四氟化硅气体中杂质的检测及净化研究进展

介绍了四氟化硅气体中杂质的4种检测方法:气相色谱法、红外光谱法、气相色谱质谱法、原子发射光谱法。其中,气相色谱法一般用来测定四氟化硅气体中的烃类杂质,红外光谱法主要用来测定四氟化硅气体中的氟硅烷、氟氧硅烷、氟硅醇杂质。气相色谱质谱法用来测定四氟化硅气体中的六氟化硫杂质,原子发射光谱法主要用来测定四氟化硅气体中的金属杂质。然后对四氟化硅气体的不同净化方法进行列举,并对净化工艺的条件、优缺点进行了阐述。     

磷矿伴生硅资源制备单质硅的探讨

综述了国内外以四氟化硅、氟硅酸钠（钾）、无定SiO2为硅源制备单质硅的主要方法,并对以无定SiO2为硅源制备单质硅的工艺条件进行了研究与探索。     

四氟化硅气体中杂质的检测及净化研究进展

介绍了四氟化硅气体中杂质的4种检测方法:气相色谱法、红外光谱法、气相色谱质谱法、原子发射光谱法。其中,气相色谱法一般用来测定四氟化硅气体中的烃类杂质,红外光谱法主要用来测定四氟化硅气体中的氟硅烷、氟氧硅烷、氟硅醇杂质。气相色谱质谱法用来测定四氟化硅气体中的六氟化硫杂质,原子发射光谱法主要用来测定四氟化硅气体中的金属杂质。然后对四氟化硅气体的不同净化方法进行列举,并对净化工艺的条件、优缺点进行了阐述。     

四氟化硅的制备与提纯

四氟化硅(SiF4)是电子和半导体行业中的一种重要原料,在光伏产业中占重要地位.详细介绍了四氟化硅的主要制备方法:硫酸法、Si-F2直接合成法、氟硅酸盐热解法和氢氟酸法,并对四氟化硅提纯工艺进行了比较.     

特殊电子气-四氟化硅分析检测

四氟化硅是一种重要的特殊电子气体,可用于电子和半导体行业,高纯度的四氟化硅还可作为非晶体硅、硅烷、多晶体硅、光纤等制备的原料,文章介绍了四氟化硅气体中气体杂质、金属杂质及碘的分析检测方法,初步确定了四氟化硅气体中的杂质分析。     

氟硅酸钙热解制备四氟化硅的工艺研究

针对四氟化硅的行业需求,本研究探讨了由磷肥副产物氟硅酸制备的氟硅酸钙热解生成四氟化硅的工艺条件,通过正交实验分析获得了适用于工业生产的氟硅酸钙最优脱水及热解条件,并对制备的粗品四氟化硅、副产品氟化钙与市售产品进行了质量指标对比,本实验所得的目标产物和副产物均满足行业的质量要求.该工艺具有流程短、能耗低、对环境危害小的特...     

高纯四氟化硅的制备技术研究进展

四氟化硅是一种有机硅化合物合成材料,被广泛应用于半导体行业,其需求量日益扩大,对其纯度要求也越来越苛刻。本文介绍了四氟化硅常用制备方法及其优缺点,列举了四氟化硅的纯化方法。在实际生产过程中,企业需根据自身实际生产情况选择合理的生产路线,结合制备工艺中杂质种类,选择合适纯化方法,获得高纯四氟化硅产品。     

四氟化硅的工艺研发及进展状况

四氟化硅是电子工业中的一种重要原料,随着多晶硅等行业迅猛发展需求量逐渐增大。详细介绍了四氟化硅的应用及市场情况,并对氟气合成法、氟硅酸盐热解法、硫酸法、氢氟酸直接反应法这4种主要生产方法进行详细论述,讨论了各工艺方法的生产原理、工艺简述、研究状况并对工艺的优缺点进行了评价。就目前市场形势分析,国内四氟化硅需开发高端产品,以适应市场需求和参与国际竞争。     

四氟化硅

1 SiF4的应用及经济概况 四氟化硅在电子和半导体行业中主要用于氮化硅、硅化钽等的蚀刻剂、P型掺杂剂、外延沉积扩散硅源等．还可用于制备电子级硅烷或硅。四氟化硅还可用作光导纤维用高纯石英玻璃的原料．它在高温火焰中水解可产生具有高比表面积的热沉二氧化硅。此外，四氟化硅还广泛用在制备太阳能电池、氟硅酸和氟化铝、化学分析、氟化剂．油井钻探、镁合金浇铸、催化剂、蒸熏剂、水泥及人造大理石的硬化剂等。在预制水泥中使用四氟化硅后．可增进其耐蚀性和耐磨性．改善其孔隙度和增加压缩强度。     

利用磷肥企业副产氟硅酸制备无水氟化氢的技术

通过比较国内外氟硅酸制备无水氟化氢的各种技术,提出将氟硅酸先氨解氟硅分离成氟化铵溶液和二氧化硅,然后将氟化铵溶液转化为易于浓缩结晶的氟硅酸铵,将氟硅酸铵固体和浓硫酸反应生产氟化氢和四氟化硅,酸解混合气体经冷却制备无水氟化氢,四氟化硅返回系统循环使用。     

