磷肥行业含氟硅胶综合利用技术综述

如何综合利用磷肥行业的含氟硅胶是大型磷复肥行业亟待解决的问题之一。探讨了磷肥行业含氟硅胶国内外研究现状及综合利用技术,重点介绍了云南云天化国际化工股份有限公司在含氟硅胶综合利用方面取得的成绩,并提出了今后开展含氟硅胶综合利用方面的建议。     

亟待开发利用的磷肥工业副产含氟硅胶

我国磷肥工业每年副产1.5万吨以上的含氟硅胶,由于排放含氟硅胶而夹带走的8～10％氟硅酸溶液便有6万吨,对环境污染较为严重,也是氟资源的极大浪费。本文重点介绍了含氟硅胶的来源及治理的必要性,简述了含氟硅胶综合利用的可能性并提出了建议。     

磷肥工业副产含氟硅胶的综合利用

磷肥工业副产含氟硅胶的资源化利用是磷肥行业亟待解决的问题之一，若不对其回收利用，不仅是一种资源的浪费，还会对环境造成污染。介绍了磷肥工业副产含氟硅胶制备液体硅酸钠、五水偏硅酸钠、层状结晶二硅酸钠、4A分子筛、白炭黑、工业硅、碳化硅、氟硅酸铵和氟化氢铵等资源化利用技术，并就磷肥工业副产含氟硅胶的利用问题提出建议。     

含氟硅胶制水玻璃

1 概况 过磷酸钙生产中氟吸收系统产生的含氟硅胶(主要为SiO_2),需要很大的堆场。因含有部分氟和细小的SiO_2,严重污染环境,长期以来被人们视为“废物”,处在难以处理又不能堆积的境况之中。全国年产过磷酸钙约1530万吨,按0.125％折算,每年将有1.91万吨含氟硅胶产生。带着这个问题,笔者进行了多方考察,就含氟硅胶的利用问题,提出“湿法生产水玻璃”这一措施,现就其生产方法作一介绍。     

普钙生产中副产品硅胶的回收

普通过磷酸钙生产中产生的含氟废气，用水吸收后生成氟硅酸和硅胶。现仅需添置少量设备就可将硅胶加以回收，不但能为工厂增加可观的经济效益，同时也更有效地保护了环境。     

电石渣处理含氟废水

萧山化工厂用电石渣处理含氟废水获得成功。经过半年运行,各种性能指标均符合设计要求,含氟废水从处理前的1820mg/l处理后降至14mg/1。该厂用含20～35％P_2O_5的磷矿石[Ca_5F(PO_4)_3]和H_2SO_4生产普通过磷酸钙。生产过程中排放的含氟废气回收综合利用生产氟硅酸钠,1986年产量350t,在此工艺过程中产生的合成母液、洗涤液和硅胶悬浮液排入内河影响县城自来水水质。该厂将冲洗吸收室和氟硅酸储槽内所产生的含氟硅胶悬浮液汇拢,排入沉淀池。回收上面     

普钙生产中含氟硅胶利用的新途径

水电部成都勘测设计院科研所利用什邡磷肥厂含氟硅胶掺入水泥砂浆和混凝土中,进行了试验室试验,试验表明在水泥砂浆、混凝土中掺入占水泥重量的2～3％的含氟硅胶,能使其凝结时间延缓,泌水率降低30～45％,普通水泥砂浆及混凝土28天强度提高20～30％,贫砂浆及贫混凝土28天强度提高30～50％。四川     

含氟废气的治理及资源化利用研究进展

针对含氟废气治理与资源化利用的重要性,介绍含氟废气各种治理方法 (干法、湿法、半干法)的脱氟原理、应用情况、优缺点。湿法中的水吸收法因工艺成熟、操作简单及成本低等优点成为我国含氟废气治理的主要方式,但存在硅胶堵塞以及设备腐蚀等问题,需进行进一步工艺优化。含氟废气的资源化利用方式主要有制氟化盐、无水氟化氢和白炭黑。提出对含氟废气中氟、硅资源进行同时利用的资源化方式是今后主要的研究方向。     

