钒酸钠钙化-碳化铵沉法清洁制备钒氧化物新工艺

钒酸钠的后续产品转化是钒渣亚熔盐法钒铬共提清洁生产工艺的关键环节,针对钒酸钠产品转化提出了钒酸钠钙化-碳化铵沉法清洁制备钒氧化物新工艺,系统研究了钒酸钠钙化、钒酸钙碳化铵化、偏钒酸铵冷却结晶等几个重要工序。结果表明：通过钙化-碳化铵化-偏钒酸铵结晶可实现钒酸钠产品清洁制备钒氧化物,钒回收率达96.99%,所得钒氧化物产品V₂O₅质量分数达98.53%以上,且从源头避免了高盐氨氮废水的产生,工艺清洁环保。     

燃煤电厂废弃SCR脱硝催化剂元素回收研究进展

随着选择性催化剂还原法（SCR）脱硝技术在国内的普及以及SCR脱硝工程的大量建设,废弃SCR脱硝催化剂的高效处置已引起了广泛关注,针对高附加值成分的元素回收是较为合理的处置方案。本文总结了目前关于废弃SCR脱硝催化剂3种主要元素Ti、V、W（或Mo）回收的主要技术方案,其中Ti元素的回收主要是通过钠化焙烧法或浓碱浸出法首先分离Ti元素,而后通过酸洗法回收获得二氧化钛;V元素的回收方法主要包括铵盐沉淀法、萃取法和电解法,从而得到五氧化二钒或者偏钒酸铵;W元素的回收方法主要包括钙盐沉淀法、钠盐结晶法和酸沉法,从而得到三氧化钨。在此基础上,对各技术方案进行了比较,为开发高效合理的元素回收技术提供依据,并指出后续研究中还需要优化酸洗法回收Ti元素的酸洗条件以及V、W元素的纯化技术,从而进一步提高回收产品的纯度。     

The effect of embedded vanadium catalyst on activated electrospun CFs for hydrogen storage

In this paper, the effect of embedding vanadium pentoxide in electrospun carbon fiber was investigated in relation to textural properties and hydrogen storage behavior. Electrospun carbon fibers involving vanadium were prepared from polyacrylonitrile/N,N-dimethyl formamide/vanadium pentoxide through electrospinning method and heat treatment. Chemical activation of electrospun carbon fibers was carried out in order to generate the pore by using potassium hydroxide as a chemical agent. Eventually, vanadium embedded activated electrospun carbon fibers (AECFs) with high specific surface area 2780 m²/g were prepared as a hydrogen storage medium. As the effects of vanadium pentoxide, it was found that dissociated oxygen from vanadium pentoxide in electrospun fibers would generate the ultra-micropore (0.6 nm) by forming carbon monoxide and carbon dioxide during the carbonization. Also, vanadium in electrospun carbon fibers is considered to act as a catalyst for the improved capacity of hydrogen adsorption. Vanadium embedded AECFs have the high capacity of hydrogen storage, about 2.5 wt% at room temperature and 100 bar.     

硝酸浸取磷矿制轻质碳酸钙工艺研究

硝酸萃取磷矿后的酸解液,通过冷冻结晶法得到硝酸钙晶体,然后以硝酸钙为原料,通过加入碳酸氢铵进行碳化制取轻质碳酸钙。结果表明,碳化反应的初始反应温度为常温,硝酸钙溶液的质量分数为23%左右,碳酸氢铵和氨水按理论加入量的110%进行反应,用产品质量的4倍洗水量洗涤产品,制备的轻质碳酸钙产品各项指标均达到HG/T 2226-2000《工业沉淀碳酸钙》标准的要求。     

氯化铵分解制氨气和氯化氢工艺

对NH4Cl分解的硫酸氢铵法和镁氧化物法分别进行了验证性实验研究,结果表明,NH4HSO4工艺NH4Cl转化率很低,不具有可行性;镁氧化物转化率较高,具有深入研究的价值. 对镁氧化物法的MgO, Mg(OH)2和Mg(OH)Cl三种工艺路线进行了系统研究,结果表明,这3种工艺的NH4Cl转化率均可达到90%以上. 与Mg(OH)Cl和Mg(OH)2工艺相比,MgO工艺具有流程简单、生产周期短、能耗小等优点. 当MgO:NH4Cl及H2O:NH4Cl的摩尔比分别为0.76:1和8.3:1时,在110℃反应4 h,氨气收率可达95%.     

