Increasing the Efficiency of Vacuum Belt Filter in Gol-E-Gohar Iron Ore Concentrate Production by Adding Surfactants

In this research, filtration experiments were carried out by four types of surfactants as filter aid. Sodium dodecyl sulfate and sodium lauryl ether sulfate as anionic surfactant (SDS and SLES), polyethylene glycol as nonionic surfactant (PEG) and cetyl trimethylammonium bromide as cationic surfactant (CTAB) were used to were used in order to evaluate their effects on moisture reduction of concentrate and improvement of the filtration process. All of the tests were done at the optimal conditions include 60 KPa vacuum pressure, 120 s filtration time, 105 microns particle size and 60% (w/w) solid content of pulp. Results showed that in all of the tests, cake moisture decreased by adding surfactants; however, anionic surfactants SDS and SLES were better than other chemicals. By adding 100 g/t SDS and SLES to the pulp, the filter cake moisture content was reduced by 2%. SDS and SLES improves filtration performance by increasing the ratio of throughput to moisture. At the concentration of 100 g per ton SDS and SLES, the highest throughput and lowest moisture was achieved. Although both of SDS and SLES have similar chemical structure and action, SLES was selected due to better solubility in hard water, economic justification and availability.

Ammoniacal Carbonate Leaching: Effect of Dissolved Sulfur in the Distillation Operation

The distillation process in the Ammoniacal Carbonate Leaching technology was studied at bench-scale and on industrial scale. The dissolved sulfur effect in the Product-liquor that feeds to the columns, on the Basic Nickel Carbonate (BNC) properties and the operation expenses was determined. When increasing the sulfur in the liquor, we augment the selectivity towards the sulfate formation in the BNC molecule; therefore the energy consumption to the BNC thermal decomposition in the calcination process increases. Also, the nickel dissolved in the columns effluent increases due to complex reaction with [SO42–] and [S2O32–] ions, thus the expenses for consumption precipitation reagent increase too. Feeding carbonated liquor in the range 1.60 ≤ NH3/CO2 < 1.80 and CO2-rich solution increases the CO2 in the BNC with decreasing in sulfate; then, the mean diameter particle increases, the filtration resistance and the cake moisture diminish, which augments the productivity and reduces the energy consumption in the process of filtration and calcination. Keeping a pH between 8.4 and 8.7 in the columns outlet the greatest economic benefit is obtained of 0,125 ($ · h–1) per (m3 · h–1) of Product-liquor.

Chitosan Modified Cationic Polyacrylamide Initiated by UV-H2O2 for Sludge Flocculation and New Insight on the Floc Characteristics Study

In the present study, a novel graft modified flocculant CTS-g-PAMD was synthesized and applied to conduct sludge conditioning and dewatering. CTS-g-PAMD was copolymerized with AM, DMC and chitosan (CTS) under UV-H2O2 initiation. In addition, the effects of single factor experiments on the molecular weight (MW) CTS grafting efficiency (GE) of CTS-g-PAMD were determined and the optimal copolymerization conditions were achieved. The GE of CTS-g-PAMD reached 91.1% and the MW was 4.82 × 106 Da. As revealed from the characterized results of Fourier-transform infrared spectra (FT-IR), 1H/ NMR, X-ray diffraction (XRD), scanning electron microscopic (SEM) and X-ray photoelectron spectroscopy (XPS), the successful synthesis of CTS-g-PAMD was confirmed, which is considered to be conducive to explaining sludge dewatering performance. Under the optimal conditions (pH = 7.0, flocculant dosage = 35 mg/L), the best flocculating performance (FCMC: 73.7%; SRF: 4.7 × 1012 m·kg−1, turbidity: 9.4 NTU) and large and dense sludge flocs (floc size d50 = 379.142 µm, floc fractal dimension Df = 1.58) were formed. The DMC and CTS chain segments exhibiting cationic properties significantly improved the positive charge density and enhanced the electrical patching effect of CTS-g-PAMD. The long molecular chain of CTS-g-PAMD exhibited superior extensibility, which enhanced bridging effect on adsorption. Moreover, the sludge floc after undergoing CTS-g-PAMD conditioning exhibited robust shear resistance and regeneration ability. After the sludge floc was crushed and broken, a large and dense sludge floc was formed, helping significantly reduce the sludge specific resistance (SRF), turbidity and cake moisture content (FCMC) and enhance the sludge dewatering effect. The novel CTS-g-PAMD flocculant shows promising practical applications and high market value.

Effects of Moringa Peregrina and Ferric Chloride (FeClƒ ) On Water Treatment Sludge Dewatering

In the present study, an active component of Moringa peregrine (MP) was used in comparison with ferric chloride (FeCl₃) for the conditioning of water treatment sludge. The comparison was based on dewatering characteristics of the conditioned sludge determined by capillary suction time (CST), specific resistance to filtration (SRF), tests of time of filtration (TTF) and sludge cake moisture content. The results indicated that MP showed relatively comparable conditioning effect as ferric chloride. Sludge conditioned with ferric chloride, showed better results than MP. According to CST, SRF and tests of time of filtration (TTF) and sludge cake moisture content results, optimum dose for MP, and ferric chloride was 100 ml/l. From the results of the study it could be concluded that MP alone could be effectively used and replace ferric chloride for dewatering of water treatment sludge.