湿法磷酸含氟气体回收过程常见问题及建议

阐述湿法磷酸生产的萃取分解、萃取料浆闪蒸冷却及浓缩系统含氟气体的产生过程;红磷化工有限责任公司现有3套不同工艺的湿法磷酸装置其含氟气体回收的工艺流程及回收利用中存在的问题(回收洗涤率低、设备管道被硅胶堵塞及被腐蚀磨蚀);对存在问题进行分析并提出整改措施。特别提出应对含氟尾气的治理工作引起关注。     

化肥信息

化肥信息利用磷肥副产物硅胶生产白炭黑的研究江苏徐州磷肥厂开发了磷肥副产物硅胶生产白炭黑的工艺，该工艺以含氟硅胶为原料，经水洗、抽滤、沉淀处理后，再经抽滤洗涤、干燥等工序生产白炭黑，产品二氧化硅含量达９０％以上，各项技术指标符合国家标准。减轻回转干煤窑...     

利用废弃物含氟硅渣生产白炭黑产品

利用磷矿伴生氟资源生产2万t/a无水HF装置将产生1万t/a干基含氟硅渣,直接排放将导致环境污染,危害人类健康,同时浪费大量的氟硅资源。为了充分利用磷矿伴生氟硅资源,研究了废弃物含氟硅渣生产白炭黑项目,实验结果表明含氟硅渣在100℃左右能完全溶解在氟化铵溶液中制得氟硅酸铵溶液,氟硅酸铵和氨气在温度为60℃、氨气用量为理论用量的1.1倍、间歇沉淀时,制得的白炭黑产品能达到行业标准要求;同时研究了表面活性剂对产品质量的影响,得出适量的表面活性剂对提高产品的吸油值有促进作用。     

氨解沉淀法白炭黑的研究进展

氨解沉淀法白炭黑的合成方法是以氨水溶液或液氨等氨化剂为主要原料与磷肥工业产生的含氟硅副产物(如氟硅酸、氟硅酸铵、含氟硅胶、含氟硅渣等)进行氨化沉淀反应合成白炭黑的一种方法.它是近年来随着磷肥工业含氟硅废弃物的产生而形成的一种特殊的沉淀法白炭黑的合成方法.介绍了氨解沉淀法白炭黑的反应原理、研究进展.从反应原理、生产成本、工艺控制、产品质量以及对环境的影响等方面,对氨解沉淀法和传统沉淀法进行了对比,突出了氨解沉淀法的优势.对中国沉淀法白炭黑的发展方向提出了建议.     

Synthesis and characterization of polyimide–silica nanocomposites using novel fluorine‐modified silica nanoparticles

Polyimide–silica nanocomposites were synthesized with 4,4′‐oxydianiline, 4,4′‐(4,4′‐isopropylidenediphenoxy)bis(phthalic anhydride), and fluorine‐modified silica nanoparticles. Fluorinated precursors such as 4″,4?‐(hexafluoroisopropylidene)bis(4‐phenoxyaniline) (6FBPA) and 4,4′‐(hexafluoroisopropylindene)diphenol (BISAF) were employed to modify the surface of the silica nanoparticles. The microstructures and thermal, mechanical, and dielectric properties of the polyimide–silica nanocomposites were investigated. An improvement in the thermal stability and storage modulus of the polyimide nanocomposites due to the addition of the modified silica nanoparticles was observed. The microstructures of the polyimide–silica nanocomposites containing 6FBPA‐modified silica exhibited more uniformity than those of the nanocomposites containing BISAF‐modified silica. The dielectric constants of the polyimide were considerably reduced by the incorporation of pristine silica or 6FBPA‐modified silica but not BISAF‐modified silica. The addition of a modifier with higher fluorine contents did not ensure a lower dielectric constant. The uniformity of the silica distribution, manipulated by the reactivity of the modifier, played an important role in the reduction of the dielectric constant. Using 6FBPA‐modified silica nanoparticles demonstrated an effective way of synthesizing low‐dielectric‐constant polyimide–silica nanocomposites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 882–890, 2007     

白炭黑中氟含量的测定方法

介绍了利用磷肥企业含氟硅渣生产白炭黑工艺中,白炭黑中氟含量的分析方法。对氧硅酸钾法、电极法、比色法3种氟含量分析方法进行了比较,得出电极法操作简单,能快捷地分析出氟含量,是较合适的分析方法;如氟含量较高,采用氟硅酸法分析比较合适。     

