Removal of Water from Spent Phosphoric Acid Using a Sandwich Silicon Carbide Ceramic Membrane

It is important to develop an energy- and cost-efficient method of concentrating phosphoric acid because it is widely used in several industries. Three different ceramic membranes, namely, a silicon carbide (SiC) membrane, a TiO₂-coated SiC membrane, and a sandwich membrane of TiO₂ between SiC, were successfully applied for the selective separation of water from spent phosphoric acid. SiC was selected as raw material, TiO₂ as supporting material. The membrane was characterized by various instruments to check all parameters. Using the solution diffusion, statistical modeling of these membranes was performed and the membrane parameters, such as membrane diffusivity and mass transfer coefficient, were calculated. By reducing the porosity of the membrane, the desired separation can be improved.     

Removal of Trace Metal Impurities from Pretreated Phosphoric Acid by Foam Fractionation

Demands for phosphoric acid are growing rapidly in various industries. This has highlighted the importance of optimizing its production and purification methods. Phosphoric acid can be produced by a wet process. However, due to the presence of many organic and inorganic impurities in the wet product, purification of the resulting product is a major concern in this industry. Removal of trace metal impurities (such as magnesium, cadmium, chromium, zinc, etc.) from produced phosphoric acid in a wet process was investigated by foam fractionation in a semi-batch setup using sodium dodecyl sulfate (SDS) as the surfactant. Effects of inlet air velocity, surfactant concentration, and surfactant selectivity were investigated. The optimum air velocity and surfactant concentration were obtained as 0.020 cm/min and 0.7 g/L, respectively. At the optimum condition, the total removal efficiency and enrichment factor reached were 70.2% and 4.39, respectively, while the acid loss was 8.3%. The total metal removal efficiency was increased to 95.3% in a two-stage experimental run.     

BESA磷酸工艺─溶剂萃取与原料选择

着重介绍了ＢＥＳＡ湿法磷酸的净化工艺。     

湿法磷酸生产中的搅拌和泵设备的腐蚀与防腐

分析二次湿法制取磷酸装置搅拌桨和泵设备的腐蚀因素。通过采取对策和措施 ,确保该装置长周期运行。     

298.15K时浓磷酸水溶液的体积性质

在２９８．１５ｋ的浓磷酸水溶液中，认为存在Ｈ３ＰＯ４＝Ｈ＾＋Ｈ２ＰＯ４＾和Ｈ２ＰＯ＾１＋Ｈ３ＰＯ４＝Ｈ５Ｐ２Ｏ８两个化学平衡。用修正的Ｐｉｔｚｅｒ离子相互作用模有达磷酸水溶液的过剩Ｇｉｂｂｓ自由能，推导出能精确描述浓度高达１８．０ｍｏｌ．ｋｇ＾－１的磷酸水溶液体积性质的数学模型。     

乙草胺生产工艺副产品—磷酸的回收利用

对除草剂乙草胺生产过程中的副产品———磷酸的回收利用进行了研究 ,通过分析其性质和组成 ,设计出切合实际的回收利用方案 ,既节约了能源又减少了对环境的污染     

磷酸燃料电池及其应用

综述了磷酸燃料电池中气体扩散电极的材料、电极制备方法及发展趋势。介绍了磷酸燃料电池及其技术应用的现状和前景。     

磷酸分解磷矿石的动力学

采用间歇反应器,在反应温度６０－８０℃,磷酸浓度在２０－４０％Ｐ２Ｏ５,磷矿粒径０．１３８－０．７ｍｍ;搅拌速度５００转／分的条件下,研究了磷酸分解上蒜磷矿的酸解反应动力学,研究表明,在上述条件下,该过程的速率控制步骤为氢离子通过Ｃａ（Ｈ２ＰＯ４）２的固态膜向反应界面的扩散。并建立了酸解过程的动力学模型,该模型在ａ＝０．５上显著,表观活化能Ｅａ＝１０．０８ｋＪ．ｍｏｌ＾－１。     

二水物湿法磷酸萃取槽薄壁防腐衬里

湿法磷酸萃取槽防腐内衬,一直都采用厚壁防腐,其厚度在25mm以上,投资高,工期长。目前初步研究成功14mm厚的薄壁防腐内衬,经二年生产使用,光泽尚如初,比厚壁内衬节约设资35％～80％。     

用湿法磷酸预净化重结晶制工业磷酸试验总结

湿法磷酸中含有大量的杂质,包括Pb2 、Cr2 、SO2-4、氟以及砷等,它们影响磷酸的结晶过程,采用化学沉淀法及溶剂沉淀法相结合的方法预净化湿法磷酸,研究了各沉淀剂用量、温度、时间对磷酸预净化效果的影响.结果表明,以碳酸钡为脱硫剂预净化湿法磷酸后可以脱除95.5%的硫酸根、95.2%的砷和78%～90%的铁、铝、镁金属离子,预净化后湿法磷酸中的杂质不影响其结晶,且磷酸经过重结晶后达到了工业磷酸质量的要求.     

