Conditioning is more effectively done in so-called contact tanks than in ordinary agitation tanks. Generally, a conditioning tank is a small agitator into which the pulp is pumped just after lime, cyanide, or flotation reagents have been added to it, the chief purpose being a thorough mixing. The period of contact is determined in the laboratory and depends upon the nature of the ore, the physical condition of the pulp, and the amount and kind of reagents.

The size of the conditioning tank is dependent upon the period of contact and the tonnage to be treated. Broadly speaking, any preparatory machine may be spoken of as a “conditioner.” Grinding is merely conditioning the ore for cyanidation proper. If fine grinding is essential, then ball mills, tube mills, and classifiers become important conditioners.

The thickening of pulp may be termed conditioning for subsequent cyaniding operations. Air lifts in agitators are likewise conditioners.

I have done engineering design for a conditioning tank used for selective molybdenum flotation feed pulp pretreatment. A residence time of 1 hour was used. The plant reported that flotation performance was significantly affected (meaning losses of molybdenum) whenever the conditioning step was by-passed due to agitator breakdown.

One example of conditioning would be in the conditions that takes place in the differential flotation of lead and zinc ore that also has pyrite in it. First there is conditioning in the ball mill as certain reagents are added to depress the zinc and pyrite so that you can float the lead. Then the classifier overflow go's to a conditioning tank that is of the size to keep the pulp in it until it has been in there long enough to give you the proper contact time, determined in the laboratory and or the pilot mill. The reagents for lead flotation are added here and lead flotation follows. The pulp then flows into another conditions tank where the pH is kicked up to depress the pyrite and help zinc flotation. The pulp then go's into another conditioning tank where the reagents are added to float the zinc. As you can see there are several places where conditioning takes place each done to prepare the pulp for the next step.

f your feed throughput to the leach agitation tanks is 2500 tpd (104 t/hr) and the ore feed is @ S.G of 2.6, how do you work out your required thickener volumes downstream?