硝酸脲的制备

研究了硝酸脲制备过程中可控因素的影响以及固体硝酸脲的晶体形状、吸湿性、水溶液的酸性、X射线衍射图、核磁共振图、红外图谱。实验表明硝酸脲制备过程中的主要影响因素为：尿素与硝酸的比例、硝酸的浓度、反应温度及反应时间等。其中最佳工艺条件是：n（尿素）：n（硝酸）=1：1,硝酸浓度为5．5mol/L,反应温度为20℃,反应时间为20min;显微镜下观测其晶体呈现棱柱状;吸湿性比较弱：水溶液的酸性较同等浓度的硝酸弱而比柠檬酸强;X射线衍射图表明生成物与可能生成的其它物质的X射线衍射图完全不同;核磁共振及红外图谱证明生成的产物为比较纯的硝酸脲。     

硝酸脲与RDX共晶炸药研究

为解决RDX生产过程中废硝酸的再利用问题,采用(a)在分离出RDX后,直接加入一定量尿素水溶液,废硝酸与尿素反应制成硝酸脲,(b)RDX和硝酸脲在稀硝酸中共结晶,生成共晶混合炸药(RDX的质量分数60%～70%).经测试,其爆炸性能优于两者直接混合炸药,爆速可达7 500m/s左右,提高了4%;红外光谱分析结果表明,这种混合炸药是一种具有分子间氢键的共晶体.     

关于氮肥方面的专利信息（上）

再生硝酸高铈酸性溶液的方法；无泄漏尿素造粒器；一种枇杷专用复合肥及其制作方法；长效保水稀土复混肥及其生产工艺；硫酸铵包衣尿素颗粒化肥及制备方法；一种磷酸三铵复合肥及其制造方法。[编者按]     

一种尿素法制备二苯基脲的清洁工艺

正本发明公开了属于二苯基脲制备技术领域的一种尿素法制备二苯基脲的清洁工艺。在惰性气体的保护下,先把过量苯胺加入反应器中加热到第一段反应温度,并保持一定的惰性气体流量,然后尿素通过连续加料漏斗,在一定的时间内连续加入反应器中,再加热到第二段反应温度,进行反应制备二苯基脲。该过程中,把反应器中的苯胺加热到反应温度,     

一种颗粒脲甲醛缓释复合肥的生产方法

脲甲醛复合肥既有缓释肥的特点又兼具控释肥的特点。以磷酸一铵、尿素为原料,硫酸氢钾和气氨进行预中和后加入脲甲醛料浆生产颗粒脲甲醛缓释复合肥料。介绍颗粒脲甲醛缓释复合肥的生产工艺流程。生产12-18-15复合肥,脲甲醛加入量为40~70 kg/t,生产15-15-15复合肥,脲甲醛加入量为70~130 kg/t。     

有机消毒、漂白剂——二氯氰尿酸钠的试制

国外技术简介氰尿酸的生产:工业上主要用固体尿素在窑中热解;其它有循环60～90％粗氰尿酸于原料尿素中热解;真空中热解尿素;先生成尿酸脲,然后在流化床上热解尿酸脲;在165℃预处理尿素约2小时,生成尿素、缩二脲、氰尿酸和缩三脲的液体混合物,最后进入旋转园筒中在240～270℃时热解10分钟;还有用尿素与硫酸在200℃下反应5小时,生成氰尿酸和硫酸铵;尿素在高沸溶剂中(如N—环已基—2—毗咯烷)反应等等方法。氰尿酸的纯化:用15～20％硫酸纯化,也有加入19％硝酸回流纯化。氰尿酸的氯化:在反应中加入氯仿、四氯化碳等有机溶剂,可增大结晶5～10倍;     

硝酸制硝基NPK复合肥生产技术开发

云天化云峰分公司对使用硝酸分解磷矿进行技术开发,在装有磷酸的反应槽中加入一部分硝酸、硫酸、磷酸形成的混酸溶液,在管式反应器中与气氨反应制成含有中微量元素的高浓度NPK复合肥产品,以满足市场需要。介绍了生产工艺原理、磷矿分解条件、复合肥生产工艺流程和控制要点等,对硝基NPK复合肥生产做了总结。     

稳定性复合肥的生产

稳定性复合肥是在生产尿基复合肥的过程中加入脲酶抑制剂,介绍了其生产工艺流程和控制要点。稳定性复合肥施入土壤后,不仅可以减少尿素中铵态氮的硝化和挥发,而且可对土壤中的磷元素起到活化作用,从而提高氮、磷利用率,延长肥效期。     

简讯

脲硫酸复合肥生产工艺研发取得新突破近年来,国内四川大学、上海化工研究院、河北工业大学等对磷矿直接制尿基复合肥进行了研究。四川大学长期以来研究对我国难反应磷矿和中低品位磷矿的分解应用,最近采用了新的强化方法,研发成功了脲硫酸复合肥生产新工艺。这项新工艺采用磷矿、硫酸和尿素等原料直接合成含有缓释作用的氮磷钾硫多元复合肥,产品为粒状     