磷酸萃取料浆应用立式压滤机脱水的试验研究

对磷酸萃取料浆用立式压滤机脱水、洗涤进行了试验研究,对试验结果进行了分析,认为立式压滤机可以替代其它脱水设备对磷酸萃取料浆进行脱水处理。     

铝合金表面阳极化处理及其胶接性能分析

采用磷酸电解质对铝合金板进行了阳极化处理并测试了其胶接性能,测试了阳极化过程中铝合金板的基本力学性能,观察了阳极化处理后的铝合金板的表面形貌,分析了阳极化处理后铝合金粘接副的胶接界面、拉伸剪切失效模式.结果表明,铝合金板经过酸洗、碱洗和阳极化等过程后,其破坏强度、屈服强度、弹性模量和断裂延伸率等力学性能基本保持不变.阳极化后铝合金板表面形成了一层凹凸不平、多孔结构氧化膜,胶接时胶黏剂能渗透进入该氧化膜,形成一层胶接过渡层,阳极化处理提高了铝合金粘接副之间的拉伸剪切强度,其拉伸剪切强度最大可提高1.76倍.阳极化处理后的铝合金板粘接副之间的破坏模式为混合破坏,即存在胶黏剂的剪切破坏,同时存在粘接界面的剥离破坏.     

铝在磷酸体系中复合阳极氧化研究

在磷酸介质中加入亚微米级Ａｌ２Ｏ３难溶性粉体,对铝进行复合阳极氧化结果表明,Ａｌ２Ｏ３难溶性粉体的加入使铝阳极氧化膜厚度提高了４５％,显微硬度提高了７０％以上,耐ＮａＯＨ腐蚀性能提高了一倍以上。阴离子型表面活性剂和两性型表面活性剂对复合阳极氧化效果降低。文中对复合阳极氧化过程进行了相应的讨论。     

Modeling of Phosphoric Acid Purification by Liquid‐Liquid Extraction

Phosphoric acid is an important industrial chemical. It is mainly produced by the wet process which consists of an attack of the phosphate rock by sulphuric acid leading to a complex solution containing a large number of impurities such as metal ions like Fe³⁺, Al³⁺, Mg²⁺, Cd²⁺ etc., which can effectively be recovered by solvent extraction process. In this present work a model of the liquid‐liquid extraction process is presented. It is mainly based on thermodynamics, where two different routes have been tested for the modeling of the complexation process. The method has been tested using a model system with Al³⁺ as the contaminant, dodecyl naphthalene sulphonic acid (HDDNSA) as the complexing agent and kerosene as the diluent. The study has also investigated the influence of various parameters such as the pH of the aqueous phase and the initial concentration of the phosphoric acid.     

采取有效措施实现磷酸生产水平衡

针对磷酸生产用水的特殊性,总结了大装置磷酸生产用水封闭循环使用存在的问题,并因地制宜地找到了解决此问题的方法。     

磷酸快速萃取原理概述

磷矿酸解反应并非是离子间的交换,而是功能基团之间的交换。因此,磷酸萃取过程的P2O5萃取率、磷酸及后继产品性质、磷石膏结晶晶形和过滤性能与磷矿物特性有关。影响装置生产能力的主要因素是泡沫而不是反应时间和温度;磷酸快速萃取技术的核心是提高萃取和料浆过滤系统的温度。     

磷酸系无机粘合剂的研究动态

本文叙述了磷酸系无机粘合剂在提高耐水性、耐热性、粘接强度等方面的研究开发动态。     

磷酸贮槽橡胶衬里设计结构改进

针对云天化国际红磷分公司磷酸二铵装置浓磷酸贮槽投用6年后频繁出现橡胶衬里失效导致槽体泄漏的现象,对磷酸贮槽在使用和维护中容易出现防腐失效的部位进行橡胶衬里设计结构改进。改进后的酸槽在经相同的使用时间后,橡胶防腐衬里使用状况仍良好,设计结构改进对防腐可靠性的提高明显。     

湿法(浓)磷酸化学法脱氟净化的研究

试验研究了湿法(浓)磷酸两种化学脱氟法，即氟硅酸钾一乙醇沉淀法和氟铝酸钠沉淀法。认为，后者优于前者，比I．M．C真空蒸汽深度脱氟法更经济，更适合于中小企业。文中关键探讨了铝在脱氟过程中的机理，同时对湿法(浓)磷酸(选择性)净化做了综述。     

Purification of Wet‐Process Phosphoric Acid by Hydrogen Peroxide Oxidation,Activated Carbon Adsorption and Electrooxidation

In this work, three technologies are studied for the purification of phosphoric acid produced by the wet process: chemical oxidation with hydrogen peroxide, adsorption onto activated carbon, and electrochemical oxidation by boron‐doped diamond anodes. The treatment of wet‐process phosphoric acid by chemical oxidation with H₂O₂ as oxidizing agent can remove 75 % of the initial TOC as maximum, indicating that this wet‐process phosphoric acid contains an important amount of organics that cannot be oxidized by hydrogen peroxide under the operation conditions used. High temperatures and hydrogen peroxide/TOC ratios close to 150 g H₂O₂/g TOC allow obtaining the best chemical oxidation results. The adsorption onto activated carbon can remove between 40 and 60 % of the initial TOC as maximum. Adsorption times of 2 hours and activated carbon/WPA ratios close to 12 g AC/Kg WTP assure both steady state and maximum adsorption of organics. The electrochemical process is the only technique by which complete mineralization of WPA organics can be achieved. Operating at 60 mA cm^–2 and at room temperature, high current efficiencies are achieved which only seem to decrease by mass transport limitations.