Influence of Cavitation Treatment on the Physicochemical Properties of Calcium Hydroxide
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INFLUENCE OF CAVITATION TREATMENT ON THE PHYSICOCHEMICAL PROPERTIES OF CALCIUM HYDROXIDE V. T. Yavors’kyi,1 Z. O. Znak,1,2 and R. V. Mnykh1
UDC 66.081
Changes in the dispersion of particles of calcium hydroxide and their morphology under the action of cavitation processes are studied. It is shown that charged particles of calcium hydroxide of the colloid type are formed in the cavitation fields parallel with dispersion. It is shown that the chemical activity of the suspension of calcium hydroxide substantially increases as a result of the cavitation treatment, especially in jet-type hydrodynamic cavitators. Keywords: calcium hydroxide, activation, cavitation, hydrodynamic cavitator.
Calcium hydroxide is extensively used in various technological processes, in particular, in the production of building materials, purification of sugar, softening of natural waters, conditioning of waste waters, cleaning of
gaseous emissions from acidic components, etc. However, due to its low solubility (∼ 1.5 g/dm 3 ), the efficiency
of its application in the technologies of conditioning of water and purification of sugar and gas media is low. The indicated technological processes run as typical heterogeneous processes. Thus, the extension of the field of applications of calcium hydroxide and high rates of chemical processes running with its participation can be attained either by using traditional methods, such as, e.g., the increase in its dispersion and, hence, in the area of phase contact, or with the help of specific methods, e.g., by the activation of the surface. However, there exists a possibility to realize both methods simultaneously by using the acoustic (cavitation) methods for the intensification of chemical technological processes [1–4]. The main condition for the activation of the heterophase is the excitation of cavitation phenomena in heterogeneous aqueous systems with application of ultrasonic [5, 6] and hydrodynamic cavitators [7, 8]. The aim of the present work is to enhance the chemical activity of calcium hydroxide by treating its suspension in cavitation fields and to choose the most efficient design of cavitators. Methods In our studies, we used calcium hydroxide (DSTU B.V. 2.7-46-96). The cavitation fields in suspensions of Са(ОН)2 were created by a UD-20 (Ultrasonic Disintegrator) magnetostriction ultrasound emitter (with a power
of 12.67 W/cm 2 and an emission frequency of 20 kHz) and hydrodynamic cavitators (the power of the drive is
equal to 1.1 kW and pressure is equal to 0.6 MPa) with cavitating elements including a bluff body and nozzles. The application of units with different powers and means of excitation of the cavitation phenomena (ultrasound emitters and hydrodynamic cavitators) is determined by the necessity of identifying the processes running in the cavitation medium and by the subsequent scaling of the processes of activation of Ca(OH)2 for their implemen-
1 2
“L’vivs’ka Politekhnika,” National University, Lviv, Ukraine.
Corresponding author; e-mail: [email protected].
Translated from F
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