磷酸装置稳定浓缩生产能力的措施

针对湿法磷酸生产中生产高浓度复合肥时,磷酸的质量分数要求w(P2O5)在45%以上,稀磷酸需要浓缩,介绍了生产过程中稳定控制操作指标,加强系统的清理清洗、添加浓缩助剂和采取先进工艺方法等措施,实现了磷酸浓缩装置稳产和高产。     

降低湿法磷酸MER值的探索性实验

为了应对磷矿贫化对w(总养分)64%DAP生产的影响,对降低湿法磷酸中铁、铝、镁含量进行了探索性实验。结果表明,向浓缩磷酸中添加助剂A可以达到降低铁含量的效果,铁脱除率约为30%;向浓缩磷酸中添加助剂B可以达到降低铝、镁含量的效果,其加入量为浓缩磷酸质量的1.0%,陈化时间24 h,陈化温度60℃,铝脱除率为16.47%,镁脱除率为7.67%,MER值从0.101降低至0.087。以加入助剂B所得澄清浓缩磷酸为原料制备DAP,总氮含量提高约0.44百分点,可以满足生产w(N_总)大于17.5%的w(总养分)64%的DAP的要求。     

磷酸浓缩装置扩能工艺及其运行探析

针对国内磷复肥行业磷酸浓缩工艺,介绍了单套和多套磷酸浓缩装置扩能新工艺及理论基础,生产应用产生的效益明显。应用磷酸浓缩装置扩能新工艺后,磷酸浓缩两级蒸发的循环水耗量低,可减少约1/3循环水用量;负荷提高相当于减少大量投资与折旧费,同时节省大量电耗、维修费用和土地费用,生产的磷酸杂质少质量好。     

湿法磷酸净化及盐类生产技术:7.湿法磷酸浓缩脱氟生产磷酸氢钙

介绍了国内外使用蒸汽浓缩湿法磷酸脱氟净化技术,以及利用浓缩脱氟磷酸生产磷酸氢钙技术的开发、应用及存在的问题。提出开发直接式燃煤热风炉供气取代蒸汽浓缩湿法磷酸脱氟净化技术,使用沉降助滤剂也可以解决蒸汽浓缩和钾、钠盐脱氟分离困难的问题。     

大型湿法磷酸装置使用低品位磷矿的工艺技术

针对宜昌低品位磷矿,通过CaSO4-H3PO4-H2SO4-H2O四元相图,研究二水湿法磷酸工艺,得到扩大低品位磷矿生产硫酸钙二水结晶稳定区的条件范围,并在生产中应用,获得湿法磷酸生产优惠的工艺技术指标,过滤速率大幅提高。同时提出磷酸浓缩系统阻垢、清洗工艺新技术,并在生产中实施,提高了浓缩效率。     

石墨块孔换热器在磷酸浓缩工艺中的应用

石墨块孔换热器在磷酸浓缩工艺中的应用姚建斌（江西贵溪化肥厂）１前言随着大型磷资源矿山的开发利用。国际上具有代表性的先进的磷酸生产工艺被我国陆续引进。目前国内已建成投产和即将建成投产的大型磷酸生产装置已有好几套，不论是哪种工艺，磷酸浓缩系统是必需的，而...     

磷酸蒸发浓缩助剂的实验研究

实验研究各种表面活性剂作为磷酸浓缩蒸发的助剂,用以提高水的蒸发强度,加入量只需磷酸质量的200×10-6,以TWEEN+NNO和TWEEN+GC效果较好。同时实验研究了各种阻垢剂,其中以SO-3和十二烷基苯磺酸钠最佳,对氟硅酸钾(钠)的阻垢率可达60%以上。湿法磷酸浓缩过程中同时加入上述表面活性剂,可提高蒸发强度,减少蒸汽用量,提高浓缩酸浓度,并有一定的阻垢作用。     

湿法磷酸两级浓缩技术应用现状与展望

介绍了国内湿法磷酸浓缩装置技术现状,阐述了磷酸两级蒸发的特点和在大型磷酸浓缩装置上开发应用的进展,总结了前中国石化集团南京设计院开展两级浓缩技术推广的成功案例,面向未来展望湿法磷酸两级浓缩技术在我国磷复肥工业"十二五"期间的应用和发展。     

