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针对湿法磷酸反应槽的含氟尾气排放不达标而造成环境污染及氟、硅资源浪费的问题,对尾气吸收系统进行技改。通过工艺改进、增加设施设备,使外排尾气达标,尾气中ρ(F)为6~8mg/m~3,氟、硅资源基本回收,洗涤液中w(H_2SiF_6)达10%以上,相关设备更换周期及清理周期延长,实现了氟吸收系统的自动化操作和连续性生产。 相似文献
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脱氟渣是湿法磷酸化学净化过程中产生的固体废渣,其主要成分为氟硅酸钠,并夹带大量磷酸。为实现脱氟渣的资源化利用,本文研究了硫酸分解Na_2SiF_6的反应特性和脱氟渣的酸解回收工艺。考察了浓硫酸分解氟硅酸钠反应中,酸浓度、H_2SO_4与Na_2SiF_6摩尔比、反应温度、反应时间对氟硅酸钠分解率的影响,得到最优工艺条件为:H_2SO_4与Na_2SiF_6摩尔比为2.6、硫酸质量分数为98%、反应温度140℃、反应时间1 h。在此基础上,用浓硫酸分解脱氟渣,酸解处理后脱氟渣分解率达到98%以上,酸解残渣主要成分为硫酸氢钠。以酸解残渣作为脱氟剂,对湿法磷酸脱氟,脱氟率达到82.8%。文中脱氟渣酸解工艺可满足饲钙生产需要,实现了磷酸回收和钠资源循环利用。 相似文献
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针对某公司氟化氢生产装置副产含氟二氧化硅渣,为了氟资源化利用,提出了硅渣制备氟化氢铵产品的工艺,硅渣中的氟转化成氟化氢铵产品,研究了硅渣溶解温度及时间、氟化氢铵浓缩温度、氟化氢铵溶液浓度等对硅渣溶解量、氟化氢消耗及氟化氢铵产品品质的影响。生产装置试运行结果表明:硅渣溶解再沉淀、过滤得到的氟化铵滤液质量分数控制在30%—33%,浓缩温度控制在125—135℃,浓缩后氟化氢铵质量分数控制在80%时,氟化氢的消耗最低,氟化氢铵产品质量最优。经过工业化装置的验证,该工艺可行,生产装置可连续稳定运行,产品质量达标,该工艺提高了氟资源利用率及公司的经济效益。 相似文献
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充分利用磷化工生产副产的含氟渣回收其中的氟元素,减少环境污染和氟资源浪费。研究了用硫酸与脱氟渣反应回收氟制取氢氟酸联产过磷酸钙的工艺流程,该工艺先将脱氟渣转化为氟硅酸再升级生产高附加值的工业氢氟酸或无水氟化氢,同时联产过磷酸钙产品。 相似文献
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脱氟渣是湿法磷酸化学沉淀脱氟过程产生的固体废渣。分别用甲醇、乙醇和丙酮浸取脱氟渣来回收脱氟渣中的磷酸,研究了浸取时间、温度和液固比对于五氧化二磷、氟的浸取率以及浸出液磷氟比[m(五氧化二磷)/m(氟)]的影响,得到了适宜的浸取条件。浸取液经蒸发浓缩回收浸取剂后,浓缩液均可满足饲料级磷酸氢钙生产对于湿法磷酸磷氟比的要求。综合考虑浸取剂成本、五氧化二磷浸取率和浸出液磷氟比,确定甲醇为优选浸取剂,并用响应面法对甲醇浸取工艺条件进行优化。优化工艺条件下五氧化二磷的浸取率为97.13%、浸出液磷氟比为51.62,甲醇在5次循环回收利用后对脱氟渣仍有较好的浸取效果。 相似文献
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为了充分利用磷矿伴生氟硅资源,研究了用废弃物含氟硅渣生产白炭黑的工艺,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,采用间歇加料沉淀后制得的白炭黑产品能达到HG/T 3061-1999行业标准的质量要求;同时研究了表面活性剂对产品质量的影响,适量的表面活性剂对提高产品的吸油值有促进作用。 相似文献
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用氟离子选择电极对多种矿石中的氟进行了测定,其测定范围在0.005%~x%.研究表明,用本方法测定多种矿石中氟含量精密度好,回收率在94.0%~103.2%,方法简便.此方法已应用于实际工作中. 相似文献
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Matthew N. Hopkinson Antony D. Gee Véronique Gouverneur 《Israel journal of chemistry》2010,50(5-6):675-690
Performing gold-catalyzed organic transformations in the presence of fluorinating reagents can lead to both fluorinated and non-fluorinated products. Gold(I) complexes can activate alkynes towards nucleophilic attack by fluoride leading to fluoroalkenes under mild conditions. Fluorinated products can also be prepared upon performing gold-catalyzed transformations in the presence of electrophilic sources of fluorine. In most cases, however, the combination of gold and electrophilic fluorinating reagents does not lead to fluorination but delivers products of oxidative homo- or cross-coupling. In these processes the “F+” source is likely acting as a sacrificial two-electron external oxidant performing the key oxidation of gold(I) to gold(III) in the redox cycle. Oxidative coupling is an emerging field of gold catalysis which, when combined with the well-established reactivity of gold as a soft π-acid, holds promise as a mild and efficient method for the construction of complex organic molecules. 相似文献
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Böhm HJ Banner D Bendels S Kansy M Kuhn B Müller K Obst-Sander U Stahl M 《Chembiochem : a European journal of chemical biology》2004,5(5):637-643
Fluorinated compounds are synthesized in pharmaceutical research on a routine basis and many marketed compounds contain fluorine. The present review summarizes some of the most frequently employed strategies for using fluorine substituents in medicinal chemistry. Quite often, fluorine is introduced to improve the metabolic stability by blocking metabolically labile sites. However, fluorine can also be used to modulate the physicochemical properties, such as lipophilicity or basicity. It may exert a substantial effect on the conformation of a molecule. Increasingly, fluorine is used to enhance the binding affinity to the target protein. Recent 3D-structure determinations of protein complexes with bound fluorinated ligands have led to an improved understanding of the nonbonding protein-ligand interactions that involve fluorine. 相似文献
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《Fuel》1987,66(6):794-798
Comparison of two methods of determining fluorine in coal showed that lower fluorine values were obtained by oxygen bomb decomposition (as in the ASTM method) than by the pyrohydrolysis method. The difference is probably due to the resistance of some fluorine-containing minerals in the coal to decomposition in the bomb. Fluorine values in Australian coals, as determined by pyrohydrolysis, are mostly in the range 20–300 with a mean of ≈ 110 μg g−1F. 相似文献
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