水泥赤泥混凝土强度形成机理

用磨细赤泥代替部分水泥形成的水泥赤泥混凝土，具有良好的力学特性，并能降低水泥混凝土的成本，且对环境保护有利。本文通过分析水泥赤泥体系的水化过程、水化生成物、硬化水泥赤泥浆体的微观结构形态，探讨分析了水泥赤泥的相互作用及水泥赤泥混凝土的强度形成机理。     

Preparation and Bloating Mechanism of Porous Ultra-lightweight Ceramsite by Dehydrated Sewage Sludge and Yellow River Sediments

To solve the disposal problems of solid wastes, dehydrated sewage sludge and Yellow River sediments were tested as components for production of ultra-lightweight ceramsite. The effects of Yellow River sediments addition on the characteristics of ceramsite were investigated. Ceramsite with different Yellow River sediments additions was characterized using thermal analysis, X-ray diffraction, morphological structures analyses, pore size distributions and porosity analyses. Chemical components, especially ratios of Si O2 + Al2O3/Flux, were used to explain the glassy shell formation, physical properties and pores distribution of ultralightweight ceramsite; physical forces for instance expansion force and frictional resistance which combined with Si O2 + Al2O3/Flux ratios were used to explain the bloating mechanism. Results showed that the maximum addition of Yellow River sediments for making ultra-lightweight ceramsite was 35%. Macropores(between 0.226 μm and 0.554 μm) of ultra-lightweight ceramsite were dominant in the pore structures of ultra-lightweight ceramsite and its porosity was up to 67.7%. Physical force of expansion force was constant with the variation of Yellow River sediments content and physical force of frictional resistance was decreased with the increase of Yellow River sediments addition. The relationship between expansion and frictional resistance could determine the expansion rate of ceramsite. Larger pores inside the ceramsite bodies could be obtained as Yellow River sediments additions ranged from 10% to 30%. Ceramsite with higher Yellow River sediments additions of 40%(Si O2 + Al2O3/Flux ratios 4.25) became denser and have lower porosity. Crystal components analysis proved that the sintering process made some components of raw materials transfer into other crystals having better thermostability.     

赤泥脱硫剂强度及耐水性影响因素研究

将具有较强碱性的赤泥制成粒状脱硫剂,通过正交试验,考察了烧结温度、烧结时间和添加剂掺比3个因素对脱硫剂强度和耐水性的影响,并确定最佳制备脱硫剂的方案.结果表明,烧结温度对赤泥粒状脱硫剂的强度和耐水性影响较显著;烧结时间和添加剂掺比的影响较小,并且两者影响相当.烧结温度为800℃、烧结时间为0.5 h、添加剂掺比为20%的条件下,制得的脱硫剂强度和耐水性最好.     

赤泥中氧化铝和氧化铁的浸出

为回收赤泥中的铝和铁,解决赤泥污染和占地问题,研究了用盐酸溶出废赤泥中的氧化铝和氧化铁的工艺,考察了赤泥的焙烧、盐酸与赤泥的液固比、盐酸的浓度、酸浸时间、酸浸温度及酸浸方式对赤泥中氧化铝、氧化铁浸出率的影响.结果表明：赤泥不需要焙烧,盐酸与赤泥的液固比4∶1,盐酸的浓度为6mol/L,酸浸温度在109℃左右,酸浸时间为60 min,酸浸方式为二次浸出,氧化铝和氧化铁的浸出率分别为89.00%和98.39%.     

赤泥在环境污染修复中的应用

赤泥用作环境修复材料具有成本低、工艺简单、以废治废的特点．系统介绍了赤泥对水体、土壤中重金属离子、有毒非金属离子、有机氯、染料颜料等无机、有机污染的环境修复作用．赤泥环境修复材料是附加值较高的赤泥开发产品，在开发利用过程中需对赤泥进行脱碱处理以避免其对环境的污染，在对水体修复时应避免赤泥留在水中造成水体浑浊。     

邯钢赤泥用于脱除硫化氢的研究

研究了以邯钢废赤泥脱除硫化氢,结果表明:活性赤泥具有较好的脱硫性能,其脱硫效率明显高于未加添加剂的废赤泥。同时实验了不同烘干温度、不同配比下赤泥的脱硫效率,筛选出活性赤泥的最佳配比为:赤泥85%,木屑5%,氧化钙10%,烘干温度130℃,并且与活性炭相比简要说明了赤泥的应用前景。     

赤泥处理含镉废水的影响因素

研究了赤泥对模拟废水中镉离子的吸附作用,以及反应时间、溶液中镉离子初始浓度、赤泥的掺加量、温度和pH值等因素对吸附的影响.结果表明,赤泥对镉离子有很好的吸附作用,对废水中镉离子的去除率最大可达99.4%.溶液中镉离子初始浓度不但影响吸附率而且影响吸附量,最大吸附量可达5.34 mg/g.在碱性环境中,该反应是吸附和沉淀共同作用的结果.该吸附以化学吸附为主,符合二级动力学方程和Freundlich吸附等温式.     

