太阳能级硅切割废料的回收技术

太阳能级硅棒在切割生产硅晶片过程中会产生大量的切割废料。概述了废料中切割液和碳化硅回收技术的进展,重点介绍和分析了价值更高的硅与碳化硅微粉分离回收技术的特点及现状,并比较各种方法的优缺点,同时结合自身的课题研究,提出了新的解决思路。分析认为先通过离心、浮选等方法对切割废料初步提纯后再经高温热处理或合金化等方法将其进一步分离,是较有前景的回收技术。     

太阳能电池硅片线锯砂浆中硅屑的回收技术研究

多线切割是当前硅太阳能电池片生产的主要工艺.在线切割过程中约有1/2的晶体硅成为锯屑进入到切割砂浆.砂浆中的各种污染物并未进入高纯硅屑晶体内部,因此可以期望通过物理分离、清洗等技术来提取获得高纯硅粉,而不需要通过高耗能的高温化学或相变过程.综述了硅片线切割过程、硅屑形成及废砂浆特性,评述了从线切割废砂浆中回收高纯硅粉的研究现状和进展,包括本研究组近期的研究结果.     

从蓄电池中回收铅的技术进展

废铅蓄电池是再生铅的主要原料，其中的铅除金属外还含有不同数量的PbO、PbO2和PbSO4，因此其再生过程较为复杂，目前国内外主要采用火法和湿法回收铅。本文详细阐述火法和湿法回收铅的原理和工艺流程。     

废退锡液中硝酸和锡的综合回收

通过考察铁盐、铜盐和亚锡盐对硝酸扩散系数的影响研究了采用扩散渗析法从废退锡液中回收硝酸的可行性,实际样品的研究表明,扩散渗析法回收硝酸的回收率在70％以上．余液利用离子膜-电沉积法回收其中的金属锡,最佳工艺条件为:温度30-40℃、槽电压3．5 V、电流密度1．0-2．3 A／dm2,并保持阳极液搅拌,此时锡的回收率达62％,电流效率在60％以上．结果表明,扩散渗析-离子膜-电沉积组合工艺可有效回收硝酸型废退锡液中的硝酸和锡,以实现其资源化利用．     

采用主峰切割带转化炉的FID气相色谱仪分析高纯一氧化碳、高纯甲烷中微量二氧化碳的方法

用Porapak-T填充柱和TDX-01填充柱双柱串联的带转化炉的FID气相色谱仪,在所选的色谱条件下,采用主峰切割的方法,分析高纯二氧化碳、高纯甲烷以及其混合气中的微量二氧化碳。     

单晶及多晶硅切割废料中的高纯硅回收

为提高在切割废料中高纯硅的回收率,对沉降方法和条件进行了优化.根据单/多晶硅切割废料浆的物理、化学性质,在m（水）∶m（聚乙二醇）=（8～9）∶1、含有少量无机盐的水溶液体系中,在不同沉降时间和不同固液配比的条件下进行正交试验,通过盐酸、氢氟酸进行除杂,最后在1 500～1 600℃下进行硅的铸锭.通过X射线衍射、元素...     

Bi-stable pore size during electrochemical etching of n-type silicon during a thermal ramp

We have investigated the change in size and density of pores during electrochemical etching of n-type (5 Ωcm) silicon under backside illumination and subjected to a thermal ramp. The pore structure was allowed to self organize, and for the parameters reported here this results in macropores with diameters in the ∼ μm order of magnitude range. As the etching progressed under constant current conditions, the electrolyte and the sample heated slowly up in the temperature range 20-60 °C. The resulting pore structure was obtained by scanning electron microscope examination of cross sections of cleaved samples. The temperature ramp caused the pore diameters and pore densities to change abruptly rather than continuously. The change can thus phenomenologically be described as a transition between two stable pore size configurations; bi-stable switching or phase transition. This phenomenon is observed for a range of parameters yielding macropores: current densities between 2-20 mA/cm² and varying light intensity. The transition is between known configurations.     

