脱硫灰渣与钾长石混合焙烧制钾复合肥的研究

研究了钾长石-硫酸钙-碳酸钙体系加入硫酸钠、氯化钠的热分解反应动力学,结果表明硫酸钠可以有效促进钾长石的热分解.当硫酸钠添加量为4.76%时,反应温度可降至1050℃,表观活化能可降至81.97 KJ/mol;对于添加脱硫灰渣的钾长石体系,当硫酸钠添加量为3%时能显著提高钾溶出率,此时钾溶出率为71%～74%.并对烧成物进行了XRD分析,主要物相为:2CaO·SiO2、K2SO4,钾含量大于5%,是一种很好的钾复合肥.     

钾长石-石膏-碳酸钙热分解过程动力学实验研究

实验研究了钾长石-石膏-碳酸钙体系加入硫酸钠时的热分解反应动力学,结果表明,改变反应温度、硫酸钠浓度和钾长石粒径,热分解过程均受克-金-布固膜扩散控制.反应过程对硫酸钠的反应级数为0.545,反应速率与钾长石初始粒径的平方成反比,表观活化能为164.5kJ?mol-1,并用扫描电镜和X-ray衍射分析对产物进行物相分析,结合热分析和热力学分析结果,初步分析了该体系热分解过程的反应机理,拟定了反应步骤.     

钾长石-硫酸钙-碳酸钙热分解体系的再探索

对钾长石-硫酸钙-碳酸钙体系提钾反应进行了热力学计算,系统研究了物料配比、焙烧温度、反应时间和Na2SO4添加量对热分解体系的影响,最后得出物料摩尔配比为n(钾长石):n(CaSO4):n(CaCO3)=1:1:14,在1423K温度下反应2h,钾长石中钾溶出率为92.02%.当Na2SO4添加量为2.94%时,反应温度可降为1273K,此时钾溶出率可达92%～94%.对焙烧产物进行了XRD分析,得出其主要物相为:K2SO4、3CaO·Al2O3和2CaO·SiO2,与物料摩尔配比1:1:14所确定化学反应的产物相吻合.     

氯化钙和氯化钠分解钾长石提钾的动力学实验

采用焙烧法对添加氯化钙和氯化钠混合助剂的钾长石体系进行动力学实验,结果表明,改变反应温度、助剂用量和钾长石粒度,分解反应过程符合Ginstling-Brundshtein动力学方程,根据Arrhenius经验公式,求得分解反应表观活化能为58.6 kJ/mol,比氯化钙体系降低68.34 kJ/mol,比氯化钠体系降低...     

钾长石-磷矿-硝酸脲体系分解钾长石的探讨

详细研究了钾长石与磷矿、硝酸脲反应的提钾新工艺, 验证了钾长石-磷矿-硝酸脲体系分解钾长石提取有效钾的可行性。通过正交实验得到各因素对钾溶出率影响大小依次为：反应温度>硝酸用量>反应时间>尿素与硝酸物质的量比。得到适宜的工艺条件：尿素和硝酸物质的量比为1:1;5.5 mol/L的硝酸用量为4 mL;反应温度为120 ℃;反应时间为2 h。在此条件下有效钾的溶出率可达96.23%,水溶性钾溶出率可达29.65%。通过单因素寻优实验得出钾长石与磷矿、硝酸脲反应提取有效钾的适宜工艺条件：反应温度为105～115 ℃,硝酸用量约为4.7 mL,反应时间约为2 h。     

钾长石焙烧熟料的浸出动力学

以钾长石和Na2CO3焙烧熟料为原料,研究其在NaOH溶液中的浸出动力学. 考察了在不同温度和搅拌强度条件下SiO2浸出率与时间的关系. 结果表明,SiO2浸出的优化工艺条件为：浸出温度95℃、搅拌强度400 r/min、熟料粒度74~89 mm、NaOH溶液浓度0.2 mol/L和浸出时间80 min. 在该条件下,SiO2浸出率可达99%. 熟料浸出过程受无固体膜生成的化学反应和外扩散混合控制. 浸出过程分为两个阶段：0~10 min为反应前期,10~80 min为反应后期,表观活化能分别为15.24和29.94 kJ/mol. 前期和后期的浸出动力学方程分别为1-(1-a)1/3=7.074exp[-15239/(RT)]t和1-(1-a)1/3=45.85exp[-29940/(RT)]t.     

