微细颗粒分离过程强化研究

STUDY ON THE SEPARATION PROCESS INTENSIFICATION OF MICRONIZED MINERAL PARTICLES 

周宝楠

11749203

硕士

化学工程

刘科

2019-05-25

2019-06-28

哈尔滨工业大学

深圳

微细矿物颗粒具有质量轻、比表面积大、表面能高以及组分复杂等特点，因此在分离过程中比大颗粒矿物更难进行分选。煤泥是来自于煤炭洗选加工所产生的固态废弃物，主要由可燃的煤炭颗粒与无机矿物质组成，无机矿物含量一般高于30%，粒度细，易泥化，难以分离其中的可燃组分。2017年，我国原煤入洗量达28.7亿吨，煤泥伴生量达4.31亿吨，随着我国原煤入洗量的不断增加，煤泥伴生量将会持续上升。而现有技术对于煤泥的分离效率低，且处理量有限。煤泥的大量堆积不仅会造成严重的环境污染问题，也会导致煤炭资源的损失。因此，细粒煤泥高效分离工艺的开发具有重要的学术意义及行业意义。本文将以平均粒度10-30μm、灰分高于50%的烟煤煤泥作为研究对象，对其分离过程进行研究。主要研究包括：（1）本文提出了基于强剪切调浆、柱浮选过程的预矿化-浮选工艺。该工艺使用强剪切设备将能量高效传递给矿浆中的微细颗粒，使其在强剪切条件下与药剂及气泡发生充分混合，完成矿化后进入浮选柱内进行分离。依据新型的工艺概念进行试验平台的搭建，建立处理量为4-18kg/h的60mm浮选柱装置进行工艺条件研究，并建立了处理量为40-140kg/h的200mm浮选柱装置进行工艺放大验证。200mm浮选柱的放大试验表明，在进料强度为1.33mm/s、淋泡水强度为0.8mm/s的条件下，精煤灰分可从51.03%下降到8.29%，尾煤灰分达71.55%，可燃体回收率达60.75%。（2）本文对于预矿化-柱浮选过程强化进行研究，表明精煤产品品位与可燃体回收率呈现出矛盾关系。通过单柱一次浮选，精煤灰分最低可达9.3%，可燃体回收率最高可达74%。根据金达煤泥在预矿化-浮选过程中的分离行为研究，提出了基于预矿化的三柱流程分离工艺。开路试验结果表明，在保证精煤产品灰分9.5%左右时，通过三柱流程可将可燃体回收率提升11%左右。（3）本文结合了MLA以及扫描电镜对金达煤泥及其分选精煤的矿物成分、嵌布关系展开分析。结果表明金达煤泥中矿物质主要以高岭石、石英、伊利石、方解石等为主，其中高岭石含量占总灰分含量的66%。在金达精煤中，四种无机矿物的脱除率均在80%以上，表明由夹带而造成的精煤污染被得到很好的控制。此外，通过电镜图像发现了强剪切对于颗粒表面的清洗作用。此作用有利于脱除细泥盖罩，增强浮选药剂与煤泥中可燃组分的接触，提升浮选效果。

Since micronized mineral particles have the characteristics of light weight, large specific surface area, high surface energy and complex composition, it is more difficult to be separated than large mineral particle in the separation process. Coal slime is solid waste generated from coal preparation plants and is mainly composed of combustible coal particles and inorganic minerals. The inorganic mineral content is generally higher than 30%. It is hard to move the inorganic mineral particles apart due to the sludging effect of micronized clay and the small particle size of coal slime. With the continuous increase of the washing rate of raw coal in China, the coal washing volume reached 2.87 billion tons, which produced 431 million tons of coal slime. The production of coal slime is continuing to increase till now. However, the low efficiency and low capacity of the process of coal slime separation leave massive of coal slime wasted and stacked all around coal preparation plants, which causes serious environmental pollution. Besides, the combustible component in the coal slime could be wasted due to the low efficiency of recovery methods. Therefore, the development of high-efficiency separation process of micronized coal slime has important academic significance and industry significance.In this paper, the bituminous coal slime with an average particle size of 10-30μm and ash content higher than 50% is taken as the research object, and the separation process is studied. The main research includes:1) A high-shear pre-mineralization flotation process based on high-shear slurry mixing and column flotation process was proposed. The process uses strong shearing equipment to efficiently transfer energy to the micronized particles in the slurry, so that it is fully mixed with the reagents and bubbles under strong shear conditions. After mineralization, it enters the flotation column for separation. According to the new process flow, the test platform was built, and a 60mm flotation column device with a capacity of 4-18kg/h was established to study the pre-mineralization-flotation process. The 200mm flotation column unit with a capacity of 40-140kg/h was established for scale-up verification. The scale-up test of the 200mm flotation column shows that the ash content of the overflow can be reduced from 51.03% to 8.29% and the ash content of tailing is 71.55% under the conditions of feed strength of 1.33mm/s and spray water strength of 0.8mm/s. The combustibles recovery is 60.75%.2) In this paper, the pre-mineralization-column flotation process intensification study shows that the clean coal product grade and the combustible recovery show a contradiction. Through single-column flotation, the clean coal ash is as low as 9.3%, and the combustible recovery rate is up to 74%. According to the separation behavior of Jinda slime in pre-mineralization-flotation process, a three-column separation process based on pre-mineralization was proposed. The open circuit test results show that the combustible recovery can be increased by about 11% through the three-column process when the ash content of the clean coal product is about 9.5%.3) In this paper, MLA (Mineral Liberation Analysis) and scanning electron microscopy are used to analyze the mineral composition and inlay relationship of Jinda coal slime and its sorted clean coal. The results show that the minerals in Jinda coal slime are mainly kaolinite, quartz, illite and calcite, and the kaolinite content accounts for 66% of the total ash content. In Jinda clean coal, the removal rate of the four inorganic minerals is above 80%, and the liberation degree decreases, indicating that the fine coal pollution caused by entrainment is well controlled. In addition, the cleaning effect of strong shear on the surface of the particles was found by electron microscopy images. This effect is beneficial to remove the fine mud cover, enhance the contact between the flotation agent and the combustible components in the slime, and enhance the flotation effect.

高灰煤泥 微细颗粒 预矿化 浮选 MLA 多柱流程

high ash content coal slime micronized particles pre-mineralization flotation MLA   multiple stage flotation process 

中文

联合培养

南方科技大学

周宝楠. 微细颗粒分离过程强化研究[D]. 深圳. 哈尔滨工业大学,2019.