水泥浆体中矿渣反应程度测试方法

分别采用选择性化学溶解法(以下简称溶解法)和背散射电子图像分析法(以下简称图像法)定量测试掺磨细矿渣粉水泥混合浆体1~360 d龄期中矿渣的反应程度,综合其他性能测试结果比较两种测试方法的准确性并探讨测试误差的形成原因.结果表明,相同硬化浆体溶解法测得矿渣反应程度值显著低于图像法,前者由于溶解不完全导致测试值低于矿渣反应程度真值,后者由于背散射电子图像中颗粒边界效应及图像处理中的过滤操作使测试值高于真值;图像法所得的矿渣反应程度与硬化体抗压强度、微观图像分析结果较溶解法有更好的一致性,说明在定量测试水泥混合浆体中矿渣反应程度方面图像法较溶解法准确性更高.     

煤熔渣对镁铝尖晶石质耐火材料的侵蚀机制

为了实现水煤浆气化炉炉衬材料的无铬化,研究开发合适的耐火材料代替水煤浆气化炉用高铬砖,以尖晶石骨料及细粉、α-Al_2O_3微粉和轻烧Mg O微粉为原料,于1 600℃保温5 h烧成,制备了φ50 mm×40 mm、内孔为φ25 mm×25 mm的镁铝尖晶石质坩埚试样。采用静态坩埚法,借助XRD、SEM+EDS研究了高温煤熔渣对试样的侵蚀行为。结果表明:1)侵蚀后的镁铝尖晶石材料结构疏松,出现较明显的裂纹,煤熔渣完全渗入试样内部。2)经煤熔渣侵蚀后的镁铝尖晶石材料,物相组成发生变化,除原有的镁铝尖晶石外,还有新物相镁铁铝复合尖晶石相存在。3)煤熔渣对镁铝尖晶石材料的侵蚀机制是物理渗透为主,化学熔蚀为辅。     

高碱熟料掺入钢渣提高强度的实践与应用

葛洲坝集团水泥公司于2016年10月在下属单位当阳公司,采用钢渣配料消解该公司碱、钾对熟料影响。采用钢渣配料后,该公司熟料28 d强度由原来51 MPa提升到57 MPa,熟料需水量由135 ml降低到122 ml以内。最终使熟料28 d强度得到提升和性能得到较大改善。     

晶核剂Cr2O3、Fe2O3对玻璃熔化性能的影响

高炉渣的主要成分与玻璃相似,采用熔融法以高炉渣为主要原料制备微晶玻璃(高炉渣配比为70%),以少量纯化学试剂调整基础玻璃成分,通过实验研究了晶核剂Cr2O3、Fe2O3对玻璃熔化性能的影响规律.结果表明:基础玻璃中加入0.5%~2.5%的Cr2O3作晶核剂时,随着Cr2O3加入量的增多,熔化温度呈现逐渐升高趋势,当向基础玻璃中加入1.0%~3.0%Fe2O3作晶核剂时,随着Fe2O3加入量的增多,熔化温度逐渐降低.将0.5%~2.5%Cr2O3、1.0%~3.0%Fe2O3按一定比例配合作为复合晶核剂,总量控制在3.5%,Cr2O3与Fe2O3对玻璃熔化性能的影响可以互相抵消.晶核剂Cr2O3、Fe2O3的引入,可明显降低玻璃的熔化性温度,为了保证玻璃液的顺利浇注成型,至少应将温度控制在1360 ℃以上.     

ZnO对黄磷炉渣微晶玻璃析晶影响

以黄磷炉渣为主要原料,通过添加不同比例ZnO,采用熔融法制备了CaO-Al2O3-SiO2系微晶玻璃.借助Kissinger方程分析黄磷炉渣基础玻璃的析晶能力,借助化学热力学软件FactSage 6.4模拟计算黄磷炉渣微晶玻璃晶相类型,借助X射线衍射仪(XRD)和扫描电子显微镜(SEM)进行验证.结果表明:随着ZnO添加量的增加,黄磷炉渣基础玻璃的析晶峰温度Tp和析晶活化能E逐渐减小;当ZnO添加量为7wt％时,黄磷炉渣基础玻璃的析晶活化能E最小,析晶能力最强;随着ZnO的加入量的增大,黄磷炉渣微晶玻璃晶相类型并不发生改变,主晶相为硅灰石(CaSiO3),次晶相为铝透辉石(Ca(Mg,Al)(Si,Al)2O6),这与FactSage 6.4模拟计算结果一致.     

