煤液化残渣萃余物(ER)是指煤直接液化残渣通过萃取手段得到重质油和沥青后剩余的物质,约占原煤量的15%。利用扫描电镜(SEM)观察到萃余物表面疏松多孔的结构,通过浮选手段降低灰分后,可用于制作活性炭。由于萃余物中重质油和沥青附着在未反应煤表面导致萃余物中各种物质均具有无差别的疏水性,难以进行浮选,因此采用热处理手段将重质油及沥青脱除,使萃余物整体疏水性降低,增加疏水性的未反应煤和亲水性的硅铝酸盐矿物及催化剂(Fe7S8)之间的差异性。重质油和沥青经热处理去除后,剩余的硅铝酸盐矿物及催化剂等具有亲水性,仍保留在未反应煤的孔隙和表面,因此采用超声处理手段将这些亲水性物质去除,暴露出未反应煤的疏水性表面,此时萃余物疏水性增加,煤与亲水性杂质之间的差异性增大,有利于浮选。对处理前后的萃余物进行浮选试验,结果表明:萃余物原样难以浮选,在马弗炉中260℃焙烧1h后的萃余物可以浮选。在热处理的基础上进行超声处理,随超声处理时间增加,精煤产率呈上升趋势,灰分呈下降趋势。超声处理10min的萃余物浮选精煤产率为58.20%,灰分为23.63%,相比仅经过热处理的萃余物,浮选精煤产率提高17.80%,灰分降低2.88%。热处理及超声处理均对浮选有促进作用。采用扫描电镜和DSA100接触角分析仪分别对超声处理前后萃余物的表面特性进行检测分析。通过扫描电镜观察到萃余物表面黏结有大量杂质,随超声处理时间增加,表面杂质逐渐减少,接触角逐渐增大,疏水性增加。扫描电镜及接触角分析均支持浮选结果。

Extraction residue of coal liquefaction residue (ER) refers to the substance remaining after obtaining heavy oil and asphaltthrough extraction from coal direct liquefaction residue, accounting for about 15% of the original coal amount. By using scanning electron microscopy (SEM) to observe the loose and porous structure on the surface of the ER, the ash content can be reduced by flotation,and it can be used to produce activated carbon. Due to the adhesion of heavy oil and asphalt to the surface of unreacted coal in the extract,various substances in the ER have indistinguishable hydrophobicity, making flotation difficult. Therefore, heat treatment was used to remove heavy oil and asphalt, reducing the overall hydrophobicity of the ER and increasing the difference between unreacted coal with hydrophobicity and hydrophilic silicate minerals and catalysts (Fe7S8). After heat treatment to remove heavy oil and asphalt, the remainingsilicate minerals and catalysts remain hydrophilic and remain in the pores and surface of unreacted coal. Therefore, ultrasonic treatmentwas used to remove these hydrophilic substances, exposing the hydrophobic surface of unreacted coal. At this time, the hydrophobicity ofthe ER increases, and the difference between coal and hydrophilic impurities increases, which is beneficial for flotation. Flotation testswere conducted on the EER before and after treatment. The results shows that it is difficult to perform flotation on the original sample of theER. The ER after calcination at 260 ℃ for 1 hour in a muffle furnace can be subjected to flotation. On the basis of heat treatment, ultrasonic treatment was carried out. With the increase of ultrasonic treatment time, the clean coal yield shows an upward trend and theash content shows a downward trend. The flotation clean coal yield and ash content of the ER treated with ultrasound for 10 minutes are58.20% and 23.63%, respectively. Compared with the ER treated only with heat, the flotation clean coal yield increases by 17.80% andthe ash content decreases by 2.88%. Both heat treatment and ultrasonic treatment have a promoting effect on flotation. Scanning electron microscopy and DSA100 contact angle analyzer were used to detect and analyze the surface characteristics of the ER before and afterultrasonic treatment. Through scanning electron microscopy, it is observed that there are a large number of impurities adhered to the surface of the ER. As the ultrasonic treatment time increases, the surface impurities gradually decreases, the contact angle gradually increases, and the hydrophobicity increases. Scanning electron microscopy and contact angle analysis both support the flotation results.

0 引言

1 萃余物基本性质

   1.1 试验样品

   1.2 萃余物化学成分

   1.3 萃余物工业分析及元素分析

   1.4 X射线衍射分析（XRD）

   1.5 萃余物微观结构

   1.6 热重分析

   1.7 粒度分析

2 试验结果与分析

   2.1 热处理浮选效果分析

   2.2 超声处理浮选效果分析

   2.3 多次浮选降灰试验

   2.4 描电镜结果与分析

   2.5 接触角结果与分析

3 结论