复混肥生产装置改产脲甲醛缓释复合肥料的技术

利用转鼓蒸汽造粒或圆盘造粒复混肥生产装置改造并开发生产脲甲醛缓释复合肥。介绍脲甲醛的生产原理、反应条件控制和脲甲醛缓释复合肥的生产过程。尿素熔融喷浆工艺的转鼓蒸汽造粒复混肥装置改产脲甲醛缓释复合肥具有投资少、工期短、生产成本低于包膜控释肥等优点。该肥料中包含了速效、中效、长效的氮素养分．其氮素利用率可达50％,减少30...     

氨基磺酸镍制备的研究

以镍粉和氨基磺酸为原料 ,并加入H2 O2 ,制备了氨基磺酸镍 ,H2 O2 加入镍粉与水的混合物中的速度不能太快 ,氨基磺酸分批加入。还以电铸后形成的镍片为原料制备了氨基磺酸镍 :先将这些金属镍片制成硝酸镍 ,然后由硝酸镍制成氢氧化镍或碳酸镍 ,最后将其与氨基磺酸反应生成氨基磺酸镍。在合成氨基磺酸时 ,发烟硫酸分两批加入 ,第一批发烟硫酸加入后反应温度为 30℃ ,第二批发烟硫酸加入后 ,反应温度分两阶段提升 ,第一阶段反应温度为 5 5～ 6 0℃ ,第二阶段为 70～ 80℃ ,产品晶型好 ,易纯化 ,产率较高     

尿素燃烧法制备镍基甲烷化催化剂及其催化反应性能

以拟薄水铝石、硝酸镍以及镁、钴、镧和铁的硝酸盐为原料,尿素为燃烧剂,采用尿素燃烧法制备系列镍基(以及含助剂)甲烷化催化剂。通过XRD和BET等对催化剂结构进行表征,采用固定床反应器评价催化剂的合成气甲烷化催化反应性能,考察Ni含量、尿素与原料质量比、焙烧温度和不同助剂等对催化剂结构和性能的影响,评价催化剂的稳定性。结果表明,Ni O质量分数为7.5%~44.8%时,采用尿素燃烧法均可制备γ-Al2O3为载体的镍基甲烷化催化剂,最佳制备条件为:尿素与原料质量比3∶1,焙烧温度450℃,燃烧时间40 min。26.1%Ni O/γ-Al2O3催化剂表现出较好的催化性能,在230℃和常压条件下,CO转化率和CH4选择性分别达99.5%和98.3%。26.1%Ni O-2.6%La2O3/γ-Al2O3催化剂在(230~700)℃经过多次升降反应温度和1 460 h的长周期稳定性测试,表现出较好的稳定性和耐热冲击性能。     

尿素氮测定方法的探讨

通过实验,将HG/T 4137-2010中测脲甲醛缓释肥中游离尿素氮含量测定条件,40℃水浴恒温反应时间,可由30min缩短为5min;或于室温(25~30℃)下反应15min;1%脲酶溶液用量由25ml减少为8ml。改进后的方法回收率在98.6%~99.5%之间,相对标准偏差RSD≤1.5%,精密度和准确度较改进前有所提高,可满足工业生产控制及分析检测要求,达到准确、快速、节约、简便易行的目的。     

不同因素对HAP-尿素缓释肥中养分释放性能的影响

以羟基磷灰石(HAP)作为载体材料制备羟基磷灰石-尿素缓释复合肥,利用DMAB显色法检测尿素的含量,考察温度、肥水比、pH值对HAP-尿素复合物养分在水中释放率的影响,复合物在水中溶出养分释放率最佳条件是:肥水比为1∶20,温度为30℃,pH值为7。     

聚氨酯缓/控释肥制备与膜层表征

利用多亚甲基多苯基异氰酸酯与蓖麻油在尿素表面反应成膜,制备了聚氨酯包覆的尿素缓/控释肥,通过红外光谱和扫描电镜研究了聚氨酯包覆量对膜层结构的影响,采用凯氏定氮法测定了尿素的溶出曲线。结果表明,不同包膜量聚氨酯膜层的反应程度存在差异;随着包膜量的增加,膜层的厚度增加;当聚氨酯的包覆质量分数为3.3%时,25℃下尿素的缓释期达到40～50 d;根据尿素的溶出曲线推测该缓/控释肥的释放为扩散机制。     

Recovery of nitrogen by spring barley from ammonium nitrate,urea and sulphur-coated urea as affected by time and method of application

