一次烧成外墙砖变形及解决办法

烧成是陶瓷生产中的关键工序 ,产品质量的优劣在很大程度上决定于烧成工序。烧成的质量与制品的烧成工艺及窑炉结构有密切关系。对于低温快烧墙地砖来说 ,制品的烧成质量更与工艺控制和窑炉设计有关。目前 ,低温一次快烧外墙砖大多采用劣质原料 ,以辊道窑作为烧成工具 ,一般烧成收缩比较大( 5 %～ 8% ) ,烧成温度较低 ( 1 0 5 0℃～ 1 1 70℃ ) ,烧成周期为 30～ 80分钟。由于收缩大 ,成瓷温度低且烧成时间短 ,控制不好就更易出现问题。变形 ,就是生产中最常见的缺陷之一。为了在烧成中很好地控制变形 ,下面对该缺陷的产生及克服谈一下我们…     

卫生陶瓷的低温快速烧成

建筑卫生陶瓷工业是耗能行业之一。为了节约能源,保护环境,提高效率和增加效益,采用低温快速烧成是必要的。实践经验表明,在卫生陶瓷生产成本中,烧成燃料占成本高达25%;当烧成温度达到1000℃以上时,各种热传导方式同时起作用,散热增强,烧成温度每提高30～50℃,烧成单位制品的燃耗就可能提高1%～5%,烧成时间缩短1h,烧成单位制品的能耗则可能降低5%以上。现在,我国卫生陶瓷生产广泛应用现代隧道窑、梭式窑和辊道窑烧成,烧成单位制品能耗达到1100～1400Kcal/kg制品,烧成温度达到1170～1210℃,烧成周期达到9～12h的先进水平。但是,与世界先进国…     

降低日用瓷烧成温度的几点看法

日用瓷的烧成温度一般在1250℃以上,如果用还原焰烧制,烧成温度更高。以湖南省各瓷厂为例,烧成温度达1410～1430℃。根据轻工部张锡秋工程师所提供的资料:意大利一公司采用天然气烧制炻器,烧成温度为1250℃时,每公斤制品所需热耗为1800～2000大卡,当烧成温度提高为1350℃,所需热耗为4500～5000大卡。烧成温度相差100℃,所需热耗就增加了一倍。以隧道窑烧成瓷器来说,烧成温度越高,尤其是高温阶段,那怕是增加烧成温度几十度,燃料的消耗量便     

晶体缺位理论在陶瓷工艺中应用

在陶瓷烧成时，晶体结构中产生的阳离子缺位和阴离子缺位，给予质量扩散传递有决定性影响，从而最终影响陶瓷烧成，包括在烧成过程中晶型转变，晶体生长，烧成温度，烧成速度，气孔率等等，该文在生产实际出发，将讨论缺位对氧化物陶瓷烧成过程中晶型转变，晶体生长，烧成温度，烧成速度及气孔率的影响。     

降低日用陶瓷烧成温度与节能关系的分析、计算——试论降低日用陶瓷烧成温度的节能裕度

本文提出了分析计算降低陶瓷烧成温度与节能间关系的一种简易方法,并通过实例分析了降低陶瓷烧成温度的节能裕度;指出,降低烧成温度,缩短烧成时间,提高产品产量,才能大幅度地降低单位陶瓷烧成能耗,提高窑炉的热效率.     

烧成制度对锆铁红颜料合成的影响

以实验为依据,探讨烧成温度、升温速度、保温时间、烧成气氛等烧成工艺条件对锆铁红颜料合成的影响,依此得出确定颜料烧成制度的基本原则。     

日用陶瓷烧成能耗状况与节能分析

介绍了我国日用陶瓷烧成能耗的状况,在窑型、装烧方式、烧成工艺、窑炉余热利用等方面对日用陶瓷烧成能耗进行了分析,指出了日用陶瓷烧成节能途径。     

陶瓷制品烧成周期的调节范围与节能

陶瓷制品烧成周期有一合适的调节范围，其上下限随制品类、壁厚及升温曲线的不同而变化。若烧成周期小于调节范围下限，器壁内外温差将随烧成周期的减小而急剧增加，引起器壁内部应力的突变，造成烧成缺陷；若烧成周期大于调节范围上限，器壁内外温差几乎不再随烧成周期的增加而减小，靠延长烧成周期减少烧成缺陷将得不偿失。     

