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In general, the electrical conductivity and pH values dropped rapidly due to the consumption of OH − ions in the initial Ca (OH) 2 precipitation process caused by the reaction of NaOH with Ca 2+ resulting from the dissolution of phosphogypsum as explained in [ 25, 26 ]. The plateau indicates the end of the chemical reaction.
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The process evaluated consisted of the following stages: reduction of gypsum to calcium sulphide; H2S-stripping and sulphur production. Thermal reduction showed that gypsum could be reduced to CaS...
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municipal solid waste and ethanol MCFA selectivity 83% VPR 28.1 g.l-1.d ... sulfur recovery bleed . Strong efficiency improvement S 8 (mol%) 90 97 SO 4 2-(mol%) 5 2 S 2 O 3 ... Amorphous calcium phosphate and calcium carbonate . Nitrogen is an climate issue * STOWA Report 2011-30 .
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Gypsum is a good source for the recovery of sulphur (Wewerka et al., 1982). The recovery of sulphur and CaCO 3 from gypsum is eco- nomically feasible. From 1 t of gypsum it is calculated that 0.18 t of sulphur and 0.58 t of CaCO 3 can be recovered. From 1 t of gypsum, sulphur with a value of R180 can be recovered and CaCO 3 with a value of R116.
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By changing the carbonation conditions, Rare Earth Elements are transferred to a carbonate solution in the form of water-soluble complexes. Then they can be recovered by precipitation. Also, there were found the optimum conditions with the maximum degree of recovery into the solution. Export citation and abstract BibTeX RIS,
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Recovery of sulfur dioxide from waste gases: 1960-03-01: Tarbutton et al. 423/242: 2311202: ... The solution is then neutralized within the neutralizing tank by calcium carbonate to convert the sulfate ion into precipitated gypsum, and filtrated by a centrifugal separator. After the filtrate is neutralized to the same basicity of the crude ...
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Abstract We recently showed that the production of elemental sulphur and calcium carbonate (CaCO3) from gypsum waste by thermally reducing the waste into calcium sulphide (CaS) followed by its direct aqueous carbonation yielded low-grade carbonate products (i.e. 99 mass% as CaCO3) or precipitated calcium carbonate (PCC).
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The calcium carbonate slurry is formulated with a solids content of between about 5 and about 50%, preferably about 10 to about 35%. The calcium carbonate slurry and pond water are agitated in reactor 10 for about 5 minutes, although shorter reaction times or long reaction times as described above can also be employed.
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Mining industries produce vast waste streams that pose severe environmental pollution challenge. Conventional techniques of treatment are usually inefficient and unsustainable. Biological technique employing the use of microorganisms is a competitive alternative to treat mine wastes and recover toxic heavy metals. Microorganisms are used to detoxify, extract or sequester pollutants from mine ...
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The reaction of gaseous CO2 with the CaS slurry leads to the stripping of sulphide to form H2S gas and the precipitation of CaCO3. The H2S generated was then reacted with SO2 in the PIPco processes to form elemental sulphur. Sulphur with the purity between 95 % and 99 % was recovered from waste gypsum in this study. 1 Year: 2015
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The deposition of sulfate scales i.e., calcium sulfate (CaSO 4), barium sulfate (BaSO 4), and strontium sulfate (SrSO 4) on tubes and vessels can result in plant shutdown, production losses, equipment replacement, and cleaning costs. 4 In desalination by reverse osmosis (RO), the scale formed on RO membrane surface not only affects the quality ...
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Two methods that may minimize corrosion are: (1) reheating the gases to above their dew point, or (2) using materials of construction and designs that allow equipment to withstand the corrosive conditions. Both alternatives are expensive. Engineers determine which method to use on a site-by-site basis.
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The reaction of gaseous CO2 with the CaS slurry leads to the stripping of sulphide to form H2S gas and the precipitation of CaCO3. The H2S generated was then reacted with SO2 in the PIPco processes...
