High-porosity mullite ceramic foams prepared by selective laser sintering using fly ash hollow spheres as raw materials

A novel method to prepare high-porosity mullite ceramic foams by selective laser sintering (SLS) using fly ash hollow spheres (FAHSs) as raw materials was reported. The complex-shaped FAHS green bodies and ceramic foams without delamination or cracks were prepared by SLS. The influence of sintering temperatures on linear shrinkage, phase composition, porosity and mechanical properties was investigated. With the increase of sintering temperature from 1250?°C to 1400?°C, the compressive strength of ceramic foams increased from 0.2?MPa to 6.7?MPa causing the fracture mechanism change from fracturing along FAHSs to across FAHSs, while the porosity of ceramic foams decreased from 88.7% to 79.9% which was higher than those of ceramic foams prepared by the conventional methods. The relatively high porosity of ceramic foams was resulted from the inner hollow structure of FAHSs, the interspaces between stacking FAHSs, and the gaps between FAHSs directly related to SLS. The results above indicated that the fabrication of high-porosity FAHS ceramic foams by SLS could achieve the advanced utilization of FAHS solid waste.     

Fabrication and characterization of anorthite-based ceramic using mineral raw materials

The purpose of this study is to design a novel single crystalline phase ceramic based on anorthite whose properties fulfill the tableware market requirements such as high appearance quality, strength and thermal shock resistance. To obtain the single phase anorthite ceramic, ball clay, quartz, calcite, feldspar and alumina were used as raw materials. The single phase anorthite ceramic was fabricated by slip casting and sintering at 1230 °C for 1 h. It has a high flexural strength of 103 MPa, which is higher than that of the conventional porcelain. The single phase anorthite ceramic had relatively low (4.9 × 10^?6 K^?1) thermal expansion coefficient which can be matched with applicable glaze easily. Furthermore, the single phase anorthite ceramic had high degree of whiteness (L* = 94) and excellent translucency behavior which could achieve a high-quality decorative effect.     

Synthesis of manganese ferrite from non-standard raw materials using ceramic technique

Manganese ferrite spinel has been synthesized by using mill scale and fines of manganese ore sinter as sources of iron oxide and manganese oxide, respectively. The magnetic and physico-mechanical properties of the produced sample are largely dependent not only on the sintering condition but also on the Mn:Fe mole ratio. The effect of silica (which is one of the constituents of the fines of manganese ore sinter) on the properties of the sintered samples is investigated. The results show that a single phase of manganese ferrite spinel with weak magnetic properties is obtained in a sample containing a Mn:Fe mole ratio of 1.4:2 and sintered at 1300 °C for 2 h. On the other hand, a maximum saturation magnetization (62 emu/g) with reasonable physico-mechanical properties is obtained for a sample containing a Mn:Fe mole ratio of 1.3:2 and sintered at the same sintering conditions.     

电石渣做钙质原料的熟料形成动力学研究

对电石渣做钙质原料烧制熟料形成动力学进行研究,探索电石渣配料对熟料烧成的影响。根据金斯特林格方程和阿累尼乌斯公式计算熟料形成反应的表观活化能。研究表明：电石渣配料煅烧水泥熟料的形成反应动力学较好地满足金斯特林格方程,电石渣替代石灰石配料烧制水泥熟料是可行的。但电石渣在替代石灰石煅烧熟料时熟料形成的表观活化能升高,会引起煅烧困难,在实际操作中要控制电石渣的掺量和改变工艺参数。     

用安徽当地原料研制抛光砖

我们受安徽省淮北市当地企业委托，在立足于淮北市及周边地区的陶瓷矿产资源的前提下，根据企业现有的生产设备条件，进行抛光砖试制研究。经过系统的研究，试制出采用当地原料70％，周边地区原料20％的抛光砖配方及试验样品，基本满足企业的生产需要。现就研制情况作以总结，以供同行参考。     

Thermoluminiscence analysis of raw and ceramic materials

A method for analysis of silicate materials based on excitation of the materials with x-ray radiation and subsequent recording of thermally stimulated luminescence is considered. The possibility of analyzing the structure of raw materials and ceramics using the method proposed is displayed.     

