钠化富硼渣中硼化物析晶动力学分析与实验研究

富硼渣经熔态钠化—热处理析晶—水浸工艺可制得硼砂晶体。硼的浸出率与渣中硼组分析出形态直接相关,若以NaBO2为主晶相析出,硼浸出率高;若以玻璃态存在,硼浸出率低。根据非晶固体形成动力学理论,计算富硼渣钠化过程中NaBO2成核速度(I)和晶体长大速度(IL),获得了NaBO2晶体在熔体中的最佳形成温度。采用化学分析方法研究了热处理温度对渣中硼浸出率的影响。结果表明,钠化渣的最佳热处理温度与理论计算所得最佳温度一致。     

富硼渣制备BN-MgAlON复合粉体热力学研究

以富硼渣和炭黑为主要原料,在热力学分析的基础上,采用碳热还原氮化法制备合成了BN-MgAlON复合粉体.利用X射线衍射(XRD)、能谱分析(EDS)和扫描电镜(SEM)等测定了产物的相组成和显微结构,结果表明,在高纯氮气、1480℃保温8h条件下,富硼渣中的B2O3生成BN,MgO,Al2O3反应生成MgAlON相.反应产物的主要成分为MgAlON,Sialon,CaAl4O7,BN,生成的MgAlON为八面体结晶,发育良好.该工艺为富硼渣的综合利用提供了新的途径.     

富硼渣制备BN-MgAlON复合材料及氧化机理分析

在热力学分析的基础上以富硼渣和炭黑为主要原料合成了BN-MgAlON复合材料,并利用X射线衍射(XRD)、能谱分析(EDS)、扫描电镜(SEM)和DSC-TG等测定了产物的相组成、显微结构和氧化性能。实验结果表明,在实验条件下,富硼渣中的B2O3生成BN、MgO、Al2O3反应生成MgAlON相。BN-MgAlON复合粉体的主要成分为MgAlON、Sialon、BN。以制备的复合粉体为原料,Y2O3为添加剂,烧结制备出了BN-MgAlON复合材料,主要物相为Mg-AlON、Sialon和BN,有少量Al5Y3O12和CaYAl3O7相生成。复合材料氧化温度988℃左右,继续升高温度,试样开始增重,增重速率增大,随着温度的升高,温度高于1320℃时,最大增重率为5.54%。     

溶胶-凝胶法制备SiO2基光学玻璃薄膜的红外光谱研究

本文应用傅立叶变换红外光谱仪研究了组分、热处理温度对溶胶 凝胶技术制备的SiO2 、P2 O5 SiO2 、B2 O3 SiO2 以及P2 O5 B2 O3 SiO2 系统薄膜结构的影响规律。随热处理温度增加 ,薄膜中硅氧、硼磷氧、磷硅氧和硼硅氧网络逐渐增强。但薄膜中P2 O5和B2 O3 的含量存在一个饱和值 ,多余的P2 O5和B2 O3 掺入量不能有效进入薄膜网络中     

溶胶—凝胶法制备SiO2基光学玻璃薄膜的红外光谱研究

本文应用傅立叶变换红光谱仪研究了组分、热处理温度对溶胶-凝胶技术制备的SiO2、P2O5-SiO2、B2O3-SiO2以及P2O5-B2O3-SiO2系统薄膜结构的影响规律。随热处理温度增加，薄膜中硅氧、硼磷氧、磷硅氧和硼硅氧网络逐渐增强。但薄膜中P2O5和B2O3的含量存在一个饱和值，多余的P2O5和B2O3掺入量不能有效进入薄膜网络中。     

两段焙烧法制备六硼化镧工艺研究

研究了以氧化镧(La2O3)、氧化硼(B2O3)和石墨(C)为原料采用两段焙烧工艺制备六硼化镧(LaB6)粉末的工艺路线。首先采用TG-DTA测试确定了La2O3、B2O3、C原料在室温至1100℃下的反应情况,随后采用X射线衍射分析了低温段(1100~1500℃)和高温段(1500~1700℃)的反应温度和保温时间对产品相组成的影响,从而确定两段焙烧法制备LaB6的工艺流程及参数,最后采用扫描电镜和ICP-MS分析方法分析了产品LaB6粉末的颗粒尺寸、形貌及纯度。实验结果表明,采用La2O3-B2O3-C体系制备LaB6,在1300℃保温4h,将原料B2O3中的B元素转化进入中间体,随后在1700℃高温反应4h可得到紫红色LaB6粉末,测试结果显示LaB6的含量大于99.9%,其中La和B的原子比为1∶6,粒径约为2μm。     