氟化铵在湿法磷酸装置氟吸收系统中的应用研究

为了解决磷酸浓缩装置氟吸收系统被硅胶堵塞问题,在磷酸浓缩装置氟吸收系统中引入氟化铵溶液。实验表明,加入氟化铵溶液带入的F为氟吸收系统中氟总量的5%左右,能有效溶解系统中的硅胶,确保循环系统吸收液的品质,使系统正常运行。     

磷肥生产中的氟回收

分析我国磷肥生产中氟回收利用现状:磷肥生产废气中的氟、硅资源每年分别达数十万t,但回收利用很差。介绍一种利用磷肥生产中的含氟废气生产氟化合物与白炭黑的清洁生产方法:用氟化铵或氨直接吸收含氟气体生成氟硅酸铵,然后氨化得氟化铵与白炭黑(S iO2),氟化铵可进一步加工为其它高价值氟化物产品。提出磷肥生产中的氟、硅资源化和接替战略资源——萤石的可能性。并介绍了该技术的开发现状,呼吁有关部门重视,促成该技术早日产业化。     

Investigation into doping of silica glasses with fluorine by modified chemical vapor deposition

The equilibrium observed during modified chemical vapor deposition (MCVD) of silica glasses doped with fluorine is investigated by chemical thermodynamics. The influence of the flow rate of Freon-12 and sulfur hexafluoride on the efficiency of the incorporation of fluorine into the condensed phase is analyzed. It is revealed that, at very low flow rates of fluorinating reactants, more than 50% of fluorine can be incorporated into the glass. The refractive index and the efficiency of the conversion of SiCl₄ into the fluorine-doped silica glass are studied as functions of the vapor-gas phase composition.     

磷肥副产硅胶中氟含量的测定

采用离子选择性电极法测定磷肥副产硅胶中的氟含量。提出用盐酸浸出磷肥副产硅胶中的氟杂质,以柠檬酸-柠檬酸三钠缓冲溶液作总离子强度调节剂。该方法的检出限为0.05mg/L(以F-计),相对标准偏差为2.34%(n=18),加标回收率为96.50%～99.25%。     

溶胶-水热合成法制备纳米4A分子筛

以磷肥行业副产的含氟硅胶为原料,采用溶胶-水热合成法成功制备纳米4A分子筛,并采用XRD、SEM、激光粒度分析等手段与常规水热合成的4A分子筛进行了对比。结果表明,纳米4A分子筛钙交换容量为325mg/g,白度为95%,可满足洗涤助剂的要求。     

Molecular dynamics study on the co-doping effect of Al2O3 and fluorine to reduce Rayleigh scattering of silica glass

Further attenuation of Rayleigh scattering of silica glass is required to extend the capacity of long-distance optical fiber communication. To theoretically examine the effect of aluminum and fluorine co-doping on the density fluctuations of silica glass, which is related to Rayleigh scattering, a set of force-matching potentials (FMP) for simulating F-doped aluminosilicates was developed using Bayesian optimization based on density functional theory calculations. Molecular dynamics (MD) simulations with the new FMP could evaluate the densities of silica glasses to which a small amount of fluorine was doped and those of aluminosilicate glasses with a wide range of aluminum contents within reasonable accuracy. The FMP successfully represents the changing role of aluminum from a network former without a compensating cation (threefold coordination) to that with a compensating cation and a charge compensator in the aluminosilicates. Indeed, relative concentrations of four, five, and sixfold-coordinated aluminum observed by NMR measurements were reproduced better than the original Teter potential at a high aluminum content. At an aluminum content lower than 1 mol%, threefold-coordinated aluminum was observed, which is consistent with ESR measurements. After careful validations of the FMP, the effect of the co-doping of alumina and fluorine on the density fluctuations of silica glass was computationally examined. Consequently, it was expected that the co-doping might not sufficiently attenuate the Rayleigh scattering, even though 1 wt% fluorine would be able to reduce the density fluctuations of aluminosilicate glasses for some extent. This is because more alumina-doping increases density fluctuations of silica glass if the drawing temperature and procedure are the same with those for silica glass fiber. Thereby, a possible fabrication process to sufficiently attenuate the Rayleigh scattering of the F-doped aluminosilicate glass was proposed, according to the density fluctuation analysis at high temperature.