含锗煤烟尘造球粘结剂的选择

Selectionof Pelletizing Agglomerant for Germanium-Bearing Coal Dust

探索膨润土、淀粉、羧甲基纤维素、硅酸钠、水玻璃、氧化钙、丙烯酰胺等粘结剂对一次煤烟尘球团强度的影响。结果表明,淀粉、氧化钙和丙烯酰胺不能提高球团强度。羧甲基纤维素可以有效提高球团强度,但在焙烧过程中,羧甲基纤维素会被氧化分解掉,焙烧后的球团为粉末状。固体硅酸钠和液体水玻璃做粘结剂时,粘结剂与煤灰质量比接近1∶1时球团才能达到所需强度,加入量过多,且温度过高会造成球团的熔融,对锗的挥发率有一定影响。选择膨润土做粘结剂,加入量为烟尘的16%左右,球团强度好,对锗的挥发率基本没有影响,锗的挥发率可达99%以上,综合考虑用膨润土做粘结剂。

Effects of bentonite, starch, carboxymethyl cellulose, sodium silicate, water glass, calcium oxide and acrylamide on strength of primary coal dust pellets were investigated. The results show that starch, calcium oxide and acrylamide can not improve pellet strength. Though effectively improving pellet strength, carboxymethyl cellulose will oxygenolysis during roasting, and ball turns into powder. When applying solid sodium silicate and liquid water glass as binder, pellet can obtain required strength with mass ratio of binder to coal ash of 1 ： 1, but will melt with extreme high temperature and too much binder, exerting a certain impact on germanium volatilization rate. Pellets have good strength and germanium volatilization rate is 99% above when applying bentonite as binder with mass addition of 16% of dust. Bentonite is selected as binder.