优质矾土熟料生产中的原料均化过程

原料的均化过程是指矿山开采到煅烧之前的各主要环节。它包括矿山搭配开采运输；预均化与贮存；磨细混练压球；各料仓贮放、干燥等工序．承担均化任务量最大的是原料预均化，约占总量的７０％～８０％。原料预均化最优方式为长形料仓式原料预均化库。它具有投资低、占地面积小、作业条件好、粉尘少、均化效果高等优点．     

矾土熟料和矾土均化料的性能及其在高铝浇注料中的应用

对矾土熟料和矾土均化料两种耐火原料的理化性能进行了比较,研究以其为骨料制备的水泥窑用高铝浇注料的性能.结果表明:经过均化提纯工艺制备的矾土均化料较矾土熟料理化性能均一稳定,并基本上克服了后者不同粒度间化学组成差异的问题;与矾土熟料相比,以矾土均化料为骨料制备高铝浇注料具有更好的性能,可以满足更高一级水泥窑用高铝浇注料指标的要求.     

小型原料预均化库

本文论述了小型原料预均化库的研究过程、试脸结果、均化原理、结构及经济效益等。这种均化库可进行多种原料均化,均化倍数达3～8。设备简单实用,便于操作管理,且具有易防尘、占地少、投资省、电耗低等优点,便于小水泥厂使用。     

原料预均化的选择和应用

水泥生产所需的原燃料来自形成年代非常久远的各种矿物,由于受自然条件的影响,这些矿物的成分大多是不稳定的,对水泥的生产有很大影响。现代干法水泥生产的质量是通过一系列环节控制的,通常我们称它为一个控制链。在这个控制链中,包括了矿山的搭配开采、原料预均化、原料粉磨前的配料以及生料入窑前的均化。为了获得高质量的熟料以及烧成系统     

炭黑对轻量均化矾土孔结构的影响

以均化矾土生料和炭黑为主要原料,研究了炭黑种类(炭黑N990和炭黑N774)、加入量(加入质量分数分别为0、4％和8％)及热处理温度(1450、1500和1550℃下保温3 h)对轻量均化矾土孔结构的影响.结果表明:随着温度的升高,轻量均化矾土气孔数量逐渐减少,平均孔径增大;炭黑N990易于分散,所制得的轻量均化矾土气...     

水泥原料预均化方式的比较与选择

介绍了我国不同规模、不同条件的水泥厂采用的原料预均化各种方式，着重分析了原料自然条件、工艺要求、设备运行、建筑结构、占地面积、粉尘治理等因素的影响。通过对技术经济等方面的分析与比较，说明工厂需要根据自身条件和工艺要求进行方案对比后才能选出适合本厂的原料预均化方案。     

w（Al2O3）≥80%的矾土熟料和矾土均化料的性能及应用

通过对w(Al2O3)≥80%的矾土熟料和矾土均化料的性能检测发现:均化料的致密度(体积密度3.42g·cm-3,显气孔率0.84%)优于矾土熟料的(体积密度3.32 g·cm-3,显气孔率4.19%);应用试验表明:以矾土均化料为骨料制成的铝镁碳砖的高温抗折强度高于以矾土熟料为骨料的。因此,矾土均化料更适用于矾土与非氧化物复合的耐火材料。     

水泥原料均化理论与提高圆库均化效果的技术途径

通过对原料均化原理的分析，建立了均化效果的理论计算方法，给出了均化系数计算公式Ｋ＝σ１／σ２＝√Ｎ。在此基础上，分析论证了提高圆库均化效果的技术途径，从而为实现低投资型设计方案提供了理论基础和技术途径，并对生料均化，水泥均化及其它物料的均化具有普遍的指导意义。     

矩形石灰石预均化堆场原料配比调整

新型干法水泥生产中,矩形石灰石预均化堆场的均化效果较好,缺点是换堆前后原料配比难以掌握。表1是石灰石换堆后连续9个小时的生料KH值,由于中控操作员经验不足,数据离散性很大,如果生料粉库存量不足,均化效果差,将严重影响窑系统热工制度的稳定。目前,由于缺少适合新型干法水泥的生料配料调整控制软件,多数企业还是采用手工调整的老方法,具有一定的肓日性和滞后性。本文通过石灰石分析成分和生产成分对应关系的研究,提出了出磨生料原料配比的生产成分调整法,根据堆头石灰石生产成分的变化规律,进行不同时间段原料配比的分别调整,可有效解决长期困扰我们的难题。     

Effect of mineral acids on the production of alumina nanopowder from raw bauxite

In this study a novel synthetic method for the large-scale production of spherical, high surface area and ultra-fine alumina (Al₂O₃) powder has been described. Synthetic Bayer liquor was extracted by alkali fusion of raw bauxite with sodium hydoxide. Alumina nanopowders were synthesised through a ball mill-aided precipitation method using the synthetic Bayer liquor and mineral acid precipitants. The powders produced were characterised by X-ray diffraction (XRD), particle size distribution (PSD), Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller surface area and pore size analysis, energy-dispersive spectroscopy (EDS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In this article, the effects of precipitants such as H₂SO₄, HCl and HNO₃ on crystallite and particle size, surface area, pore volume, and pore size and shape are reported. The experimental results prove that precipitation leads to an aggregated particle that is disaggregated by the ball-milling method. The ball milling process strongly influences the formation of uniform-sized spherical particles with a high surface area. It was revealed that nitric acid is an effective precipitant for controlling particle size and textural properties of Al₂O₃ powder. A nanopowder of γ-Al₂O₃ with an average crystallite size of 3 nm and an average particle size of 58 nm with a specific surface area (SSA) of 190 m² g^− 1 is produced. This article elucidates a new method with a simple reaction scheme for the mass production of Al₂O₃ nanoparticles from raw bauxite for various commercial applications.     