铝电解槽干式防渗料在电解过程中的反应机理探讨

通过对大修铝电解槽中废防渗料的成分和物相组成进行分析,探讨了干式防渗料与电解质的反应机理。研究结果表明,渗透电解质中的NaF和冰晶石均会与干式防渗料反应生成霞石(NaAlSiO₄)玻璃体层,可起到防止电解质进一步向下渗透的作用。但随着渗透电解质的增加,冰晶石会继续与霞石反应生成β氧化铝,β氧化铝层不具有防渗作用,这是导致防渗料中电解质继续渗透的主要原因之一。渗透电解质与防渗料反应还可生成SiF₄气体,使硅元素向防渗料下部迁移,导致废防渗料上层硅元素含量降低。     

Production of Ultra Clean Coal: Part I—Dissolution behaviour of mineral matter in black coal toward hydrochloric and hydrofluoric acids

The mineral matter in an Australian black coal has been isolated using a low-temperature ashing (LTA) procedure. This LTA procedure is a modification of the Australian Standard for LTA at 370°C, and alleviates adverse effects to the minerals caused by the heat of combustion. The leaching behaviour of the mineral matter towards aqueous HCl and hydrofluoric acid (HF) is presented. HCl can dissolve simple compounds such as phosphates and carbonates, yet it cannot completely dissolve the clays. HF reacts with almost every mineral in the mineral matter, except pyrite, and most of the reaction products are water soluble. However, at HF concentrations greater than that required to dissolve the aluminosilicate compounds in the mineral matter, insoluble compounds form. These compounds include CaF₂, MgF₂ and a compound containing Na, which is believed to be NaAlF₄. It is proposed that HF reacts preferentially with the aluminosilicates in the mineral matter to form largely AlF₂⁺, AlF₃ and SiF₄, and that the concentrations of free fluoride (F⁻) and AlF₄⁻ are not high enough to complex cations such as Ca²⁺, Mg²⁺ and Na⁺. When the mineral matter is treated with HF concentrations greater than that required to dissolve all of the aluminosilicates, AlF₃, AlF₄⁻ and SiF₆²⁻ form, the concentration of F⁻ is high enough to complex Ca²⁺ and Mg²⁺ and form insoluble CaF₂ and MgF₂, and the concentration of AlF₄⁻ is high enough to complex Na⁺ and form insoluble NaAlF₄. This work has application toward the development of a process for producing Ultra Clean Coal with less than 0.1% by weight mineral matter.     

湿法磷酸过程氟回收技术研究进展

磷酸（H₃PO₄）作为一种广泛使用的化工产品,在其生产制备的过程中往往伴随大量的含氟物质产生,而氟作为一种高附加值的物质资源,对其进行回收利用已成为当今磷化工产业的主要研究方向。综述了湿法磷酸化工流程中氟回收技术的研究现状,详细介绍了氟回收技术在3个方面的国内外研究现状：气相氟回收技术、液相氟回收技术、固相氟回收技术。分析了氟回收技术原理及其优缺点,总结了氟回收各部分的技术关键点,以期促进今后氟回收技术的发展。     

Simultaneous preparation of TiO2 and ammonium alum,and microporous SiO2 during the mineral carbonation of titanium-bearing blast furnace slag

In this study, a route for simultaneous mineralization of CO₂ and production of titanium dioxide and ammonium alum, and microporous silicon dioxide from titanium-bearing blast furnace slag (TBBF slag) was proposed, which is comprised of (NH₄)₂SO₄ roasting, acid leaching, ammonium alum crystallization, silicic acid flocculation and Ti hydrolysis. The effects of relevant process parameters were systematically investigated. The results showed that under the optimal roasting and leaching conditions about 85% of titanium and 84.6% of aluminum could be extracted while only 30% of silicon entered the leachate. 84% of Al³⁺ was crystallized from the leachate in the form of ammonium aluminum sulfate dodecahydrate with a purity up to 99.5 wt%. About 85% of the soluble silicic acid was flocculated with the aid of secondary alcohol polyoxyethylene ether 9 (AEO-9) to yield a microporous SiO₂ material (97.4 wt%) from the crystallized mother liquor. The Al- and Si-depleted solution was then hydrolyzed to generate a titanium dioxide (99.1 wt%) with uniform particle size distribution. It was figured out that approximately 146 kg TiO₂ could be produced from 1000 kg of TBBF slag. Therefore, the improved process is a promising method for industrial application.     

