Application of sewage sludge in the manufacturing of ceramic tile bodies

The substitution of clayey raw materials urban sewage sludge in the production of traditional ceramics could give place to a cost saving due to the utilisation of wastes as secondary raw material. At the same time, it can help to solve the environmental problems associated to such wastes. This research shows the results of the substitution of clay for sewage sludge in different proportions in a ceramic body. The sludge characterisation has been carried out by an analytical protocol. After that, the most suitable products were selected regarding to the chemical composition and the technological characterisation of the resulting ceramic material.     

Incorporation of wastes from granite rock cutting and polishing industries to produce roof tiles

The present work aimed at studying the incorporation of wastes from natural rock cutting and polishing to produce roof tiles. The sintered products incorporating the sludge were targeted to have similar or even enhanced properties in comparison to those made of a standard reference paste industrially used to fabricate concurrent products available in the market. Firstly, the raw materials, including the sludge, were characterised by particle size distribution, density, X-ray diffraction (XRD), thermal properties and loss on ignition. Different formulations were prepared to evaluate the effects of each component on plasticity of pastes, drying and firing processes, and on the final properties of the tiles. Finally, the most promising formulations were selected and characterised for sintered density, water absorption, and flexural bending strength. The results obtained made it possible to conclude about the possibility of producing roof tiles incorporating 10% of granite wastes having excellent properties (water absorption <6%, lower pyroplastic deformation index, and bending strength values of about 14 MPa and 38 MPa for the green and sintered products, respectively). Therefore, the sludge derived from the granite cutting and polishing industries can be classified as a by-product suitable to replace natural non-plastic raw material in traditional ceramic formulations. This will contribute to preserve non-renewable natural resources, while it allows minimization of the negative environmental impact due to its disposal.     

New waste-based clinkers for the preparation of low-energy cements. A step forward toward circular economy

This paper describes the use of industrial wastes arising from different production processes of the ceramic and marble industries as raw materials for the design and formulation of new cement clinkers with a high content of dicalcium silicate (Belite). The aim was to reintroduce these wastes in the industrial sector and take advantage of them for a greater environmental benefit, as indicated by the principles of the circular economy. Formulations containing 2.5, 5 and 10 wt% of chamotte and marble sludge, respectively, and a waste-free formulation have been designed to obtain clinkers with a content of dicalcium silicate higher than 60 wt%. The different blends have been studied up to a maximum temperature of 1390°C by Thermal Analysis. Other techniques such as XRD, XRF, Modified Bogue Equation, Quality Indexes (LSF, AM, SM) and Optical Microscopy have been used for the study and characterization of industrial wastes, the raw materials and the high belite-type cement dosages. The results indicate that this type of cements can be designed using different types of wastes and in this way reduce the environmental impacts caused by the extraction of raw materials and the deposition of the wastes in landfills, improving the circular economy of the construction industry.     

The effects of fine fire clay sanitaryware wastes on ceramic wall tiles

In the last decade, environmental preservation has become an important issue. Specifically, recycling of sanitaryware fine fire clay (FFC) waste is important for reducing costs. In this study, the use of FFC waste as an alternative raw material in the production of ceramic wall tiles was investigated. Five ceramic wall tile bodies were prepared by substituting kaolin (max. 15 wt%) with FFC wastes. All formulations were mixed, pressed into pellets and sintered at 1145 °C. The sintering behaviour was evaluated using an optical dilatometer. Water absorption, linear shrinkage and bending strength were also measured. This study revealed that FFC wastes are good alternative raw materials, and the corresponding formulations were shown to be viable in the manufacturing of ceramic tiles. The most remarkable conclusion from this study was that the addition of FFC waste decreased moisture expansion.     

