Study on the impact of APAM residue on the settlement characteristics of coal slurry agglomerates

ABSTRACT

Residual dosage has a significant impact on the settling characteristics of coal slurry flocs and the sedimentation efficiency of coal slurry. This study conducted sedimentation stirring experiments to measure the supernatant grayscale, floc size, settling velocity, and residual anionic polyacrylamide (APAM) under varying energy inputs. The investigation focused on the correlation between different levels of APAM residual and the settling characteristics of coal slurry flocs. The results show that having APAM residuals in the first three stages helps with sedimentation. This leads to lower residual levels, higher grayscale in the supernatant, bigger floc sizes, and better settling velocities. However, in the fourth stage, as APAM residual levels increased once more, the supernatant grayscale decreased linearly, floc breakup became severe, and settling velocities neared stagnation. In the second stage, a correlation was noticed between higher APAM residual levels and better settling properties of coal slurry flocs. By studying residual dosage and energy input, guidance on how to optimize the sedimentation efficiency of the thickener and reduce dosage can be provided.

KEYWORDS:

• APAM residue
• grayscale
• floc size
• settling velocity
• energy input

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The authors gratefully acknowledge the support of the Anhui Provincial Excellent Young Scientific Research Project [Grant No. 2022AH030085], Anhui Provincial Key Research and Development Project [Grant No. 2022n07020001], Anhui Provincial Scientific Research Foundation for the Returned Overseas Chinese Scholars [Grant No. 2022LCX029], Anhui Province University Natural Science Research Major Project [Grant No. KJ2021ZD0046], and National Natural Science Foundation of China [Grant No. 52104242 and 52074014] for this work.