The objective of this study was to increase the efficiency of fall-applied N either by placement in bands or by using a slow-release fertilizer. Four field experiments were conducted in north-central Alberta to determine the influence of N source, time of application and method of placement on the recovery of fall-applied N as soil mineral N in May, and on yield and recovery of N in grain of spring-sown barley. The recovery in soil of mineral N by May from the fall-applied fertilizers varied among treatments. More specifically, the recovery was lowest with topdressed application, highest with banding, and tended to be less with incorporation application as compared to banding. Recovery of mineral N was least for sulphur-coated urea (SCU) compared with A.N. and urea, regardless of method of application. The loss of fall-applied N was substantial, but leaching did not go beyond 60 cm deep.Yield and recovery of N in barley grain were much greater with spring application than with fall application at the 4 sites for ammonium nitrate (A.N.) and at 3 sites for urea. The SCU treatments were inferior. The A.N. and urea had greatest yield and N recovery with banding, followed by incorporation and then with topdressing for both fall- and spring-applied N. Method of application had little effect on yield and N uptake with SCU. In all, the greatest yield or crop N uptake was obtained with spring banding of A.N. or urea, while SCU did not function well as a fall- or spring-applied N fertilizer.(Contribution No. 680)     

The comparative effect of a mixed urea,ammonium nitrate,ammonium sulphate granular formulation on the efficiency of N recovery by perennial ryegrass

The¹⁵N isotope was used to study the mode of action of individual nitrogen sources in a 30% urea:30% ammonium nitrate: 10% ammonium sulphate:30% filler (w/w) granular fertilizer for perennial ryegrass in a greenhouse pot experiment. The fertilizer consisted of two types of granules, one containing 80% urea and 20% filler and the second containing 48% ammonium nitrate (AN), 16% ammonium sulphate (AS) and 36% filler. In addition the effect of dolomite compared with silica as the filler was investigated on nitrogen recovery from the 30:30:10:30 formulation.Dolomite adversely affected the recovery of nitrate N from the system and evidence suggested that MgCO₃ was the active component. Granules containing dolomite resulted in a lower dry-matter yield than those containing silica, however the difference was not significant as nitrate contributed only 20% of the N in the formulation. AN gave the greatest DM yield and urea the lowest with AS being intermediate. The¹⁵N budget in shoots, roots and soil indicated that only 65% of the N from urea was recovered at the end of the experiment compared with 86% for AN and 91% for AS. The dry-matter yield of the 30:30:10:30 formulation using silica as the filler was intermediate between urea and AN; however, the apparent N recovery was significantly higher than expected from the sum of the individual components. The use of¹⁵N labelling indicated that using separate granules for ammonium N and urea the recovery of urea was improved by 11% in the triple N mixture when both AN and AS were present in the second granule compared to the recovery on its own. The enhanced recovery of urea appeared to be a function of AN and AS acting together as neither source in double combination with urea had any effect on urea N recovery.Urea enhanced the recovery of nitrate N by 10% but decreased the recovery of AS by 6% (in the 30:30:10:30 formulation) in comparison with the single sources on their own. The results indicate that interactions can occur between N sources even when they are physically separated by being in different granules.     

均匀沉淀法制备纳米氧化镍及其工艺优化

为研制生物质气化用纳米N iO催化剂,文中以六水合硝酸镍为原料、尿素为沉淀剂,采用均匀沉淀法制备了纳米N iO,并利用TGA,XRD,TEM等分析手段对前驱体和产品的性能进行了表征。同时,探讨了制备条件对产品粒径和产率的影响,得出了最佳工艺条件:反应物n(六水合硝酸镍)/n(尿素)=1∶3,沉淀反应温度和时间分别为115℃和2.5 h,煅烧温度400℃,煅烧时间1 h。最佳条件下所得纳米N iO粒子呈球形,分散性好,纯度较高,属立方晶系结构,平均粒径约为7.5 nm。     

甲基异脲酸式硫酸盐的制备

向硫酸二甲酯和尿素的反应产物中,依次添加浓硫酸和异丙醇,ｎ（ＣＨ３ＯＳＯ２ＯＣＨ３）∶ｎ（Ｈ２ＮＣＯＮＨ２）∶ｎ（Ｈ２ＳＯ４）∶ｎ（ＣＨ３ＣＨＯＨＣＨ３）＝１∶１∶１－２∶１－９７,控制温度不超过４０ ℃;０ ～５ ℃下静置１５ ｈ,析出白色固体甲基异脲酸式硫酸盐。产品收率６０％ ,纯度达９８％ 以上。     

正交设计法优化磷光体SrAl2O4：Eu^2＋，Dy^3＋的制备工艺

为了探讨SrAl2O4：Eu^2＋,Dy^3＋磷光体的最佳制备工艺,利用正交设计法对合成条件进行了优化,以初始亮度和余辉时间为指标,考察煅烧温度、尿素与硝酸盐的质量比、硼酸的物质的量分数、镝与铕物质的量比对制备工艺的影响。结果表明：最佳制备工艺是煅烧温度600℃,尿素质量等于硝酸盐质量的2倍,硼酸的物质的量分数为0．08,镝与铕的物质的量比为1．0。