Enhancing the sedimentation of clay-based tailings in seawater by magnesium removal treatment

Jeldres, Matías; Piceros, Eder; Toro, Norman; Robles, Pedro; Nieto, Steven; Quezada, Gonzalo R.; Jeldres, Ricardo I.

doi:10.1016/j.seppur.2020.116762

Cited by 17 publications

(9 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This phenomenon was later demonstrated by through molecular dynamics simulations [13]. Recently, Jeldres et al [14] proposed a strategy to improve flocculation efficiency in seawater by reducing the magnesium content of the seawater before introducing it to the process. It was suggested that the flocculation response was improved when the magnesium concentration was reduced because an increase in bridging flocculation between the particles was possible.…”

Section: Introductionmentioning

confidence: 94%

Analysis of Kaolin Flocculation in Seawater by Optical Backscattering Measurements: Effect of Flocculant Management and Liquor Conditions

Jeldres

MacIver

et al. 2020

Minerals

Self Cite

View full text Add to dashboard Cite

Optical backscattering (OBS) signal values were used to evaluate the flocculation of kaolin slurries and seek the implications of using seawater. Two anionic flocculants were applied to kaolin suspensions at several dosages and in water of varying pH and electrolyte concentration. An OBS height scan method was used to estimate the degree of aggregation, supernatant quality, and solids concentration of the sediments. The residual solids of the supernatant depended of the extent of particle coagulation before flocculant was added, where the pH and salinity displayed a significant impact on flocculation. The OBS results were highly sensitive to the presence of fine particles, which was estimated in parallel from the focused beam reflectance measurements (FBRM.) In seawater, without flocculant added, the samples had increased root-mean-square scattering (Frms) values and larger final sediment volume than samples prepared in water with lower electrolyte concentration. This indicates a higher initial state of aggregation of the particles in seawater. Then, the aggregation degree was best linked to the square-weighted chord length distribution of the FBRM data, which intensifies the sensitivity to coarse aggregates.

show abstract

Section: Introductionmentioning

confidence: 94%

Analysis of Kaolin Flocculation in Seawater by Optical Backscattering Measurements: Effect of Flocculant Management and Liquor Conditions

Jeldres

MacIver

et al. 2020

Minerals

Self Cite

View full text Add to dashboard Cite

show abstract

“…With this, it is suggested that the effort in the treatment of seawater be focused on removing Mg 2+ ions to reduce the presence of solid precipitates, but Ca 2+ does not show harmful effects. However, it is necessary to be careful with the selected treatment, since Jeldres et al [16] used lime to form the precipitates, which were subsequently removed by vacuum filtration. Although the authors focused on reducing the magnesium content, the remaining calcium concentration was over 2000 ppm.…”

Section: Calcium and Magnesium Influence In Settling Rate (Sr) And Turbidity (T)mentioning

confidence: 99%

Use of Radial Basis Function Network to Predict Optimum Calcium and Magnesium Levels in Seawater and Application of Pretreated Seawater by Biomineralization as Crucial Tools to Improve Copper Tailings Flocculation

et al. 2020

View full text Add to dashboard Cite

The combined use of the Radial Basis Function Network (RBFN) model with pretreated seawater by biomineralization (BSw) was investigated as an approach to improve copper tailings flocculation for mining purposes. The RBFN was used to set the optimal ranges of Ca2+ and Mg2+ concentration at different Ph in artificial seawater to optimize the performance of the mine tailings sedimentation process. The RBFN was developed by considering Ca2+ and Mg2+ concentration as well as pH as input variables, and mine tailings settling rate (Sr) and residual water turbidity (T) as output variables. The optimal ranges of Ca2+ and Mg2+ concentration were found, respectively: (i) 169–338 and 0–130 mg·L−1 at pH 9.3; (ii) 0–21 and 400–741 mg·L–1 at pH 10.5; (iii) 377–418 and 703–849 mg·L−1 at pH 11.5. The settling performance predicted by the RBFN was compared with that measured in raw seawater (Sw), chemically pretreated seawater (CHSw), BSw, and tap water (Tw). The results highlighted that the RBFN model is greatly useful to predict the settling performance in CHSw. On the other hand, the highest Sr values (i.e., 5.4, 5.7, and 5.4 m·h–1) were reached independently of pH when BSw was used as a separation medium for the sedimentation process.

show abstract

“…The authors achieved good recovery of molybdenite and chalcopyrite at an alkaline pH, promoting pyrite depression. Recently, Jeldres et al [ 26 ] studied thickening operations, finding that a lime removal treatment can improve the performance of the thickeners. The authors considerably increased the sedimentation rate of mineral tailings at pH 11, obtaining higher values than at natural pH.…”

Section: Introductionmentioning

confidence: 99%

“…More recently, Arias et al [ 27 ] proposed a biotechnological treatment to remove divalent ions from seawater, using a fluidized bed bioreactor completed with the halotolerant ureolytic strain Bacillus subtilis LN8B. These latest studies [ 26 , 27 ] have yielded promising results in reducing magnesium in seawater, opening up a new line of research that needs to be explored systematically.…”

Section: Introductionmentioning

confidence: 99%

Lime/Sodium Carbonate Treated Seawater to Improve Flocculation and Sedimentation of Clay-Based Tailings

et al. 2021

Self Cite

View full text Add to dashboard Cite

Seawater treated with lime and sodium carbonate in different proportions to reduce magnesium and calcium contents is used in flocculation and sedimentation tests of artificial quartz and kaolin tailings. Solid complexes were separated from water by vacuum filtration, and factors such as lime/sodium carbonate ratio, kaolin content, flocculation time, and flocculant dose are evaluated. The growth of the aggregates was captured in situ by a focused beam reflectance measurement (FBRM) probe. Solid magnesium and calcium complexes are formed in raw seawater at pH 11, impairing the performance of flocculant polymers based on polyacrylamides. The results show that the settling rate improved when the treatment’s lime/sodium carbonate ratio increased. That is, when a greater removal of magnesium is prioritized over calcium. The amount of magnesium required to be removed depends on the mineralogy of the system: more clay will require more significant removal of magnesium. These results respond to the structural changes of the flocs, achieving that the more magnesium is removed, the greater the size and density of the aggregates. In contrast, calcium removal does not significantly influence flocculant performance. The study suggests the necessary conditions for each type of tailing to maximize water recovery, contributing to the effective closure of the water cycle in processes that use seawater with magnesium control.

show abstract

Enhancing the sedimentation of clay-based tailings in seawater by magnesium removal treatment

Cited by 17 publications

References 41 publications

Analysis of Kaolin Flocculation in Seawater by Optical Backscattering Measurements: Effect of Flocculant Management and Liquor Conditions

Analysis of Kaolin Flocculation in Seawater by Optical Backscattering Measurements: Effect of Flocculant Management and Liquor Conditions

Use of Radial Basis Function Network to Predict Optimum Calcium and Magnesium Levels in Seawater and Application of Pretreated Seawater by Biomineralization as Crucial Tools to Improve Copper Tailings Flocculation

Lime/Sodium Carbonate Treated Seawater to Improve Flocculation and Sedimentation of Clay-Based Tailings

Contact Info

Product

Resources

About