在普通过磷酸钙的化学反应原理中,两个分步反应相加并不等于总反应式,本质上是7∶3的关系.根据过磷酸钙的国家标准和本理论依据进行合理推测,两个分步反应所分解的磷矿粉的比例并不是相关教材上所说的70%和30%的关系.以过磷酸钙优等品为例,第一步反应硫酸分解的磷矿粉理论上约为76.92%,实际上达80.77%;第二步反应磷酸分解的磷矿粉理论上约为19.23%,实际上仅约为14.17%;产品中游离磷酸量为5.0%时,残留磷矿粉约为5.06%,二者的数量几乎相等.本文不仅是对普通过磷酸钙反应原理切合实际的补充和完善,也对在实际生产中计算硫酸的理论用量具有一定的指导意义
关键词: 普通过磷酸钙 / 化学反应原理 / 分步反应 / 总反应 / 硫酸当量 / 磷酸当量
Abstract:
In the chemicalreaction principle ofordinary superphosphate,the addition oftwo subG step reactions does not equalthe total reaction formula,instead,itis essentially a7 :3 relationship．As perthe nationalstandard on superphosphate and the theoreticalbasis,itis reasonable to speculate thatthe proportion ofphosphate rock powderdecomposedbythesetwo subG step reactionsisnotthe70% :30% statedin the relevant textbooks．Taking superior superphosphate as an example,the phosphate powderdecomposedby sulfuricacidin the firststep is about76 . 92% in theory, but is80 . 77% in practice;and that decomposed by phosphoric acid in the second step is about19 . 23% in theory, but only about 14 . 17%in practice．When the amountoffree phosphoricacidin the productis5 . 0% ,the residualphosphate rock powderis about5 . 06% ,and the amountsofthesetwo arealmostequal．Thispaperisnotonlyapracticalsupplementandimprovementto theprincipleofordinarysuperphosG phate reaction,butalso has a certain guiding significance for calculating the theoreticaldosage ofsulfuric acidin actualproduction.
Keywords: ordinary superphosphate / chemical reaction principle / subG step reaction / overall reaction / sulfuric acid equivalent / phosphoric acid equivalent