拜耳法赤泥中主要组分分离研究

采用铵盐焙烧、水浸、酸浸等工艺对拜耳法赤泥进行处理,分离出了赤泥中的主要组分铁、铝、钙、硅,得到其相应的化合物：氧化铁、硫酸铝、石膏和水玻璃．研究了焙烧、水浸和酸浸工艺对拜耳法赤泥成分的影响,探索了从拜耳法赤泥中分离铁、铝、钙、硅的工艺方法和技术条件,分析了制备样品的化学成分和物相组成．     

中州铝厂赤泥堆放场对环境的影响及治理对策

对中州铝厂所排灰水进行采样分析,并对其堆放赤泥做了大量的化验,实验证明,赤泥及冲灰水对环境具有一定的影响.在对赤泥成分进行细致分析的基础上,结合当前国内外对赤泥的研究现状,提出了治理赤泥污染的对策,探索赤泥的综合利用途径,从而为焦作水环境改善做出努力.     

采用烧结法处理高铁赤泥回收氧化铝

利用氧化铝热力学数据库,对高铁赤泥炉料烧成过程中的相关化学反应进行热力学计算,并在此基础上,研究烧成温度、烧成时间、炉料配比等烧成工艺条件对高铁赤泥炉料烧成效果的影响。研究结果表明：赤泥炉料的配钙量可以在较宽的范围内变化,并且在烧成过程中可能生成不溶盐类,导致熟料中氧化铝的溶出率降低：延长烧成时间和增加配料铁酸钠含量均有利于烧结：高铁赤泥炉料的最佳配料是：熟料中Na2O-Fe2O3质量分数为10％12％,钙铁摩尔比为1．0-1．2：烧成工艺条件是：温度为1000-1050℃,烧成时间为30--40min。在最佳配料和烧成工艺条件下,当熟料中氧化铝含量为15％左右时,熟料中Al2O33回收率可达85％-90％。     

铝厂赤泥“霜”物质成分分析

在氧化铝生产中产生的赤泥,堆放一段时间后表面常形成白色"霜"状物质,影响着将其作为建材原料的资源化利用.以中州铝厂各年期烧结法赤泥为研究对象,通过X-衍射、扫描电子显微镜、原子吸收等方法对各年期赤泥和赤泥"泛霜"物质进行研究,分析其化学成分与矿物组成,按溶解性将"霜"物质分为可溶钠钾盐类(NaCl,KCl,Na2CO3,KHCO3,NaNO3等)与不可溶钙镁盐类(CaCO3,MgCO3等).     

Strength development and microstructure of hardened cement paste blended with red mud

Red mud was activated to be a mineral admixture for Portland cement by means of heating at different elevated temperatures from 400 °C to 700 °C. Results show that heating was effective, among which thermal activation of red mud at 600 °C was most effective. Chemical analysis suggested that cement added with 600 °C thermally activated red mud yielded more calcium ion during the early stage of hydration and less at later stage in liquid phase of cement water suspension system, more combined water and less calcium hydroxide in its hardened cement paste. MIP measurement and SEM observation proved that the hardened cement paste had a similar total porosity and a less portion of large size pores hence a denser microstructure compared with that added with original red mud. Funded by the National 973 Program of China (No. 2001CB610703)     

拜耳法赤泥水洗脱碱工艺的研究

赤泥是氧化铝冶炼工业中排放的一种强碱性固体废弃物.为降低赤泥中碱的含量,实现赤泥综合、资源化的利用,对水洗脱碱工艺进行了初步研究.实验结果表明,洗涤次数和浸泡时间对脱碱效果影响较大,在室温下,液固比为5∶1时,赤泥浸泡1d后,洗涤5次以上时,可以去除赤泥中95%以上的Na＋.     

