Carbonate coprecipitation

FIGURE 1.37 The Arrhenius plot of Ce08Sm0i2Oli9 from different methods (A) solid-state reaction [95] (B) sol-gel process [116] (C) oxalate coprecipitation [91] (D) carbonate coprecipitation, our work and (E) glycine-nitrate process [157]. 

Kinetics of Carbonate Coprecipitation Reactions and Solid Solution Formation The uptake of a cation into a carbonate has been studied by Davis et al. (1987), by Wersin et al. (1989), and by Stipp and Hochella (1991), Morse and Mackenzie (1990) have reviewed extensively the geochemistiy of dolomites and magnesian calcites. 

Yu, B. B. Goldman, A. (1982). Effect of processing parameters on morphology of Mn-Zn ferrite particles produced by hydroxide-carbonate coprecipitation. In Ferrites Proceedings of the Third International Conference on Ferrites, 1980, Japan. Eds. H. Watanabe, S. lida and M. Sugimoto. Center for Academic Publications, Tokyo, pp. 68-73. 

Petrov Al, Volodkin DV, Sukhorukov GB (2005) Protein-calcium carbonate coprecipitation atool for protein encapsulation. Biotechnol Progr 21 918-925... 

A. Petrov, D. V. Volodkin and G. B. Sukhorukov, Protein-Calcium Carbonate Coprecipitation A Tool for Protein Encapsulation, Biotechnology Progress, 21(3), 918-925 (2005). 

Pt-Pd-Rh/ glassy carbon Coprecipitation method Pt Pd Rh = 4 3 I (weight ratio) Cyclic voltammetry at room temperature in 0.1 MNH3-t0.5 M H2SO4 Peak current density ca. 0.3 mA cm (y = 50mV s ) 55... 

By far the most common lead salt used for PVC stabilization is tribasic lead sulfate. It can be found either alone or combined with another lead salt in almost every lead-stabilized PVC formulation. Many of the combinations are actually coprecipitated hybrid products, ie, basic lead sulfophthalates. Dibasic lead stearate and lead stearate are generally used as costabilizers combined with other primary lead salts, particularly in rigid PVC formulations where they contribute lubrication properties dibasic lead stearate provides internal lubrication and lead stearate is a good external lubricant. Basic lead carbonate is slowly being replaced by tribasic lead sulfate in most appHcations due the relatively low heat stabiHty of the carbonate salt which releases CO2 at about 180°C during PVC processing. 

Raw juice is heated, treated sequentially with lime (CaO) and carbon dioxide, and filtered. This accomplishes three objectives (/) microbial activity is terminated (2) the thin juice produced is clear and only lightly colored and (J) the juice is chemically stabilized so that subsequent processing steps of evaporation and crystalliza tion do not result in uncontrolled hydrolysis of sucrose, scaling of heating surfaces, or coprecipitation of material other than sucrose. 

The possible strategies are coprecipitation to prepare mixed hydroxides or carbonates [5], cosputtering of gold and the metal components of the supports by Ar containing O2 to prepare mixed oxides [23], and amorphous alloying to prepare metallic mixed precursors [24]. These... 

Coprecipitation is a partitioning process whereby toxic heavy metals precipitate from the aqueous phase even if the equilibrium solubility has not been exceeded. This process occurs when heavy metals are incorporated into the structure of silicon, aluminum, and iron oxides when these latter compounds precipitate out of solution. Iron hydroxide collects more toxic heavy metals (chromium, nickel, arsenic, selenium, cadmium, and thorium) during precipitation than aluminum hydroxide.38 Coprecipitation is considered to effectively remove trace amounts of lead and chromium from solution in injected wastes at New Johnsonville, Tennessee.39 Coprecipitation with carbonate minerals may be an important mechanism for dealing with cobalt, lead, zinc, and cadmium. 

A method described by Florence and Farrer [584] separated tin from its associated lead by distillation from an aqueous sulfuric acid medium into which the vapour from boiling 50% hydrobromic acid is passed. The distillate provides an ideal supporting electrolyte for the determination of tin (II) (produced by reduction with hydrazinium hydroxide) by anodic stripping at a rotating vitreous-carbon electrode in the presence of codeposited mercury [585,586]. The tin is deposited at -0.70 V versus the SCE for 5 minutes, and then stripped at -0.50 V during a sweep from -0.70 V to -0.45 V at 5 V per minute. Tin in seawater is coprecipitated on ferric hydroxide, and the precipitate is then dissolved in the aqueous sulfuric acid, and subjected to the above procedure. The average content for Pacific coastal waters was found to be 0.58 xg/l. 

Tsunogai and Nozaki [6] analysed Pacific Oceans surface water by consecutive coprecipitations of polonium with calcium carbonate and bismuth oxychloride after addition of lead and bismuth carriers to acidified seawater samples. After concentration, polonium was spontaneously deposited onto silver planchets. Quantitative recoveries of polonium were assumed at the extraction steps and plating step. Shannon et al. [7], who analysed surface water from the Atlantic Ocean near the tip of South Africa, extracted polonium from acidified samples as the ammonium pyrrolidine dithiocarbamate complex into methyl isobutyl ketone. They also autoplated polonium onto silver counting disks. An average efficiency of 92% was assigned to their procedure after calibration with 210Po-210Pb tracer experiments. 

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