The leaching of NaOH from 4 : 5-sodium-titanate produced in an autocausticization process: Filtration properties of the 1 : 3-sodium-titanate and leaching in a filter press

The filtration properties of 1:3 sodium titanate and the leaching of sodium hydroxide from 4:5 sodium titanate have been studied experimentally as wel l as theoretically. The experimental part was carried out using two differe nt sets of equipment: one for the filtration experiments and one for the le aching experiments. The filtration analysis showed that the average specifi c resistance decreased with increasing pressure. This is likely due to "flo w stabilisation" which occurs at high liquid velocities in a filter cake. T he leaching experiments showed that there are several parameters which infl uence the leaching rate, e.g. temperature, concentration and flow rate of t he washing liquid. The mathematical model developed within this work was fo und to describe the overall kinetic behaviour with reasonable accuracy, but it did not describe the detailed kinetic behaviour. Thus, there are still phenomena that must be taken into account.