公开(公告)号：CZ251293A3

公开(公告)日：1994-06-15

申请号：CZ251293

申请日：1993-11-23

Applicant: DEGUSSA

Inventor： RIEMENSCHNEIDER HERBERT DR ,  ALT CHRISTIAN ,  CLAUS MARTIN ,  LOROSCH JURGEN DR ,  LEUTNER JOSEF ,  MONCH HEINZ DR

IPC: B01J2/04 ,  B01J2/16 ,  C01C3/10

Abstract: The invention relates to new alkali cyanide granules based on sodium cyanide or potassium cyanide and also a process for the preparation thereof. Commercial alkali cyanide granules comprise irregular particles: disadvantages are, in particular, the tendency to form dust and lumps. Alkali cyanide granules of the invention have practically no abrasion and a reduced tendency to form lumps. The granules are characterised by essentially spherical particles, particle diameters in the range from 0.1 to 20 mm, a bulk density above 600 g/dm , an abrasion of less than 1% and a caking index of at most 4. The granules can be prepared by fluidised-bed spray granulation, by an aqueous solution containing an alkali cyanide being sprayed on alkali cyanide nuclei in a fluidised bed and water being evaporated.

公开(公告)号：PH24130A

公开(公告)日：1990-03-05

申请号：PH36007

申请日：1987-10-30

Applicant: DEGUSSA

Inventor： KNORRE HELMUT DR ,  LOROSCH JURGEN DR ,  FISCHER JOACHIM

IPC: C22B11/08

Abstract: Leaching of gold and/or silver from ores or ore concentrates in an aqueous alkaline cyanide solution with added hydrogen peroxide has so far not been used industrially, because it is uneconomical, i.e. the consumption of H2O2 and NaCN was unduly high. It has been found that the process can be made very economical and disadvantages of the conventional leaching technology can be avoided if the addition of the aqueous H2O2 solution is controlled via the concentration of the oxygen dissolved in the leaching solution, which contains 2 to 20 mg of O2 and preferably 7 to 13 mg of O2 per litre. Preferably, 0.5 to 5% by weight of H2O2 solutions are added under control. The process is applicable to agitation leaching and heap leaching, the H2O2 addition being controlled via measuring the O2 concentration in a measuring stream. At low consumption of H2O2 and NaCN, sometimes the gold yield is even increased and the leaching time is shortened.