· A series of crucial parameters of the roasting temperature, amount of oxygen, sodium sulfate addition amount, and heating rate are optimized to achieve efficiently separation of valuable
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· The metal sulfide precipitation and settling properties were significantly affected by the residual phosphate, sulfate, and acetate present in the biogenic sulfide matrix (Liu et al., 2019). Natural organic matter (NOM) was found to strongly associate with copper and other copper-loving metals, interfering with sulfide precipitation and
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· However, aromatic and sulfur functional groups in wastewater can effectively increase the precipitation process of metal sulfide by providing additional sites for metals to attach to sulfide [84]. In practice, the delocalized electrons in benzene rings and other aromatic compounds stabilize the bonding process with metal ions [ 85 ].
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· Precipitation and biosorption are the most employed process for metal ion removal from water. Microalgae, fungi and bacteria have been used successfully in the removal of metals, but in the last decade, sulfate-reducing bacteria (SRB) have taken great relevance in the processes of metal removal from wastewater.
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· Water analyses included pH, dissolved oxygen, dissolved sulfide and sulfate, total organic carbon, total suspended solids and dissolved heavy metal analyses, as well as quantification of
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· Formation of calcium sulphate (gypsum) by the interaction of calcium ions with sulphate ions in the pulp produces fines slime coatings on the sulphide minerals and hinders the flotation of the desired minerals ( Raghavan and Hsu, 1984, Grano et al., 1995, Zanin et al., 2019 ). Sulphate may also increase capital expenditure because of its
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The two stages involve: 1) treatment with alkaline ferrous sulfate and sodium sulfide to reduce hexavalent chrome and precipitate all of the hazardous metals, and 2)
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Ferric sulfate contains iron in its +3 oxidation state, while ferrous sulfate contains iron in its +2 oxidation state. This difference in oxidation state affects their chemical properties and applications. Ferric sulfate is commonly used as a coagulant in water treatment processes and as a mordant in dyeing and printing textiles.
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· The re-mobilization risks of potentially toxic elements (PTEs) during stabilization deserve to be considered. In this study, artificial simulation evaluation methods based on the environmental stress of freeze–thaw (F-T), acidification and variable pH were conducted to assess the long-term effectiveness of PTEs stabilized by MgO in Pb/Zn
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A process for treating industrial waste water containing hexavalent chromium (Cr +6) and other heavy metals is disclosed which comprises reduction of Cr +6 to trivalent chromium (Cr +3) and the precipitation thereof with other heavy metals by addition of sulfide ion and ferrous ion to the waste stream at a pH of about 7 to 9 under conditions such that sludge
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: S. K. Janikowski, S. N. Ugaki, P. M. Wikoff, D. F. SuciuIn Phase I, jar and dynamic testing showed that the sodium sulfide/ferrous sulfate process was a viable method for reducing hexavalent chromium and removing heavy
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· Capture and conversion of hydrogen sulfide (H 2 S) has been one of the longstanding economic and environmental challenges of the past century. H 2 S is a highly irritating, odorous, and toxic chemical found as an impurity in many important fuel gases, such as natural gas, biogas, syngas, coke oven gas, landfill gas, refinery gas, etc., and
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· A novel process was proposed for the separation of Cu and As from Cu-smelting waste acid (CSWA). This process includes three steps, namely, the oxidization of As via the addition of H2O2, the selective separation of Cu through the use of Na2S, and the removal of As via the synthesis of scorodite. The CSWA was initially oxidized using
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· The chapter summarizes the main treatment processes used for the removal of heavy metals from water and wastewater. Heavy metals present a recalcitrant and persistent character, a bioaccumulating ability in the environment, therefore their removal from water and wastewater represents a worldwide concern. This chapter
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· Herein, FeS and CMC-FeS were prepared using the homogeneous precipitation method. First of all, the deionized water was purged with N 2 to remove air. Then, 13.90 g of FeSO 4 ·7H 2 O and 0.36 g of CMC were dissolved in 50 mL of deionized water and added to a three-neck flask, and 12.00 g of Na 2 S·9H 2 O was dissolved in 50
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· 2.4. Coupled reduction/stabilization experiments COPR II samples were used with a Na 2 S/Cr(VI) mass ratio of 5.7. The reduction process with sodium sulfide was carried out for the initial 20 min, and then the stabilizing agents were added and mixing continued for 10 min. Water (25 L) with a flow rate of 3 L/min was added 5 min after start
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· Restrictive requirements for maximum concentrations of metals introduced into the environment lead to search for effective methods of their removal. Chemical precipitation using hydroxides or sulfides is one of the most commonly used methods for removing metals from water and wastewater. The process is simple and inexpensive.