溶胶-凝胶法制备氧化硅-氧化铝体系凝胶及合成过程研究进展

氧化硅-氧化铝（SiO₂-Al₂O₃）体系凝胶不仅应用广泛,而且其制备及反应机理还可借鉴到碱激发胶凝材料等领域。通过对溶胶-凝胶法合成氧化硅-氧化铝体系凝胶的制备过程及影响因素和影响规律、凝胶的性质和结构表征及合成机理研究进展进行综述,提出目前仍缺乏有关碱（土）金属离子对凝胶结构性能的影响研究以及硅铝含量变化的定量描述数据,建议拓宽研究范畴,结合核磁共振等检测方法,得出该体系结构性能变化准确数据,为氧化硅-氧化铝体系凝胶的设计和应用夯实基础。     

二氧化硅制备水溶性硅钾肥的研究

采用二氧化硅和碳酸钾为原料,通过高温煅烧活化二氧化硅制备水溶性硅钾肥。研究了煅烧温度、煅烧时间、氧化钾与二氧化硅物质的量比、二氧化硅粒径等条件对制备水溶性硅钾肥的影响,并通过热重-差示扫描量热法（TG-DSC）、X射线衍射（XRD）和扫描电镜（SEM）等对样品进行了表征。最佳工艺条件：煅烧温度为900 ℃,煅烧时间为30 min,氧化钾与二氧化硅物质的量比为0.85,二氧化硅平均粒径为160 μm。在此条件下制得的硅钾肥具有全水溶性,硅活化率为99.34%,有效硅（以二氧化硅计）质量分数为39.55%,氧化钾质量分数为53.23%。在高温下二氧化硅与碳酸钾的化学反应可抑制碳酸钾的挥发,反应产物的组成不仅含有硅酸钾（K₂SiO₃）,可能还存在二硅酸钾（K₂Si₂O₅）和四硅酸钾（K₂Si₄O₉）。     

硫铁矿生产硫磺尾渣用于建筑涂料的生产研究

采用磁选分离方法从生产硫磺的硫铁矿尾渣中回收四氧化三铁精矿粉后,余下的废渣为铁、铝、硅、钙、镁的混合物,经加工配料可制备建筑外墙涂料。分析了尾渣的化学成分、矿物成分、粒度分布;对尾渣生产建筑外墙涂料的可行性进行了研究;叙述了尾渣制备外墙涂料的制备工艺并给出了优化的实验配方;对该方法的经济效益进行了评估与分析。实验结果证明,该方法使低品位硫铁矿生产硫磺工艺产生的尾渣得到全面利用,具有很好的经济与社会效益。     

Preparation, structural and optical characterization of BaWO4 and PbWO4 thin films prepared by a chemical route

Polycrystalline BaWO₄ and PbWO₄ thin films having a tetragonal scheelite structure were prepared at different temperatures. Soluble precursors such as barium carbonate, lead acetate trihydrate and tungstic acid, as starting materials, were mixed in aqueous solution. The thin films were deposited on silicon, platinum-coated silicon and quartz substrates by means of the spinning technique. The surface morphology and crystal structure of the thin films were investigated using scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction, and specular reflectance infrared Fourier transform spectroscopy, respectively. Nucleation stages and surface morphology evolution of thin films on silicon substrates have been studied by atomic force microscopy. XRD characterization of these films showed that BaWO₄ and PbWO₄ phase crystallize at 500 °C from an inorganic amorphous phase. FTIR spectra revealed the complete decomposition of the organic ligands at 500 °C and the appearance of two sharp and intense bands between 1000 and 600 cm⁻¹ assigned to vibrations of the antisymmetric stretches resulting from the high crystallinity of both thin films. The optical properties were also studied. It was found that BaWO₄ and PbWO₄ thin films have Eg=5.78 eV and 4.20 eV, respectively, of a direct transition nature. The excellent microstructural quality and chemical homogeneity results confirmed that soft solution processing provides an inexpensive and environmentally friendly route for the preparation of BaWO₄ and PbWO₄ thin films.     

Preparation of β-Silicon Nitride Seeds for Self-Reinforced Silicon Nitride Ceramics

This paper describes a method for the preparation of silicon nitride (Si₃N₄) seeds that have an average aspect ratio of ∼4. The seeds are prepared via heat treatment of a powder mixture that contains alpha-phase-rich Si₃N₄ and 0.5 wt% Y₂O₃ at a temperature of 1800°C and a nitrogen pressure of 35 kPa. A Y-Si-O-N liquid forms during heat treatment; this liquid acts as a flux for seed precipitation. During cooling, the Y-Si-O-N liquid transforms to a thin intergranular grain-boundary phase and causes strong agglomeration of the seeds. The seeds can be isolated by dissolving the grain-boundary phase in hot phosphoric acid, followed by an ultrasonic treatment (for 30 min). The method can be used to produce large quantities of seeds.     

氮化硅粉体制备技术及粉体质量研究进展

氮化硅(Si₃N₄)具有优异的物化性能,在国防、电子信息等关键领域都占据重要的地位。高质量粉体是制备高性能Si₃N₄陶瓷的首要前提。通常高质量Si₃N₄粉体需要满足粒径细、分布窄、α相含量高、杂质含量低等条件。基于合成反应体系综述了当前国内外制备Si₃N₄粉体的方法,着重从强化传热与传质角度介绍了改善粉体质量的研究进展,并介绍了当前工业生产现状,展望了高质量Si₃N₄粉体制备技术的发展趋势和方向。