1.湿法磷酸的生产工艺
硫酸法的特点是矿石分解后的产物磷酸为液相,副产物硫酸钙是溶解度很小的固相。两者的分离是简单的液固分离,具有其他工艺方法无可比拟的优越性。因此,硫酸法生产磷酸工艺在湿法磷酸生产中处于主导地位。但是其产生的大量磷石膏废渣无法得到有效的利用,三废问题严重。
反应式(1-3)中n的值取决于硫酸钙结晶的形式,可以是0,1/2,2。在不同的反应温度和磷酸浓度下,可以生成无水硫酸钙(CaSO4),半水硫酸钙(CaSO4·0.5H2O)和二水硫酸钙(CaSO4·2H2O)。
二水法流程至今仍存在着一些难以克服的缺陷。由于加工工艺粗放,矿石中的有害杂质大部分进入磷酸中。特别是氟元素,一旦进入液相,很难再分离出来。更严重的是,产生大量的磷石膏废料,造成严重的污染和浪费。因此,陈学玺等[31]通过研究,对现行的工艺过程进行了改进,分两步进行反应。
第一步:采用磷酸浸取磷矿石,从控制化学反应的条件出发,减少化学反应本身对目标产物的污染。磷酸与磷矿的主要反应方程式如下:
Ca5F(PO4)3 + 7H3PO4 +5 H2O → 5Ca(H2PO4)2·H2O + HF (1-4)
第二步:提供适宜的结晶条件,使副产磷石膏中的杂质含量,尤其是磷含量显著降低,提高磷回收率,使磷石膏满足建筑材料生产的要求,从源头上解决磷石膏污染的难题。硫酸的离子化反应可瞬时完成:
Ca(H2PO4)2·H2O + H2SO4 +(n-1)H2O → CaSO4·nH2O + 2H3PO4 (1-5)
这种分步反应的思想方法与“先污染后治理”的传统思路完全不同,符合绿色化学的基本原理,完全符合可持续发展战略的要求。次方法有待实际的考验。
2.湿法磷酸的净化
湿法磷酸净化方法 1化学沉淀法 化学沉淀法是指加入一定量的沉淀剂,使杂质沉淀出来。
这是湿法稀磷酸脱氟或除去各种有害重金属普遍采用的方法之一。该法优点:工艺流程简单,操作控制要求不高,投资小,生产成本低。
缺点:净化深度不够,同时引入了其他离子,给深度净化带来新的麻烦。 2 溶剂沉淀法 溶剂沉淀法是在湿法磷酸中加入与水完全互溶的溶剂(如甲醇、乙醇、丙醇、异丙醇等)以及少量的氨,使所含的杂质离子形成不溶性的金属磷酸铵络合物与氟化物自液相析出,固液分离后通过蒸馏溶剂可得净化酸。
该法优点:只需简单的溶解操作就可达到较高的收率,废液量少,磷酸盐沉渣可作肥料用,溶剂为通用型,多数价廉。 缺点:磷酸与溶剂的分离需蒸馏,能耗大(以碱进行反萃时例外),且溶剂回收时有一定损失,杂质去除率不高。
3 离子交换树脂法 离子交换树脂法是指用强酸性离子交换树脂处理湿法磷酸,除去其中大部分阳离子杂质。还有一种方法是将磷矿用过量磷酸分解,滤去不溶物,再将Ca(H2PO4)·22H2O冷却结晶,将结晶分离,洗涤后溶解于水,通入H型阳离子交换树脂塔中,可制得精制磷酸。
其优点是操作控制简单,净化酸纯度高。缺点是树脂用量大,且需再生处理,一般只限于阳离子的脱除。
1。4 结晶法 根据磷酸结晶析出的方式,此方法可分成3类。
1)使H3PO4·0。5H2O(熔点29。
32℃)从磷酸中析出。在缓慢冷却磷酸溶液时引入晶种,使H3PO4以H3PO4·0。
5H2O的形式从溶液中结晶出来。该法虽是湿法磷酸净化最有效的方法之广-,却很少被采用,尚未有工业化的报道。
2)生成磷酸及其复盐。用尿素在50-70℃下与磷酸反应,再冷却到20℃结晶出复盐,因液体呈酸性,故铁、铝等杂质被留在母液中,使结晶的纯度提高,结晶洗涤后用浓硝酸复分解析出硝酸尿素复盐,分离得到液体磷酸。
也可用三聚氰胺代替尿素。3)结晶析出磷酸盐。
例如析出磷酸钙或磷酸铵,然后将其转化成磷酸。该法优点是工艺流程短,投资费用较低且操作控制要求不高。
但由一次结晶得不到高纯度磷酸,必须进行多次结晶。同时要尽可能使纯的结晶与不纯的母液分离,所以还必须研究不纯母液的利用等。
溶剂萃取法 溶剂萃取也叫液-液萃取或抽提,是基于磷酸可溶于有机溶剂中,而其他杂质则不被萃出,从而使磷酸与杂质分离而达到净化。在湿法磷酸净化技术中,溶剂萃取法具有所得产品纯度高、生产工艺和设备相对比较简单、能耗低、原料消耗少、生产能力大、分离效果好、回收率高、环境污染小、生产过程易于实现自动化与连续化,而且有利于资源的综合利用等优点,因而引起了广泛的关注。
目前,溶剂萃取法已成为国外用来净化湿法磷酸的最有效方法之一,也是唯一大规模工业化的方法。许多发达国家已正式用溶剂萃取法生产工业级和食品级磷酸。
3.磷酸三甲酚酯的论文
1.三氯氧磷直接法:甲酚以吡啶和无水苯为溶剂同氧氯化磷反应,产物经加水溶解回收吡啶、水洗、无水硫酸钠脱水、过滤除去硫酸钠、常压蒸馏回收苯、减压蒸馏,再经冷却、结晶、粉碎即为成品。
2.三氯化磷间接法:混合甲酚和三氯化磷反应,生成亚磷酸三甲苯酯;然后人氯气,生成二氯代亚磷酸三甲苯酯;再进行水解,而生成磷酸三甲苯酯。最后经水洗、中和、蒸发和减压蒸馏,作为成品。
每吨产品消耗混合甲酚(间位含量>40%)1100kg,三氯化磷(95%)510kg,液氯(99.5%)265kg。
4.科学小论文提出3个问题突出3个问题,再根据3个问题写一篇科学小论
上个星期天,我在剪指甲时,一不小心把一块手指甲丢进了喝剩的可乐里,我漫不经心地看了眼已经沉下去的手指甲,回房去了.第二天,我凑到玻璃杯前,吃惊地发现:指甲的颜色变了.这下我可来劲了,想看看究竞会有什么变化.就小心翼翼地把它放在书桌上,几天过去,我竟然把这事给忘了.一星期后,我在书桌前写作业时无意中看到玻璃杯,想起了杯子里的指甲,我仔细观察以后,好像指甲不见了,然后我就把可乐倒在地上,才找到指甲,比起以前的指甲变薄变小了.我想会不会是可乐中的某些成份与指甲起了化学反应?因此,我就上网查资料.电脑告诉我,可乐中含有磷酸,而磷酸属于强酸,即使经过稀释还有一定的酸度,对物体有腐蚀作用.我想指甲变小变薄很有可能是可乐中的磷酸所造成的.另外我知道了可乐中含有咖啡因,长期饮用会上瘾,喝可乐还会使牙齿受到腐蚀,更容易长胖.碳酸饮料虽然具有提神的作用,但一般适合成年人偶尔感觉疲劳、精神不济的时候喝,不太适合我们儿童饮用.像我们这样年龄的儿童还是喝白开水比较好.。
5.李军的发表的主要论文
1. Luo,J.H.,Li, J., Study on Mg2+ Removal from Ammonium Dihydrogen Phosphate Solution by Predispersed Solvent Extraction, Ind. Eng. Chem. Res., 2009 , 48, 2056–2060
2. 任永胜,李军等, 萃取法脱除黄磷中铁的研究, 无机盐工业, 2009, 41(1),12-14