钾长石-磷矿-盐酸反应体系实验研究

建立钾长石-磷矿-盐酸反应体系,综合利用钾长石和磷矿,全面考察影响该体系磷、钾溶出率的各种因素。用过0．074mm标;住筛的钾长石和磷矿为原料,最适宜反应条件为：磷矿石与钾长石质量比为1,盐酸（1＋1）加入量为5．6mL／g钾长石,反应温度为200℃,反应时间在70min以上,此时钾和磷的溶出率都能达到90％以上。     

钾长石-硫酸钙-碳酸钙体系的热分解过程动力学研究

试验研究了钾长石-硫酸钙-碳酸钙体系[n(KAS6):n(CaSO4):n(CaCO3)=1:1:14]加入脱硫灰渣组分脱硫时的热分解反应动力学.结果表明:改变反应温度、脱硫灰渣组分和钾长石粒径,热分解过程均受金斯特林格模型固膜扩散控制;反应速率与钾长石初始粒径的平方成反比;添加脱硫灰渣组分有利于降低表观活化能,有利于利用脱硫灰渣热分解钾长石生产钾肥.     

钾长石-氧化钙-氢氧化钾体系提钾工艺研究

采用球磨反应和静态水热反应对钾长石-氧化钙-氢氧化钾体系提钾工艺进行了研究,结果显示：温度对钾长石提钾有较大的影响,静态水热反应提钾效果优于球磨反应.较适宜的静态水热反应工艺条件为：m（氧化钙）/m（钾长石）为1.5,m（钾长石）/m（氢氧化钾）为15,恒温220℃下反应10h,每克钾长石加水量为20 mL,此时钾溶出率达到90％以上.     

氯化钠熔浸钾长石提钾过程

对熔融氯化钠浸取钾长石的提钾过程进行了研究. 结果显示，最佳反应条件是：反应温度890~950℃；氯化钠与钾长石的质量配比为1；钾长石的粒径为0.208 mm以下. 动力学分析显示，过程由Na+和K+在钾长石内部的离子扩散控制，扩散系数与反应温度之间的关系服从Arrhenius公式，即Deff=D0exp(–Ea/RT)，其中，Ea=81.42 kJ/mol，D0=0.324 mm2/h.     

Ferroelectric Ceramics in the PbMg1/3Nb2/3O3-PbCd1/3Nb2/3O3 System

Solid solutions (1-x)PbMg_1/3Nb_2/3O₃ + xPbCd_1/3Nb_2/3O₃ with x = 0-0.30 are investigated with purpose to work out a capacitor ceramics with good dielectric properties and low sintering temperature. It is found that the perovskite phase forms at sintering near to 980°C and begins to decompose at higher temperatures. When x grows from 0 to 0.30, the Curie temperature linearly grows from -10°C to +25°C, the dielectric permittivity ε_m in the Curie point T_C decreases from 18000 to 6800 and the phase transition becomes more diffused. The dielectric permittivity at room temperature is rather high and the temperature stability is improved. The system is of interest, because it can serve as a base for working out some ceramic materials for capacitors with low sintering temperature, which needs of no special atmosphere at burning.     

3-溴甲基-3-甲基氧杂环丁烷的合成

以2,2-二溴甲基丙醇（BBMP）为初始原料,通过与碱发生关环反应生成3-溴甲基-3-甲基氧杂环丁烷（BrMMO）。讨论了碱的种类和用量对BBMP关环产率的影响以及反应体系中碱的浓度、反应温度和反应时间对合成BrMMO产率的影响。通过实验确定的最佳工艺条件为：BBMP与NaOH摩尔比为1.0∶1.1,NaOH醇溶液的质量分数为12%,反应温度为78℃,反应时间为4h时,BrMMO产率为65%。最终产品经元素分析、IR和1HNMR检测确定为BrMMO。该试验工艺简单,原料易得,且溶剂便于回收、污染小。     

3-叠氮甲基-3-甲基氧丁环的合成

以三羟甲基乙烷与碳酸二乙酯为原料,经环化反应合成了3-羟甲基-3-甲基氧丁环(HMM O)。在低温下,HMM O与对甲苯磺酰氯反应生成3-磺酸酯甲基-3-甲基氧丁环(M TM O)。M TM O和叠氮化钠发生叠氮化反应形成叠氮单体3-叠氮甲基-3-甲基氧丁环(AMM O)。三步反应收率分别为76%,96%,85%。用核磁、红外、元素分析和DSC表征了化合物的结构与性能。结构鉴定表明为目标化合物AMM O。     

3-溴甲基-3-甲基氧杂环丁烷的合成

以2,2-二溴甲基丙醇(BBMP)为初始原料,通过与碱发生关环反应生成3-溴甲基-3-甲基氧杂环丁烷(BrMMO).讨论了碱的种类和用量对BBMP关环产率的影响以及反应体系中碱的浓度、反应温度和反应时间对合成BrMMO产率的影响.通过实验确定的最佳工艺条件为:BBMP与NaOH摩尔比为1.0∶1.1,NaOH醇溶液的质量分数为12%,反应温度为78℃,反应时间为4 h时,BrMMO产率为65%.最终产品经元素分析、IR和1HNMR检测确定为BrMMO.该试验工艺简单,原料易得,且溶剂便于回收、污染小.     

