The amount of precipitated calcium carbonate in the CCC depends on the production temperature. The highest amount of calcium carbonate precipitation in the CCC was found at 60–70 °C, followed by 80 °C, 50 °C, and 40 °C and lowest value was at 90 °C. Download: Download high-res image (217KB) Download: Download full-size image; Fig. A2.
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We can establish this equilibrium either by adding solid calcium carbonate to water or by mixing a solution that contains calcium ions with a solution that contains carbonate ions. …
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Precipitated calcium carbonate (PCC) is conventionally produced through the gas–solid–liquid carbonation route, which consists on bubbling gaseous CO 2 through a concentrated calcium hydroxide (Ca(OH) 2) slurry. However, atmospheric carbonation processes are slow and have low carbonation efficiency.
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PSD courses for calcium carbonate precipitated in EG solutions are similar, and the shift towards smaller size with increase of EG concentration is observed. Bimodal PSD courses are for particles obtained from glycerol solutions with picks around 0.5 µm and 2 µm. The increase in GLY concentration results in the increase in the share of ...
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The warm lime softening process operates in the temperature range of 120-140°F (49-60°C). ... Waters producing high calcium-to-magnesium precipitation ratios usually need sludge bed conditioning ...
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If we mix a solution of calcium nitrate, which contains Ca 2 + ions, with a solution of sodium carbonate, which contains (ce{CO3^2-}) ions, the slightly soluble ionic solid CaCO 3 will precipitate, provided that the concentrations of Ca 2 + and (ce{CO3^2-}) ions are such that Q is greater than K sp for the mixture.
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2) and soda ash (sodium carbonate, Na 2CO 3). Lime is used to remove chemicals that cause carbonate hardness. Soda ash is used to remove chemicals that cause non-carbonate hardness. When lime and soda ash are added, hardness-causing minerals form nearly insoluble precipitates. Calcium hardness is precipitated as calcium carbonate (CaCO 3 ...
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The vast application potential and broad prospect of microbial-induced calcium precipitation (MICP) technology has been demonstrated in a variety of fields, which has attracted extensive attention from relevant researchers (Dopffel et al., 2018).MICP is a form of biomineralization that induces calcium precipitation by altering the mineralized environment …
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The complexity of the description of the solubility of calcium carbonate in water is due to the presence of simultaneous chemical equilibria of a high number of species (CO 3 2−, HCO 3 −, CO 2, etc.) involved in this process between solid, liquid and gas phases.Furthermore, if hydrocarbon phases are also present in reservoir conditions, CO 2 will also be present in the …
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Limestones commonly form in oceans, which do not evaporate away. For example, when cold sea water heats up, it can no longer hold as much calcium carbonate (calcite, the mineral that limestones are made out of) in solution. …
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Since low-temperature solid-state diffusion can be discounted as a method for Mg incorporation into calcium carbonate (as it operates on time scales too long to matter), the replacement of CaCO3 ...
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When calcium and carbonate ions have formed calcium carbonate and precipitated, the solution will be below saturation and more calcium hydroxide can dissolve. The commercially available carbonation process for PCC production is an example of this practice: the solid content of the slurry in the carbonation reactor is as high as 20% [17] .
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Five scale formation solutions were used; the composition of calcium and carbonate in each solution was varied such that the molar concentration of each solution has values from 0.01 mol/L to 0.05 mol/L. CaCO 3 was precipitated spontaneously by mixing equal amounts of the two solutions. Solution A and Solution B were poured into the crystallizer.
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The precipitation of calcium carbonate from solutions with the same initial supersaturation and different initial [Ca] T ([HCO − 3] + [CO 2− 3]) ratio, has been studied …
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In the present paper, precipitated calcium carbonate (PCC) has been produced from waste marble powder (WMP) by the Calcination-Dissolution-Precipitation (CDP) method.
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Calcium carbonate, for example, is often found precipitating in proximity to hot springs. In contrast, carbon dioxide is more soluble in cold water than in warm.
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Even a low concentration of sulfuric acid in solution lowers the pH sufficiently to inhibit carbonate precipitation . We calculate that siderite precipitation halts if solution pH is lower than occurred during sediment …
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SEM of the calcium carbonate crystals precipitated in WSM solutions at different pH values revealed various crystalline structures, as shown in Fig. 4 A. For pH values ranging from 5.5 to 9.0, calcite and aragonite crystals precipitated synchronously at all ranges of pH, which is tremendously different from the results in the control group ...
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A thorough experimental analysis of the precipitation of calcium carbonate from pure aqueous solution was performed. Trials were carried out …
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hydroxide solution used is highly corrosive and should be handled with extra care: ideally wear rubber gloves when preparing and handling it. Introduction This method, called a complexometric titration, is used to find the calcium content of milk, the 'hardness' of water and the amount of calcium carbonate in various solid materials.