3. 任永胜,李军等, 物理法净化工业黄磷综述, 磷肥与复肥, 2009, 24(1),68-72
4. 张海燕,李军等, 综合回收利用磷铁的新工艺研究, 无机盐工业, 2009, 41(3),32-34
5. 段潇潇,李军等, 萃取法制取磷酸二氢钠的研究, 无机盐工业, 2009, 41(10),50-52
6. 郑东升,李军等, WPA-TBP体系中多组分萃取行为的研究, 过程工程学报, 2009, 9,增刊1,87-91.
7. 郑东升,李军等, 振动筛板塔中杂质对湿法磷酸萃取体系的影响, 过程工程学报, 2009, 9,增刊1,61-65
8. 罗建洪,李军等, 对叔丁基杯[4]芳烃乙酸萃取磷酸二氢铵溶液中Mg的研究, 高校化学工程学报, 2009 , 23(2)
9. 任永胜,李军等, 工业黄磷制备高纯磷的实验研究, 四川大学学报(工程科学版), 2009, 41(6),73-78
10. Huang, M.Y. Zhong, B.H., Li, J., Viscosity of the Tributyl Phosphate + Methyl Isobutyl Ketone + Phosphoric Acid System, J. Chem. Eng. Data, 2008, 53, 2029–2032
11. Zhou, K., Li, J., Solubility of Rifapentine in Different Organic Solvents, J. Chem. Eng. Data, 2008, 53, 998–999
12. Zhou, K., Li, J., Solubility of Rifapentine in the Binary System of Acetic Acid and n-OctanolSolvent Mixtures, J. Chem. Eng. Data, 2008, 53, 1978–1979
13. 黄美英,李军等, 溶剂萃取法净化湿法磷酸萃取体系研究, 化工矿物与加工, 2008,1,4-7
14. 尤彩霞,李军等,甲醇沉淀法净化湿法稀磷酸制磷酸氢二铵,无机盐工业,2008,40(6),27-30
15. 黄平,李军等,净化精制磷酸深度脱氟研究,无机盐工业,2008,40(11),44-46
16. 王邵东1 ,张红映1 ,李 军,湿法磷酸净化的萃余酸联产磷酸二氢铵和磷酸氢二钠,无机盐工业,2008,40(11),39-40
17. 雷婷。李军,王珊,微波强化聚磷酸铵聚合的研究,无机盐工业,2008,40(11),24-26
18. 金央,李军,张海燕,盐酸浸取磷矿石的研究,无机盐工业,2008,40(10),28-30
19. 段潇潇,李军,章怡,萃取法制取磷酸二氢钠的研究,2008,40(12),24-26
20. 喻婵娟,应建康,李军,硫磷铝锶矿制取磷酸的研究,化工矿物与加工,2008,(2),7-11。
21. 黄美英,钟本和,李 军,溶剂萃取法净化湿法磷酸萃取体系研究,化工矿物与加工,2008,(1),4-7
6.有关湿法磷酸的5000字中英文翻译
湿法磷酸 wet -process phosphoric acid资料bine with themselves to form a variety of compounds referred to as phosphoric acids in a more general way. The term phosphoric acid can also refer to a chemical or reagent consisting of phosphoric acids, usually mostly orthophosphoric acid.Orthophosphoric acid chemistryPure anhydrous phosphoric acid is a white solid that melts at 42.35 °C to form a colorless, viscous liquid.Most people and even chemists refer to orthophosphoric acid as phosphoric acid, which is the IUPAC name for this compound. The prefix ortho is used to distinguish the acid from other phosphoric acids, called polyphosphoric acids. Orthophosphoric acid is a non-toxic, inorganic, rather weak triprotic acid, which, when pure, is a solid at room temperature and pressure. The chemical structure of orthophosphoric acid is shown above in the data table. Orthophosphoric acid is a very polar molecule; therefore it is highly soluble in water. The oxidation state of phosphorus (P) in ortho- and other phosphoric acids is +5; the oxidation state of all the oxygen atoms (O) is -2 and all the hydrogen atoms (H) is +1. Triprotic means that an orthophosphoric acid molecule can dissociate up to three times, giving up an H+ each time, which typically combines with a water molecule, H2O, as shown in these reactions:H3PO4(s) + H2O(l) ⇌ H3O+(aq) + H2PO4–(aq) Ka1= 7.5*10−3 H2PO4–(aq)+ H2O(l) ⇌ H3O+(aq) + HPO42–(aq) Ka2= 6.2*10−8 HPO42–(aq)+ H2O(l) ⇌ H3O+(aq) + PO43–(aq) Ka3= 2.14*10−13 