scholarly journals Immobilization of fluorides from spent carbon cathode in a copper smelting slag

2021 ◽  
pp. 54-54
Author(s):  
L. Li ◽  
G.-D. Wu ◽  
F.-G. Tian
Keyword(s):  
Chemical Analysis ◽  
Melting Temperature ◽  
Thermodynamic Analysis ◽  
Residence Time ◽  
Flow Rate ◽  
Molten Copper ◽  
Copper Smelting ◽  
Carbon Cathode ◽  
Smelting Slag ◽  
N2 Flow Rate

The fluorides from spent carbon cathodes could be effectively solidified in a molten copper smelting slag (FeO-Fe3O4-SiO2-CaO-Al2O3) in forms of CaF2 and Ca4Si2F2O7. The results of thermodynamic analysis, chemical analysis, and XRD and EPMA analyses showed that the F solidification efficiency increased with the CaO amount and decreased with the addition of Al2O3 and SiO2. In addition, it was noteworthy that the F solidification efficiency decreased with an excessive CaO amount, which could be ascribed to the consumption of SiO2 through forming CaSiO3 and Ca3Si2O7. It restricted the solidification of the fluoride into Ca4Si2F2O7. Under the conditions of melting temperature of 1300?C, residence time of 60 min and N2 flow rate of 40 ml/min, the optimum CaO and NaF amounts were found to be 20 wt.% and 6 wt.% respectively, in which the F solidification efficiency in the copper smelting slag of FeO-Fe3O4-SiO2-CaO-Al2O3 obtained 98.35%.

Removal of trichloroethylene and trichloroethane using a novel hollow-fibre gas-permeable membrane

2003 ◽  
Vol 3 (5-6) ◽  
pp. 67-72
Author(s):  
S. Takizawa ◽  
T. Win
Keyword(s):  
Boundary Layer ◽  
Flow Regime ◽  
Removal Efficiency ◽  
Residence Time ◽  
Flow Rate ◽  
Air Flow ◽  
Hollow Fibre ◽  
Permeation Rate ◽  
Permeable Membrane ◽  
Diffusional Boundary Layer

In order to evaluate effects of operational parameters on the removal efficiency of trichloroethylene and 1,1,1-trichloroethene from water, lab-scale experiments were conducted using a novel hollow-fibre gaspermeable membrane system, which has a very thin gas-permeable membrane held between microporous support membranes. The permeation rate of chlorinated hydrocarbons increased at higher temperature and water flow rate. On the other hand, the effects of the operational conditions in the permeate side were complex. When the permeate side was kept at low pressure without sweeping air (pervaporation), the removal efficiency of chlorinated hydrocarbon, as well as water permeation rate, was low probably due to lower level of membrane swelling on the permeate side. But when a very small amount of air was swept on the membrane (air perstripping) under a low pressure, it showed a higher efficiency than in any other conditions. Three factors affecting the permeation rate are: 1) reduction of diffusional boundary layer within the microporous support membrane, 2) air/vapour flow regime and short cutting, and 3) the extent of membrane swelling on the permeate side. A higher air flow, in general, reduces the diffusional boundary layer, but at the same time disrupts the flow regime, causes short cutting, and makes the membrane dryer. Due to these multiple effects on gas permeation, there is an optimum operational condition concerning the vacuum pressure and the air flow rate. Under the optimum operational condition, the residence time within the hollow-fibre membrane to achieve 99% removal of TCE was 5.25 minutes. The log (removal rate) was linearly correlated with the average hydraulic residence time within the membrane, and 1 mg/L of TCE can be reduced to 1 μg/L (99.9% removal).

