为开发用于含碳浇注料中能替代石墨的可再生碳材料,分别以秸秆和稻壳粉为原料制备生物质炭,研究了生物质种类和处理工艺(直接热解+900℃碳化、180℃水热+900℃碳化、180 和200℃水热催化+900℃碳化)对碳化产物的物相组成、显微结构及对原位合成SiC晶须的影响.结果表明:稻壳与秸秆的原始结构经水热处理后部分坍缩并发生水解聚合生成碳微球.秸秆经200℃水热催化+900℃碳化后产物中存在明显的非晶态二氧化硅与碳,且碳含量最高,大量碳微球晶核在碳骨架表面形成.相较于以石墨为碳源,添加秸秆基生物质炭的粉体中生成大量交错的SiC晶须.

A low-carbon Al2O3–C composite refractory was prepared with white fused alumina, flake graphite, active α-Al2O3 micron-sized powder, Al powder and Si powder as raw materials, and h-BN (in mass fraction 0%, and 3%) as additives. The effect of h-BN addition on the microstructure, physical properties and oxidation resistance of Al2O3–C refractories at different nitriding temperatures was investigated. The results show that the addition of h-BN promotes the formation of SiC whiskers. The cold compressive strength and cold modulus of rupture of the samples with h-BN addition after nitriding at 1400 ℃ are 6% and 10% greater than those of the samples without h-BN addition, respectively. Also, the oxidation resistance of the samples with h-BN addition is significantly improved. Among those samples, the oxidation resistance of the samples with h-BN addition after nitriding at 1500 ℃ is improved by 21%, compared with the samples without h-BN addition.

以碳化后的松木作为碳模板、金属钼粉作为钼源、硝酸铁作为催化剂制备多孔Mo2 C/C复合陶瓷材料.研究催化剂含量、反应温度和保温时间对多孔Mo2 C/C复合陶瓷材料物相组成和显微结构的影响,并探索了材料对CO2的吸附性能.结果表明:与不加催化剂相比,添加4％(质量分数)的催化剂可促进材料中Mo2 C的生成,其形貌主要为树枝状;而加入过量催化剂会导致生成的Mo2 C晶粒团聚.1150℃的烧成温度及保温4 h的条件有利于材料中Mo2 C的生成,制备的多孔Mo2 C/C复合陶瓷材料具有优异的CO2吸附性能,其吸附量为52 cm3·g-1.

含碳浇注料因碳材料的水润湿性差及高温氧化引起的材料性能差等问题一直备受关注.分别以热氧化石墨、ZrC包覆改性石墨和水热碳化生物质碳材料为碳源制备铝碳浇注料,研究不同碳材料对铝碳浇注料显气孔率、物理性能、物相组成,以及抗氧化性和抗渣侵蚀性能的影响.结果 表明:引入热氧化石墨的浇注料具有最高的加水量,残留孔隙破坏了材料内部结构,浇注料机械性能较差;添加ZrC表面改性石墨可以降低浇注料的加水量,抗氧化性能较好,但对力学性能的提升无显著影响;以生物质碳材料为碳源可以显著提高浇注料的物理性能,相比于添加石墨的试样,生物质碳材料并未显著提升试样的抗渣侵蚀性能.

为了优化MgO-C耐火材料的性能,以电熔镁砂、鳞片石墨和负载硝酸铁的硅粉为主要原料,热固性酚醛树脂为结合剂,经高温氮化制备了MgO-C耐火材料,并研究了催化剂的添加及不同氮化温度对MgO-C耐火材料结构和性能的影响.结果表明:氮化温度为1200℃时,与不含催化剂的试样相比,催化剂的添加促进了α-Si3N4、SiC和Mg2SiO4的生成,并显著改善了材料的机械强度,含1％催化剂的试样中生成的α-Si3N4呈颗粒状和晶须状,并交织生长,Mg2SiO4以块状形貌存在;随着氮化温度升高到1300℃,有少量的针状Mg2SiO4生成,且块状Mg2SiO4晶粒长大,此时材料表现出较好的机械强度,其常温抗折强度和常温耐压强度分别为10.82 MPa和55.17 MPa.

为解决目前国内无机高温黏结剂存在固化温度高,粘接强度低,脆性大和使用温度不高等问题,以不同粒度的板状刚玉、ρ-Al2O3细粉和硅微粉为主要原料,硅酸盐水泥为结合剂,轻质氧化镁为添加剂制备了一种可室温固化,使用温度在1300℃以上,剪切强度较大的无机高温黏结剂.研究了不同烧成温度和不同原料配比对无机高温黏结剂的微观结构和力学性能的影响.采用XRD、SEM分析烧后试样的物相组成和显微结构,并对试样进行体积密度、显气孔率、常温抗折强度、常温耐压强度和剪切强度等性能测试.结果表明:制备的黏结剂室温下可固化;在1300℃烧后,Al2O3、SiO2质量比为5:1、5:2和5:3的试样中均有 α-Al2O3、β-SiO2和3Al2O3·2SiO2物相,Al2O3、SiO2质量比为5:3的试样在1300℃烧后β-SiO2为主要物相;当Al2O3、SiO2质量比为5:2、烧成温度为1600℃时,长柱状莫来石生成量增加,试样的力学强度较大,其抗折强度、耐压强度和剪切强度分别为9.40、22.17和1.74 MPa.

为寻求一种简单、安全、成本低、产率高的合成ZrN的方法,以ZrO2和Mg粉为主要原料,在熔盐介质中氮化合成ZrN粉体.研究了熔盐介质(MgCl2和MgCl2-NaCl)、氮化温度(1000和1100℃)对产物物相和显微形貌的影响,并研究了合成的ZrN对硅粉氮化的影响.结果表明:熔盐介质MgCl2与NaCl物质的量比为1:2时,合成了纯相的ZrN;温度的升高有利于提高ZrN晶体的结晶度;与直接氮化硅粉相比,ZrN的添加可显著促进α-Si3N4晶须的生成.

