Abstract: Disclosed is a method of pretreating sulphide ores or sulphide ore concentrates having high bismuth contents that have a disturbing influence on further processing of the ores or concentrates, such as to enable the ores or concentrates to be further processed for the recovery of their valuable metal contents or at least to facilitate such processing. The method is characterized by leaching the ore or the concentrate with sulfuric acid over a predetermined time period while supplying heat at a pH below 2, and thereafter separating from the leachate a leaching residue in the form of a product which is leaner in bismuth and more enriched with regard to its valuable metal content than the input material.

Abstract: In compacting an asphalt layer which is continuously deposited by a paver machine, a compacting machine reciprocates behind the paver. With the aid of signals from sensors (3) for temperature, sensors (5) for movement velocity of the compacting machine, sensors (7) for change of path, and sensors (9) for static/vibratory compacting operation, a processor (1) determines the position of the compacting machine continuously in relation to the paver, and other variables for each area segment passed by the compacting machine. The position of the compacting machine is displayed symbolically on a monitor (19) and the variables measured and determined for each passed area segment are stored in a memory (17). For each passed area segment, a total index number can be determined for this area segment, which on the monitor (19) is displayed as a field having a color or light intensity which is proportional to this total index number.

Abstract: A roller machine for compacting is provided with control devices for varying the oscillation movement of the body. The movement of the body may be affected by a weight attached thereto. The oscillation of the vibration body is measured. From this measurement, the portion of the oscillation is determined having a frequency corresponding to half the excitation frequency and the portion for other oscillation, in particular the excitation frequency, are also determined. The excitation of the vibrating body is controlled so that the harmonic component having half the excitation frequency will be in a predetermined proportion of the component of the oscillation component. Such control avoids undesired oscillation movement.