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Calcium sulfide is an inorganic solid formed by the element calcium (Ca) and the element sulfur (S), the chemical formula is CaS. ... CaS is also generated by burning coal waste. ... (2014). Conversion of calcium sulphide to calcium carbonate during the process of recovery of elemental sulfur from gypsum waste. Waste Manag, 2014 Nov; 34 (11 ...
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The metal sulfate was separately milled with CaCO 3 in aqueous solution. Fig. 1(a) displays the XRD pattern of milling the mixture containing copper sulfate and calcium carbonate. CaSO 4$2H 2O (dihydrate gypsum) (JCPDS-ICDD card no. 33-0311) and Cu 2CO 3(OH) 2 (malachite) (JCPDS-ICDD card no. 41-1390) were determined in the sample, indicating ...
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The initial chemisorption of Cd/sup 2 +/ on calcium carbonate was very rapid, ... Phosphorus-32 is easily and quantitatively separated from the bulk of sulfur targets by shaking carbon disulflde solutions of neutron irradiated sulfur with dilute ammonia. Extraction with acid solution gives a lower recovery. Bromoform is another solvent for ...
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1 Conversion of calcium sulphide to calcium carbonate during the process of recovery of elemental sulphur from gypsum waste M. de Beera,b*, J.P. Mareec, L. Liebenbergb, and F.J. Doucetd* a DST/CSIR National Centre for Nanostructured Materials, Council for Scientific and Industrial Research, PO Box 395, Pretoria 0001, Republic of South Africa.
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How does sulfur dioxide change calcium carbonate? Sulfur dioxide can dissolve in water to form an acid. This acid can react with calcium carbonate, causing it to become products that are not solids. As a result the mass of solid falls. This is the basis of the reactions caused by acid rain.
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Only the calcium sulfate and calcium carbonate deposited scale. The solution containing 300 me/liter of barium sulfate exhibited copious amounts of precipitate, but none of the precipitate adhered. The fluids from the effluents were also allowed to impinge on glass slides.
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Eventually, the precipitated CaF 2 was recuperated by using a glass filter of pore size 3 and dried in the oven at 105 °C. On the other hand, the filtrate was evaporated at 40 °C to obtain a transparent salt NaHSO 4 ·H 2 O (see Fig. 2 ). Fig. 2 Different steps of the PG conversion process by HF and NaF Full size image
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Abstract We recently showed that the production of elemental sulphur and calcium carbonate (CaCO 3) from gypsum waste by thermally reducing the waste into calcium sulphide (CaS) followed by its direct aqueous carbonation yielded low-grade carbonate products (i.e. <90mass% as CaCO 3 ).
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Characterization and purification of waste phosphogypsum to make it suitable for use in the plaster and the cement industry. ... Recovery of nano-calcium fluoride and ammonium bisulphate from phosphogypsum waste. ... Conversion of phosphogypsum to sodium sulfate and calcium carbonate in aqueous solution. Journal Materials and Environmental Science
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• Calcium Carbonate -96% as CaCO 3 -Less than 0.5% by weight of sulfate, chlorides and other constituents • Calcium Sulfate (Gypsum) -75 to 85% pure for use in cement -Gypsum used in wallboard is negatively affected by certain salts •The maximum content of Na 2 O, K 2 O, and Mg 2
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Figure 1 shows a simplified diagram of the phases to obtain pulp from wood, highlighting the cycles for recovering sodium, sulphur and calcium as well as for energy recovery. These cycles aim not only at the recovery of inorganic chemicals but also to obtain energy from the combustion of organic matter and prevent pollution to the environment.
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Calcium Carbonate from Biogenic Waste Abdu Zubairu1, Abdullahi S.B. Gimba2and A'isha H. ... for whom sodium hydroxide recovery is the main objective, and often the coarse PCC ... Commercial grades of sodium tri-oxo-carbonate IV, ferrous ammonium sulfate and cobalt nitrate solutions
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Create a marketable product from a waste or process by-product. Increase the value of a material through improved characteristics. Some transformations include turning sludges into organic-based fertilizers, clays and saw dust into litter, fuel pellets from petroleum coke dust, and recovering valuable metal from spent batteries.