提高磷酸浓缩系统运行率的技改措施

介绍瓮福紫金化工股份有限公司湿法磷酸装置自投料生产以来磷酸浓缩系统的运行状况,分析磷酸浓缩系统运行率低的原因,通过采取增加备用设备、更换浓缩管道材质、提高稀磷酸沉降效果、优化循环水管网等一系列措施,使磷酸浓缩系统运行率提高45.7百分点,总产值增加6 601.5万元。     

磷酸生产技术改造

山东明瑞化工集团有限公司针对磷酸生产中磷酸渣处置、废水处理及磷酸浓缩能力不足问题进行了技术改造,通过将磷酸渣及废水用于磷铵生产消化以及对磷酸浓缩文氏管的改造,磷酸产量提高,原材料及能源消耗下降,废渣、废水得到有效利用,吨产品生产成本下降200余元。     

水泥助磨剂对不同质量指标水泥熟料强度影响研究

通过对不同质量指标熟料与系列助磨剂之间的性能测试分析,研究助磨剂组合对不同质量指标熟料的强度影响关系。研究表明:T2、T4、T5助磨剂综合表现较好,在28 d强度方面,T系列助磨剂对于C3熟料强度增长率数据集中度好,对于C2、C4熟料强度数据离散性大。熟料3 d、28 d强度增长率与T系列助磨剂掺量的相关系数R>0.9,其中与3 d强度相关系数R> 0.95。助磨剂有效掺量起点0.01%,饱和点分别为0.02%和0.025%。助磨剂对于KH值较低的熟料3 d强度促进作用高于KH值较高的熟料。     

Processing aids for poly(vinyl chloride)

Processing aids are an important class of additives for poly(vinyl chloride) (PVC). At relatively low concentration, processing aids enable the melt processing of rigid PVC and enlarge its processing windows. Discussed in this presentation are some major functions of processing aids, such as promoting PVC fusion, modifying PVC's melt rheology, and lubricating to prevent adherence of PVC melt to the processing equipment. Some examples are given to show the effects of processing aids on PVC die swell, melt fracture, melt viscosity, and PVC fusion. Commercial sources of various processing aids and typical PVC formulations for various applications are also discussed.     

Ultra-fine grinding mechanism of inorganic powders in a stirred ball mill

An experimental investigation on grinding mechanism for calcite used in a stirred ball mill was carried out. The slurry concentration and the amount of grinding aids were chosen as main experimental factors of the grinding process. The effect of grinding aids on particle size distribution and grinding efficiency, defined as the increases of specific surface area per the specific grinding energy, was investigated. It was demonstrated that the grinding rate for calcite could be improved by addition of grinding aids. The grinding energy efficiency by adding a specific grinding aids was improved approximately 45.2% in comparison with and without grinding aids (n=700rpm, J=0.7, d_B= 1.0 mm, C_s=60wt%). This paper was presented at the ‘First Asian Particle Technology Symposium’ held at Bangkok between December 13 and 15, 2000.     

FORMULATION OF INJECTION MOLDING BINDER SYSTEMS

A polyethylene and three ethylene vinyl acetate (EVA) copolymers were evaluated to determine the best mix of binder components. The effect of plasticizers and processing aids was investigated. One weight percent of silane coupling agent was added to improve the ceramic and binder mix stability. These mixes were evaluated from the Brabender torque data and capillary viscosity. A limited number of molding experiments were also performed. The results showed that polyethylene and EVA copolymers with a melt index of around 25 are the most suitable binders, that plasticizers improve the flowability of the mix; and that processing aids containing a double bond and amines reduce viscosity and improve moldability. Combining plasticizers, processing aids and a small concentration of an appropriate coupling agent results in a low primary binder concentration. EVA mixes have shown better flow and moldability.     

Processing aids for chlorinated polyvinyl chloride

Comparative studies of melt processability showed that chlorinated polyvinyl chloride (CPVC) had low melt index and high Brabender melt temperature and torque, as compared with conventional rigid polyvinyl chloride (PVC). Of 3 processing aids at 10 percent concentration, triphenyl phosphate increased melt index 30-fold, fusion rate 10-fold, melt temperature 20°C, and torque 31 percent in CPVC. Two other processing aids, an acrylic and a styrene/acrylonitrile copolymer, were less effective. Improvements in PVC were less dramatic than in CPVC. Overall, use of processing aids made CPVC processability equal or even superior to conventional rigid PVC.     