为了降低中间包用耐火材料的成本并节约资源,以马钢生产的市售镁质中间包涂料为基础,添加20％(w)的烧结或不烧镁橄榄石颗粒(3～1 mm)替代同粒度的烧结镁砂制成含镁橄榄石的镁质中间包涂料,并研究了该涂料经1 500℃保温3h热处理后的常温物理性能、抗渣侵蚀性能和显微结构.结果表明:添加烧结镁橄榄石颗粒的中间包涂料的体积密度高于不添加镁橄榄石颗粒的,且显气孔率降低,常温抗折强度和耐压强度较不加镁橄榄石颗粒的略有降低;添加不烧镁橄榄石颗粒的体积密度和强度略低于不加镁橄榄石颗粒的;静态抗渣试验显示,无论是否含有镁橄榄石颗粒,三种中间包涂料均以渗透侵蚀为主,其抗渣侵蚀能力基本相当.

The solubility of FeSO4·7H2O in black titanium solution is studied using balance method and the crystallization metastable zone is measured with FBRM online monitoring. The crystallization kinetics of FeSO4·7H2O is investigated with the method of moments through batch cooling crystallization experiments based on the population balance equation. Nucleation rate equation and growth rate equation are obtained by regressing the experimental data with the multiple linear least square method. The key parameters of the crystal size distribution are associated with stirring rate and solution temperature, which can be used to predict and control the crystal size distribution in industrial crystallization process. According to the crystallization kinetics of FeSO4·7H2O, cooling rate and stirring rate have a great effect on crystal size. Cooling crystallization process is carried out under the optimized operating conditions. The results show that the particle size of FeSO4·7H2O increases significantly and small particles reduces greatly, compared to the original process.

YSZ casting film is widely used in the production of ceramic sensors,but its loose structure and low density impact on product strength seriously.The effects of isostatic pressing process on YSZ casting film were stu-died.By testing the density,bending strength and observation of microscopic structure,it shows that temperature isostatic pressing process is more suitable for YSZ casting film processing and the optimum process parameters are found out.

Electrochemical NOx sensors based on ZrO2 is the most reasonable choice for detection of diesel exhaust NOx concentration.This paper studied the formula of the inactivated electrode paste used for NOx sensors,adjusted the content of pore-forming agent and Au,compared the offset current Ip2,and obtained the best formula.It is found that when the pore-forming agent content is 4% and Au content is 0.4%～0.8%,the requirements of NOx sensor can be met.

To offer the theoretical basis for optimizing the structure of a new coke oven dustless gunning machine,Fluent,a fluid simulation software,was employed for 3D modeling and numerical simulation of the injection suction feeder,and the distribution in the interior flow field of the injection suction feeder was studied in two situations when the connecting pipe has stretched into the feeder pipeline and when the connecting pipe hasn't.The results show that when the connecting pipe hasn't stretched into the feeder pipeline,the minimum inlet pressure that can overcome the fall resistance of powder is 0.1 9 1 0 MPa and under this circumstance,the minimum pressure on the pipeline wall is0.089 3 MPa.When the connecting pipe has stretched into the feeder pipeline,the internal flow field of the injection suction feeder is subject to obvious interference,and the inhaled effect of gunning mix is comparatively the best when the pipe elongation is 8 mm.

介绍了以硫酸法钛白生产过程中的中间产物硫酸氧钛为原料,采用直接沉淀法和均匀沉淀法制备纳米TiO2的工艺路线,通过对2种制备工艺及几种中试方案的比较,提出了纳米TiO2工业化生产的原料与技术路线,并指出在的问题及解决方法.

纳米二氧化钛是一种重要的新型无机功能材料,其制备及应用在当代愈来愈受到重视.本文重点介绍以硫酸法钛白生产过程中的中间产物硫酸氧钛为原料生产纳米二氧化钛的沉淀法、胶溶法、水热法的制备工艺及特点.

采用廉价、简单的工艺方法制备高性能纳米TiO2,是现今工业化生产纳米TiO2技术所追求的主要目标.介绍了以硫酸法钛白生产过程中的中间产物硫酸氧钛或偏钛酸为原料,采用直接沉淀法和均匀沉淀法制备纳米TiO2,通过对两种制备工艺的及几种中试方案的比较,提出了纳米TiO2工业化生产的原料与技术路线,对存在的问题及解决方法进行了介绍.

简要介绍了以硫酸法钛白生产的中间产物硫酸氧钛为原料采用均匀沉淀法生产纳米二氧化钛过程中水洗和煅烧所存在的问题,并对工业化生产中采用旋流动态煅烧炉和旋转闪蒸干燥器组合煅烧金红石型纳米二氧化钛的方案作了详细介绍.

The function of nanograde TiO2 powders characterizes the high additional value of product, which depends on powder's particle size and crystal type. The influencing factors of heat treatment for nanograde TiO2 was analyzed by the sol-gel method and the research progress in recent years was reviewed.

The materials for producing nano titanium dioxide(TiO_2) can be organic titanate,titanic chloride or titanyl sulfate,the last one is an intermediate during the production of TiO_2 by sulfuric method.In this paper,the process for the industrial production of nano TiO_2 with titanyl sulfate is presented,including the homogeneous precipitation method,separation technique using porous ceramic membrane and the calcinations coupled rotary calcinator with spin flash dryer.The process was successfully applied in a 15 t/a pilot test installation of nano TiO_2 and the other one of 500 t/a of nano TiO_2 sol,the existing problems and solutions to them were also introduced.