Bioleaching of Iron, Copper, Lead, and Zinc from the Sludge Mining Sediment at Different Particle Sizes, pH, and Pulp Density Using Acidithiobacillus ferrooxidans

Abstract

Globally, the amounts of metal ore deposits have been declining, so the research directions investigating the extraction of metals from materials that are classified as waste are gaining more importance every year. High concentrations of Cu, Pb, Zn, and Fe were analyzed in the sludge sediment (Zlaté Hory, Czech Republic), which is a waste product of the mining industry. In the bioleaching process, bacterial cells have been established as being able to convert metals from solid to liquid phase. However, the most important parameters of bioleaching are particle size, pH, and pulp density, thus our research focused on their optimization. The acidophilic and mesophilic bacteria Acidithiobacillus ferrooxidans were applied due to the high Fe content in the sample. The recovery of metals in the leachate was determined by F-AAS and the residual metal concentrations in the waste fraction were analyzed by XRF. The grain size fractions <40 µm –200 µm were investigated. The atomic absorption spectrometry (AAS) results show that the highest Fe (76.48%), Cu (82.01%), and Pb (88.90%) recoveries were obtained at particle size of 71–100 μm. Zn was dissolved for all fractions above 90%. Experiments with different pH values were performed at a pH of 1.6–2.0. The highest dissolution rates of Zn, Fe, and Cu were achieved with a suspension pH of 1.8, where 98.73% of Zn, 85.42% of Fe, and 96.44% of Cu were recovered. Due to the high percentage dissolution of metals, experiments were performed under pilot conditions in a bioreactor at a pulp density of 2.5% and 4.2% (w/v). From an economic point of view, the leaching time of 28 days was evaluated as sufficient.

Extraction of Metals from Polluted Soils by Bioleaching in Relation to Environmental Risk Assessment

“…Rouchalova (2020) pointed out that particle size (71–100 μm), pH (1.8) and microorganism density (9K medium) are the most important parameters in achieving high depollution yields [ 31 ]. Groudev et al (2001) pointed out that microbial activity is the most important factor in Cu, Zn, Cd and As bioleaching, the exception being Pb [ 32 ].…”

“…Studies in the literature have shown that bioleaching is efficient for the extraction of metals from water treatment sludge (Cr 92.6%, Cu 80.6%, Fe 95.6%, Mg 91%, Ni 89.7%, Pb 99.5%, Zn 93% [ 33 , 34 , 35 ], Fe 76.5%, Cu 82%, Pb 89.9%, Zn 90%) [ 31 ] or from municipal and industrial waste [ 36 ]. Pyrotite bioleaching could increase Fe recovery by bacterial adaptation and biological contact oxidation [ 37 ], and Fe can be removed (18%) by adding 9K medium [ 38 ].…”

“…Results obtained in the literature regarding the bioleaching of metals from soils, obtained under similar experimental conditions (use of Thiobacillus microorganisms, sample agitation (120–170 rpm), extraction time (5–48 days) and temperature (28–30 °C)) have shown that good extraction yields can be obtained for: Cu: 44% [ 39 ], 46% [ 40 ], 20–73% [ 41 ], 72. 8% [ 42 ], 69–92% [ 43 ], 95% [ 44 , 45 ], 51–72% [ 46 ], 78% [ 47 ], 80.6% [ 33 , 34 , 35 ], 82% [ 31 ], 83% [ 48 ], 89–96% [ 49 ], 95–96% [ 50 ]; Pb: 10–54% [ 43 ], 16–60% [ 50 ], 18% [ 40 ], 33–72% [ 51 ], 39.4% [ 42 ], 75–84% [ 49 ]; Ni: 10–47% [ 50 ], 35–65% [ 51 ], 69–92% [ 43 ], 75–93% [ 49 ], 78% [ 40 ], 90% [ 33 , 34 , 35 ]; and Cr: 14% [ 40 ], 10–41% [ 43 ], 9–20% [ 51 ], 53–92% [ 49 ], 64% [ 39 ].…”

The Effects of Milling and pH on Co, Ni, Zn and Cu Bioleaching from Polymetallic Sulfide Concentrate

“…It has been shown that by decreasing the particle size, the specific surface area increases, and leaching is enhanced both by kinetics and yields [10][11][12] (Torma et al, 1972, Torma et al, 1977, Miller et al, 1999. However, results showing no clear benefits regarding additional milling have also been reported [13]. Moreover, too fine of a particle size has been considered inhibitory to bioleaching microorganisms (reviewed in [14,15]).…”

Study and Analysis on the Influence Degree of Particle Settlement Factors in Pipe Transportation of Backfill Slurry

“…There are many methods to study particle sedimentation: the bottom suction pipe method based on the Oden theory [10,11], repetition depth pipette method based on the McLaughlin formula [12,13], and sand sink method to study the effect of flow turbulence on the particle settling rate [14][15][16]. Some studies were conducted to perform sedimentation tests on a sediment suspension in a sedimentation cylinder, and formulae for the sedimentation rate were obtained [17,18]. Other studies analyzed experimental data to design a conical settlement cylinder and establish a settlement rate formula for nonuniform sand groups [19].…”