基于有机-无机改性的赤泥沥青混合料综合性能

聚焦赤泥的资源化利用与筑路材料紧缺问题,提出采用赤泥替代石灰岩矿粉制备沥青混合料。针对赤泥-沥青界面遇水强度衰减问题,提出无机粉体共混(水泥、消石灰)和有机偶联剂表面修饰(硅烷偶联剂KH-550、KH-560)的改性工艺,并研究改性前后的赤泥对沥青混合料性能的影响规律。通过动稳定度试验、马歇尔试验、汉堡车辙试验、动态模量试验和两点弯曲试验对改性前后的赤泥沥青混合料进行系统评价,发现普通赤泥可以提高沥青混合料的高温稳定性,但是对水稳定性、低温抗裂性与疲劳性能有不利影响。通过对赤泥改性处理,赤泥沥青混合料的高低温性能、水稳定性与长期耐久性均得到不同程度提高,而采用硅烷偶联剂表面修饰改性效果更好。证实了使用赤泥进行沥青混合料生产的可行性,为赤泥的资源化利用开拓了方向。     

广西平果县赤泥堆场周边岩溶地下水动态变化特征

根据地下水的长期观测资料,广西平果县赤泥堆场周边的岩溶地下水位、泉流量、地下水水温动态都明显地随季节呈周期性变化,为此判断其动态成因类型为降雨入渗亚型。该区地下水动态随降雨变化的基本特征是：峰丛洼地比峰林谷地的明显,峰林谷地比孤峰平原区的显著,这种变化是由于地貌和岩溶发育程度的差异所致。利用统计分析求出地下水水位和泉流量的衰减方程,并根据泉水流量的衰减方程推算出泉域内岩溶地下水储存量为 １７５７万 ｍ^３,并反算出泉域范围内的平均降雨入渗系数约为０.４２     

Preparation of Porous Ceramisite for Waste Water Treatment Made from Red Mud

The porous ceramisites for wastewater treatment were made from red mud, which is the industrial waste discharged from the production of Al2O3. The sintering process and the degreasing experiments with porous ceramisites have been finished. The results show that the sintering temperature control is dominant for the preparation of the porous ceramisites. The optimal sintering temperature is between 1 110-1120℃, a narrow range. The surface of ceramists is distributed with a lot of coarse holes with diameters of about 1-10μm. Moreover, the sintering temperatures have a great influence on the efficiency of degreasing, and the curve between the sintering temperature and the efficiency ofdegreasing is like a parabola.     

钢管赤泥混凝土粘结滑移影响因素

为了研究钢管赤泥混凝土粘结滑移性能,考虑了截面形式等5个变化参数,制作了短柱试件进行推出试验,获得了钢管赤泥混凝土的荷载-滑移曲线,并对变化参数的影响进行了分析.结果表明:粘结峰值荷载随赤泥替代率的提高先增加后降低,赤泥替代率为5%时,粘结峰值荷载达到最大;赤泥替代率为20%时,粘结峰值荷载与标准钢管混凝土相当;粘结峰值荷载随混凝土强度及长径比的增加而增加,随宽(径)厚比的增加而减小;圆截面试件的粘结滑移性能优于方形截面试件.     

Thermal decomposition behaviour of polyacrylamidomethyltrimethyl ammonium chloride in red mud separation process

In order to provide references for selecting highly efficient red mud flocculants, the behaviour of polyacrylamidomethyltrimethyl ammonium chloride （PATAC） in red mud separation process was investigated. PATAC was employed as a flocculant for red mud separation from the caustic aluminate liquor at 95 ℃. The used red mud was generated from Chinese diaspore bauxite in Bayer process of alumina production. And the changes of PATAC before or after being treated in caustic solution at 95 ℃ were studied by thermogravimetry （TG） and Fourier transform infrared （FTIR） spectral analysis. The results show that PATAC fails in effectively focculating red mud and PATAC is readily converted to a quaternary ammonium hydroxide （PATAH） in caustic solution. PATAH can be decomposed to a new polymer （HPATAH） even at 95 ℃. Furthermore, there is an intramolecular hydrogen bond formed in the HPATAH polymer chain with two functional groups of--CH2--OH and --CONH2. Therefore, the poor flocculation property of PATAC for red mud separation can be attributed to the thermal decomposition of PATAC in the caustic red mud slurry at 95 ℃ and the formation of intramolecular hydrogen bond in the polymer chain of HPATAH during the thermal decomposition, which causes the absorbable functional groups of PATAC to decrease greatly.     

Particle characteristics and rheological constitutive relations of high concentration red mud

Red mud has relatively small solid particles (d50=13.02 μm) and will flow in paste form under high pressure during pipeline transport. Red mud belongs to a two-phase flow of materials with high viscosity and a high concentration of non-sedimentation, homogeneous solid-liquids. It is difficult to test its rheological properties under atmospheric pressure. Measurements such as rotational viscometry can not reflect the real state of the material when it is flowing in a pipe. Tested rheological parameters are somewhat higher than the actual values. In our investigation, grain shape, distinctive modality and grain size distribution of red mud were tested. Based on the principle of tube measurement, rheological experiments on red mud at different concentrations were carried out by using our independently developed tube-type pressure rheology test facility, and obtained constitutive equations. We conclude that red mud behaves as non-Newtonian pseudo-plastic fluid in pipe flows. Its consistency and power-law indices vary considerably with different concentrations.