Electric precipitator, components

The properties of gas ions are of great importance for the electrical performance of an electrostatic precipitator. They also are very important for particle-charging processes. The size of gas ions is normally such that they can be regarded as gas molecules carrying a single elementary charge. It can even be assumed that ions form a gas component with a very low- partial pressure. Thus, the thermal motion of gas ions is assumed to be similar to that of gas molecules. The most important parameters describing the properties of gas ions are... 

In the case of Lysimeter Teuftal, most dissolved heavy metal and metalloid concentrations are directly correlated to electrical conductivity. The plot in Fig. 7 shows the relative dilution of different components during a rain event in comparison to that of electrical conductivity. The trend is independent of the speciation of these components. It should be noted that there are three notable exceptions, namely Ni(H), Co(II), and Cu(II). The common property of these cationic species is that they are extremely insoluble under the highly basic conditions encountered in the leachates of cement-stabilized residues (pH 12.8). It is possible that precipitation is the cause of such behaviour. 

There is still another type of internal solid state reaction which we will discuss and it is electrochemical in nature. It occurs when an electrical current flows through a mixed conductor in which the point defect disorder changes in such a way that the transference of electronic charge carriers predominates in one part of the crystal, while the transference of ionic charge carriers predominates in another part of it. Obviously, in the transition zone (junction) a (electrochemical) solid state reaction must occur. It leads to an internal decomposition of the matrix crystal if the driving force (electric field) is sufficiently high. The immobile ionic component is internally precipitated, whereas the mobile ionic component is carried away in the form of electrically charged point defects from the internal reaction zone to one of the electrodes. 

When the dissolved components are not adsorbed on the solid matrix and do not precipitate, they migrate together with water (e.g., chloride ion). Of course, every part of the solution must be electrically neutral so that the migration of negative chloride ions is followed by the migration of cations, or the migration of cations decreases the migration of anions. In spite of this fact, most literature discusses the diffusion of ions on the basis of chemical potentials, not electrochemical... 

Fig.2 shows the flow sheet of the HAW processing. The use of the waste solution directly for separation leads to the dissipation of avery large part of the electric energy for the electrolytic transport of the hydrogen and nitrate ions. The concentration of the nitric acid is therefore reduced to about 0.05 M through denitration by means of formic acid. To prevent the hydrolysis and the precipitation of some components, particularly Pu, acetic acid is added as complexing agent to the solution before denitration. The elements Nb,... 

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