磷渣基人造大理石的实验研究

以磷渣为主要原料,研究磷渣粉与粉煤灰和熟石灰的质量比、水胶质量比、胶骨质量比、骨料组成等对磷渣基人造大理石性能的影响,采用SEM电镜和抗折抗压实验仪表征材料性能。结果表明：磷渣基胶凝材料各物料配比为m（磷渣粉）:m（粉煤灰）:m（熟石灰）=90:4:6,水胶质量比为0.18,胶骨质量比为1:1.5,骨料组成为m（炉渣）:m（细磷渣）:m（粗磷渣）=10:40:10,磷渣基人造大理石的抗压强度和抗折强度可以达到94.38 MPa和12.09 MPa,其抗压强度和抗折强度均高于天然大理石,可在广泛领域替代天然大理石使用,为磷渣的资源化利用开辟一条新的路径。     

Circular economy in cementitious ceramics: Replacement of hydrated lime with a stoichiometric balanced combination of clay and marble waste

Cementitious ceramics, produced from the hydration of cement and hydrated lime, are responsible for a great deal of damage to the environment due to the high emission of CO₂ that occurs in the production of cement and lime. Therefore, the objective of this work was to substitute the hydrated lime with a combination of clay residue and marble waste extracted from ceramic and ornamental rock producing industries, respectively, which constitutes a circular economy for the ceramic industry related to masonry applications. Ceramics were produced in the proportion 1:1:6:1.5 (cement:lime:sand:water), through the molding procedure, and were studied by replacing hydrated lime with 100% clay residue and 100% marble residue, in addition to stoichiometric calculated parts of marble to clay. The molar ratios used were 1:1, 1:2, and 2:1 (marble:clay). Tests of consistency, incorporated air content, water retention, compression strength, density, water absorption by capillarity, adhesion, and electrical resistivity were performed. The results obtained demonstrate that the use of residue of marble and clay together, as long as they are correctly balanced, provides a high gain in technological properties, enabling the circular economy of cementitious ceramics, mainly for the composition 1 marble:1clay, which presented the best properties, both in the fresh and hardened state. The economic analysis carried out proved the financial gains for the industrial sectors involved (civil construction, ornamental rock, and ceramic).     

均匀设计在优化多孔陶粒制备工艺中的应用

本文以城市污泥和絮凝污泥为主要原料,石英和煤炭为辅料制备多孔陶瓷.通过均匀试验设计,系统研究各因素对多孔陶瓷性能的影响,找出回归方程和最佳工艺条件.多孔陶瓷制备的优化配方为:城市污泥为16.67％,石英为33.33％,絮凝污泥为25％,煤炭量为25％,煤炭颗粒为0.1 ～0.9 mm,转化时间为150min,烧成温度为1230℃.由最优配方所制备的多孔陶瓷的吸水率为57.2％,显气孔率为60.89％,体积密度为1.065 g/cm3,抗压强度为1.8 MPa,耐酸性为97.1％,耐碱性为98.3％.     

Use of nonferrous metal ore concentration wastes in production of ceramics

The possibility of using copper-nickel ore concentration wastes as a component of ceramic pastes for production of ceramic tiles was investigated. The optimum content of the wastes in the ceramic pastes and the firing conditions were determined. The physicomechanical properties of the materials obtained were investigated. It was found that copper-nickel ore concentration wastes can be used in ceramic paste compositions for making facing tiles with satisfactory properties: water absorption of 12.7–13.3%, flexural strength of 10.0–12.9 MPa, and cold resistance of more than 25 cycles.     

Usage of marble wastes in traditional artistic stoneware clay body

Recycling of industrial wastes aids environmentally friendly production and has the advantage of lowering costs. Marble production generates large amounts of waste. Recycling of such wastes by incorporating them into ceramic industry is a practical solution for pollution problem. The aim of this work is to assess the possibility of the recycling of marble wastes in the production of stoneware clay bodies as a raw material for ceramic artwork production. Five different clay body mixes containing marble waste up to 27% were prepared and evaluated for firing color, water emission, morphology, microstructure, thermal expansion coefficient and thermal behavior. The results of the tests show that the utilization of marble waste in stoneware body is feasible for ceramic artwork production.     