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Abstract: A process for the recovery of chemicals from the waste liquors of sulfate cellulose digestion and from the waste waters of bleaching, wherein a melt from a soda-ash roaster, mainly containing sodium sulfide and sodium carbonate, but also sodium chloride, is dissolved and clarified to produce green liquor containing carbonate, sulfide a...
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Gypsum is produced as a waste product by various industries, e.g. the fertiliser industry, the mining industry and power stations. Gypsum waste disposal sites are responsible for the leaching of saline water into surface and underground water. ...
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Therefore, separation and purification were necessary for removal of iron and recovery of vanadium from TWWL. Common methods including ion exchange, solvent extraction and activated carbon adsorption have been applied for separation of iron and vanadium (Xing et al. 2021).Solvent extraction has been widely applied for the high concentration sulfuric acid system (Li et al. 2012; Peng et al. 2019).
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Waste Management. Volume 34, Issue 11, November 2014, Pages 2373-2381. Conversion of calcium sulphide to calcium carbonate during the process of recovery of elemental sulphur from gypsum waste. Author links open overlay panel M. de Beer a b J.P. Maree c L. Liebenberg b F.J. Doucet d.
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The phosphogypsum used during this work, comes from the waste of the preparation of phosphoric acid in the complex Maroc phosphore settled at Jorf Lasfar near El Jadida. It undergoes a lot of washes to eliminate the residual acidity, the salts and the suspension material which floats on the surface of the washing water (organic matter).
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Recovery of Copper from Ammoniacal Leachates by Ion Flotation. ... Sulfidic mine tailings and marl waste rock as compatible resources in a microwave-assisted roasting process. ... Kim, Hyewon Mun, Yongsik Chu, Dongkyu Roh. Characterization of direct reduced iron for reduction and elimination of sulfur using calcium carbonate. Journal of the ...
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Municipal wastewaters typically contain considerable quantities of calcium, carbonate and sulfate ions, and therefore have potentially high calcium carbonate and calcium sulfate scaling tendency. The logical approach for ASP treatment of municipal wastewater would, therefore, be to use calcium carbonate (calcite) or calcium sulfate (gypsum) as ...
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Calcium Recovery Shell Residue Wastes such as egg shells, snail shells, seashells such as clam & Oyster shells may be processed into Recovered Calcium Powders (Calcium carbonate CaCO3). Recovered Calcium ByProducts may be used in Supplements or as Soil Amendment Products and Cement Kiln feedstocks. Powdered Lime is used as a ...
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The reaction of gaseous CO2 with the CaS slurry leads to the stripping of sulphide to form H2S gas and the precipitation of CaCO3. The H2S generated was then reacted in the iron (IIII) and PIPco processes to form elemental sulphur. Sulphur with the purity between 96% and 99% was recovered from waste gypsum in this study. Description:
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These agro and industrial by-products could be processed for the recovery of calcium carbonate and calcium oxide particles by physical and chemical method. The recovery of calcium carbonate and calcium oxide particles from such by products make them biocompatible. Moreover, the products are economical due to their synthesis from waste materials.
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Gypsum waste is not only an environmental problem but has measurable economic value as well. However, all these environmental and economical concerns can be avoided should valuable/saleable by-products like sulphur and calcium carbonate be recovered from the low quality gypsum.
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The carbonation process is the most widely used process, in which the base raw material is burned in a lime kiln at the designed temperature where it decomposes (calcines) into calcium oxide (CaO) and carbon dioxide. The dry CaO is slaked (hydrated) with water at temperature of 30-50⁰C, producing a Ca(OH) 2, slurry.
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Gypsum is produced as a waste product by various industries, e.g. the fertiliser industry, the mining industry and power stations. Gypsum waste disposal sites are responsible for the leaching of saline water into surface and underground water. ...
WhatsApp:+8617329420102
Gypsum waste is not only an environmental problem but has measurable economic value as well. However, all these environmental and economical concerns can be avoided should valuable/saleable by-products like sulphur and calcium carbonate be recovered from the low quality gypsum.
WhatsApp:+8617329420102