微纳HIP乳液对矿物颗粒表面改性作用研究

SURFACE MODIFICATION OF MINERAL PARTICLES VIA MICRO-NANO HIGH INTERNAL PHASE (HIP) EMULSION

唐云敏

11849232

硕士

化学

刘科

2020-05-30

2020-06-08

哈尔滨工业大学

深圳

原煤的清洁化加工，产生了大量高灰、细粒煤泥。传统捕收剂用于高灰细粒煤泥的浮选时，存在药剂耗量大和分选效率低等问题。对传统捕收剂进行乳化处理可以有效降低药剂用量，比如水包油型乳化捕收剂已有大量报道。本论文通过对传统捕收剂进行乳化处理，制备得到一种新型油包水高内相（High Internal Phase, HIP）乳液捕收剂，在其性质分析的基础上，探讨了HIP乳液的配比对其捕收性能的影响，研究了其在高剪切下的絮团规律和浮选动力学，并对HIP乳液的煤泥絮团浮选工艺条件进行了优化。采用显微镜、电导率仪和旋转流变仪等仪器探究了HIP乳液的微观结构、稳定性和流变性。显微镜的观测表明，HIP乳液分散相液滴粒径在1~10 μm，流变性研究发现HIP乳液属于非牛型流体中的假塑性流体。通过将HIP乳液置于水中并高速搅拌，探讨了HIP乳液的稳定性和分散性，结果表明HIP乳液在搅拌20 s后，80%以上的内相盐溶液会释放，形成一种均匀的、具有较高流动性的乳液，同时含有原HIP乳液的碎片。采用絮团分选法对HIP乳液的配比进行了优化。以金达煤泥为实验煤样（灰分≈52%，粒度d50≈8 μm），考察了司班80和煤油体积比，氯化钠浓度、硫酸钠浓度和氯化钾浓度对HIP乳液捕收性能的影响。同时考虑分选结果和药剂成本，确定HIP乳液最佳配比为司班80和煤油体积比为3:5，无机盐溶液为0.3 mol/L硫酸钠溶液。考察了浮选之前的剪切调浆搅拌转速和浮选时间对HIP乳液的絮团-浮选的影响。结果表明，增大搅拌转速可以增强浮选效率，适当延长浮选时间可以在显著增大可燃体回收率的同时保证精煤产品的质量。采用激光粒度仪检测絮团粒径，讨论了不同高剪切时间对煤泥絮团粒径的影响，研究了HIP乳液和煤油的絮团能力。结果表明，HIP乳液的絮团能力强于煤油，20 s左右的高剪切预处理可以取得最高可燃体回收率，大于20 s时在保证较高可燃体回收率的同时能够降低精煤灰分。通过对比HIP乳液和煤油浮选效果，对HIP乳液的经济性进行了评价。与煤油相比，HIP乳液可以节约90%捕收剂用量。考察了HIP乳液对矿浆表面张力的影响，对浮选过程进行了浮选动力学模型的拟合。结果表明，HIP乳液可降低矿浆表面张力，一级矩阵分布模型对HIP乳液的浮选动力学具有最佳拟合度。

The clean processing of raw coal produces a large amount of high ash content, fine-grained slime. When the traditional collectors were used in the flotation processes for the above mentioned coal slime, the large consumption of reagents and low separation efficiency emerge as very challenging problems. The emulsification treatment of traditional collectors could effectively reduce the dosage of reagent. For example, oil-in-water emulsion collectors have been widely reported. In this paper, a novel collector of water-in-oil high internal phase (HIP) emulsion was prepared by emulsifying the traditional collector. Based on the analysis of its properties, the effects of the HIP recipe on its flocculating ability was studied, and the flocculating pattern as well as flotation kinetics under high-shear stirring were also discussed. The employment of HIP emulsion for floc-flotation process was optimized to achieve the best separation efficiency. By using microscope, conductivity meter and rotary rheometer etc., the internal microstructure, stability and rheology of HIP emulsion were studied. The observation by microscope showed that the diameters of internal dispersed phase were in the range of 1~10 µm. The rheology test demonstrated that the HIP emulsion was non-Newtonian pseudo-plastic fluid. The stability and dispersion of HIP emulsion were studied by stirring HIP emulsion in water with high speed, the result of which showed that over 80% of internal salt solution phase would be released after 20 seconds stirring and subsequently transformed into an emulsion of homogeneity and flowability accompanied with original HIP emulsion fragments. Taking Jinda coal slime as the experimental coal sample (ash content on air-dried basis is ~52% and averaged particle size of d50 is ~8 μm), the recipe of HIP emulsions was optimized by evaluating its performance in the floc-separation process. The volume ratio of Span80 and kerosene, concentrations of NaCl, Na2SO4 and KCl were considered. With the floc-separation performance and economy as the optimizing target, the HIP emulsion of 3:5 volume ratio of Span 80 and kerosene, 0.3 mol/L sodium sulfate solution was identified. The stirring speed for slurry conditioning and flotation time were investigated on the HIP emulsion floc-floatation process. The results showed that a higher stirring speed could benefit the separation efficiency and a proper elongation of the flotation time could significantly improve the combustible recovery with a satisfying ash content of product. By laser particle size analyzer, the effects of stirring time on the variation of floc size using HIP emulsion and kerosene were studied, the results showed that the flocculating ability of HIP emulsion was stronger than kerosene, and high shear pretreatment of about 20 s would lead to the highest recovery of combustibles with HIP emulsion. When the time of high shear pretreatment was longer than 20 s, the ash content of clean coal would be reduced with a high recovery of combustibles. Compared with kerosene, the HIP emulsion could save 90% of the amount of collector. The effect of HIP emulsion on the interfacial tension of slurry was studied and various flotation kinetic models were employed to predict the flotation behavior, the results showed that the HIP emulsion could reduce the interfacial tension of slurry and the first order matrix distribution kinetic model fitted best.

乳液 高内相 絮团 浮选 煤泥

emulsion high internal phase (HIP) flocculation flotation coal slime

中文

联合培养

南方科技大学

唐云敏. 微纳HIP乳液对矿物颗粒表面改性作用研究[D]. 深圳. 哈尔滨工业大学,2020.