANFIS-Based Prediction of the Decomposition of Sodium Aluminate Solutions in the Bayer Process

This article presents the results of nonlinear statistical modeling of the decomposition process of sodium aluminate solution, as part of the Bayer technology for the production of alumina. Based on the data collected in 2011 and 2012 from industrial production in the Bira? Alumina Factory, Zvornik (Bosnia and Herzegovina), nonlinear statistical modeling of the industrial processes was derived. The model was developed as an attempt to define the dependence of the degree of decomposition of sodium aluminate solution as a function of the input parameters of the leaching process: caustic ratio (α_k) of the solution; ratio of the crystallization; content of Na₂O_(caustic) in the solution; the initial temperature of the solution; the final temperature of the solution; average diameter of the crystallized seeds; and duration of the crystallization process. As a tool for statistical modeling, Adaptive Network Based Fuzzy Inference System (ANFIS) was applied. The defined model using ANFIS methodology expressed a high level of fitting, and could be used to effectively predict the degree of decomposition of the sodium aluminate solution as a function of the input process under industrial conditions.     

拜耳法赤泥脱硫概述

介绍了大气中硫的污染及国内外脱硫技术,分析了各种技术的处理现状。结合拜耳法赤泥的性质,阐述了拜耳法赤泥吸收含硫废气的研究现状。经过吸收SO2、SO3、H2S改性后的赤泥,更易于开发利用,能大量作为建筑、铺路材料,达到"以废治废、变废为宝、综合利用"的目的。     

论过程工业的工序能力

本文以化学工业为例，简述了过程工业的特殊性，着重阐述了过程工业工序能力的量度、工序能力指数的实质、工序能力的评价及过程工业工序能力的其它问题，为正确理解和应用工序能力进行质量管理阐明了正确的概念和方法     

氧化铝压煮器的制造技术

本文介绍了溶出压煮器的典型结构,分析了制造上的难点,有针对性地提出了解决难点的特殊工业方案,记录了实际制造经验数据,对类似设备的制造有着重要的参考价值。     

硫酸法钛白生产中钛铁矿液相酸解反应的实验研究

低浓度硫酸液相酸解钛铁矿可以大幅度减少硫酸法钛白生产中的废酸、废气排放。通过在高液固比、强搅拌下进行的实验研究表明,65%～80%硫酸液相酸解仍具有很好的反应活性。工业酸矿比条件下,采用反应过程中不断加入稀酸或水稀释的方法,增加料浆的流动性能和搅拌性能,可以实现液相酸解操作。液-固相酸解的对比实验表明,工业条件下固体产物层对酸解率有很大影响;通过SEM、EDS等表征,发现液相法酸解矿粒表面产物层比固相法要薄,分布更疏松。液相酸解工艺条件优化结果表明,在酸矿比1.4下,用65%～75%硫酸,150～160℃,120min,酸解率高于85%。可以得到总钛浓度116kg/m3,F值为2左右的合格钛液。操作周期缩短到2～3h。     

Reaction behavior of quartz in gibbsite-boehmite bauxite in Bayer digestion and its effect on caustic consumption and alumina recovery

A high content of quartz is usually present in Australian gibbsite-boehmite bauxite. The reaction between quartz and sodium aluminate solution at high temperatures in the Bayer process can lead to loss of alumina and sodium oxide. Therefore, to improve alumina recovery, the reaction of quartz needs to be avoided. The digestion behavior of Australian gibbsite-boehmite bauxite and pure quartz in the Bayer process at 230–250 °C was systematically studied in this paper. The mineral composition and morphology of the reaction products were characterized and the kinetics of the quartz dissolution process was studied in detail. It was shown that boehmite in gibbsite-boehmite bauxite can be completely digested at high temperature (250 °C) with a short digestion time (5 min). A short digestion time results in a low reaction rate of quartz in bauxite, and is ideal for alumina recovery at high temperatures. The quartz reaction rate rapidly increases with longer digestion times. The apparent activation energy of the dissolution of quartz in bauxite in the caustic solution is 151.9 kJ mol^?1, and the rate-controlling step of this reaction process is the interfacial chemical reaction. By controlling the particle size of bauxite, the digestion temperature, and the digestion time, the reaction rate of quartz in bauxite can be inhibited, which is beneficial for improving alumina recovery and reducing caustic consumption. Therefore, based on the above theoretical research, a process for digesting gibbsite-boehmite bauxite is proposed using high digestion temperature (250 °C), short digestion time (5 min) and large mineral size. An economic benefit of about US$101.9 million for a refinery with the annual output of 2 million tons of alumina can be created by the proposed process.     

拜耳法赤泥综合利用研究现状

赤泥是氧化铝生产过程中排放的固体废渣,其组成和特性因铝土矿的种类和生产工艺的不同而不同。论述了赤泥被用于环境污染治理和低附加值的建筑材料等领域的研究状况,以及从赤泥中回收有价金属的研究。针对目前拜耳法赤泥利用的现状,提出了一种综合高效利用拜耳法赤泥的新工艺。