The Preparation and Crystal Structure of TlMnCl3, TlFeCl3, TlCoCl3 and TlNiCl3

The compounds TlMnCl₃, TlFeCl₃, TlCoCl₃ and TlNiCl₃ were prepared by heating T1C1 with the corresponding transition metal dichloride in an evacuated ampoule. Atomic positions were determined from powder photographs. All four compounds were found to be related to the perovskite type structure. TlMnCl₃ has a cubic structure, space group Pm3m, with a_o = 5.025 Å. The other three compounds are hexagonal, probable space group P6₃mc, with cell dimensions (in Å) a₀ = 6.976 and c₀ = 6.008 for the Fe compound, a₀ = 6.907 and c₀ = 5.981 for the Co compound and a₀ = 6.863 and c₀ = 5.881 for the Ni compound. The three hexagonal compounds are isomorphous. A measureable concentration of basal plane stacking faults was found to occur in TlFeCl₃ and also, to a lesser degree, in TlCoCl_3.     

Tunable color emission in LaScO3:Bi3+,Tb3+,Eu3+ phosphor

LaScO₃:xBi³⁺,yTb³⁺,zEu³⁺ (x = 0 − 0.04, y = 0 − 0.05, z = 0 − 0.05) phosphors were prepared via high-temperature solid-state reaction. Phase identification and crystal structures of the LaScO₃:xBi³⁺,yTb³⁺,zEu³⁺ phosphors were investigated by X-ray diffraction (XRD). Crystal structure of phosphors was analyzed by Rietveld refinement and transmission electron microscopy (TEM). The luminescent performance of these trichromatic phosphors is investigated by diffuse reflection spectra and photoluminescence. The phenomenon of energy transfer from Bi³⁺ and Tb³⁺ to Eu³⁺ in LaScO₃:xBi³⁺,yTb³⁺,zEu³⁺ phosphors was investigated. By changing the ratio of x, y, and z, trichromatic can be obtained in the LaScO₃ host, including red, green, and blue emission with peak centered at 613, 544, and 428 nm, respectively. Therefore, two kinds of white light-emitting phosphors were obtained, LaScO₃:0.02Bi³⁺,0.05Tb³⁺,zEu³⁺ and LaScO₃:0.02Bi³⁺,0.03Eu³⁺,yTb³⁺. The energy transfer was characterized by decay times of the LaScO₃:xBi³⁺, yTb³⁺, zEu³⁺ phosphors. Moreover absolute internal QY and CIE chromatic coordinates are shown. The potential optical thermometry application of LaScO₃:Bi³⁺,Eu³⁺ was based on the temperature sensitivity of the fluorescence intensity ratio (FIR). The maximum S_a and S_r are 0.118 K⁻¹ (at 473.15 K) and 0.795% K⁻¹ (at 448.15 K), respectively. Hence, the LaScO₃:Bi³⁺,Eu³⁺ phosphor is a good material for optical temperature sensing.     

2,2,3-三氯-3-苯基-3-(3-甲基苯甲酰基)丙腈的合成研究

以苯甲酰氯、四氯化碳、间甲基苯甲酰氰为原料,合成了标题化合物。重点考察了氰化过程中不同原料配比、反应温度、时间、溶剂和催化剂用量对收率的影响。实验结果表明,其最佳反应条件为:n(1,1,2-三氯-2-苯基乙烯)∶n(3-甲基苯甲酰氰)=1∶1.2,二氯甲烷为反应溶剂,3 mmol催化剂三乙胺,室温反应5 h,总收率达80.6%。     

Thermal analyses of poly(3-hydroxybutyrate), poly(3-hydroxybutyrate-co-3-hydroxyvalerate), and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)

Thermal analyses of poly(3-hydroxybutyrate) (PHB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(HB–HV)], and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) [P(HB–HHx)] were made with thermogravimetry and differential scanning calorimetry (DSC). In the thermal degradation of PHB, the onset of weight loss occurred at the temperature (°C) given by T_o = 0.75B + 311, where B represents the heating rate (°C/min). The temperature at which the weight-loss rate was at a maximum was T_p = 0.91B + 320, and the temperature at which degradation was completed was T_f = 1.00B + 325. In the thermal degradation of P(HB–HV) (70:30), T_o = 0.96B + 308, T_p = 0.99B + 320, and T_f = 1.09B + 325. In the thermal degradation of P(HB–HHx) (85:15), T_o = 1.11B + 305, T_p = 1.10B + 319, and T_f = 1.16B + 325. The derivative thermogravimetry curves of PHB, P(HB–HV), and P(HB–HHx) confirmed only one weight-loss step change. The incorporation of 30 mol % 3-hydroxyvalerate (HV) and 15 mol % 3-hydroxyhexanoate (HHx) components into the polyester increased the various thermal temperatures T_o, T_p, and T_f relative to those of PHB by 3–12°C (measured at B = 40°C/min). DSC measurements showed that the incorporation of HV and HHx decreased the melting temperature relative to that of PHB by 70°C. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 90–98, 2001