全白土催化剂生产旋液废水处理

针对某催化剂厂全白土车间旋液排放废水中悬浮物含量高的特点,采用分级沉降技术有效分离旋液废水中所含的白土催化剂,催化剂的分离率不低于80%;对分级沉降后的废水利用聚合氯化铝+助剂在废水温度为40～55℃、沉降时间为10min下进行处理,在聚合氯化铝最佳用量为80.0mg/L、助剂最佳用量为6.0mg/L时,悬浮物的平均质量浓度由27120mg/L降到20.0mg/L以下,废水中悬浮物去除率高于99.50%;浊度由1020FTU降到10.0FTU以下。     

Ultra-fine grinding mechanism of inorganic powders in a stirred ball mill

Recently, in various industrial processes, the need for fine particles, especially submicron-sized particles, has increased in the field of preparing raw powders such as fine ceramics and high value added products. Therefore, the research in fine grinding has gained more importance, especially, in submicron grinding. In the previous paper, a series of wet grinding experiments using inorganic powders by a stirred ball mill were performed. The grinding consumption power was measured, and the grinding rate constant, K, in the grinding kinetics equation was examined, based on a grinding kinetics analysis of experimental specific surface area with particle size distribution of ground products obtained under various grinding conditions. Also the effect of grinding aids on grinding rate constant K was investigated. It was confirmed that the grinding rate constant K, when using grinding aids improved by 1.95% and 25.6% for a 60 wt% and 70wt% slurry concentrate, respectively, when compared with the case of the absence of grinding aids. It was found that grinding aids have an important effect on increasing the grinding rate, especially for a slurry of high concentration.     

降低饮用水浊度保障水质安全

论证了降低饮用水浊度．有利于降低水中的藻密度、有机物含量,降低Ames致突变率,降低病毒传染病的发病病例,提高变形虫贾第氏虫的去除率,对保障饮用水安全有重大作用。降低浊度的途径是强化混凝,沉淀,过滤工艺,即提高混凝剂剂量,投加助凝剂聚硅酸,聚丙烯酰胺等,投加助滤剂。     

On the Improvement of the Processability of UHMW‐HDPE by Adding a Liquid Crystalline Polymer and a Fluoroelastomer

Ultra‐high molecular weight polyethylene possesses many interesting properties but a very bad processability. This material is not usually processed in conventional devices but only by compression moulding and RAM extrusion. Low molecular weight polyethylene can be used to improve the processability. In this work small amounts of a fluoroelastomer and of a liquid crystalline polymer have been used as processing aids to improve the extrudability of this polymer. In fact, the die pressure decreases whereas the output flow rate slightly increases with increasing concentration of the processing aids. Solution viscosity data shows that reduction of the mechanical stress during extrusion decreases the degradation of the polyethylene.     

The Effect of Flocculants and Surfactants on the Filtration Dewatering of Iron Ore Fines

Abstract

The filtration and separation characteristics of iron ore fines have been investigated. The experimental work included: characterization, evaluation of suitable flocculants to enhance settling and dewatering rate, determination of optimum dosages of flocculants, and influence of surfactants on nitration dewatering of both flocculated and unflocculated iron ore fines by vacuum filtration. The results showed that 1) the settling rate can be enhanced many-fold (from 2.52 to 90 m/h) by a suitable flocculant, 2) the residual filter cake moisture content can be reduced from 18.2% without reagents to 12.6% with suitable surfactant dewatering aids while the filtration rate can be enhanced from 4.8 to 97.2 L/h with suitable dewatering filter aids, and 3) the specific cake resistance to filtration can be brought down from 8.6 × 10⁹ to 1.0 × 10⁹ m/kg by using a surfactant sodium petroleum sulfonate at a concentration of 1.47 × 10^?3 kg/t. The economics of using flocculant filter aids and surfactant dewatering aids before thermal drying is described and discussed.