Influence of flow rate of solution and determination of reasonable flow rate

For any given heap, there is clearly an optimum flow rate or a reasonable range of flow rates. A reasonable flow rate causes the solution to flow down the surface of the ore as a liquid film. In the case of a crack, the position occupied by the air is gradually replaced by the solution due to the capillary force. At this time, the gas-liquid interface existing in some large voids does not change much. The only change is the thickening of the circulating water film. When the flow rate of the solution is large, the large gap originally occupied by the air will be pinched off, forming a part of the large gap with both solution and air, which are surrounded and divided, and finally the air bubbles as a solution due to gravity. The form is squeezed out and rises into the open atmosphere, and the void passage is completely penetrated by the solution.

From the above discussion, we can know that when the solution flow rate is too large, most of the solution flows downward through the non-mineral voids, instead of flowing downward in the liquid film, so that the leaching solution does not leaching. At this point, the solution flow rate is controlled by the hydrostatic pressure at the location where the mineral-free void is located. When the solution flow rate is reasonable, the solution flow rate is mainly controlled by capillary force and gravity.

In the heap leaching operation, the choice of the critical (optimal) flow rate of the leaching solution has been done by the predecessors. Equation (1) is an empirical formula:

K seepage = (1)

Where, K _permeability - the permeability of the heap;

d _ρ - the equivalent particle size of the ore;

v _Pro -critical solution flow rate.

It can be seen from the above formula that the critical flow velocity is related to the equivalent particle size of the ore, that is, to the capillary force, and also to the permeability of the heap. Once the equivalent particle size and permeability of the ore are determined, the feed flow rate of the heap can be determined.

Liquid supply speed is greater than the critical velocity, not only a waste of energy pumping leaching solution, but also the cost of the metal in the leach liquor to reduce the concentration, addition of the subsequent steps.

The liquid supply speed is too low, although the metal concentration of the leachate is increased, but the disadvantages are also many, such as slow metal dissolution rate, long leaching period, and increased impurities in the leachate, which easily cause scaling.

Fully Automatic Washing Machine

Fully automatic washing machine can make your clothes more clean in a very convenient way. With PCB control, different procedures can choose more ways to wash different clothes. Nowadays fully automatic washing machines are widely used in home, hotels and laundry shops.