采用新型生料质量控制系统取代生料均化库的可能性分析

本文论述了目前国内普遍采用的生料质量控制系统存在的主要问题，介绍了一些国内尚未采用的新的生料质量控制系统的技术方案。同时就新控制技术方案中的前置式在线生料质量控制系统特点的分析，提出了新型干法生产线使用该系统，将使缩小或取消生料均化库成为可能。     

铝土矿生产氧化铝过程脱硫方法的研究进展

介绍了硫在铝土矿中存在的形态、硫及其化合物对生产工艺、产品氧化铝质量的影响。对浮选法、碱性铝酸盐溶液浮选法,电位调控浮选法、碱石灰烧结法以及添加脱硫剂的氧化铝湿法除硫等几种脱硫方法的主要优缺点作了简要评述,详述了氢氧化钡、铝酸钡、氧化钙脱硫剂湿法脱硫的原理及其特点。     

降低氯乙酸生产原料消耗的经验

根据多年的生产实践,提出了降低氯乙酸生产原料消耗的经验。     

A novel chemical composition estimation model for cement raw material blending process

Raw material blending process is an essential part of the cement production process. The main purpose of the process is to guarantee a certain oxide composition for the raw meal at the outlet of the mill by regulating the four raw materials. But the chemical compositions of raw materials vary from time to time, resulting in difficulties to control the oxide compositions to a predefined value. Therefore, a novel algorithm to estimate the chemical compositions of the raw materials is developed. The paper mainly consists of two parts. In model construction part, a novel constrained least square model is proposed to overcome the deviation introduced by long-term drift of the material components, and the model parameters are estimated with an online strategy. And in validation part, the approach is implemented to two examples including datasets from simulation model and the actual industrial process. The final results show the effectiveness of the proposed method.     

Comparison of the fixation of heavy metals in raw material, clinker and mortar using a BCR sequential extraction procedure and NEN7341 test

The release potential and leaching behavior of five heavy metals (As, Cd, Cr, Cu and Pb) in raw material, clinker and mortar were studied by the three-step sequential extraction procedure proposed by the commission of the European Communities Bureau of Reference (BCR) and NEN7341 leaching test. The results of two experimental methods were compared to show the fixation difference of heavy metals among three kinds of samples. The results of NEN7341 leaching test show that the maximum leached concentration of cement products is low and the leached fraction of five heavy metals represents less than 15% of the total heavy metal content of the cement product. To refer to the bulk content as a criterion of environmental impact is not appropriate. The results of sequential extraction procedures show that the bonding forms of heavy metals change a lot in three samples. The contamination factor (Cf) and the leached fraction of each element in three samples indicate that all the elements are better fixed in cement products than in raw material due to calcination and hydration. To most elements, the relative metal retention is higher in mortar than in clinker. Compared within the five analyzed elements, Cd is better retained and Cu is worse retained in the same kind of sample.     

贵州中低品位铝土矿综合利用分析

简要介绍了中国铝土矿资源的整体分布情况,较为详细地分析了贵州修文中低品位铝土矿的化学成分特点、矿物成分特点及XRD特征,综合阐述了中低品位铝土矿在生产氧化铝、耐火材料、化学制品方面以及其他方面的应用情况。认为贵州铝土矿资源丰富,但属于高铝高硅型,且铝硅比较低,除了少数可以用拜耳法来生产氧化铝外,大部分铝土矿属于中低品位铝土矿,在生产氧化铝方面往往采用联合法来处理。对于中低品位铝土矿,除了用于生产氧化铝外,在耐火材料、陶瓷及聚合物等方面的应用也在日渐发展,实现了铝土矿的综合利用。     

Evaluation of aluminum dross waste as raw material for refractories

An aluminum dross waste from plasma processing for Al metal reclamation was tested as a replacement raw material in refractories. The main phases of the starting Al dross waste material were MgAl₂O₄ and AlN. The waste was tested to replace calcined alumina in castables and refractory clay in a molded refractory at levels below 6.5%. The results of physical and mechanical tests indicated that the waste may be applied directly, without prior calcination, as a substitute for fine structural components in refractories. The waste and water contents used in processing, however, must be optimized to avoid the formation of crack-like defects in the microstructure. The origin of these defects is related to the generation of gas from the waste at high temperatures. It is not known if these crack defects impact physical properties. The waste was also tested as a replacement for anti-oxidant elements (Al and Si powders) in a resin-bonded refractory. Oxidation tests, however, indicated a negative effect on oxidation resistance.     

Effects of raw material homogenization on the structure of basalt melt and performance of fibers

In this study, basalt from a base in Hebei, China, was selected as the raw material. Water-quenched basalt glasses and basalt fibers were prepared at different homogenization times and temperatures. The water-quenched glass structure was characterized by XRD and a Raman spectrometer followed by fitting of their Raman spectra by Gaussian curves to obtain information about melt structure. The fiber performance was characterized by fiber strength meter and fiber fineness meter. The results demonstrate that homogenization time and temperature had significant effects on the structure of basalt melt. The degree of polymerization of the melt increased with increasing homogenization time and decreased with increasing homogenization temperature. The fiber strength increased with increasing the degree of polymerization. As the homogenization time and temperature increased, coefficients of variation of fiber strength and fiber diameter decreased, indicating enhanced fiber stability.