Magnesium monophosphate cements derived from diammonium phosphate solutions

Rapid-setting magnesium monophosphate cementitious materials were prepared by mixing calcined magnesium oxide (MgO) powder with an aqueous solution of diammonium phosphate (ADP) at 24°C. The activation energy for the curing reaction of the cement paste was determined to be 30.29 kcal/mole, and at age 1 hr the compressive strength was ≈900 psi (6.2 MPa). X-ray diffraction studies of the cured cement indicated that the major reaction product was magnesium orthophosphate tetrahydrate [Mg₃(PO₄)₂·4H₂O]. Magnesium ammonium phosphate hexahydrate [MgNH₄PO₄·6H₂O] and Mg(OH)₂ were also detected. Subsequent heating of the cement to 1300°C resulted in the conversion of the three compounds to a single phase of anhydrous magnesium orthophosphate [Mg₃(PO₄)₂]. The resultant product had a compressive strength of 7000 psi (48.23 MPa) and was thermally stable in air at temperatures >1000°C.     

Leaching kinetics of magnesium extraction from boron mud in ammonium bisulphate solutions

In this study, the leaching kinetics of magnesium of boron mud (BM) is evaluated using NH₄HSO₄ solution. The effects of leaching temperature, leaching time, ammonium bisulphate solution concentration and liquid–solid ratio on the extraction ratio of magnesium are investigated. Optimum leaching parameters are determined through an orthogonal test based on single factor experiments. Under the optimum leaching temperature (333 K), leaching time (40 min), NH₄HSO₄ concentration (2.8 mol · L⁻¹), and liquid–solid ratio (9:1 mL · g⁻¹), the extraction ratio of magnesium was 76.73%. In addition, the leaching kinetics data of magnesium from BM are analyzed through graphical and statistical approaches, which reveal that the leaching process conforms to the grain model. The leaching process is diffusion-controlled with an activation energy of 41.67 kJ · mol⁻¹.     

聚磷酸铵的研究进展

聚磷酸铵(APP)是一种重要的无机阻燃剂，是膨胀型阻燃剂的主要成分之一。介绍了Ⅰ-型和Ⅱ-型聚磷酸铵的结构、性质，着重讨论了Ⅰ-型和Ⅱ-型聚磷酸铵的合成方法、改性途径的研究新进展，以及Ⅰ-型聚磷酸铵到Ⅱ-型聚磷酸铵的转化机理、转化方法。研究目的在于制备难溶于水的聚磷酸铵。     

水溶性聚磷酸铵制备微量元素螯合物的实验研究

以水溶性聚磷酸铵和硫酸铜、硝酸铁为原料,研究制备聚磷酸铵铜螯合物、聚磷酸铵铁螯合物的工艺条件。实验结果显示,Cu^2＋和Fe^2＋的最适宜螯合工艺条件：pH值=7．0,反应温度为35℃（Fe^3＋为40℃）,反应时间为60min。测定了两种螯合物在10～50℃的溶解度数据,并运用拉曼光谱和红外光谱验证了螯合物的生成。     

聚磷酸铵中缩二脲含量的测定

参照尿素中缩二脲含量的测定方法 (分光光度法),加入适量的氢氧化钠溶液,调节聚磷酸铵溶液至碱性,建立了聚磷酸铵中缩二脲含量的检验方法。该方法的相对标准偏差1.88%,加标回收率为96.40%~102.40%,测定结果与高效液相色谱法一致,准确度高,重现性好。     

不同聚合度水溶性聚磷酸铵螯合镁离子的研究

聚磷酸铵作为一种富含氮、磷元素的新型缓溶性长效氮磷肥,对微量元素具有良好的螯合能力,可有效防止土壤中金属离子被固定,从而被植物更好地利用。采用滴定分析法测定了不同聚合度的水溶性聚磷酸铵（APP）对中量元素镁离子的螯合能力,探索了水溶性聚磷酸铵对镁离子的螯合规律,为聚磷酸铵-中微量元素螯合物的制备奠定基础。实验结果显示,水溶性聚磷酸铵聚合度越高,对镁离子的螯合能力越强,且螯合能力随着pH增大先减小后增大、随着温度升高逐渐降低,在pH=6.0、温度为5 ℃时高聚聚磷酸铵对镁离子的螯合量达到8.2 g（以100 g APP计）,在pH=8.0、温度为5 ℃时低聚聚磷酸铵对镁离子的螯合量达到5.6 g（以100 g APP计）。采用傅里叶变换红外光谱分析验证了螯合物的生成。     