MgO—B2O3—SiO2—Al2O3—CaO中含硼组分析晶动力学

根据玻璃形成动力学理论，计算了ＭｇＯ－Ｂ２Ｏ３－ＳｉＯ２－Ａｌ２Ｏ３－ＣａＯ渣系中含硼组分２ＭｇＯ·Ｂ２Ｏ３的成核速度（Ｉ）和晶体长大速度（Ｕ），获得了２ＭｇＯ·Ｂ２Ｏ３晶体形成的最佳温度．采用化学分析、Ｘ射线衍射分析（ＸＲＤ）和差热分析（ＤＴＡ）等方法研究了热处理温度对ＭｇＯ—Ｂ２Ｏ３—ＳｉＯ２—Ａｌ２Ｏ３—ＣａＯ渣系硼提取率的影响．结果表明：硼渣最佳热处理温度与２ＭｇＯ·Ｂ２Ｏ３晶体形成最佳温度一致。     

氧化硼对硅酸盐玻璃固化体结构及抗浸出性能的影响

以SiO2、Al2O3、B2O3、CaO、Na2O为原料,加入5%CeO2(质量分数)作为模拟核素,利用熔融法制备硼硅酸盐玻璃固化体,对含锕系元素的放射性废物进行固化处置。通过傅里叶红外光谱仪、紫外激光拉曼光谱仪和差热分析仪等对热处理后玻璃固化体进行表征,以电感耦合等离子体质谱测试玻璃固化体抗浸出性能。结果表明:B2O3含量为15.79wt%时固化体玻璃化转变温度Tg最大;玻璃中存在[SiO4]、[BO3]、[BO4]等基团,随着B2O3含量的增大,部分[BO4]转变为[BO3];Ce在产品一致性测试法(PCT)下标准化浸出率NR先减小后增大,B2O3含量达到15.79wt%时玻璃抗浸出效果最好。     

ZnO-B_2O_3-P_2O_5无铅玻璃结构的红外光谱研究

借助于红外光谱研究了ZnO-B2O3-PzO5磷酸盐玻璃的结构,分别讨论了玻璃中B2O3/ZnO组成的变化和P2O5/ZnO组成的变化对磷酸盐玻璃结构的影响.结果表明:玻璃中硼氧三角体[BO3]随B2O3含量的增加而增多,而硼氧四面体[BO4]减少,当B2O3≥30%(摩尔含量)时,[BO3]急剧增多,导致玻璃的化学稳定性先缓慢下降后急剧下降;随P2O5含量的增加,[BO3]减少而[BO4]增加,当P2O5≥45%(摩尔含量)时,玻璃中的B3+主要以硼氧四面体[BO4]的形式存在.     

硼硅酸盐包层玻璃化学稳定性的研究与结构分析

研究了紫外光纤用包层玻璃组分的变化以及外掺ZrO2对光纤包层玻璃化学稳定性的影响.结果表明,通过改变SiO2/B2O3、B2O3/Al2O3、B2O3/(K2O Na2O)的值,以及适当增加外掺ZrO2含量,可以明显提高碱硼硅酸盐玻璃化学稳定性.核磁共振和红外光谱分析表明玻璃化学稳定性提高的主要原因在于Zr4 的加入促进了玻璃内部的[BO3]层状结构逐渐转变为[BO4]网络状结构.     

Characterization of the lead smelter slag in Santo Amaro, Bahia, Brazil

For 33 years, a primary lead smelter operated in Santo Amaro (Brazil). Since the 1970s, large amounts of Pb and Cd have been widely documented in the blood and hair of people living near the smelter. The plant closed down in 1993, and several years later, the Pb levels in the blood of children under 4 years of age living near the smelter were high, where the disposed lead slag was suspected to be the main source of this contamination. The objective of this study is to elucidate the source of the Pb contamination and any other potentially toxic contamination, focusing on the characterization of the slag. The samples used for this characterization study were taken from the slag heaps. The results of the chemical analysis showed that the major constituents of the slag, in decreasing order of wt%, were the following: Fe(2)O(3) (28.10), CaO (23.11), SiO(2) (21.39), ZnO (9.47), MgO (5.44), PbO (4.06), Al(2)O(3) (3.56), C (2.26), MnO (1.44), Na(2)O (0.27), S (0.37), K(2)O (0.26), and TiO(2) (0.25). The Cd content of the slag was 57.3mg/kg, which is relatively low. The X-ray diffraction and the electron probe microanalyzer X-ray mapping indicated that the major phases in the slag were wüstite, olivine, kirschsteinite, and franklinite. Only spheroidal metallic Pb was found in the slag. The leaching study showed that the slag was stable at a pH greater than 2.8, and only in an extremely acidic environment was the solubilization of the Pb enhanced significantly. The solubilization of Zn was very limited in the acidic and alkaline environments. These results can be explained by the limited leachability of the metallic Pb and Zn-bearing compounds. The leaching study used TCLP, SPLP, and SWEP and indicated that the lead slag was stable in weak acidic environments for short contact times.     