盐酸法生产饲料级磷酸氢钙应用矿粉脱氟工艺的探讨

使用贵州福泉磷矿粉,盐酸法生产饲料级磷酸氢钙,利用矿粉脱氟工艺,通过实验得出配酸量数值。介绍萃取脱氟操作、中和操作反应原理及工艺控制点。与传统工艺比较,原料消耗降低,五氧化二磷收率提高。     

利用酒石制取天然右旋酒石酸铵工艺的研究

将葡萄酒厂下脚废料粗酒石用盐酸溶解 ,活性炭脱色 ,用氨水调节pH =3 5以析出精制酒石 ,然后将精制酒石依次与氨水和氯化钙作用生成酒石酸钙。将酒石酸钙过滤并洗去钾离子后 ,用盐酸溶解得到右旋酒石酸水溶液 ,其中的钙离子与硫酸铵反应以硫酸钙形式去除。过滤 ,滤液以氨水调节pH =3 3～ 3 5 ,将析出的酒石酸氢铵过滤 ,并洗涤去除其中的氯离子。酒石酸氢铵和氨水反应并经脱色、脱水可制得最终产品右旋酒石酸铵。由于整个制取过程采用 5 0℃以下较低温度处理 ,可避免右旋的中间体酒石酸和产品酒石酸铵由于受高温处理而发生的消旋化现象 ,所得到的酒石酸铵右旋比旋光度 [α]2 0D =+38 5 ,高于用工业酒石酸直接铵化所得到的酒石酸铵比旋光度 [α]2 0D =+34 4。由于采用副产品廉价的酒石为原料 ,酒石酸铵生产成本大大降低     

Separation and recovery of vanadium from leached solution of spent residuehydrodesulfurization (RHDS) catalyst using solvent extraction

Leached solution, generated by oxalic acid washing of spent residue hydrodesulfurization (RHDS) catalyst, was used for separation and recovery of vanadium. First of all, solvent extraction, using mixture of 20% (v/v) Alamine-336 and 5% (v/v) tri-butyl phosphate (TBP) as a phase modifier, was conducted to extract molybdenum completely at pH 0.50. Then molybdenum-free solution was used for vanadium extraction at pH 1.25 with 20% Alamine-336 and 5% TBP. Stripping of vanadium from loaded organic solution was performed with 1.5 M H₂SO₄ at O/A phase ratio of 5:1 where more than 99% of vanadium was stripped in two stages. The stripped vanadium solution was further processed by precipitating with ammonium hydroxide to recover ammonium-meta-vanadate which was calcined to obtain vanadium pentoxide. Finally a conceptual process was established for recovery of high purity vanadium pentoxide from oxalic acid leached solution of spent residue hydrodesulfurization (RHDS) catalyst.     

钙化提钒溶液沉钒的影响因素及沉钒动力学

用(NH4)2SO4对钒渣钙化焙烧、稀酸浸取、化学沉淀净化后的酸性含钒溶液进行沉淀富集,考察了钒浓度、初始pH值、加铵系数(NH3/V摩尔比)、沉钒温度和时间对沉钒率及V2O5含量的影响,研究了沉钒动力学,对沉钒产物进行了表征. 结果表明,在初始pH为2.00?0.05、加铵系数1.5、温度大于95℃、沉钒时间120 min、钒液中V浓度大于20 g/L的条件下,沉钒率超过96%,产品中V2O5含量大于98%,杂质含量符合98级氧化钒的国家标准. 75~99℃下的沉钒过程可由Avrami动力学方程描述,表观活化能Ea=93.23 kJ/mol,指前因子A=9.14×1011 min?1. 铵盐沉钒产物为(NH4)2V6O16?1.5H2O,高温煅烧所得V2O5晶体为柱状,平均粒径1.25 ?m,主要杂质Mn以MnV2O6形式存在.     

