Abstract: A method for the re-treatment of residue generated in the course of removing fluorine from waste water.The method comprises the step of: drying the residues consisting of rare earth fluorides, which are generated in the course of treating the waste water with a rare earth compound to remove fluorine ions from the waste water; mingling the rare earth fluorides with a sodium hydroxide solid; heat treating the rare earth fluorides at temperatures ranging from approximately 320.degree. to approximately 450 .degree. C. for times ranging from approximately 0.5 to approximately 5 hours; and applying wash and dry to the heat-treated resultant, in due order.The invention pertains to the reuse of rare earth elements used in the treatment of fluorine. Products obtained by carrying out the method contain rare earth hydroxides, which are useful as materials for glass abrasive or for treating fluorine, catalysts, and other materials for the fields of using a variety of rare earth.

Abstract: An apparatus for automatically magnetizing pieces cut to have an optional shape and size and sorting magnets magnetized in terms of quality. For the sorting, the apparatus includes a testing station for applying an external magnetic field in the form of pulses or the like to each magnet, sensing a variation in characteristic of the magnet caused by the applied magnetic field, and performing a measurement, an analysis and an evaluation for the characteristic of the magnet. The apparatus also includes a feeding station for separating one from magnets stacked in a supplying station and feeding it to the testing station, and a sorting station for sorting the tested magnet as a good one or as a bad one, based on the test result obtained in the testing station and putting it in a container.

Abstract: Disclosed herein is a method for treating a spent copper-refining electrolyte to remove impurities such as copper (Cu), arsenic (As), antimony (Sb), bismuth (Bi), nickel (Ni) and the like by using a hydrogen sulfide gas. The method comprises the steps of: (a) blowing a hydrogen sulfide gas into the spent electrolyte to precipitate copper sulfide (CuS); (b) blowing air into the coprecipitates solution obtained in the above step (a) to oxidize arsenic, bismuth and antimony thereby redissolving them into the solution, and the solution is subjected to solid-liquid separation to separate copper sulfide from the liquid; (c) blowing a sulfur dioxide gas into the copper-depleted liquid to reduce arsenic, bismuth and antimony and blowing a nitrogen gas to purge the remaining sulfur dioxide gas; (d) blowing a hydrogen sulfide gas to precipitate arsenic, bismuth and antimony in the form of sulfides and blowing a nitrogen gas to purge the remaining hydrogen sulfide gas and separating arsenic sulfide (As.sub.2 S.sub.