The fate of iron during the alkali‐activation of synthetic (CaO‐)FeOx‐SiO2 slags: An Fe K‐edge XANES study

Slags from the nonferrous metals industry have great potential to be used as feedstocks for the production of alkali‐activated materials. Until now, however, only very limited information has been available about the structural characteristics of these materials. In the work presented herein, synthetic slags in the CaO–FeO_x–SiO₂ system, representing typical compositions of Fe‐rich slags, and inorganic polymers (IPs) produced from the synthetic slags by activation with alkali silicate solutions have been studied by means of X‐ray absorption near‐edge structure (XANES) spectroscopy at the Fe K‐edge. The iron in the slags was largely Fe²⁺, with an average coordination number of approximately 5 for the iron in the amorphous fraction. The increase in average oxidation number after alkali‐activation was conceptualized as the consequence of slag dissolution and IP precipitation, and employed to calculate the degrees of reaction of the slags. The degree of reaction of the slags increased with increasing amorphous fraction. The iron in the IPs had an average coordination number of approximately 5; thus, IPs produced from the Fe‐rich slags studied here are not Fe‐analogs of aluminosilicate geopolymers, but differ significantly in terms of structure from the latter.     

Slag corrosion mechanism of lightweight Al2O3–MgO castable in different atmospheric conditions

The slag resistance of ladle lining refractory in different atmospheric conditions is of utmost importance due to the strong variation of atmospheric environment in ladle during the process cycle. In this study, by adopting dynamic induction furnace corrosion test, the corrosion mechanism of lightweight Al₂O₃–MgO castable with different environmental oxygen partial pressure was investigated through macro and microanalysis, XRD, and thermodynamic simulation. The atmospheric condition was set to P (O₂) = 0.21 atm or P(Ar) = 1.0 atm. The attained results showed that a reduced slag corrosion but intensified slag penetration happened at low environmental oxygen partial pressure condition. With P(O₂) = 0.21 atm, Mn and Fe in slag were present in the form of divalent and/or trivalent cations and were incorporated into spinel to form MnFe₂O₄ solutions and MgAl₂O₄ solutions during the corrosion process. Since Fe, Mn ions were largely consumed, liquid with high viscosity formed and the continuing infiltration was suppressed. Under P(Ar) = 1.0 atm, Fe ions in the slag were totally reduced into elemental iron while Mn existed mainly in the state of MnO, and the amount of liquid slag was therefore reduced, leading to significantly weakened corrosion on castable aggregates. Corrosion reaction products under this condition were mainly MgAl₂O₄ and CA₆.     

Boron removal from silicon by slag refining using Na2O-SiO2 in industrial applications

Boron (B) removal by slag refining using Na₂O-SiO₂ was investigated in industrial applications. The experimental results showed that the reasonable ratio range of slag to silicon is about 0.7–0.8; the suitable holding time is about 30 min; the concentration of B is reduced from 1.90 ppmw to 0.17 ppmw by three times slag re?ning; and the removal efficiency of B reaches 91.1%. Moreover, it is discussed that B in silicon is more inclined to be oxidized by Na₂O than SiO₂ according to thermodynamic analysis and then volatilized to the atmosphere in the form of Na₂B₂O₄ according to kinetic analysis.     

660 MW超超临界CFB锅炉冷渣器选型技术经济性研究

为比较不同型式的冷渣器对660 MW超超临界CFB锅炉机组能耗的影响,通过分析使用风水联合冷渣器及滚筒冷渣器时锅炉效率、厂用电率的变化,计算超超临界CFB机组使用不同冷渣器时供电煤耗的大小。提出冷渣器选型方案,对不同方案进行经济性比较。研究表明,底渣量和标煤单价对冷渣器选型有重要影响,标煤单价高、底渣量大的项目,宜选用风水联合冷渣器,技术经济性好。为了兼顾冷渣器的技术经济性和运行可靠性,可采用风水冷渣器与滚筒冷渣器搭配使用的方案。研究内容可为燃用低热值煤的CFB锅炉冷渣机选型提供参考。     

离心分离技术在焦油脱渣脱水工艺中的应用

采用离心分离技术对攀钢焦油进行预处理,分析不同转速离心、不同离心时间对煤焦油原料脱渣的效果,同时分析不同转速离心对煤焦油原料脱水的影响,结果表明,采用离心分离处理后煤焦油除渣率≥90%,得到焦油含渣量≤0.3%,含水≤2.0%。