以湿法磷酸与碳酸氢铵为原料连续生产磷酸-铵的技术

介绍以湿法磷酸和碳酸氢铵为原料连续生产磷酸一铵的工艺流程、主要设备;比较碳酸氢铵代替液氨生产磷酸一铵的优缺点,两种工艺应根据具体情况选用。     

以湿法磷酸与碳酸氢铵为原料连续生产磷酸一铵的技术

介绍以湿法磷酸和碳酸氢铵为原料连续生产磷酸一铵的工艺流程、主要设备；比较碳酸氢铵代替液氨生产磷酸一铵的优缺点，两种工艺应根据具体情况选用。     

粉状磷酸一铵扩产技术改造

湖北中孚化工有限公司磷酸一铵装置于2007年投产,年设计产能100kt。由于生产的W（总养分）60％的高品位磷酸一铵难以满足市场需求,以及100kt／a复合肥装置的投产对磷酸一铵的需求,公司技术人员对中和浓缩、喷粉干燥、供氨及包装工序原有设备进行改造,使磷酸一铵装置产量由设计产能100kt／a提高到150kt／a,产品质量稳定,且解决了整套磷酸一铵生产装置的水平衡问题。     

肥料级磷酸一铵和工业级磷酸一铵联合生产工艺

介绍肥料级磷酸一铵和工业级磷酸一铵联合生产工艺,即共用中和、浓缩装置,部分料浆用于生产肥料级磷酸一铵,部分料浆用于生产工业级磷酸一铵,工业级磷酸一铵生产中产生的渣浆和清液重新返回肥料级磷酸一铵系统生产肥料级磷酸一铵。两条工艺路线优势互补,节能降耗,是肥料级磷酸一铵技术改造的新思路。     

管式反应器—喷雾流化干燥制粉状磷酸一铵新工艺

简述规模为20万t/a管式反应器—喷雾流化干燥制粉状磷酸一铵新工艺的特点、工艺流程与主要设备,以及主要工艺控制指标,为国内粉状磷酸一铵的生产开辟了一条新的途径。     

用湿法磷酸生产高纯度磷酸一铵的工业装置

针对精细磷酸铵盐需求快速增长和热法磷酸价格上涨,介绍了采用湿法磷酸生产高纯度磷酸一铵的工艺流程,探讨了湿法磷酸脱硫,磷酸铵料浆过滤,磷酸一铵溶液浓缩、结晶、过滤以及干燥等的工艺条件和设备选型,分析了高纯度磷酸一铵产品的主要化学组成和车间生产成本,认为该工艺技术的经济效益是显著的。     

粒状磷酸一铵造粒的影响因素与改善措施

分析瓮福磷肥厂利用磷酸二铵装置生产粒状磷酸一铵影响造粒的因素,结合装置情况,从工艺控制和设备技改方面阐述了改善粒状磷酸一铵造粒的措施及对策.     

华山10万t磷酸一铵装置开车

陕西华山化工集团公司年产10万t磷酸一铵装置日前一次开车成功，并生产出合格产品。该公司针对磷矿供应不足、品质下降、价格上涨的不利形势，投入4000万元，借助新技术、新设备，采用品位较低的磷矿，用制浆法生产磷酸一铵，既提高了装置利用率，同时调整了产品结构。     

料浆法粉状磷酸一铵装置联产GMAP和GDAP产品

随着国内外大规模磷铵装置的投产,粉状磷酸一铵(MAP)市场价格比粒状磷铵产品低,生产企业受市场、关税影响大。为了拓宽磷铵的市场,利用料浆法粉状磷酸一铵装置联产粒状磷酸一铵(GMAP)和粒状磷酸二铵(GDAP)产品,以满足市场需求,从而也盘活粉状MAP装置。以下介绍利用粉状磷酸一铵生产装置联产粒状磷酸一铵、粒状磷酸二铵的工艺。     

利用中低品位磷矿生产高品质磷酸一铵的工业试验

根据宜昌中低品位磷矿特点,考察了磷矿中金属离子钾、钠、镁、铁、铝、硅等对磷酸一铵生产的影响,开发了自动配矿系统,保证了高品质磷酸一铵生产对磷矿的要求。通过利用氟硅酸去除钾钠离子、选用芳基磺酸作助沉剂、采用冷空气降温等物理措施,有效去除渣酸中的各种杂质,保证了渣酸有效再利用。通过改进配酸装置和反应器喷口、控制通氨量,开发出单管一步法中和-转鼓造粒工艺。工业试验表明,在磷酸二铵生产设备的基础上,可以实现利用中低品位磷矿生产高品质磷酸一铵。     

