熔体过热处理对一种镍基合金氮含量的影响

研究在采用CaO坩埚真空感应熔炼的条件下,经不同温度的熔体过热处理后,一种镍基合金中氮含量的变化,并对镍基合金中脱氮机理进行了探讨.结果表明,在采用相同的浇注温度和模壳温度条件下,提高熔体过热处理温度能促进合金的脱氮,且试验值与理论预测值吻合的较好.超过1 790℃时,合金产生吸氮现象.采用稳定性较高的CaO坩埚,合金中氧含量一直保持在较低的水平.     

激光化学反应法制备CaO超精细粉末及激光多相催化1—庚烯异构化的研究

采用激光固相热解反应法，以ＣＷＣＯ２激光作为辐照光源，成功地合成了ＣａＯ超精细粉末。实验结果表明：本法生成的粉末呈球状结构，粒径在２０～５０ｎｍ之间。激光多相催化１－庚烯反应使１－度烯异构化的转化率升高。并且使得顺式的相对含量大于反式的相对含量。     

高性能膨胀剂(CMA)的研究与生产

综合目前国内膨胀剂领域的发展方向和借鉴以往研究成果，采用CaO（钙质熟料）、钙矾石、MgO三个膨胀源的相互作用，三者膨胀适当组合，取长补短，以获得更适宜的膨胀量和膨胀发挥，使膨胀曲线更趋合理。研究了不同掺量不同活性钙质熟料对CMA膨胀剂性能的影响，提出了制备钙质熟料的理化指标，并将CMA与传统膨胀剂的性能进行了对比。     

Residual oil cracking combined with hydrogen production by steam-iron reaction

A new residual oil upgrading process has been developed. Residual oils were cracked over an iron oxide catalyst with simultaneous generation of hydrogen. The newly-developed iron oxide catalyst containing CaO and Cr₂O₃ was found to be a good catalyst for this process because it exhibited stable activity in the steam-iron reaction in the laboratory experiment and also in a large scale pilot plant. Effects of these foreign oxides on redox cycles were investigated. The catalyst was designed so as to maintain the stoichiometric balance between the reduction of magnetite and the oxidation of wustite by adding CaO and Cr₂O₃.     

Cao—SiO2—CaF2三元渣系的挥发率

通过质量损失法对ＣａＯ－ＳｉＯ２－ＣａＦ２三元渣系挥发率与温度、渣组成的关系进行了研究。结果表明：在渣完全熔化之前有一临界温度，其值大小因渣而异，即酸性渣具有低温临界点；碱性渣具有高温临界点；中性渣则两个临界点均存在；当渣的碱度过高（Ｒ≥１．４）或ＣａＦ２含量减少（≤１０％）时，这两个临界点均不存在。临界温度对渣的挥发率有明显影响；在渣完全熔化之后，挥发率将随碱度的降低及ＣａＦ２含量的增加而提高。     

Al-substituted tobermorite: shows cation exchange

It has been found that the tobermorite family--fundamental to cement chemistry can exhibit base exchange behavior. Several Al-substituted tobermorites were synthesized and these 11Å type tobermorites were discovered to have cation exchange as well as selective cation adsorption properties. For example, Al-substituted tobermorite (synthesized from a mixture of clinoptilolite and mortar) has a cation exchange capacity of 56 meq/100g and a selective Cs adsorption K_d of 3400 (ml/g). The cation exchange and selective properties of Al-substituted tobermorite are analogous to those of zeolites because of its rigid structure but unlike those of smectites or vermiculites where the basal spacing varies with the nature of the interlayer cation.     

基于逾渗理论的CaO吸收CO2动力学模型研究

石灰石循环吸收技术被认为是一种高效、经济的减排烟气中CO2技术。但这种方法循环效率降低较快,吸收剂利用率也较低。为了对这一过程有很好的认识,改善吸收剂的利用率,针对颗粒典型气固反应模型的缺点,将逾渗理论应用于CaO与CO2反应模型中,对CaO颗粒吸收烟气中CO2的过程进行描述。实验数据与模型数据相结合,表明新的模型可以很好地对吸收过程进行描述,并得出:烟气中CO2体积分数对CaO转化率的影响主要是在反应初期的化学反应阶段;小粒径CaO颗粒在一定程度上可以提高CaO的钙转化率。这为实际过程提高循环吸收效率提供理论指导。     

CaO催化制备碳酸甘油酯

以甘油和碳酸二甲酯为原料,CaO为催化剂合成了碳酸甘油酯。通过正交实验及单因素实验,考察了反应温度、回流温度、碳酸二甲酯用量、催化剂用量、反应时间对反应的影响,确定了优化工艺条件:反应温度75℃,回流温度60℃,碳酸二甲酯与甘油摩尔比2.5∶1,催化剂质量分数0.8%(以原料总质量计,下同),反应时间2h,在该条件下,甘油转化率及碳酸甘油酯收率分别可达97.89%和96.78%。CaO的存储稳定性及重复利用性实验结果表明,CaO虽具有较佳的存储稳定性,但其重复利用性较差,使用1次后活性即显著降低。     

Ni/CaO-SiO2催化剂对β-O-4木质素模型化合物氢解产物分布的影响

采用均匀共沉淀法制备Ni/CaO-SiO₂固体碱催化剂,选择2-(2-甲氧基苯氧基)-1-苯基乙醇作为典型β-O-4木质素模型化合物进行催化剂性能评价。考察了不同Ni、CaO质量分数的Ni/CaO-SiO₂催化剂对β-O-4氢解转化反应的催化活性,探究其对β-O-4产物分布的影响。结果表明：Ni在β-O-4催化转化反应中起主导作用,Ni质量分数的增加有利于β-O-4的催化转化;不同质量分数的Ni, CaO均会对β-O-4的转化产物分布造成一定影响,随着Ni质量分数的增加,β-O-4转化产物种类增加,而CaO的添加会影响1-苯基乙醇的生成。考察不同载体的催化剂对β-O-4 催化转化产物分布的影响,并结合XPS表征发现：其产物分布变化主要由Ni与CaO的相互作用引起,与载体无关。在此基础上,提出了Ni/SiO₂与Ni/CaO-SiO₂催化裂解β-O-4中C-O醚键可能的反应路径。     

Improvement in hydration resistance of CaO granules by addition of Zr(OH)4 and Al(OH)3

Improving the hydration resistance of CaO aggregates is the key to successful application of lime-based refractories in metallurgical industry. Additive Zr(OH)₄ and Al(OH)₃ were introduced in the preparation of CaO granules using granulation equipment and calcination method in this study. The results showed that the hydration resistance of CaO granules was improved significantly, especially for granules with 0.6 wt.% Zr(OH)₄ and 0.9 wt.% Al(OH)₃, respectively. The shell of CaO granules was relatively dense after calcination and the volume of open pores of CaO granules decreased from 3.56 × 10⁻² to 1.80 × 10⁻² cm³/g when additive was introduced. Zr(OH)₄ and Al(OH)₃ have the opposite effect on the closed porosity of CaO granules, the closed porosity of CaO granules was decreased with Zr(OH)₄ addition, but increased with Al(OH)₃ addition.