Arsenic(V) removal from enargite leach solutions by precipitation of magnesium ammonium arsenate

This study investigated a potential method for the removal of arsenic from enargite leach solution containing 5.86 g/L As(V) by precipitation of magnesium ammonium arsenate (MAA). The experimental results showed the As(V) concentration can be reduced to 1.8 mg/L under the optimum conditions. The molar ratio NH₄/Mg/As in precipitates formed at different pH values was checked by wet chemical analysis, indicating that some of by-products such as Mg₃(AsO₄)₂, Mg(OH)₂, and MgHAsO₄ will be formed at the solution pH above or below pH 9.5. Notably, this study indicated MAA has a better ability for arsenic removal than magnesium arsenate. The precipitates also were characterized by XRD and SEM.     

Aluminous cements containing magnesium aluminate spinel from Egyptian dolomite

Three mixes of calcium aluminate cements containing MA spinel were prepared using appropriate mixtures of Egyptian dolomite (MgO, 20.16% and CaO, 31.32%) with active alumina (99.50% A)¹. The cement mixes were prepared at 1600°C using the sintering method. The products were finely ground and their chemical and mineralogical compositions were investigated using the appropriate techniques. Also, their physicomechanical and refractory properties had been determined. The results indicated that their mineralogical compositions were refractory MA spinel, in addition to CA and/or CA₂ phases depending on the composition of the starting materials. The prepared cements exhibited a compromise between considerable strength and higher refractoriness. When 10% of such cements were added to refractory grade magnesia aggregate, in the presence of 0.1% Li₂CO₃ as a strength modifier, refractory castable bodies with improved hot-strength and thermal shock resistance had been achieved.     

农用肥料聚磷酸铵的制备与应用

聚磷酸铵是一种性能优良的非卤阻燃荆,国内在农业上应用较少.介绍一些聚磷酸铵的生产方法.重点介绍磷酸与尿素缩合法生产农用短链低聚磷酸铵的生产方法、性质、用途.低聚磷酸铵是液体肥料一种很好的原料,并具有缓释与螯合作用.     

氧化镁铵盐法制备高纯过氧化镁

在氯化铵溶液体系中,以氧化镁、过氧化氢为原料,制备高纯过氧化镁。研究表明,在氧化镁活性100左右,氯化铵占氧化镁质量10%,磷酸氢钠占氧化镁质量0.1%,过氧化氢与氧化镁质量比4∶1,反应温度40℃,反应时间30min的条件下,可制备出纯度大于90%的过氧化镁。     

Sintering of magnesium hydroxide obtained from magnesium chloride solutions

Conclusions We studied two batches of magnesium hydroxide obtained by precipitating out (using dolomite milk) from magnesium chloride solution formed when processing potassium ores.The effect of the compaction pressure, the firing temperature, and prior heat treatment on the sintering process of magnesium hydroxide was investigated.The experimental samples of magnesium hydroxide exhibit high sinterability and facilitate the production of periclase powders (powder bodies) having a porosity of 6.8–9.9% at a firing temperature of 1600°C. The degree of sintering of magnesium hydroxide increases with increasing compaction pressure and firing temperature. Prior heat treatment of the material at 800–1000°C intensifies the sintering process with simultaneous reduction of shrinkage.The studies conducted on the specimens prepared from a fired briquette established that the periclase (magnesite) powder obtained from magnesium hydroxide is suitable for the production of magnesia refractories.A. V. Kushchenko and G. G. Eliseeva (UkrNIIO) participated in this investigation.Translated from Ogneupory, No. 2, pp. 7–10, February, 1988.     

聚磷酸铵阻燃型水性聚氨酯的阻燃性能

以聚碳酸酯二醇、异氟尔酮二异氰酸酯为原料,添加不同用量的聚磷酸铵(APP),制备了一系列阻燃水性聚氨酯。UL-94测试表明,随着APP添加量的增大,水性聚氨酯的阻燃性逐渐增大。锥形量热仪测试表明,随着APP含量从0%增加25%,水性聚氨酯的点燃时间由29 s延长到45 s,最大热释放速率(HRR)由413.2 k W/m2降低到314.3 k W/m2。热重测试表明,水性聚氨酯膜的热稳定性随着APP含量的增加而逐渐升高,当APP为25%时,热稳定性最好。力学性能测试表明,随着APP含量的增加,涂膜的拉伸强度及断裂伸长率逐渐下降。综合考虑以上因素,阻燃水性聚氨酯中聚磷酸铵的适宜用量为20%。     