冷冻法硝酸磷肥副产粗硝钙液用于磷矿脱镁的研究

针对冷冻法硝酸磷肥副产粗硝钙液中的磷进入滤渣难以回收利用导致硝酸磷肥装置产能低、胶磷矿富集技术浸取工段氨逃逸率低致使浸取液中硝酸铵含量高造成下游无法使用的问题,开展了粗硝钙液用于磷矿脱镁的研究。实验方法及最优反应条件：原矿经破碎、煅烧（煅烧温度为900~1 100 ℃,煅烧时间为1.5~3.0 h）,用粗硝钙液浸取,利用粗硝钙液的热能和化学反应热控制反应温度为60~70 ℃（不需加热,节省了蒸汽消耗）,反应pH为4.5~6.5,反应过程中无磷析出。在此条件下制取的磷精矿中五氧化二磷质量分数≥35%、氧化镁质量分数≤1.0%,磷回收率为100.49%~100.60%。将制取的磷精矿进行酸解,提高了酸不溶物的分离效率,可满足下游生产白色硝酸磷肥对原料的要求,副产的浸取液可用于生产氨基酸液体肥和中量元素营养母粒。该方法无尾矿产生,绿色环保,为磷矿的高效利用提供了新的研究思路。     

一步脱氟制备饲料级磷酸氢钙及硫酸铵新工艺

介绍用硫酸萃取磷矿粉生产磷酸，然后经一步脱氟，氢氧化钙中和，过滤，干燥生产饲料级磷酸氢钙；再利用反应生成的磷石膏与碳铵反应制备碳酸钙和硫酸铵的新工艺。该工艺解决了磷石膏中的钙无法充分利用的问题，充分合理地利用了资源；另外采用一步脱氟生产肥料级磷酸氢钙，大大提高了磷矿石中磷转化到饲料级磷的比例，显著地降低了生产成本，简化了工艺。     

Kinetics of pyrolysis of some fire retardants and treated fabrics

Intermediate phases and reactions occurring on decomposing diammonium hydrogen phosphate, ammonium para molybdate, sodium tungstate dihydrate and ammonium meta vanadate were established by thermal analysis and X-ray examination. These salts promote fabric degradation at low temperatures but are effective at high temperatures. Diammonium hydrogen phosphate produced maximum amount of gases, absorbed the highest amount of heat and gave the highest fire retardation above 350°C.     

新两步法净化湿法磷酸

以湿法磷酸为原料制取精细磷酸盐的关键在于解决湿法磷酸的净化问题。提出采用两步法对未经浓缩的湿法磷酸进行净化的特点是:第一步在湿法磷酸中加入Na2CO3预脱氟和加入磷矿粉脱除部分硫酸根,得到预净化磷酸;第二步对滤液用氨代替常用的氢氧化钙进行中和,同时补加一定量的钙,以进一步脱除其中的氟,避免中和过程生成磷酸氢钙,从而可大大提高磷收率。中和过程补钙,使脱氟率得到进一步提高,同时也能提高过滤强度。深度净化后的溶液其氟含量降至0.018%,脱氟率接近99%,SO42-含量降至0.79%,P2O5收率达到72.93%。经过净化得到的磷铵溶液经浓缩,冷却结晶,可得工业磷铵产品;与石灰乳或硝酸钙反应,可得饲料级磷酸氢钙或牙膏级磷酸氢钙产品。     

氧化镁蒸氨的试验研究

在实验室进行了重碱过滤母液与氧化镁反应蒸氨的试验条件探索,得到了影响蒸氨单元的一些工艺条件和参数,为氯化铵的转化提供了参考。     

钒化工冶金固废资源化清洁利用

采用整体化增值利用、多组元高效提取、末端无害化处置的策略，通过关键核心技术创新和集成，开发了具有产业化价值的低成本、高效钒化工冶金固废资源化清洁利用技术集成体系。提钒尾渣通过亚熔盐技术高效提钒后，渣中的钒含量(以V2O5计)降低至0.2wt%以下，铁含量(以Fe2O3计)富集至60wt%以上；再经钙化脱钠后终渣中钠含量(以Na2O计)低于2wt%，可大比例替代低钒高品位铁精矿用于配矿烧结，配矿量由原来的20 kg/t提高至60 kg/t。将块状、粉状铬泥通过添加有机粘结剂和65碳化硅做成球骨架，加工成粒径5?30 mm的球状物并烘烤，加入炼钢工序，所制钢筋的屈服和抗拉强度均比常规工艺高，对钢筋性能提高有一定作用。采用钒酸铁部分替代V2O5冶炼钒铁技术上可行，1 t钒酸铁可代替209 kg V2O5，钒铁消耗0.2 t，钒回收率在90%以上，并生产出A级50钒铁产品。50钒铁炉渣作为粘结配料可提高钒钛烧结矿强度，在回收利用渣中钒、镁、钙元素的同时，使钒钛烧结矿转鼓指数提高2%~4%。     