Redox potential of a glass mass when using off-grade raw materials

The redox conditions for glass making are investigated on a working glass-melting furnace using molding sand. Data obtained from instrumental measurements of the ROP of the glass mass and reasons for destabilization of the technological process are presented. __________ Translated from Steklo i Keramika, No. 6, pp. 6–8, June, 2007.     

玻璃原料配料称重的新探索

介绍了新型称重仪表及传感器所构成的新型配料系统,在玻璃厂原料配料系统中的应用.     

Use of nonconventional raw materials in ceramic production

This paper reports possibilities for use of nonconventional natural and synthetic raw materials in ceramic bodies and glazes.

Reactivity during the process of heating can be considered as a modern criterion for ceramic raw materials. A review of several types of alkali-containing rocks is made, which are more fusible than the common fluxes. The greater fluxing power of these raw materials compared to the traditional types provides for a higher rate of body sintering. As a result of this intensified process, a higher structural density and better mechanical strength of the bodies are achieved with shortened firing cycles. The introduction of more active fluxes reduces firing costs and allows economy of high quality traditional fluxing raw materials in the production of some tablewares, sanitary wares and faience tiles.

In combination with more reactive silicon-containing raw materials, the influence of the fluxes on sintering increases. This combined beneficial effect is experimentally confirmed in glaze frit melting and in the firing of glaze coatings. Investigations on these processes are discussed.

As a nonconventional raw material in the modern ceramic production, wollastonite can be considered. Since natural deposits of this valuable material are rarely found the use of synthetic wollastine is discussed. Obtaining an anorthite reaction phase in the ceramic bodies provides the formation of a compact and stable structure that permits firing in short and single cycle.     

以水玻璃和硫酸铝为原料合成T型沸石的研究

以工业水玻璃和硫酸铝为原料,于K2O-Na2O-SiO2-Al2O3-H2O体系中水热合成制得不同晶粒度的T型沸石.晶化温度在85～135℃可得到晶相纯的T型沸石;搅拌晶化能有效减小T型沸石的晶粒度,但搅拌速度在200～800 r/min内对晶粒大小的影响不明显;凝胶n(SiO2)/n(Al2O3)在16～32可合成出结晶度高、晶相纯的T型沸石,但大于32时晶化产物中出现钙十字沸石杂晶;凝胶n(SiO2)/n(Al2O3)改变对T型沸石产物硅铝比基本无影响.水玻璃合成体系晶化诱导期短.产物中n(K+)/n(Na+)比值远大于起始凝胶中两者的比值,这可能是由于钾离子在T型沸石晶化中起主要的结构导向作用.     

EAFD-loaded vitreous and glass–ceramic materials

SiO₂, Na₂O and CaO were mixed and co-melted with electric arc furnace dust waste. The resulting vitreous materials, produced by quenching at ambient atmosphere, were transformed into glass–ceramics by two-stage heat treatment, under thermal conditions that were determined by differential thermal analysis. X-ray diffraction, scanning electron microscopy, energy dispersive spectrometry and transmission electron microscopy were employed to investigate the physical properties of all products. It was found that whilst wollastonite (CaSiO₃) separates from the parent matrix as the dominant crystalline phase in all glass–ceramic products, the crystallization mode depends on the batch composition. Leaching tests evidenced that vitreous products were chemically durable. Devitrification did not significantly affect leach resistance so glass–ceramic materials retain the leach resistance that was achieved by vitrification.     

电感耦合等离子体发射光谱法测定陶瓷原料的化学成分

应用电感耦合等离子体发射光谱仪(ICP-OES)对陶瓷原料的化学组成中常量及微量元素Si、Al、Ca、Mg、K、Na、Fe、Ti、B、Zn、Zr、Sr、S、P、Mn、Pb、Ge等进行检测。     

Processing of some non-conventional ceramic raw materials and by-products

Technological procedures of processing selected industrial wastes into ceramic wares are described. They utilize the binding of raw materials grains by new compounds crystallizing from water solution (hydraulic binding) of from melts (eutectic binding) and hot consolidation.