大规格强化陶瓷板的研制

本研究打破了传统瓷质砖粘土-长石-石英配方的思路,引入以滑石为主的原料,研制出了适合大规格超薄瓷质砖生产的高强度坯料配方,所得产品的抗折强度达到88MPa,吸水率低于0.5%。利用XRD、SEM等对瓷坯晶相进行了研究,结果表明:瓷坯晶相量的增加是抗折强度提高的主要原因。     

Reformulation of roofing tiles body with addition of granite waste from sawing operations

A ceramic body traditionally used to produce roofing tiles was reformulated by the addition of granite waste from sawing operations. The objective was to obtain a ceramic product with better technological properties. The main tool for the reformulation was the definition of the appropriate particle size of the raw materials as given by the Winkler diagram. The raw materials were characterized with respect to their mineralogical composition by X-ray diffraction, particle size distribution as well as chemical composition and plasticity. Specimens were made by extrusion and fired at temperatures from 850 to 1100 °C. The technological properties determined were: dry bulk density, linear shrinkage, water absorption and mechanical strength. Microstructural analysis of the fired samples was carried out by X-ray diffraction. The results showed that the granite waste contributes to reduce the plasticity and the linear shrinkage of the ceramic bodies. One reformulated ceramic body exhibited better values of water absorption and mechanical strength than the industrially used.     

利用电石渣制取内墙涂料

电石渣是生产乙炔气时排放出来的废渣,经过一系列的处理,可成为生产涂料的原料,制取高性能内墙涂料“瓷光壁”,既保护了环境,又化废为宝。     

Use of titanate to improve interfacial interaction and mechanical properties of polyethylene/artificial marble wastes composites

The resource utilization of artificial marble wastes (AMWs) is urgently needed for environmental protection as a large amount of artificial marble are used as construction material. Nevertheless, it still remains challenging to achieve high performance of AMWs-filled polymer composites due to their poor interfacial interaction with hydrophobic polyolefins. Here, the unsaturated resin residue on the surface of AMWs is employed to construct strong interfacial interaction with high-density polyethylene (HDPE) matrix to prepare mechanically robust polymeric composites by use of titanate coupling agent. The mechanical properties (with a tensile strength of 28.6 MPa and a flexural strength of 27.7 MPa) of the resulting composites are comparable to or even better than those of raw calcium carbonate-filled HDPE composites. This work will not only promote the recycling and reutilization of AMWs, but also provide a feasible way for value-added application of other polymeric wastes, such as waste printed circuit board, waste artificial turf, and so on.     

Recycling of extracted titanium slag and gold tailings for preparation of self-glazed ceramic foams

Self-glazed ceramic foams were successfully synthesized via powder sintering method, using extracted titanium slag (ETS) and gold tailings (GT) as raw materials without adding any sintering aids and foaming agents. Influence of ETS addition and sintering temperature on crystal phase evolution, physical–mechanical properties, and micro-morphology of ceramic foams was systematically studied. Results indicated that products sintered at 1180 °C with 30 wt% ETS and 70 wt% GT showed the best performance, i.e., bulk density of 1.66 g cm^?3, flexural strength of 20.4 MPa, water absorption of 0.14%, open porosity of 0.23%, and glaze Vickers hardness of 6.5 GPa. Moreover, it was observed that there existed strong correlation between bulk density and bending strength. Self-glazed ceramic foams developed in this study are expected to be used as building envelope materials and provide new ideas for effective reuse of other similar solid wastes.     

城市污水厂剩余活性污泥生产生态水泥

引言 随着我国对城市生活污水处理能力以及污水处理率的不断提高,污水处理厂的污泥产量也不断增长.由于其产量较大,含水率高,同时含有大量有机质、病菌、寄生虫和重金属等[1-2],如果处理处置不当,会给环境带来严重的二次污染.     