Characteristics of slag produced from incinerated hospital waste

Ash produced from a hospital waste incinerator was treated using a high temperature melting process at 1200 degrees C. The quality of the produced slag was characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), leaching tests and sequential chemical extraction of metals. The slag contained large amounts of SiO(2,) CaO, Al(2)O(3), Sn, Ni, Cu, Ba and B. XRD analysis revealed a moderate crystal structure for the melted slag and identified the main crystals as quartz (SiO(2)), kaolinite (Al(2)Si(2)O(5)(OH)(4)), albite (NaAlSi(3)O(8)) and gibbsite (Al(OH)(3)). The observed crystal structure assists in preventing the leaching of heavy metals from the slag. Furthermore, the leaching results found the produced slag to comply with disposal limits set by the US EPA. Results from sequential chemical extraction analysis showed that metals in the slag exhibited the strongest preference to be bound to the residual fraction (stable fraction), which is known to have very low leaching characteristics. Melting was found to stabilize heavy metals in hospital waste successfully and therefore it can be an acceptable method for disposal.     

真空硅浴熔融还原白云石炼镁的实验研究

通过往煅烧白云石中添加适量的Al2O3和SiO2,使其在1500～1600℃之间形成熔融炉渣,并在真空下采用硅铁还原液态渣中的MgO。研究了造渣剂对MgO还原率的影响,结果表明,在能够获得熔融炉渣的情况下,增大Al2O3/SiO2比能够极大地提高渣中MgO的还原率,理想的炉渣成分为32.0%CaO-23.0%MgO-35.0%Al2O3-10%SiO2。同时,对该炉渣进行了正交实验,通过分析得出影响MgO还原率因素的顺序依次是:反应温度、还原剂硅铁添加量、反应时间、催化剂CaF2添加量。在熔融还原工艺参数为:反应温度1600℃,还原剂硅铁添加量n(Si)/n(2MgO)=1.2,反应2h,催化剂CaF2添加量3%条件下,渣中的MgO还原率高达97.3%。     

Predication of Component Activities in the Molten Aluminosilicate Slag CaO-Al_2O_3-SiO_2 by Molecular Interaction Volume Model

A novel thermodynamic model-the molecular interaction volume model （MIVM） which can be reduced to the Flory-Huggins equation of polymer solution was employed for the prediction of component activities in the ternary molten aluminosilicate slag CaO-Al2O3-SiO2 at different temperatures. The results show that the predicted values of activity of CaO, Al2O3 and SiO2 are in reasonably agreement with experimental data in some ranges of their concentrations which are about x1 〈0.25 for CaO, x2=0.05-0.55 for Al2O3 and x3=0.03-0.85 for SiO2. This further shows that MIVM requires only two binary parameters for each sub-binary system to predict activities of all components in a multicomponent solution and is the superior alternative in a molten slag.     

TiO2和ZrO2在B2O3—MgO—SiO2系晶化过程中的作用

采用Ｘ射线衍射（ＸＲＤ），差热分析（ＤＴＡ），扫描电镜（ＳＥＭ）和红外光谱（ＩＲ）等手段研究了ＴｉＯ２和ＺｒＯ２对Ｂ２Ｏ３－ＭｇＯ－ＳｉＯ２渣中含硼组分晶化行为的影响，结果表明，ＴｉＯ２和ＺｒＯ２作为晶核剂加入后，促进分相，降低了晶化活化能，有利于含硼组分以２ＭｇＯ．Ｂ２Ｏ３和３ＭｇＯ．Ｂ２Ｏ３，析出，加入ＴｉＯ２改变了硼渣结构，产生更多有利于２ＭｇＯ．Ｂ２Ｏ３和３ＭｇＯ．Ｂ２Ｏ３析出的（Ｂ２Ｏ５     

Development and bioactivity evaluation of bioglasses with low Na2O content based on the system Na2O–CaO–MgO–P2O5–SiO2

