Abstract:

In this paper, a new type of waterflow classifier device that can adjust the impeller speed and the upward water velocity without chemicals was adopted, which could avoid the large consumption of reagents and low efficiency of sorting during the traditional flotation. Characteristics of the product obtained by separating the residual carbon from gasification fine slag by using three methods: direct water flow classification (DWFC), screening and then step-by-step classification (SWFC), and screening a wider particle size (>0.074 mm) and then waterflow classification were examined. The results demonstrated that the floating slag yield increases with the increase of impeller speed and water velocity, while the loss on ignition (LOI) of the floating slag increased first and then decreased. Compared with DWFC, SWFC can avoid the problem of difficult separation of the fine particles (<0.074 mm), thus can significantly improve the efficiency of the carbon separation. By using wide particle size (>0.074 mm) screening and optimizing the water flow classification conditions, the scum extraction loss on ignition can reach 84.44%, the combustible body recovery rate can reach 65.85%, and the comprehensive efficiency can reach 43.39%. This research confirmed that by pre-screening and then waterflow classification, the residual carbon in the coal gasification slag could be efficiently recovered.

Key words: gasification, fine slag, separation, flotation, waterflow classifier

摘要：

针对传统浮选存在药剂消耗量大，分质效率低等问题，采用无须添加药剂，通过叶轮搅拌和上升水流作用分选的新型水流分级装置，考察了直接水流分级、先筛分再逐级分级以及宽粒级水流分级对水煤浆煤气化细渣的提炭分质特性。结果显示，水流分级的浮渣产率随叶轮转速、水流速增加而增加，浮渣烧失量则呈先增加后降低趋势。相较于直接水流分级，对气化渣先筛分再水流分级可避免灰渣细颗粒（<0.074 mm）中炭灰难以有效分离的问题，从而显著提升其提炭效率。采用宽粒级（>0.074 mm）筛分，再对水流分级条件优化，可实现提取浮渣烧失量达84.44%，可燃体回收率达65.85%，综合效率达43.39%。本研究表明通过预筛分再水流分级，可实现煤气化渣的高效提炭分质。

关键词: 气化, 细渣, 分离, 浮选, 水流分级