Abstract: A method for separating fractions of incinerated refuse with a high recuperation yield without requiring special equipment. A first portion of the separation process may be applied to either an initially dry or an initially wet refuse. The refuse is at first screened to a median size. The oversized fraction is crushed and shredded and the non-magnetic fraction separated therefrom is sent commonly to a grinding-rolling mill which also receives the undersize fraction. The undersize fraction downstream of the grinding mill is further treated by a wet separating process, the method achieving separation of ferrous and nonferrous metals, of glasses and silicates, and of magnetic slags.

Abstract: A method and apparatus for geophysical exploration which does not require the installation of a low frequency transmission source in the proximity of the drill hole.A surface pick-up 3 detects the magnetic field component of a low frequency signal, which, after amplification and filtering, is supplied as one input of a comparator 9. A pick-up 7 disposed in a drill hole detects the corresponding magnetic field components within the earth, and its output is supplied as the other comparator input. The amplitude ratios of the signals and their phase difference are provided at the outputs of the comparator. These values make it possible to determine the resistivity variations of the ground.The extent of the detected conductivity layer(s) may be determined by repeating the operation using a second low frequency transmitter positioned at a different azimuth angle from the first, and comparing the output readings.

Abstract: The present invention relates to a process for the synthesis of crystallized wollastonite from a natural material having a high content of calcium carbonate and silica.According to the invention, silica or calcium carbonate are added to the natural material so that the mixture has a silica/carbonate content which varies less than 10% from the value of the stoichiometric ratio, the silica being introduced preferably in the form of crystallized silica having a large surface area, for example, kieselguhr. Crystallized CaSiO.sub.3 is obtained between 1000.degree.C and 1100.degree.C and high-temperature wollastonite, preferably between 1100.degree. and 1200.degree.C, according to the reaction: ##EQU1## The present invention may be used to produce wollastonite intended in particular for use in road surfaces and for the charging materials required in the rubber and plastics industry.