Sorption and desorption of phosphorus by shale: batch and column studies

2010 ◽  
Vol 61 (3) ◽  
pp. 599-606 ◽  
Author(s):  
Johnsely S. Cyrus ◽  
G. B. Reddy
Keyword(s):  
Residence Time ◽  
Flow Rate ◽  
Nutrient Release ◽  
Phosphorus Sorption ◽  
Column Studies ◽  
Desorption Process ◽  
Low Concentrations ◽  
Sorbent Materials ◽  
High Concentrations ◽  
The Cost

Constructed wetland systems have gained attention as attractive solutions for wastewater treatment. Wetlands are not efficient to treat wastewater with high concentrations of phosphorus (P). In order to remove high soluble P loads by wetland, sorbent beds can be added prior to the discharge of wastewater into wetlands. Sorption by sorbent materials is identified as a method for trapping excess P in wastewaters. In the present investigation, shale has been identified as a sorbent material for removal of phosphate (PO4-P) due to the cost effectiveness, stability and possibility of regeneration. The study focuses on the removal of PO4-P from wastewater using shale and the feasibility of using the P-sorbed material as slow-release fertilizer. Phosphorus sorption experiments were conducted by using shale (2 mm and 2–4.7 mm). Results indicate that Shale I (particle size = 2 mm) showed the highest sorption of PO4-P (500 ± 44 mg kg−1). Breakthrough point was reached within 10 h in columns with flow rates of 2 and 3 ml min−1. Lower flow rate of 1 ml min−1 showed an average residence time of about 2 h while columns with a higher flow rate of 3 ml min−1 showed a residence time of about 40 minutes. Variation in flow rate did not influence the desorption process. Since very low concentrations of PO4-P are released, Shale saturated with PO4-P may be used as a slow nutrient release source of P or as a soil amendment. The sorbent can also be regenerated by removing the sorbed PO4-P by using 0.1 N HCl.

greater the probability that the particles will miss the high shear zones on a single pass through the device. For this reason the discharge of many rotor/stator devices is re-stricted with a series of holes or bars, or with a grid, which performs two separate tasks. First, a discharge grid absolutely limits the maximum particle size that can exit the mixer. If the holes on the discharge grid are 2 mm, it is virtually impossible for par-ticles larger than that diameter to pass through the machine. Rotor/stator in-line mix-ers are made with restricting grids as small as 0.5 mm, and a wide range of larger sizes up to 50 mm or even unrestricted outlets. A sample of such grids is presented in Fig. 29. But even the smallest usable discharge grid does not necessarily provide abso-lute control of the required size distributions in the range of fine dispersion. This is the second reason for the restriction on the discharge. By putting a more limiting dis-charge on the outlet, the flow rate through the device for a given set of pumping cir-cumstances (viscosity, density, system suction, and discharge head) is reduced and the residence time in the machine for a given particle or droplet is increased. The longer residence time increases the probability that a particle has to travel through the highest shearing zones and, thereby, be reduced to the smallest size that the machine is capable of producing. • • • • " ' ; • " * * «L £ J- •-

1998 ◽  
pp. 358-360
Keyword(s):  
Particle Size ◽  
Residence Time ◽  
Flow Rate ◽  
Shear Zones ◽  
High Shear ◽  
Single Pass ◽  
Fine Dispersion ◽  
Wide Range ◽  
Maximum Particle ◽  
Pass Through

Monopropellant-Driven Free Piston Hydraulic Pump for Mobile Robotic Systems

2004 ◽  
Vol 126 (1) ◽  
pp. 75-81 ◽  
Author(s):  
Timothy G. McGee ◽  
Justin W. Raade ◽  
H. Kazerooni
Keyword(s):  
Hydrogen Peroxide ◽  
High Temperature ◽  
Thermodynamic Analysis ◽  
Flow Rate ◽  
Power Supply ◽  
Robotic Systems ◽  
Hydraulic Fluid ◽  
Hydraulic Pump ◽  
Free Piston

The authors present a novel power supply for mobile robotic systems. A monopropellant (e.g., hydrogen peroxide) decomposes into high temperature gases, which drive a free piston hydraulic pump (FPHP). The elimination of fuel/oxidizer mixing allows the design of simple, lightweight systems capable of operation in oxygen free environments. A thermodynamic analysis has been performed, and an experimental FPHP has been built and tested. The prototype successfully pumped hydraulic fluid, although the flow rate was limited by the off-the-shelf components used.

