Double Injection Synthesis and Dispersion of Submicrometer Barium Titanyl Oxalate Tetrahydrate

A modified Clabaugh method has been used to produce a well-dispersed barium titanyl oxalate tetrahydrate (BTO) powder with a particle size of less than 0.2 μm. Production of the BTO powder is based on a double injection system, with reactants rapidly mixed using pressurized gas. The mixture resulting from the double injection of the reactants was subsequently quenched into a solution containing polyethyleneimine as a dispersant. The resulting dispersed BTO powder forms a suspension that is stable against coarsening or aggregation for greater than 1400 h. The dispersed BTO powder was also shown to produce BaTiO₃ with a particle size of 0.25 μm or less after calcination.     

Effect of Magnesium Ions on the Adsorption of Poly(acrylic acid) onto Alumina

The adsorption isotherms of poly(acrylic acid) (PAA) onto alumina powder have been determined as a function of pH, ionic strength, and magnesium-ion concentration. The adsorption of PAA is strongly enhanced by magnesium ions in alkaline media but less affected under acidic conditions. The adsorption isotherms display a maximum when PAA is fully complexed with magnesium ions in the solution, corresponding to a ratio of 0.25 ± 0.05 [Mg²⁺]/[acrylic acid monomer]. The decrease in adsorbed amount with an increase in PAA concentration at constant magnesium-ion concentration is related to a decrease in the complexation ratio.     

有机分散剂对含碳酸盐铁矿石浮选的影响研究

目的在于确定能够有效分散含碳酸盐铁矿石的分散剂。通过有机分散剂种类及用量条件试验,确定了最佳分散剂为NMS-3,其最佳用量为200 g/t。制定了适合选别东鞍山含碳酸盐混合磁选精矿的一次粗选、两次精选、一次扫选的分散浮选工艺流程。闭路试验获得了品位66.37%、回收率75.00%的铁精矿。该浮选指标良好,且工艺流程简单。论文运用DLVO理论对NMS-3分散机理进行了初步探讨,为含碳酸盐铁矿石的有效利用提供理论基础。     

分散剂对低阶煤制备高浓度气化水煤浆的影响

甘肃华亭煤为低阶煤,内水含量高,制浆浓度较低,在气化过程中比煤耗、比氧耗增加,影响煤气化企业的经济效益。文章选择NF水煤浆分散剂(NF)、渭化水煤浆添加剂(WH)、木质素磺酸钠(SL)、日本JM添加剂(JM)等4种水煤浆分散剂,利用红外光谱对4种水煤浆分散剂的有机结构进行表征,考察分散剂对华亭煤的制浆性能的影响。不同水煤浆分散剂对华亭煤具有选择性,WH对华亭煤的制浆效果最好,通过改变分散剂及添加量为0.4%时,华亭煤制浆浓度从61%提高到65%。     

差异预处理对竹浆纤维分散性能的影响行为研究

纸浆纤维的分散性能直接影响机械法均质制备纳米纤维素的效率。本研究分析了生物酶解预处理、TEMPO氧化预处理和PFI磨浆预处理对竹浆纤维分散性能的影响。通过表征预处理纤维的表面形态和表面电荷，探讨了引起竹浆纤维分散性能差异的原因。结果表明，TEMPO氧化预处理和PFI磨浆预处理的竹浆纤维分散性好，生物酶解预处理的竹浆纤维分散性差；PFI磨浆预处理的纤维表面分丝帚化好；TEMPO氧化预处理的纤维具有较高的羧基含量和Zeta电位绝对值；0.5%CMC分散剂可以显著提高生物酶解预处理纤维的分散性。