刚玉–莫来石–镁铝尖晶石复合陶瓷的原位合成及热震行为

以α-Al2O3、苏州土、滑石和石英为主要原料,采用无压烧结制备了刚玉–莫来石–镁铝尖晶石多相复合陶瓷,研究了烧结温度对样品的体积密度、线性收缩率和吸水率等烧结性能以及机械性能的影响。通过X射线衍射和扫描电子显微镜分析了复相陶瓷热震前后的物相组成和显微结构。结果发现：经1480℃烧结的样品吸水率为0.19%,体积密度为3.06g/cm3,抗折强度达99.59MPa,复合材料有较好的热震性能,1100℃空冷热震损失率仅6.9%,可耐受17次热冲击。该复相陶瓷可作为潜在的太阳能热发电材料。     

Environmental and technical aspects of the utilisation of tannery sludge as a raw material for clay products

This paper is a report on the results of a feasibility study on the immobilisation of tannery sludge by producing a ceramic product. The main purpose of this work was to test the clays used in the manufacture of a ceramic that could incorporate tannery sludge. The raw materials, tannery sludge and clay, were mixed together in different proportions. The ceramic specimens were characterised with respect to water absorption, porosity, linear shrinkage and transverse rupture strength. Leaching tests, in accord with the Brazilian and German regulations, were done on ceramic bodies made with different additions of sludge. In order to evaluate the possibility of air contamination during the firing process, preliminary studies of air emissions were carried out The mechanical properties of the samples evaluated were similar to those specified for ceramic bricks. All the leaching tests have shown that the main sludge contaminant i.e. chromium, could be immobilised within a finished ceramic product. The studies of air emissions have shown that zinc and chlorine are mainly collected from gas emissions and hence are not immobilised by the ceramic system. The study shows that the properties of the ceramic materials produced are acceptable for applications such as bricks for the building industry.     

铝矾土-伊利石-高岭土体系陶瓷材料制备工艺的研究

以生铝矾土、高岭土和伊利石为主要原料,采用传统陶瓷工艺方法,制备了铝矾土-伊利石-高岭土体系陶瓷材料。以Al2O3质量分数在60～65%范围的坯料为研究对象,研究了原料配比和坯料细度等因素与试样的烧成温度及抗弯强度的关系。利用XRD、SEM等分析手段对材料的物相组成和显微结构进行了表征。结果表明:铝矾土-伊利石-高岭土体系陶瓷材料,在1320～1360℃烧结范围内能够制备抗弯强度110～140MPa的高强度陶瓷材料;提高铝矾土的含量和原料的细度均有利于强度的提高;添加适量的滑石有助于强度的提高以及烧结温度的降低;在原料配比相同的条件下,烧结范围下限附近烧成的试样强度较高。     

污泥型煤添加剂的研究

污泥具有一定的热值和黏结性。以污泥与粉煤为原料，采用膨润土与硅酸钠为热固剂，有机硅与聚乙烯醇为防水剂，制备工艺性能优良的型煤。实验考察了污泥量、热固剂与防水剂的种类及添加比例。结果表明，型煤的灰分和挥发分随污泥量的增加而升高，发热量降低；热固剂与防水剂的添加使型煤的热压强度与防水性明显提高；各因素优化的工艺参数为污泥质量分数20％、膨润土热固剂质量分数6％、有机硅防水剂质量分数1．8％时，型煤抗压强度1．4MPa，热稳定性92％，发热量20．24kJ／g，浸水复干强度1．4MPa。测试值均符合山西省型煤地方标准DB14／133—2005{太原市锅炉用洁净型煤》的各项指标要求。     

Acid-resistant materials made from Uzbekistan mineral raw material

The possibility of using local raw material from Uzbekistan for production of acid-resistant materials was determined. The compositions of pastes made from porcelain stone from the Boinaksai deposit and pyroxene wastes from the Koitash ore field wee developed. It was shown that by using nontraditional mineral raw material whose mineral composition is close to the compositions of standard fine ceramic pastes, ceramic materials with good thermomechanical and chemical properties can be obtained.