陶瓷创意烧成在当代陶艺创作中的应用

在当代陶艺创作中烧成方式可谓是起到关键性的作用,这种烧成方式相对于以往传统的烧成方式还是有较大的区别意义,我们称之为“陶瓷创意烧成”。其类别包括乐烧、坑烧、熏烧等烧成方式,这些创意的烧成方式不仅是在泥坯、烟火相互作用下所产生的视觉效果,而且还给予了烧制者无限的意外收获,这对我们在当代陶艺创作中提供了更多的偶然性。陶瓷创意烧成方式不局限于单一的,它是多元化的存在,这也是值得陶艺家去探索的一种多变烧成方式。     

锂瓷石中温日用瓷的研制

采用江西宜丰锂瓷石取代部分其它陶瓷原料,研制出了烧成、工艺性能良好的日用瓷.该课题不仅降低了烧成温度,而且缩短了烧成时间,拓宽了烧成范围,对日用瓷行业节能降耗具有重要意义.     

Recent Research Progress in Burning Rate Catalysts

Burning rate catalysts are one of the most important components of rocket propellants and are able to enhance solid propellant burning rates. There are several kinds of burning rate catalysts such as nanometal burning rate catalysts, nanometal oxide burning rate catalysts, compound burning rate catalysts, ferrocene and its derivatives burning rate catalysts, and so on. This article reviews the recent research processes in burning rate catalysts.     

颗粒粘结高燃速推进剂燃速设计方法的研究

介绍了颗粒粘结高燃速固体推进剂的工艺特点,利用推进剂燃烧特征化学基团方法预估了几种小药粒和速燃粘结剂的燃速,提出了颗粒粘结高燃速固体推进剂燃速的设计方法.     

挥发性固体测试的灼烧条件研究

灼烧减重法测试有机质便捷快速,本文选定该法进行研究并设计实验。通过对特别选定的几组有机物质进行灼烧,改变灼烧温度和灼烧时间两个参数,对各组物质在不同灼烧条件下测得的挥发性固体含量进行分析,据此探讨表征堆肥污泥有效挥发性固体相对适宜的灼烧温度和灼烧时间。     

The Effect of Weight Content or Density on the Burning Behavior of Some Cellulosic Specimens

The effect of different densities of various cellulosic specimens on their burning behavior has been of interest in this investigation. By using a vertical flammability tester, burning times of different unfinished cellulosic samples, such as white paper, straw paper, and cardboard, have been chosen and their flammability characteristics have been determined. The obtained figures for the consumed identical samples show that, by increasing their densities, their burning time and temperature of burning have been increased. However a decrease in the burning rate could rationally be attributed. Furthermore a decrease in the burning temperature proved a reasonable synonymy toward the decrease in the burning rate. In addition to this, burning rate is antithetical toward the density of the consumed specimens. A thermogravimetric analysis of a selected cellulosic material fortified our hypothesis; i.e., the thermal decomposition temperature differs from the burning temperature, whereas the latter temperature is merely dependent on the weight content or density of the samples.     

Combustion of HMX-CMDB Propellants (II)

The burning rate characteristics of HMX-CMDB propellants were examined as a function of HMX concentration. In the region of low HMX concentration, below about 50%, the burning rate decreases with increasing the HMX concentration. However, in the region of high HMX concentration, above about 50%, the burning rate increases with increasing the HMX concentration. When the measured results are extrapolated to the 100% HMX concentration, it is recognized that the burning rate approaches the burning rate of an HMX single crystal. The burning rate analysis indicates that the effect of the addition of HMX particles within double-base propellants on burning rate is determined by the reaction rates in the gas phase and in the condensed phase. The gas phase reaction rate in the fizz zone decreases monotonously as the HMX concentration increases. On the other hand, the heat of reaction at the burning surface increases as the HMX concentration increases. The experimental results indicate that the burning rate with low HMX concentration is mainly controlled by the gas phase reaction rate and the burning rate with high HMX concentration is mainly controlled by the condensed phase reaction rate.     

