Abstract: In the method, the spent stripper solution for tin or a tin mixture is treated to precipitate dissolved or suspended metal compounds. On the one hand chemicals for reuse, and on the other hand metals such as copper, tin, lead and/or iron are recovered from the waste water streams. Efficiency of the precipitation is improved by heating of the stripping solution at elevated temperatures, and by the addition of a precipitating reagent. Once the precipitate is removed, the remaining liquid may be reused, typically as an admixture with a fresh solution. In the production method of a regenerated stripping solution for tin comprising at least one inorganic acid, ferric ions, at least one organic acid, and at least one organic additive, the stripping solution is heated at elevated temperatures, precipitating reagent is added, precipitated matter is separated and removed, and one or some of the acids or additives mentioned are added for the recovery of the desired tin stripping capacity.

Abstract: A method and device for characterizing the compaction result of a powder and monitoring the compaction of the powder during the compaction process. In the method sound emission produced by the compaction process is measured by a sensor and transformed into a frequency spectrum in which the sound intensity is presented as a function of frequency. The intensity of the band relating to the sound emission arising from the compaction of the powder is recorded using different compressive forces, and the compaction result is obtained as a function of the intensity of the band relating to the sound emission arising from compaction.