磷酸脲母液制备工业级磷酸二氢铵工艺研究

湿法磷酸制备磷酸脲过程中会副产大量磷酸脲母液,母液含有金属杂质及五氧化二磷含量较高。采用溶剂萃取法回收磷酸脲母液中五氧化二磷制备工业级磷酸二氢铵（MAP）,分别考察了包括萃取、洗涤、中和、精制、结晶等工艺流程对产品收率及纯度的影响,确定了最佳工艺条件：萃取相比（有机相与水相体积比）=3:1,萃取时间为5 min,萃取温度为50 ℃,洗涤相比（有机相与洗涤剂体积比）=10:1,中和pH为4.5,复合酸性萃取剂PO8皂化率为20%,精制相比（萃取剂与水相体积比）=1:1,浓缩比为1.36,结晶温度为30 ℃。在该条件下制备的工业级MAP纯度可达99.45%,母液中五氧化二磷回收率为85.34%。该工艺对环境友好,原料中五氧化二磷回收率高,具有较高的经济效益。     

Dendrimer as nanocarrier for drug delivery

Dendrimers are novel three dimensional, hyperbranched globular nanopolymeric architectures. Attractive features like nanoscopic size, narrow polydispersity index, excellent control over molecular structure, availability of multiple functional groups at the periphery and cavities in the interior distinguish them amongst the available polymers. Applications of dendrimers in a large variety of fields have been explored. Drug delivery scientists are especially enthusiastic about possible utility of dendrimers as drug delivery tool. Terminal functionalities provide a platform for conjugation of the drug and targeting moieties. In addition, these peripheral functional groups can be employed to tailor-make the properties of dendrimers, enhancing their versatility. The present review highlights the contribution of dendrimers in the field of nanotechnology with intent to aid the researchers in exploring dendrimers in the field of drug delivery.     

溶解结晶法制备磷酸一铵水溶肥

选取肥料级磷酸一铵为原料,采取溶解、除杂、一次蒸干或者浓缩重结晶的方法制得磷酸一铵水溶肥,通过讨论各工艺条件的影响,确定了较优的工艺条件:溶解温度96℃、溶解时间30 min、溶质过量1.1倍、沉降(60 min)+真空过滤。产品w(N+P2O5)≥60%,满足水溶肥料化工行业标准HG/T 4365—2012。此法开辟了粉状磷酸一铵新的用途,为於渣酸料浆法生产磷酸一铵水溶肥提供除杂依据和工艺参考。     

加压反应-自热浓缩工艺在粉状磷酸一铵生产中的应用

介绍甘肃瓮福化工有限责任公司粉状磷酸一铵装置采用加压反应-自热浓缩技术生产的工艺流程,并针对浓缩系统运行初期存在Ⅰ效下行换热器堵塞的问题,对Ⅰ效浓缩系统二次蒸汽的管路与设备等进行改造。改造后Ⅰ效浓缩系统的温度提高,换热器的结垢堵塞速度减缓,在有效利用反应热的同时延长了装置的运行周期。     

剩余污泥中磷回收的试验研究

以SBR反应器运行过程产生的剩余污泥为研究对象,采用MAP法对经超声处理后的污泥中的氮、磷元素进行回收研究。考察不同超声时间（10、20、30 min）、超声频率（40、80 kHz）和pH（7.0、8.0、9.0）条件下,剩余污泥上清液中氮、磷的回收效果,以期探求最佳回收条件。结果表明污泥在超声频率为80 kHz,时间为10 min后所释放的氮、磷量最大。在最佳的磷镁比为1.8-2.0条件下用磷酸铵镁沉淀法（MAP）进行回收,当pH值为7.0,反应时间为15 min时获得最佳磷回收效果,磷回收率可达62.3%。     

100kt/a粉状磷酸一铵节能扩产技术改造

安徽新中远化工科技有限公司根据市场的需要对产能100 kt/a的w(总养分)55%粉状磷酸一铵(MAP)生产装置进行了节能扩产技术改造。分别介绍了磷矿破碎、磷酸萃取、成品磷酸处理、中和浓缩、干燥等工序的扩能技改措施。通过改造,消除了生产瓶颈,粉状磷酸一铵产量提高了67%,年增加产量达50 kt,吨产品节水、节电效益为27.4元,年增加效益达1 500万元。     

优化配酸工艺,提高消防级磷酸一铵产品品质

介绍消防级磷酸一铵的生产工艺流程和产品质量要求,重点对配酸工艺的优化改造进行阐述。针对消防级磷酸一铵主含量(w(P_2O_(5水溶))/w(P_2O_(5总)))主要受配制混合磷酸中杂磷质量比(w(总杂质)/w(P_2O_(5总)))稳定性的影响,对配酸槽计量装置进行了优化改造。运用流体流量与截面积和通过该截面积流速的关系,在配酸槽增设液位计量刻度尺,可根据工艺配酸要求,利用液位与流量对照表进行准确配酸。改造后,混合磷酸的杂磷质量比波动小,消防级磷酸一铵主含量稳定,保证了消防级磷酸一铵产品的质量。     

50kt/a工业级磷酸一铵装置技术

以湿法磷酸与气氨为原料设计了一套50 kt/a采用连续法生产工业级磷酸一铵的生产装置。介绍其工艺流程、控制指标、主要设备选型、设备布置及吊装等技术,对肥料级磷酸一铵生产企业调整产品结构有一定意义。     

Modified Atmosphere Packaging of Guava Fruit

Fully matured fresh guava fruits (Lucknow‐49) were precooled at 10 °C for 1 h and pretreated with 500‐ppm benomyl for 5 min. The fruits were packed in 25‐µm and 50‐µm LDPE bags with active modified atmosphere packaging of 3% O₂ + 5% CO₂, 6% O₂ + 5% CO₂ and 9% O₂ + 5% CO₂ gas concentrations and stored at 5 ± 1 °C and 10 ± 1 °C temperatures as well as non‐packaged as control. The shelf life of guava could be increased up to 42 days by packaging in 50‐µm LDPE bags with a gas concentration of 9% O₂ + 5% CO₂ and stored at 10 °C without much change in physical, biochemical and sensory characteristics. Physico‐chemical changes viz., PLW, pulp to peel ratio, firmness, TSS, total sugar, ascorbic acid and titratable acidity were observed minimum for fruits packed in 50‐µm LDPE bags at 3% O₂ + 5% CO₂ gas concentration at 5 °C storage temperature, but sensory score decreased drastically after 21 days of storage. Chilling injury was observed for the fruits packed at 5 °C storage temperature after 21 days of storage, and it was severe in 25‐µm LDPE bag at later stage. Control fruits over‐ripened with the highest weight loss (12.47%) on 6 days of storage and discarded from the storage. Copyright © 2014 John Wiley & Sons, Ltd.