Optimization of Coal Washery Tailings by Flotation Process

Changliang Shi,Shengnan Wang,Gan Cheng

doi:10.3390/en12203956

Abstract

Flotation tailings are by-products of coal preparation plants, which do not only occupy cultivated land but also cause pollution. The high ash content and low calorific value of tailings limit their applications. Deashing is the precondition for the reutilization of flotation tailings. However, it is more difficult to remove ash content from flotation tailings compared with raw coal. Based on the analysis of coal properties, the flotation performance of different collectors was compared in this study. Flotation flows and the mechanism of depressants were explored. The optimized flotation conditions were as follows: pulp concentration of 100 g/L, inflation rate of 0.25 m3/(m2·min), collector (C4) dosage of 300 g/t, frother dosage of 500 g/t, and revolving speed of 2200 rpm. The ash content of clean coal was also reduced by adding a depressant. The flotation performance was best when the amount of sodium hexametaphosphate (used as the depressant) was 4 kg/t; the recovery of clean coal was 71.88%, and the ash content was 10.64%.

Highlights

Coal is one the world’s most important sources of energy [1,2], and its share in the global fuel and energy balance makes up 25–35% [3]
Shi [22] compared the performances of classified flotation with conventional flotation, and the findings revealed that the flotability of each particle size was improved with classified flotation
The collectors were labeled as Collector 1 (C1), Collector 2 (C2), Collector 3 (C3), and Collector 4 (C4)

Summary

Introduction

Coal is one the world’s most important sources of energy [1,2], and its share in the global fuel and energy balance makes up 25–35% [3]. 30%, and tailing coal yield was estimated as 30%, representing an increase of about 180 million tons in flotation tailing If these flotation tailings are not effectively treated, they will become one of the main pollution sources in the environment [8,9]. It is necessary to optimize the recycling of flotation tailings, which will improve economic benefits and save resources and protect the environment [10]. It will provide a technical guarantee for exploring the sustainable development of the coal industry

Methods

Results

Conclusion