卷烟纸燃烧调节剂对卷烟燃烧性能的影响

卷烟纸直接参与卷烟的燃烧,将直接影响着卷烟的燃烧性能。卷烟纸燃烧调节剂分为助燃剂、阻燃剂和灰分调节剂,是卷烟纸中的主要添加剂,影响盘纸的燃烧速度和灰分进而影响到卷烟的主、侧流烟气。文章综述了燃烧调节剂对燃烧速度,主、侧流烟气和灰分的影响,助剂对卷烟抽吸品质的影响,国内外对侧流烟气和灰分的研究进展。重点介绍了助剂在降低焦油、CO含量和侧流烟气中的作用。     

Combustion Process of Mg/TF Pyrotechnics

The combustion process of pyrotechnics was studied in order to obtain informations of the rate control parameters of burning rate. The pyrotechnics tested was made of Mg (magnesium) and TF (polyfluoroethylene). The burning rate measurements revealed that the burning rate of the Mg/TF propellants (pellet in shape) increases with increasing the weight fraction (ξ) of Mg in the range of ξ > 0.33. Though the adiabatic flame temperature is the maximum at ξ = 0.33, the burning rate increases with decreasing the flame temperature. The total burning surface area of the Mg particles mixed with in the unit mass of propellant plays an important role on the oxidation process in the gas phase just above the propellant burning surface. The heat flux feedback from the gas phase to the propellant burning surface increases with increasing ξ. Therefore, the burning rate increases as ξ increases.     

Burning Characteristics of Ammonium Nitrate‐based Composite Propellants Supplemented with Ammonium Dichromate

Ammonium nitrate (AN)‐based composite propellants have attracted much attention, primarily because of the clean burning nature of AN as an oxidizer. However, such propellants have some disadvantages such as poor ignition and low burning rate. Ammonium dichromate (ADC) is used as a burning catalyst for AN‐based propellants; however, the effect of ADC on the burning characteristics has yet to be sufficiently delineated. The burning characteristics of AN/ADC propellants prepared with various contents of AN and ADC have been investigated in this study. The theoretical performance of an AN‐based propellant is improved by the addition of ADC. The increase in the burning rate is enhanced and the pressure deflagration limit (PDL) becomes lower with increasing amount of ADC added. The increasing ratio of the burning rate with respect to the amount of ADC is independent of the AN content and the combustion pressure. The optimal amount of ADC for improving the burning characteristics has been determined.     

超声波燃速测试技术在固体推进剂研制中的应用

介绍了通过连续测量超声脉冲在推进剂中的反射时间,确定推进剂燃烧端面的位移,从而得到推进剂燃速的测试方法。它可以设置不同的压强变量条件来进行连续的实时燃速测量。叙述了国外超声波燃速测试技术在推进剂稳态燃速特性、非稳态燃速特性以及各种发动机燃速特性研究领域中的应用。评述了超声波燃速测试方法的特点和适用性,并建议国内研究机构开展该项技术的研究工作。     

Effect of Voids inside AP Particles on Burning Rate of AP/HTPB Composite Propellant

Bubble contamination in an ammonium perchlorate (AP)‐based composite propellant has a positive effect on the burning rate. However, the quantitative effect of the bubble contamination on the burning rate has never been revealed. In order to clarify the relationship between the increase in the burning rate and the void fraction of the propellant, propellants were prepared with fine porous AP particles (PoAP) or fine hollow AP particles (HoAPs), and their burning rate characteristics were investigated. The voids inside AP particles have the effect of increasing the burning rate. The increase in the burning rate is enhanced linearly as the void fraction increases. The effect of the void fraction on the burning rate for a propellant containing PoAP is not identical with that for a propellant containing HoAP. It was found that the effect of the void fraction on the burning rate could be estimated by the void fraction when the bubble contamination is uniform in size and shape.