Otrzymywanie mikrokryształów siarczanu baru na drodze reaktywnej krystalizacji zachodzącej w strefie zderzania strumieni reagentów

• Autorzy: Pindur K. , Pawełczyk R. , Jaschik J.

Warianty tytułu

EN

Producing of barium sulphate microcrystals by reactive precipitation in collision zone of reagents streams

• Języki publikacji: PL

Abstrakty

PL

Przedstawiono wyniki wstępnych badań doświadczalnych procesu reaktywnej krystalizacji siarczanu baru. W badaniach stosowano ekwimolarne roztwory wodne chlorku baru i siarczanu sodu o stężeniach: 0,004, 0,04 i 0,4 mol · dm ³ -3. Mieszanie reagentów prowadzono drogą ciągłego zderzania strumieni z wykorzystaniem metody DSP (Dwa Strumienie Prostopadłe). Stwierdzono wyraźny wpływ stężeń reagentów na wielkość i rozkład rozmiarów otrzymywanych kryształów.

EN

An attempt was made to obtain submicron crystals of barium sulphate. Small scale barium sulphate crystals show altered properties and already have widespread applications in such products as pigments, pharmaceuticals, cosmetics, ceramics and filling materials for rubber and polymers. An impinging technique of micromixing of two streams of reagents solutions was employed in these studies, and was called TPJ (Two Perpendicular Jets) method. Two perpendicular streams of reagents solutions issue from two separate compartments of distributor through two flat rectangular nozzles - to impinge and to mix with each other in continuous flow. In all experimental runs the TPJ distributor was operated in nonsubmerged mode. The effects of nozzles velocity, reagents concentration and configuration of distributor i.e. nozzle widths and distance of nozzles, at temperature 25 C, on crystals size distributions, were observed. Samples from stream after collision were collected into an empty flask (some 200 cm ³ of jetted sample). The size of the resulting precipitate was measured by means of a laser scattering particle size analyser Malvern Mastersizer 2000, providing distributions of crystals. Based on crystal size distributions (Fig.2 to Fig.9) it was concluded that for lower concentration of reagents only a part of crystals is smaller than 1 μm. Still effects of reagents concentration is noticeable - the higher concentration of reagents the smaller diameters of crystals. Effects of velocities of impinging jets are the same - the higher velocity the smaller crystals, though the effect of concentration of reagents is stronger. From observations made so far it is obvious that higher concentration of reagents and velocity of impinging jets lead to submicron crystals no matter what

Słowa kluczowe

PL

bar; metoda DSP; dwa strumienie prostopadłe; reagent

• Wydawca: Instytut Inżynierii Chemicznej Polskiej Akademii Nauk
• Czasopismo: Prace Naukowe Instytutu Inżynierii Chemicznej Polskiej Akademii Nauk
• Rocznik: 2009
• Tom: nr 13
• Strony: 28--41
• Opis fizyczny: Bibliogr. 8 poz.

Twórcy

autor

Pindur K.

autor

Pawełczyk R.

autor

Jaschik J.

• Instytut Inżynierii Chemicznej PAN Gliwice, ul. Bałtycka 5, 44-100 Gliwice

Bibliografia

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• [2] Barium sulfate, http://freshpatents.com/-dt20081225ptan20080314291.pht?ty.
• [3] G.G. Hen, G.S. Luo, J.H. Xu, J.D. Wang, Membrane dispersion precipitation method to prepare nanoparticles, Powder Technology, 139, 180, 2004.
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• [5] B.Bernard-Michek, M.N. Pons, H. Vivier, Quantification, by image analysis, of operational conditions on size and shape of precipitated barium sulphate, Chem. Eng. Journal, 87, 135, 2002.
• [6] N. Benet, L. Falk, H. Muhr, E. Plasari, Experimental study of a two-impinging-jet mixing device for application in precipitation processes, Proc 4th Int. Symp. Industrial Crystallization, Cambridge, UK, 1999.
• [7] R.Pohorecki, J. Bałdyga, The effects of micromixing and the manner of reactor feeding on precipitation in stirred tank reactors, Chem. Eng. Sci., Vol. 43, No.8, 1949, 1988.
• [8] M. Kucher, D. Babic, M. Kind, Precipitation of barium sulfate : Experimental investigation about the influence of supersaturation and free lattice ion ratio on particle formation, Chem. Eng. Proc., 45, 900, 2006.