Reactive precipitation

Al-Rashed, M.H., Jones, A.G., 1999b. CFD modelling of gas-liquid reactive precipitation. Chemical Engineering Science, 54, 4779-4784. 

Chen, J., Zheng, C. and Chen, G., 1996. Interaction of macro- and micromixing on particle size distribution in reactive precipitation. Chemical Engineering Science, 51, 1957-1966. 

Hostomsky, J. and Jones, A.G., 1995. A penetration model of the gas-liquid reactive precipitation of calcium carbonate crystals. Transactions of the Institution of Chemical Engineers, 73A, 241-245. 

Table 13.1 Comparison between the reactive precipitation of CaCOs in conventional equipment and in rotating packed bed reactor.

Reactive crystallization, or precipitation, has been investigated by numerous research groups. Processes of industrial relevance include liquid-phase oxidation of para-xylene to terephthalic acid, the acidic hydrolysis of sodium salicylate to salicylic acid, and the absorption of ammonia in aqueous sulfuric acid to form ammonium sulfate (60). A very special type of reactive crystallization is diastereomeric crystallization, widely applied in the pharmaceutical industry for the resolution of enantiomers (61). Another fine example of reactive precipitation is the earlier-described production of nano-size particles of CaC03 in high-gravity fields (46). 

High-gravity reactive precipitation (HGRP) has been extended to the production of aluminum hydroxide and strontium carbonate (57). Aluminum hydroxide fibrils precipitate from the reaction of sodium meta-aluminate (NaA102), water, and carbon dioxide and are formed in diameters of 1-10 nm and lengths of 50-300 nm. Rotor speed, gas- and liquid-flow rates, and initial reactant concentrations control particle size. Strontium carbonate particles of 40-nm mean diameter and narrow size distribution have been produced from the liquid-liquid reaction of strontium nitrate and sodium carbonate. 

Chen J-F, Wang Y-H, Guo F, Wang X-M, Zheng C. Synthesis of nanoparticles with novel technology high-gravity reactive precipitation. Ind Eng Chem Res 2000 39 948-954. 

Glasses can be made by a variety of processes, such as reactive precipitation, electrolytic deposition, quenching of a vapor, ion implantation. 

High-Gravity Reactive Precipitation Recipe from [2590]. A mixed TiClg + BaCl2 solution, Ba Ti 1.07, total molarity 1, was treated with excess of NaOH solution at 85°C for 15 min. 

PZC/IEP of BaTiOj Obtained by High-Gravity Reactive Precipitation Electrolyte T Method Instrument pH Reference... 

Chen. J.E at al.. Preparation and properties of barium titanate nanopowder by conventional and high gravity reactive precipitation methods, Scripta Mater., 49, 509, 2003. 

Vincent, T., Guibal, E., Chiarizia, R. (2007). PaUadium recovery by reactive precipitation using a cyanex 301-based stable emulsion. Separation Science and Technology 42 3517-3536. 

Wang, L. Fox, R. O. 2003 Application of in-sim adaptive tabulation to CFD simulation of nanoparticle formation by reactive precipitation. Chemical Engineering Science 58, 4387 401. 

DeBenedetti, B., Vallauri, D., Deorsola, F. A., and Martinez Garcia, M. (2006) Synthesis of Ti02 nanospheres through microemulsion reactive precipitation. J. Electroceramics, 17, 37-40... 

Discrepancies between the data sets were reconciled as discussed in ( ). The increasing scatter in for gibbsite with falling temperature is attributed primarily to contamination of Bayer process gibbsite with bayerite or other surface reactive precipitates, and is discussed further below. Those measurements which are believed to approach most closely the true solubility of gibbsite are reported by by Kittrick (jj ) and Russell et al. 

Zauner, R., and Jones, A.G. (1999). A Hybrid CFD-Mixing Approach for Scale-Up of Reactive Precipitation—Experimental and Modelling Results, Industrial Crystallization 1999 Proceedings of the 14th International Symposium on Industrial Crystallization, IChemE, Rugby, UK. 

R. Zauner and A.G. Jones. A hybrid CFD-mixing approach for scale-up of reactive precipitation—Experimental and modelling results. Proceedings of the 14th International Symposium on Industrial Crystallization, Cambridge, U.K., September 12-16,1999. 

Tavare, N.S. and Garside, J. (1990) Simulation of reactive precipitation in a semibatch crystallizer. Transactions of the Institution of Chemical Engineers, 68, 115-122. 

Al-Rashed etal. (1996) and Al-Rashed and Jones (1999a,b) presented a CFD-based model to predict the effects of mixing during batch-wise gas-liquid reactive precipitation in the flat interface cell used by Wachi and Jones, 1991b. A 2D flow simulation was developed for the chemical reaction with... 

To exclude sulphides can be achieved by mechanical removal of the sulphides by traditional or innovative mineral processing techniques (Thornhill Williams 1995). However, this still presents the problem of the disposal of the sulphides in a different manner elsewhere and is not applicable where sulphides are still present in large quantities underground. A more practical barrier is to exclude the sulphides by precipitation of an insoluble non-reactive precipitate thereby isolating the sulphide from oxidants. Ferric phosphates and oxyhydroxides have been proposed and the rate of sulphide oxidation has been observed to decrease in samples amended with phosphate (Achmed 1991 Huang Evan... 

For cyanides, bromides, iodides, sulfides, or nitrates, the concern is the reactive precipitation of the silver and potassium chloride in the electrolyte observable as a blackening of the junction. The solution is to use an electrolyte in an internal or external salt bridge that is compatible with the process, a differential electrode, or a solid-state reference electrode with an immobilized electrolyte or a non-porous junction. 

Co-Precipitation Method This method involves dissolving a salt precursor (nitrate, chloride, etc.) in water or other solvent to precipitate the oxo-hydroxide form with the help of a base. Very often, chemical homogeneity and control of size in the case of mixed-metal oxides are difficult to achieve. However, the use of sonochemical methods, surfactants, and high-gravity reactive precipitation appear as viable alternatives and novel to optimize the resulting solid morphological characteristics [47-49]. 

J.F. Chen, Y.H. Wang, F. Gou, X.M. Wang, C. Zheng, Synthesis of nanoparticles with novel technology High-gravity reactive precipitation, Ind. Eng. Chem. Res.39 (2002) 948-954. 

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