The anion after the first dissociation, H2PO4–, is the dihydrogen phosphate anion. The anion after the second dissociation, HPO42–, is the hydrogen phosphate anion. The anion after the third dissociation, PO43–, is the phosphate or orthophosphate anion. For each of the dissociation reactions shown above, there is a separate acid dissociation constant, called Ka1, Ka2, and Ka3 given at 25°C. Associated with these three dissociation constants are corresponding pKa1=2.12 , pKa2=7.21 , and pKa3=12.67 values at 25°C. Even though all three hydrogen (H ) atoms are equivalent on an orthophosphoric acid molecule, the successive Ka values differ since it is energetically less favorable to lose another H+ if one (or more) has already been lost and the molecule/ion is more negatively-charged.Because the triprotic dissociation of orthophosphoric acid, the fact that its conjugate bases (the phosphates mentioned above) cover a wide pH range, and, because phosphoric acid/phosphate solutions are, in general, non-toxic, mixtures of these types of phosphates are often used as buffering agents or to make buffer solutions, where the desired pH depends on the proportions of the phosphates in the mixtures. Similarly, the non-toxic, anion salts of triprotic organic citric acid are also often used to make buffers. Phosphates are found pervasively in biology, especially in the compounds derived from phosphorylated sugars, such as DNA, RNA, and adenosine triphosphate (ATP). There is a separate article on phosphate as an anion or its salts.Upon heating orthophosphoric acid, condensation of the phosphoric units can be induced by driving off the water formed from condensation. When one molecule of water has been removed for each two molecules of phosphoric acid, the result is pyrophosphoric acid (H4P2O7). When an average of one molecule of water per phosphoric unit has been driven off, the resulting substance is a glassy solid having an empirical formula of HPO3 and is called metaphosphoric acid.[1] Metaphosphoric acid is a singly anhydrous version of orthophosphoic acid and is sometimes used as a water- or moisture-absorbing reagent. Further dehydrating is very difficult, and can be accomplished only by means of an extremely strong desiccant (and not by heating alone). It produces phosphoric anhydride, which has an empirical formula P2O5, although an actual molecule has a chemical formula of P4O10. Phosphoric anhydride is a solid, which is very strongly moisture-absorbing and is used as a desiccant.[edit] pH and composition of a phosphoric acid solutionFor a given total acid concentration [A] = [H3PO4] + [H2PO4−] + [HPO42−] + [PO43−] ([A] is the total number of moles of pure H3PO4 which have been used to prepare 1 liter of solution) , the composition of an aqueous solution of phosphoric acid can be 。