Quantification of Phospholipids Classes in Human Milk

Phospholipids are integral constituents of the milk fat globule membranes and they play a central role in infants’ immune and inflammatory responses. A methodology employing liquid chromatography coupled with evaporative light scattering detector has been optimized and validated to quantify the major phospholipids classes in human milk. Phospholipids were extracted using chloroform and methanol and separated on C18 column. Repeatability, intermediate reproducibility, and recovery values were calculated and a large sample set of human milk analyzed. In human milk, phospholipid classes were quantified at concentrations of 0.6 mg/100 g for phosphatidylinositol; 4.2 mg/100 g for phosphatidylethanolamine, 0.4 mg/100 g for phosphatidylserine, 2.8 mg/100 g for phosphatidylcholine, and 4.6 mg/100 g for sphingomyelin. Their relative standard deviation of repeatability and intermediate reproducibility values ranging between 0.8 and 13.4 % and between 2.4 and 25.7 %, respectively. The recovery values ranged between 67 and 112 %. Finally, the validated method was used to quantify phospholipid classes in human milk collected from 50 volunteers 4 weeks postpartum providing absolute content of these lipids in a relatively large cohort. The average content of total phospholipids was 23.8 mg/100 g that corresponds to an estimated mean intake of 140 mg phospholipids/day in a 4-week old infant when exclusively breast-fed.     

The hydration of reactive cement-in-polymer dispersions studied by nuclear magnetic resonance

The behaviour of two novel cement-in-polymer (c/p) dispersions, namely cement-in-poly(vinyl acetate) and cement-in-poly(vinyl alcohol) upon exposure to water at room temperature was investigated by a combination of various NMR methods. The swelling, cracking, and the water ingress were monitored non-destructively using ¹H single point imaging. The hydration of the cement matrix was investigated using ²⁹Si NMR whilst ¹³C CPMAS NMR spectra allowed the quantification of the kinetics of the hydrolysis reaction of poly(vinyl acetate) into poly(vinyl alcohol). The polymer controls the rate of water ingress and swelling which in turn determines the behaviour of the c/p dispersions upon exposure to water. For the cement-in-poly(vinyl alcohol), the rates of water ingress and swelling are much faster than the hydration of the clinker whilst for the cement-in-poly(vinyl acetate) the slow rates of the two processes allow the formation of a cementious matrix which assures the stability of the sample.     

The influence of water removal techniques on the composition and microstructure of hardened cement pastes

The removal of water from hardened cement paste for analysis or to arrest ongoing hydration has been reported to affect the composition of hydrated phases and microstructure. The effect that arresting the hydration of hardened cement paste by replacing the pore water with acetone before drying, and by removing the water by freeze, vacuum and oven drying has on the hardened cement paste has been investigated. Two pastes were studied, a cemented iron hydroxide floc where a high proportion of ordinary Portland cement (OPC) had been replaced by pulverised fuel ash, and a pure hydrated OPC. The results showed that none of the water removal techniques caused any major deterioration in the composition and microstructure of the hardened cement pastes studied, but the pores appeared better preserved after arresting hydration using acetone quenching. Freeze drying appeared to cause more cracking of the microstructure than the other water removal techniques.     

Design and function of novel superplasticizers for more durable high performance concrete (superplast project)

In this article we shall describe our quest and ultimate success in furthering our understanding of the action of superplasticizers on the rheology of cement and concrete. By specifically producing superplasticizers with varied architectures, we have been able to show the important structural features of the macromolecules that lead to a successful superplasticizer or water reducing agent. Both polycarboxylate and lignosulfonate polymers have been investigated. Using both non-reactive model MgO powders, three different types of cement blends, the adsorption behaviour and the effect on the rheological properties of these two important superplasticizer families have been used to further develop a conceptual model for superplasticizer — cement behaviour. This paper will deal mainly with the conceptual model, the materials and methods used to asses the polymer adsorption behaviour and rheological properties of the systems studied. We shall briefly describe the adsorption of the polymers onto the different surfaces and their influence on surface charge and rheology and the influence of the various ionic species found in cement pore solutions that may influence polymer-cement affinity. The key factors are shown to be the effective adsorbed polymer thickness and the induced surface charge which can be influenced by the polymer architecture, the pore solution composition and the initial particle surface charge.     

