Investigation of flocculation properties and floc structure of coal processing plant tailings in the presence of monovalent and divalent ions


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Güngören C. , Kurşun Ünver İ. , Özdemir O.

Physicochemical Problems of Mineral Processing, cilt.56, ss.747-758, 2020 (SCI Expanded İndekslerine Giren Dergi)

  • Cilt numarası: 56 Konu: 5
  • Basım Tarihi: 2020
  • Doi Numarası: 10.37190/ppmp/125070
  • Dergi Adı: Physicochemical Problems of Mineral Processing
  • Sayfa Sayıları: ss.747-758

Özet

Low-rank coals are generally processed with wet methods including washing, flotation, etc.

Fine-sized tailings of these processes are discharged to tailing ponds with a significant amount of

associated water which contains a high amount of dissolved ions. These tailings should be dewatered

employing coagulation/flocculation in terms of technological and environmental aspects. In this study,

the coagulation/flocculation behavior of coal processing plant tailings obtained from Manisa, Turkey

was investigated in the presence of monovalent (Na+, K+) and divalent (Mg2+, Ca2+) ions and an anionic

flocculant (SPP-600). First, the coagulation properties of coal tailings were determined. Then, the

flocculation experiments were carried out, and the turbidity values of the suspensions were measured.

Moreover, the sizes of the flocs were determined using a laser diffraction particle size analyzer to

analyze the strength of the flocs. The results of the coagulation experiments showed that while divalent

ions were more effective at 10-1 mol/dm3, higher settling rate and lower turbidity values were obtained

in the presence of monovalent ions at 1 mol/dm3 concentration. The optimum flocculant dosage was

obtained as 150 g/Mg from flocculation experiments. The floc size and strength measurements

indicated that larger flocs were obtained with Na+ than Ca2+ in the presence of the flocculant. The

strongest flocs were obtained at 10-1 mol/dm3 Ca2+ + 150 g/Mg flocculant. It can be concluded from this

study that the coagulation followed by the flocculation method can be employed to obtain fast

flocculation behavior and low turbidity for the dewatering of coal tailings.