Precious metal-containing concentrates are subjected to high temperature chlorination using HCl gas, an optional reduction, an oxidation and finally a reduction, to remove most of the base metals especially the amphoteric elements.

Lipids, especially crude glyceride oils and phosphatides, are refined by contact under superatmospheric pressure with ultrafiltration membrane, preferably in a miscella in a solvent permeable to the membrane. An additive solute is introduced into the lipid which is impermeable to the membrane to aid the filtration, which may be a phospholipid, gum or soap. The latter may be produced in situ by neutralizing free fatty acid present, especially with ammonia or polyvalent metal compounds and the add...

Refining elements for refining discs for disc refiners for the manufacture of mechanical pulp are disclosed, having improved wear resistance by utilizing alloys with precipitated carbides. An improved service life is obtained with a refining disk having the following analysis in % by weight: 2.96 C, 0.77 Si, 0.82 Mn, 24.2 Cr, 5.16 v, 0.04 Ni, 0.03 Mo, and the reminder Fe and impurities. After casting, the refining segments are hardened and annealed and assume a hardness of 57-63 HRC.

Refining elements for use with disc refiners for the processing of fibrous materials are disclosed. The refining element include a refining surface having a plurality of bars and intermediate grooves, with the bars having an upper surface and a pair of side surfaces defining longitudinal edges, with the plurality of bars including a plurality of recesses disposed along at least one of the longitudinal edges, the recesses including open portions in both the upper surface and one of the side surfa...

Refining elements are disclosed for use in the refining of fibrous material in which the refining elements include a pattern of bars and intermediate grooves between the bars. The bars extend in an arc-shaped direction outwardly over the refining element and the upper surface of the bars includes smaller grooves which form angles of from about 10.degree. to 90.degree. with respect to the longitudinal direction of the bars so that the smaller grooves on the bars extend substantially radially.

Refining elements for use in a refining apparatus for refining lignocellulosic fibrous material between a pair of refining members are disclosed. The refining element is adapted to be mounted on the inwardly facing conical surface of an outer stationary refining member and includes a plurality of bars and intermediate grooves in which the bars extend along the refining gap and include a pair of side walls and an upper surface forming an acute angle with a least one of the pair of side walls.

Apparatus for use as at least a portion of the refining surface of a refining disk is disclosed for use in a refiner for lignocellulosic material disposed in a refiner housing, the apparatus including a refiner segment having a periphery and mountable on the refining disk in juxtaposition with an opposing refining disk for treating the lignocellulosic material in the refining gap therebetween and a guide disposed along the entire periphery of the refining segment whereby lignocellulosic material...

A method of in situ control for finishing semiconductor wafers to improve cost of ownership is discussed. A method to use business calculations combined with physical measurements to improve control is discussed. The use of lubricating layer control in the operative finishing interface is discussed. Use of business calculations to change the cost of finishing semiconductor wafers is discussed. The method aids control of differential lubricating films and improved differential finishing of semico...

Refining elements are disclosed for use in refiners in which the refining elements comprise a refining surface with a plurality of raised bars alternating with a plurality of grooves. The raised bars at the inlet of the refining path have a first spacing and form a first angle with respect to a radius or generatrix defining the refining path and the plurality of raised bars at the outlet of the refining path have a second spacing and form a second angle with respect to the radius or generatrix, ...

Refining elements for use in a disk refiner for disintegrating and refining lignocellulose-containing material is disclosed including a pair of opposed refining elements on opposed refining disks which are relatively rotatable with respect to each other, the first and second refining elements including inner, intermediate and outer refining zones including pluralities of alternating bars and grooves extending substantially radially therealong, in which the bars on the inner refining zones on bot...