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In Phase I, jar and dynamic testing showed that the sodium sulfide/ferrous sulfate process was a viable method for reducing hexavalent chromium and removing heavy
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parameters of the sodium sulfide/ferrous sulfate process, the precipitation and clarification process, and the activated sludge system. The chemical requirements
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A key step in the reactions of all the sulfide minerals is that they release iron as ferrous ion (Fe2+). Oxygen present in the water can then oxidize Fe2+ back to Fe3+: 2Fe2+ + 1 2 O2 + 2H+ → 2Fe3+ +H2O (8) (8) 2 Fe 2 + + 1 2 O 2 + 2 H + → 2 Fe 3 + + H 2 O. This Fe3+ can again react with the mineral surface.
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· This process aids the elimination of toxic metals from sulphate containing wastewater. Typically, sulphate reducing bacteria's grow in anoxic environment with pH range of 5–9 [87]. These conditions are more important for excellent removal of
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is implemented. These sodium sulfide/ferrous hexavalent chromium in Tinker AFB in 1986 and savings are based on the use of dry chemicals for the sulfate process and the treatment of 11,789 pounds of 284,406,312 gallons of industrial wastewater at
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· This article will describe five chemical treatment technologies that may be considered: Hydroxide precipitation. Sulfide precipitation. Oxidation/reduction. Ion exchange. Natural zeolites. Typical contaminants of concern in industrial waters include suspended metals, dissolved metals, nitrate, sulfate, and cyanide.
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Cost comparisons of the sodium sulfide/ferrous sulfate process and the sulfuric acid/sulfur dioxide/lime process shows a chemical treatment sludge removal savings of $370,000/yr without reclamation of the water.
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wastes. A two-stage treatment process was developed and piloted which reduced the volume of the waste sludge generated during wastewater cleanup. The two stages involve: 1) treatment with alkaline ferrous sulfate and sodium sulfide to reduce
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Abstract : The objective of this research was to validate the use of sodium sulfide and ferrous sulfate in reducing hexavalent chromium and removing heavy metals from electroplating, and industrial wastewaters. Jars tests, and dynamic tests, were conducted using distilled water, electroplating rinse waters, and industrial wastewaters from Tinker
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· Treatment of Arsenic Sulfide Sludge at Different Time The effects of reaction time on the leaching of Cu and solidification rates of As and Fe are presented in Fig. 4, and the XRD analyses of residues obtained at different reaction time are shown in Fig. 5.From Fig. 4, when the time was less than 3 h, the crystallization rate of As saw a
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The U.S. Department of Energy's Office of Scientific and Technical Information @article{osti_5765667, title = {Pilot field-verification studies of the sodium sulfide/ferrous sulfate treatment process. Final report, September 1987-May 1988}, author = {Wiloff, P M and Suciu, D F and Prescott, D S and Schober, R K and Loyd, F S}, abstractNote = {In
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Full-scale implementation of the sodium sulfide/ferrous sulfate treatment process. Final report, October 1987-March 1989 Technical Report · Fri Sep 01 00:00:00 EDT 1989 · OSTI ID: 6889324
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· In the NaHS acid hydrolysis method (Fig. 2 (b)), the process begins with the mixing of dilute sulfuric acid with NaHS to produce hydrogen sulfide gas and a sodium sulfate solution (Equation (11)). Subsequently, the sodium sulfate solution undergoes processing through an evaporation crystallization system, leading to the production of
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Trituradora de piedra vendida por proveedores certificados, como trituradoras de mandíbula/cono/impacto/móvil, etc.
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