ACIDEST - Acid Distillation Unit
The principle of surface evaporation is especially suitable for the purification of liquids by distillation. Unlike boiling evaporation no fog or aerosol is produced. The distillate is therefore of very high purity. For an analytic decomposition substances are needed which have no numerical result in a blank test. In this case it is of advantage to distill the required acid fresh. Only thereby can any contamination by storage be avoided. During the construction phase of the ACIDEST the experience of well-known trace analytical specialists was taken into consideration. All contact of liquid and sockets is avoided. The sockets of filling tube and collecting bottle are arranged in a way that drains impurities to the outer wall.
The apparatus is filled by a specially formed funnel. After having started the operation this funnel is rotated by 90°. So the Ushaped outlet is filled with liquid and acts like a syphon between apparatus and outer atmosphere. Pressure balance takes place through this syphon during the heating and cooling period.
Electric heating is done by two infrared elements of each 400 Watt at a voltage of 220 V. The full power is necessary for the distillation of sulfuric acid, whereas water, hydrochloric acid and nitric acid can be distilled with only 200- 500 Watt. In this case the ACIDEST is used best in connection with an usual in the trade electronic power regulator.
During the construction phase of the ACIDEST a high value was set on easy handling. On the stainless steel frame a high-adjustable console for the collecting flask can be installed either on the right or left side. For thorough cleaning the infrared elements can be removed easily. The coolant joints have GL 14 screw connection. The bottom is emptied through the filling tube which is installed at a hight which ensures that the liquid cannot wet either the condenser or the infrared element.
After filling the apparatus with 700 ml of liquid the following distillation yields are obtained approximately in the state of equilibrium (heating period is not considered):
The exceptional high purity of the liquids distilled only once in the ACIDEST was tested in wellknown trace analytical laboratories. As a starting material demineralized water and common p.a.-acids with metal contents of up to 100 ng/ml and more were used.