神岡鉱山における浮選技術の応用による選鉱廃水の処理

ナガーム浮選機の開発を含む

抄録

The main process of this water treatment consists of ion flotation, precipitation flotation and ultra-fine particle flotation by using NAGAHM flotation machine which was newly developed for such flotations. The characteristics of this flotation machine are as follows:
(1) Aeration rate is very great (2115l/min·m2).
(2) Air bubbles are very finely dispersed in all part of the cell.
(3) State of flowing in the cell is so smooth withont disturbance.
(4) Much froth can be taken out rapidly.
The overflow of 2700m³ per day from a zinc concentrate thickener is one of the effluents from Kamioka concentrator, containing 67ppmCu (CN) ₃^--, 14ppm CN^-, 301ppm ZnS, 1.29ppm CdS, 16.8ppm C₂H₅OCS₂^- and 18ppm frother. The trials had been made to removed copper, zinc, cadmium and cyanide from the effluent.
Sulfuric acid is added to the overflow and consequently Cu (CN) ₃^-- is decomposed into CuCN, C₂H₅OCS₂Cu and CN^-. Then, all other ingredients in the overflow than CN^- are floated and separated from the water. The treated water containing exclusively 30ppm CN^- is recycled effectively to the differential flotation circuit of lead and zinc.
This water treatment method by using NAGAHM flotation machines has remarkably improved quality of the effluent concirninig to environmental problems, bringing about a large profit to the management of the enterprise by (1) the improvement of milling recovery, (2) the recovery of copper zinc, and cadmium in the overflow, and (3) the saving of reagents consumption.