Prediction of silicon dry etching using a piecewise linear algorithm

A piecewise linear algorithm for predicting silicon etch rates in fluorine-based plasmas is shown. Discrete experimental data of pressure and RF power in reactive ion etching are used to construct a set of local two-dimensional etching functions that serve as a basis for computing numerical solutions (pressure and power values for a specific predicted silicon etch rate). It must be pointed out that, although the algorithm scans the entire data domain, a testing procedure is applied to ensure that the computing task will be invoked only when a solution exists, and otherwise it will be discarded (this avoids brute force methods). In the last step of the algorithm, all solutions are collected and interpolated to construct a solution path. In order to verify the match between the experimental etching results and numerical predictions, the algorithm has been coded and tested using Maple® Release 13.0, showing a successful validation with a difference between experimental data and computed numerical solutions as low as 1% for SF₆, and 4% for SF₆/O₂ in the best case and a root-mean squared error of 0.03.     

Patterning of porous silicon nanostructures and eliminating microcracks on silicon nitride mask using metal assisted chemical etching

A method for selective formation of reproducible, high fidelity and controllable nano and micrometer size porous Si areas over n-type Si wafers is provided. A 400 nm thick Silicon Nitride layer was used as the mask layer while Platinum and Palladium nanoparticles were deposited over the unprotected areas to obtain porous areas through metal assisted chemical etching process. Nanoparticles were deposited by electroless plating solutions containing H₂PtCl₆ and PdCl₂. Good controls over pore size and depth were obtained with well defined and sharp edges of the patterned areas. The results were compared to porous structures obtained via electrochemical etching process, indicating the superiority of metal assisted etching in terms of its simplicity as well as the ability of Silicon Nitride layer acting as the mask layer.     

Retreatment of silicon slurry by membrane processes

The purpose of the present study is to develop a process to regenerate the polish liquid used in Chemical and Mechanical Polishing (CMP), called “slurry”, and more specifically Silicon CMP slurry. Physico-chemical analyses show a considerable dilution of slurry through washing waters used in polishing. Thus, this effluent has been characterised for a better identification of the deviations from the slurry of reference (Point Of Use). Hence, the principle is to regenerate this effluent by membrane processes. The ultrafiltration results obtained at laboratory scale have led to the development of an industrial prototype. An optimal utilisation of this treatment allows completing a two-step process: the reconcentration by ultrafiltration and a chemical adjustment by addition of concentrated slurry. A stable behaviour of the slurry at the different steps of the process has been observed. Polishing results are similar with retreated and POU slurries. Furthermore, the functioning at industrial scale permits to maintain the performances obtained on the laboratory pilot.     

简单蚀刻法制备具有可控高度的金属纳米线阵列

采用多孔阳极氧化铝(AAO)作为模板,运用电化学沉积法在模板的微孔中组装金属Ni纳米线,然后用磷铬酸蚀刻表层AAO模板,暴露出规整有序、具有可控长度的Ni纳米线阵列.分别用SEM、TEM与SAED对Ni纳米线阵列进行了表征.研究了蚀刻时间与AAO模板质量的减少及暴露出来的Ni纳米线阵列长度之间的关系.结果表明,磷铬酸是较NaOH溶液更为温和有效的AAO模板蚀刻剂,通过控制模板溶解时间,可以实现对裸露于AAO模板外纳米线长度的精细有效控制.该蚀刻方法普遍适用于以AAO为模板所制得的准一维纳米阵列结构.     

Recovery of nitric acid from waste etching solution using solvent extraction

As part of our efforts to identify effective ways and means to keep source water safe, the concept of risk assessment and management is introduced in this paper to address the issue of risk assessment and management of arsenic in source water in China. Carcinogenic and non-carcinogenic risk are calculated for different concentrations of arsenic in source water using the corrective equation between potential health risk and concentration of arsenic in source water with purification process taken into consideration. It is justified through analyses that risk assessment and management is suitable for China to control pollution of source water. The permissible content of arsenic in source water should be set at 0.01 mg/L at present in China, and necessary risk management measures include control contaminated sources and improvement of purification efficiency.     

酸性蚀刻废液制备纳米铜粉及其稳定性研究

以酸性蚀刻废液为铜源,水合肼为还原剂,采用液相还原法制备纳米铜粉.研究发现,在氯离子的存在下,直接还原难以得到高纯度的铜粉.介绍了络合还原和除氯后还原两种铜粉制备方法,用铜粉导电率表征其抗氧化性能,并对两种方法制备的铜粉的稳定性进行了比较分析.