烟尘水热化合反应制备钙基脱硫剂工艺优化

运用均匀试验设计和回归分析方法优化烟尘水热化合反应制备钙基脱硫剂工艺,得到比表面积回归方程．分析不同水热条件及其相互作用对钙基脱硫剂比表面积的影响,经优化筛选并兼顾实际操作得到最佳水热条件,制备的高效钙基脱硫剂比表面积超过120 m2/g,是单一Ca(OH)2的10倍以上,优化效果显著,可以为工业生产提供依据．     

钙基脱硫过程矿物质对结渣影响的实验研究

对六盘水无烟煤中添加石灰石的钙基脱硫试样的结渣特性、加热过程中矿物质特性进行了实验研究．通过对不同混合比的钙基脱硫灰样熔融特性温度的测定、利用X射线衍射分析对加热过程中钙基脱硫灰样的矿物质特性进行了分析．结果表明：六盘水无烟煤中添加石灰石,当钙硫质量分数之比为2时,钙基脱硫灰样结渣特性由中等变为严重;当钙硫质量分数之比为3时,钙基脱硫灰样结渣特性又变为中等．究其原因是由于高温下,钙硫质量分数之比为2时钙基脱硫灰样中产生较多钙长石和钙(铝)黄长石等熔点较低的矿物质,从而使结渣特性由中等变为严重;当钙硫质量分数之比为3时,钙基脱硫灰样中的部分矿物质分解生成难熔矿物质方钙石,使结渣特性又变为中等．     

Corrosion study of resorbable Ca60Mg15Zn25 bulk metallic glasses in physiological fluids

The corrosion activity of amorphous plates of Ca_(60)Mg_(15)Zn_(25)alloy was investigated.The biocompatible elements were selected for the alloy composition.The electrochemical corrosion and immersion tests were carried out in a multi-electrolyte fluid and Ringer's solution.Better corrosion behavior was observed for the samples tested in a multi-electrolyte fluid despite the active dissolution of Ca and Mg in Ringer's solution.The experimental results indicated that reducing concentration of NaCl from 8.6 g/dm~3for Ringer's solution to 5.75 g/dm~3caused the decrease of the corrosion rate.The volume of the hydrogen evolved after 480 min in Ringer's solution(40.1 ml/cm~2)was higher in comparison with that obtained in a multi-electrolyte fluid(24.4 ml/cm~2).The values of opencircuit potential(E_(OCP))for the Ca_(60)Mg_(15)Zn_(25)glass after 1 h incubation in Ringer's solution and a multielectrolyte fluid were determined to be-1553 and-1536 m V vs.a saturated calomel electrode(SCE).The electrochemical measurements indicated a shift of the corrosion current density(j_(corr))from 1062μA/cm~2for the sample tested in Ringer's solution to 788μA/cm~2for the specimen immersed in a multi-electrolyte fluid.The corrosion products analysis was conducted by using the X-ray photoelectron spectroscopy(XPS).The corrosion products were identified to be CaCO_3,Mg(OH)_2,CaO,MgO and Zn O.The mechanism of corrosion process was proposed and described based on the microscopic observations.The X-ray diffraction and Fourier transform infrared spectroscopy(FTIR)also indicated that Ca(OH)_2,CaCO_3,Zn(OH)_2and Ca(Zn(OH)_3)_2·2H_2O mainly formed on the surface of the studied alloy.     

烟尘/Ca(OH)2水热化合反应动力学分析

采用酸溶法,建立了烟尘/Ca(OH)2水热化合反应制备脱硫剂动力学模型,得到反应级数、表观反应速率常数等动力学参数,分析了NaOH和CaSO4.2H2O激发剂对反应的影响,并优化了制备条件.结果表明,提高水热化合反应温度、适当延长水热化合反应时间及加入激发剂,有助于提高烟尘转化率,按优化条件制备的脱硫剂比表面积达113.168 m2/g,是单一Ca(OH)2的9.5倍,具有较好的对SO2的反应吸收性能.