Osteoconductive bioglasses, free of K(2)O and Al(2)O(3) and with content of Na(2)O lower than 10?mol%, were designed based on the ratio (SiO(2)?+?MgO)/(P(2)O(5)?+?CaO?+?Na(2)O) in the system Na(2)O-CaO-MgO-P(2)O(5)-SiO(2). The developed glasses have shown a strong potential for the formation of hydroxycarbonated apatite (HCA) in vitro. The particles of HCA aggregates tend to be of finer size with increasing the ratio of (SiO(2)?+?MgO)/(CaO?+?P(2)O(5)?+?Na(2)O) in the glass chemical composition indicating significant bioactivity. Critical size bone defects created in the femurs of albino adult female rats, and grafted with the glass particles for 12?weeks post implantation, were completely healed by filling with mineralized bone matrix without infection showing a strong potential for new bone formation in vivo. Osteoblasts and osteocytes were observed close to the surface of the granular implants with active areas of bone deposition, resorption and remodelling. The bioglass with lowest (SiO(2)?+?MgO)/(CaO?+?P(2)O(5)?+?Na(2)O) ratio has shown the highest bioactivity while the bioglass with the highest (SiO(2)?+?MgO)/(CaO?+?P(2)O(5)?+?Na(2)O) has shown the lowest bioactivity. The newly formed bone in vivo has shown a similar structure to that of the original bone as indicated by the histology and microstructural results. In addition, Ca/P molar ratio of the newly formed bone was found to be (~1.67), which is similar to that of the original bone.     

新法真空铝热还原炼镁的研究

对以煅后白云石和煅后菱镁石为原料,以铝粉为还原剂的新法炼镁技术的热力学进行了分析,并进行了真空热还原实验。通过X射线衍射和扫描电子显微镜对还原渣的主要物相与物质形态进行了分析。实验结果表明:以煅后白云石和煅后菱镁石为原料,以铝粉为还原剂的新法真空热还原炼镁技术是可行的,在还原温度1200℃,还原时间2 h,铝粉过量5%和无氟盐添加剂的条件下,氧化镁的还原率可达90%,CaF2或MgF2的添加可大幅度地提高还原过程中氧化镁的还原率,降低还原温度。还原后还原渣主要物相为CaO.2Al2O3,还原渣中氧化铝的含量在65%以上,氧化硅含量低于2%,是一种非常适合生产氢氧化铝的原料。     

钠镁铝硅系统微晶玻璃的分相成核行为

本文以20Na2O、4CaO、12MgO、22Al2O3、4TiO2、38SiO2(重量百分比)组成玻璃为基础,制备了具有快速微晶化特性的钠镁铝硅系统微晶玻璃。分别采用差热分析技术(DTA)、X射线衍射技术(XRD)研究了不同热处理条件下玻璃分相成核的动力学、热力学和它们之间的依存关系。玻璃分相成核最大速率时的温度接近于923K。在成核温度的热处理对分相的放热行为有影响,成核导致系统自由能的降低与分相峰面积和峰值温度变化有关。用差热分析仪测量的玻璃分相的放热效应,是快速微晶化玻璃的重要特征,用XRD证实分相放热过程中没有微晶相产生。玻璃的分相过程为成核生长机理,采用修正kissinger方程求得玻璃分相活化能为310.445KJ/mol。     

应用低钛高炉渣的半钢炼钢:脱磷热力学与工业试验

基于低钛高炉渣资源化综合利用和提高转炉半钢炼钢脱磷效果的考虑,对低钛高炉渣进行喷吹CO_2法脱硫处理后,配入25%~30%的氧化铁皮制备成半钢化渣球用于半钢炼钢。采用建立半钢渣系的脱磷热力学模型和工业试验的方法,对此半钢化渣球冶炼半钢的脱磷能力和冶金效果进行研究。研究结果表明:随着炉渣中TiO_2和Al_2O_3含量的升高,炉渣的脱磷能力降低,特别是当炉渣碱度和温度较低时,脱磷能力降低更快;在两种氧化物含量相同的情况下,TiO_2比Al_2O_3的负面影响更大;随炉渣碱度的增加,炉渣的磷分配比和磷容量均呈先升高后持平的趋势;随渣中w(FeO)的增加,炉渣的磷分配比和磷容量均先升高后降低;随w(MgO)的降低,炉渣的磷分配比和磷容量逐渐降低。采用半钢化渣球冶炼半钢,渣中w(TiO_2+Al_2O_3)和w(FeO)升高,炉渣碱度和w(MgO)降低,控制炉渣碱度在4.0左右,炉渣不仅具有较高的磷分配比和磷容量,并且可以弱化(TiO_2+Al_2O_3)对脱磷能力的影响,确定其加入比例为总渣量的15.0%~20.0%。留渣+化渣球法冶炼半钢的前期平均脱磷率增至58.59%,为原冶炼工艺的1.57倍,吨钢石灰消耗和终点钢水[O]含量分别下降3.48kg/t和112×10-6。