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Here, the waters are supersaturated in calcium carbonate, which precipitates out of solution as crystals of aragonite cement, binding the shell material together. Chemical limestones. Some limestones are formed by direct …
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In this study, CaO conversion was induced by calcining domestically mined m-CC among carbonate minerals in a rotary microwave kiln (RMK). Then, CaCO 3 was prepared …
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The precipitation of calcium carbonate is common in soils and regoliths and occurs in a variety of climatic settings, ranging from arid to subhumid and from warm to cold (e.g., Courty et al., 1994).It produces a wide variety of forms, from isolated crystals and discrete elementary features to continuous carbonate-rich horizons.
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Torrent-Burgu~s b A. Ldpez-Macipe a R. Rodlqguez-Clemente a " Institut de Ci~ncia de Materials de Barcelona, CSIC, Campus de la UAB, 08193 Bellaterra, Spain b Departament d'Enginyeria Quimica, UPC C/Colom 1, 08222 Terrassa, Spain Abstract The precipitation of calcium carbonate from solutions with the same initial supersaturation and …
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The calcium carbonate precipitation requires the calcium ions to react with carbonate ions in the condition that the saturation state Ω ≥ 1 [39], [90], [91], [92]. The saturation state here indicates the extent to which a solution is saturated with calcium carbonate.
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In the present work, we have attempted to tackle the problem of calcium carbonate precipitation by investigating the mechanism of its formation both from stable and from …
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It usually forms in clear, calm, warm, shallow marine waters. Limestone is usually a biological sedimentary rock, forming from the accumulation of shell, coral, algal, fecal, and other organic debris. ... Calcium carbonate, precipitated directly from solution, forms as a "cement" that binds the biological grains together. ... it effervesces in ...
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Microbial-induced calcium carbonate precipitation (MICP) is a technique that uses the metabolic action of microorganisms to produce CO 3 2− which combines with free Ca 2+ to form CaCO 3 precipitation. It has gained widespread attention in water treatment, aimed with the advantages of simultaneous removal of multiple pollutants, environmental protection, and …
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Why is it important to understand the conditions that lead to the precipitation and dissolution of the mineral calcium carbonate (calcite ... Tufa is made largely of the mineral calcite. The calcite was precipitated on surface from warm calcareous groundwater. ... increasing the pressure of CO2 gas in a system causes calcite to dissolve and go ...
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The microbial-induced calcium carbonate precipitation (MICP) technique has high potential in the development of bio-concrete, enhancing the strength, durability, and self-healing properties of construction materials. ... (3 × 3 × 1.5 cm) were submerged in a 50 mM calcium chloride solution containing 1.5 × 10 8 cells/mL and shaken for 45 days ...
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Nano-precipitated calcium carbonate (NPCC) exhibits multiple morphologies and unique properties to satisfy various requirements in industry. In this study, monodisperse and cubic NPCC were prepared by a solution mixing method using NaOH, Na 2 CO 3, and CaCl 2 as raw materials. The morphology of CaCO 3 was controlled by the amount of NaOH in the …
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Fig. 10 shows solution pH recordings of the carbonation experiments, while a SEM image of the precipitated calcium carbonate (rhombohedral calcite) is represented in Fig. 11. We can conclude that precipitated calcium carbonate (PCC) can be produced also from the currently used test slag using ammonium salts as solvents.
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Except for CO 2 bubbling in lime slurry, as far as we know, nano precipitated calcium carbonate (NPCC) could not be obtained by other methods. Discrete NPCC was here prepared in solution mixing process in the presence of Ca(OH) 2.CaCl 2 and Na 2 CO 3 were employed as reactant in this work. The temperature, solution flow rate, stirring speed, Ca(OH) 2 in the …
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Carbonate precipitation is encouraged by conditions that reduce the amount of dissolved carbon dioxide in the water. Specifically, this means that warm, shallow, agitated conditions tend to be …
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trations of calcium and carbonate ion were formed, only 6.8 mg/1 of calcium carbonate would be soluble. The solubility decreases with increasing temperature and increases with increasing mineral concentration. By analysis, the total calcium concentration, the alkalinity, and the pH, or negative log of the hydrogen ion activity can be determined.
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Review of precipitated calcium carbonate (PCC) synthesis, polymorphs, additives, and applications in various industries. Studylib. Documents Flashcards Chrome extension Login Upload document Create flashcards ×. Login Flashcards ...
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Precipitated calcium carbonates are usually produced, either in the industries for commercial purpose or in the laboratory for research using two main methods: by the solid–liquid route, which involves a direct reaction between Ca 2+ and CO 3 2− in an aqueous solution (Kim et al. 2005; Kimura and Koga 2011), and the solid–liquid–gas route, where CO 2 is bubbled …
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In the present work, the effect of temperature and solution pH on calcium carbonate precipitation from iron-rich waters was investigated. Calcium carbonate was precipitated by CO 2 removal. The increase in the temperature …
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The method (solubilization) involved heavy dilution of the slurry at 0 o C, and reaction of the solution with carbon dioxide to produce calcium carbonate, the precipitated product is separated ...
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