| 摘要 |
<p>PURPOSE:To separate and recover easily and efficiently both of a magnetic powder and a base material each in a pure form, by immersing a magnetic recording medium in a solution of a basic substance and a surfactant in a specified concentration and agitating the formed mixture. CONSTITUTION:A magnetic recording medium formed by coating a synthetic resin base material such as polyethylene terephthalate with a magnetic material (e. g., ferrite powder) with the aid of an organic binder based on urea resin or the like is cut into fine chips. These chips are immersed in a solution (5-100 deg.C) of a mixture of 0.1-20wt% basic substance (e.g., NaOH) and 0.01-5wt% surfactant (e.g., a 1:1 sodium oleate/dodecylbenzenesulfonic acid mixture) and agitated to precipitate peeled and pulverized magnetic substance powders within a short time and float the organic binder on the surface by adsorption on bubbles. The bubble layer is separated and removed and the remaining liquid is treated by filtration, centrifugation, or a like operation to separate the base material from the magnetic substance powder, which are then washed, dried, and recovered.</p> |