Design and Implementation of an Intensified Coprecipitation Reactor for the Treatment of Liquid Radioactive Wastes

2013 ◽  
Author(s):  
Julie Flouret ◽  
Yves Barré ◽  
Hervé Muhr ◽  
Edouard Plasari
Keyword(s):  
Reaction Zone ◽  
Residence Time ◽  
Flow Rate ◽  
High Efficiency ◽  
Solid Phase ◽  
Continuous Process ◽  
Decontamination Factor ◽  
Barium Nitrate ◽  
Molar Ratio ◽  
Experimental Conditions

The coprecipitation is a robust and inexpensive process for the treatment of important volumes of low and intermediate radioactive level liquid wastes. Its major inconvenient is the huge volume of sludge generated. The purpose of this work is to optimize the industrial coprecipitation continuous process by achieving the following objectives: - maximize the decontamination efficiency; - minimize the volume of sludge generated by the process; - reduce the treatment cost decreasing the installation volume. An innovative reactor with an infinite recycling ratio was therefore designed. It is a multifunctional reactor composed of two zones: a perfectly mixed precipitation zone and a classifier to perform liquid-solid separation. The experiments are focused on the coprecipitation of strontium by barium sulphate. The effluent containing sulphate ions and the barium nitrate solution are injected in the reaction zone where strontium and barium coprecipitate as sulphates. The produced solid phase is returned into the reaction zone by the classifier and goes out slowly from the reactor bottom with a residence time much higher than the liquid phase. This creates both a high concentration of solid phase in the reaction zone and a high efficiency of decontamination. The experimental conditions simulate the industrial effluents. The total treatment flow rate is 17 L/h, with an effluent flow rate of 16 L/h and a reactive flow rate of 1 L/h, hence a mean residence time of 10 minutes. In these experimental conditions, the molar ratio sulphate/barium after mixing corresponds to 4.9. These conditions are used in the reprocessing plant of La Hague. The decontamination factor reached in these experimental conditions is excellent: DF = 1500. The decontamination factor obtained with the classical continuous process is only equal to 60. Different process parameters are studied in order to optimize the reactor/classifier: residence time, barium nitrate flow rate and racking flow rate. The decrease of barium nitrate flow rate reduces the volume of sludge generated by the process keeping a high efficiency of strontium decontamination: DF = 400. An excess of sulphate is necessary to perform an efficient decontamination, but the molar ratio sulphate/barium can be reduced to 3 instead of 4.9 used industrially. The reactor/classifier also represents an efficient device for the coprecipitation process intensification. Indeed, it can sensibly reduce the final installation size while treating important volume of effluents. This innovative reactor optimizes both the decontamination efficiency of radioactive liquid wastes and the reduction of sludge volume. A reduction of sulphate ions in the discharge is also possible, which is environmentally friendly.

Effect of nitrogen (N2) flow rate over the tribological, structural and mechanical properties diamond-like carbon (DLC) thin film

2021 ◽  
Vol 260 ◽  
pp. 124082
Author(s):  
Ranjan Kr Ghadai ◽  
Soham Das ◽  
Kanak Kalita ◽  
Ishwer Shivakoti ◽  
Subhas Ch Mondal ◽  
...  
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Flow Rate ◽  
Diamond Like Carbon ◽  
N2 Flow Rate

scholarly journals Ferro-silico-manganese production from manganese ore and copper smelting slag

2020 ◽  
Vol 9 (6) ◽  
pp. 13625-13634
Author(s):  
Zulfiadi Zulhan ◽  
Irfan Muhammad Fauzian ◽  
Taufiq Hidayat
Keyword(s):  
Copper Smelting ◽  
Manganese Ore ◽  
Smelting Slag
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