Interactions between shrinkage reducing admixtures (SRA) and cement paste's pore solution

Shrinkage reducing admixtures (SRA) have been developed to combat shrinkage cracking in concrete elements. While SRA has been shown to have significant benefits in reducing the magnitude of drying and autogenous shrinkage, it has been reported that SRA may cause a negative side effect as it reduces the rate of cement hydration and strength development in concrete. To examine the influence of SRA on cement hydration, this study explores the interactions between SRA and cement paste's pore solution. It is described that SRA is mainly composed of amphiphilic (i.e., surfactant) molecules that when added to an aqueous solution, accumulate at the solution-air interface and can significantly reduce the interfacial tension. However, these surfactants can also self-aggregate in the bulk solution (i.e., micellation) and this may limit the surface tension reduction capacity of SRA. In synthetic pore solutions, SRA is observed to form an oil-water-surfactant emulsion that may or may not be stable. Specifically, at concentrations above a critical threshold, the mixture of SRA and pore fluid is unstable and can separate into two distinct phases (an SRA-rich phase and an SRA-dilute phase). Further, chemical analysis of extracted pore solutions shows that addition of SRA to the mixing water depresses the dissolution of alkalis in the pore fluid. This results in a pore fluid with lower alkalinity which causes a reduction in the rate of cement hydration. This may explain why concrete containing SRA shows a delayed setting and a slower strength development.     

Study of the hydration of CaO powder by gas–solid reaction

Hydration of CaO powders by reaction with water vapor has been studied in isothermal and isobaric conditions. Experimental tests were performed within the temperature range of 70 °C–420 °C and with a water vapor pressure from 5 to 160 hPa by means of a thermogravimetric device. Two powders, exhibiting slight differences in their physical properties, were studied. However, for one of the powders and under some temperature and pressure conditions, the reaction is not complete. The difference of behavior between both CaO powders was interpreted by considering the effect of the morphological properties on the mechanism of growth of Ca(OH)₂.     

2-(2'-咪唑偶氮)萘酚-4-磺酸的合成及其分析性质的研究

合成了新显色剂咪唑偶氮－２－萘酚－４－磺酸（ＩＡＮ－４Ｓ）,研究了试剂的离解常数及其与金属离子的显色反应。     

Influence of bleed water reabsorption on cement paste autogenous deformation

The effects of bleed water reabsorption and subsequent early age expansion on observed autogenous deformation are investigated in this research. Bleeding was induced by varying superplasticizer and shrinkage-reducing admixture dosages and by increasing the water-to-cement ratio. This research revealed that significant early age expansion occurs with increasing chemical admixture dosages and higher water-to-cement ratios, as expected, due to increasing bleeding of those samples. When samples were rotated, negligible early age expansion was observed. Thus, bleed water reabsorption is shown to be the primary mechanism causing initial expansion in sealed autogenous deformation samples. Thermal dilation and ettringite growth appear to have a minimal influence on the observed expansion. Rotating the samples during setting eliminates the potential for bleed water reabsorption and is recommended for all autogenous deformation testing.     

Comparison between surface and bulk hydrophobic treatment against corrosion of galvanized reinforcing steel in concrete

The effectiveness of bulk hydrophobic treatment against corrosion of galvanized steel reinforcement in concrete specimens with w/c = 0.45 and w/c = 0.75 was compared with that of surface treatment, even in the presence of cracks 0.5 and 1 mm wide in the concrete cover. In this case surface hydrophobic treatments were applied both before and after cracking as a preventive and a restorative method against reinforced concrete deterioration, respectively. The obtained results in terms of water absorption, electrochemical measurements, chlorides penetration, and visual observations carried out on reinforced concrete specimens during the exposure to wet–dry cycles in 10% NaCl solution showed that bulk hydrophobization is the most effective treatment in improving the corrosion resistance of galvanized steel reinforcements in concrete also in the presence of cracks. Surface hydrophobization is very effective just in the first few exposure cycles to the aggressive environment and when used as a restorative method which is able to cancel the deleterious effect of cracks only 0.5 mm wide.     

Effect of plasma treatment of polymeric tape carriers on wetting behaviour of aqueous ceramic tape casting slurry

Due to environmental and health aspects, aqueous ceramic slurries are preferred to traditional organic solvent systems in tape casting. An important obstacle associated with the high surface energy of water is poor wetting of aqueous ceramic slurries on polymeric tape carriers. Therefore, we measured the contact angles of an aqueous epoxy-based ceramic slurry on polyethylene terephtalate (PET), polypropylene (PP), polymethyl methacrylate (PMMA), and aluminium-coated polyethylene terephtalate (PET-Al) films and investigated approaches to improving their wetting. We evaluated the effect of plasma treatment of the tape carrier surface on the wetting behaviour and compared it with the effect of adding non-ionic amphiphilic surfactants to the ceramic slurry. The treatment of the tape carrier surface by low-temperature plasma substantially improved the wetting behaviour of aqueous ceramic slurry. The lowest contact angle of 31° was obtained on the PET film. Although the addition of non-ionic surfactants improved both the wetting behaviour of the slurry and the detachment of the polymeric carrier from the ceramic tape even better than the plasma treatment of the carrier surface did, the plasma-treated carriers still present a useful alternative to the surfactants. In the case of the plasma-treated PET carrier the surfactants could be fully eliminated and potential drawbacks related to the use of surfactants could be prevented.