Ammonia volatilization from urea and ammoniacal fertilizers surface applied to winter wheat and grassland

Ammonia volatilization from urea, diammonium phosphate, ammonium sulphate and calcium ammonium nitrate surface applied to winter wheat and grassland was determined with windtunnels. The fertilizers were applied at a rate of 8–12 g N m^–2 to plots on a non-calcareous sandy loam. Five experiments were carried out during March to June 1992, each experiment including 2 to 4 treatments with two or three replications. The daily ammonia loss rate was measured during 15 to 20 days. Cumulated daily loss of ammonia from urea followed a sigmoidal expression, while the cumulated ammonia loss from diammonium phosphate showed a logarithmic relationship with time from application. For ammonium sulphate and calcium ammonium nitrate no significant loss could be determined, because daily loss of ammonia were at the detection limit of the wind tunnels. Mean cumulated ammonia loss from plots receiving urea, diammonium phosphate, ammonium sulphate and calcium ammonium nitrate were 25%, 14%, <5% and <2%, respectively, during a 15–20 day measuring period.     

用硝酸磷肥生产中副产的磷石膏制备硫酸铵和碳酸钙

随着磷矿品位的不断下降,磷复肥企业必然面对使用中低品位的磷矿。为了解决冷冻法硝酸磷肥生产中深度除钙副产磷石膏的堆积问题,以磷石膏、碳酸铵和氨水为原料进行复分解反应制备硫酸铵和碳酸钙,以实现硫资源的循环利用。考察了影响硫酸钙转化率的各种因素,通过正交实验确定了复分解反应的优惠工艺条件,并作了验证性实验。结果表明,在优惠工艺条件下磷石膏中硫的转化率可达96.7%。用磷石膏生产硫酸铵,不仅是环境保护的需要,也是废物利用、资源回收的需要,具有潜在的社会效益和经济效益。     

The electrochemistry of nitrate-amide melts: Reactions of nickel and copper in nitrate-amide melts

Copper and nickel may be electrodeposited from their ions in solution in nitrate-amide melts at room temperature. In the ammonium nitrate-acetamide-urea melt at 23°C, the reduction to the metal competes with the corrosion reaction at low rates and with the reduction of the ammonium and nitrate ions of the melt at high current densities. Two distinct types of nickel complexes are found in solution. The nickel complex formed by the corrosion reaction is bound by at least one ammonia ligand. Nickel complexes formed by dissolving the halide in the melt show evidence of coordination by less strongly bounding ligands, probably by amides. Similarly, the visible spectra of copper chloride in solution suggest that the cupric ions are coordinated primarily by amides. The copper corrosion reaction produces a complex with a spectra distinctly different from that of cupric chloride in solution. The shift in absorption maxima suggests that the copper complex formed by the corrosion reaction has at least one ammonia ligand in the coordination sphere.     

磷矿酸解液沸点的测定

用工业湿法磷酸和硝酸钙、或硝酸分解磷矿分别制得磷矿酸解液,实验测定了磷矿酸解液沸点与硝酸钙质量分数之间的关系。结果表明,磷矿酸解液沸点随着硝酸钙质量分数的减小而下降。在硝酸钙质量分数低于45%后,沸点随硝酸钙质量分数的变化更明显。磷矿酸解液沸点可用T=Tb+ΔTb预测。在相同硝酸钙质量分数、相同含水率时,用湿法磷酸制得的模拟酸解液的沸点与用硝酸分解磷矿制得的酸解液沸点很接近。     

聚磷酸铵合成方法的研究进展

系统介绍了聚磷酸铵的生产方法,包括磷酸二氢铵法、磷酸-尿素法、磷酸脲法、磷酸二氢铵-尿素法、磷酸氨化法和磷酸铵-五氧化二磷法。磷酸二氢铵法、磷酸-尿素法、磷酸氨化法得到的产物聚合度较低,低聚合度聚磷酸铵水溶性高,呈中性,适宜作农用肥料;磷酸二氢铵-尿素法和磷酸铵-五氧化二磷法得到的产物聚合度较高,高聚合度聚磷酸铵适宜作阻燃剂。