聚磷酸钙镁的制备研究

针对湿法磷酸渣和磷尾矿难以利用的问题,提出了一种焙烧湿法磷酸渣和磷尾矿的混合物制备聚磷酸钙镁肥的策略。基于磷尾矿分解率得出磷尾矿与磷酸渣的适宜质量比为0.30,在此条件下磷尾矿的分解率为80.18%。煅烧工艺结果表明,升高温度和延长时间都能促使聚磷酸盐链的增长。在焙烧时间为1 h条件下焙烧温度从105 ℃逐渐升高到460 ℃,聚磷酸钙镁中磷的平均聚合度从1.00逐渐增加至3.23。其中,焙烧温度为340 ℃时,聚磷酸钙镁中磷的聚合率超过85%,但是聚合度还在增加。尽管肥料的水溶性随着聚磷酸盐链的增长而逐渐降低,但是当焙烧温度≤340 ℃时有效磷含量依然大于90%（质量分数）。在340 ℃焙烧1.0~2.0 h后发现,当焙烧时间为1.0 h时,聚磷酸钙镁中磷的聚合率和平均聚合度分别达到87.4%和2.80。通过工艺条件优化,可在聚合度分布水平上实现聚磷酸盐的可控制备,这也开辟了一种构建缓释肥的新方向。在340 ℃聚合1.0 h优选出聚合度为1~10分布的聚磷酸钙镁,表现为多孔的非晶态结构,其中有效磷、钙、镁养分含量超过85%（质量分数）,可作为一种新型的多元缓释肥。     

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。     

Quaternary ammonium salts derived from jojoba oil

Quaternary ammonium salts derived from jojoba oil have been prepared either from jojobyl halides and tertiary amines or from dimethyljojobyl- and dimethylhomojojobylamines and alkyl halides. These salts have special potential as germicides, surfactants, emulsifiers and phase transfer reagents, for example. The jojobyl iodide and jojobyl mesylate react more readily with amines than the chloride, which is consistent with the expected relative leaving group reactivity of the different halides. The nucleophilicity of the tertiary amine, containing one long chain derived from jojoba oil, is similar to that of other tertiary amines containing only short alkyl chains. The salts are thermally stable up to 100–110 C.     

阻燃剂聚磷酸铵的改性和应用

聚磷酸铵是一种重要的阻燃剂。介绍了其改性方法以及用途,指出了其今后的发展趋势。     

Hydrogels containing modified ammonium polyphosphate for fireproof materials

Hydrogels containing a large amount of water have been widely studied as fireproof materials. However, the organic networks that composed the gel easily burns as water evaporates. In this work, the widely used intumescent flame-retardant ammonium polyphosphate was modified by carbon–carbon double bonds (abbreviated as MAPP) and introduced in alginate/poly (acrylamide-co-stearyl methacrylate) [alginate/P(AAm-co-SMA)] hydrogel by free radical polymerization. The resultant MAPP@alginate/P(AAm-co-SMA) hydrogels show good mechanical strength of 650 kPa and healing efficiency of 80%. Thermal analysis and thermal protective performance tests indicate that the MAPP particles improve the thermal stability and heat resistance of gel. The fireproof test shows that the MAPP@alginate/P(AAm-co-SMA) gel composite shows twice of fire proof time over the pure hydrogels.     

水溶性农用聚磷酸铵的研究与应用进展

低聚合度水溶性聚磷酸铵是一种新型高浓度肥料,因其缓释高效、安全易复配的特点在近年新肥料研发和农业应用中受到广泛欢迎。综述了近期水溶性农用聚磷酸铵的合成方法和农学实验的研究进展。论述了水溶性农用聚磷酸铵在农业生产中的施用优点以及聚磷酸铵肥料的相关质量检测方法。分析了水溶性农用聚磷酸铵在土壤中的水解作用机理。阐述了当今农用聚磷酸铵肥料在实际生产应用中存在的问题与发展方向。     

聚丙烯/聚磷酸铵复合材料的等温结晶行为

采用差示扫描量热法研究了聚丙烯(PP)聚/磷酸铵(APP)复合材料的等温结晶过程。引入APP后,PP/APP复合材料的平衡熔点升高,结晶速率大幅度提高。采用Avrami方程研究了该体系的结晶动力学,发现PP/APP复合材料呈现明显的异相成核特征,随w(APP)的增加,Avrami结晶速率常数增大,半结晶时间降低。