The leaching process is a multi-phase chemical reaction process carried out at the solid-liquid interface. It can be roughly divided into three steps: the leaching reagent diffuses into the surface of the ore and the crack, and the reagent is adsorbed by the surface of the ore and reacts chemically and on the surface of the ore. The resulting reaction product dissolves and diffuses into the interior of the solution.
The increase of temperature can increase the diffusion coefficient and the velocity constant, and increase the leaching speed. Therefore, a solvent having a higher boiling point is used as a leaching agent as much as possible, and leaching is performed as close as possible to the boiling point of the reagent, and a high pressure is used to increase the boiling point of the solvent.
The particle size of the mineral raw material has a great influence on the solid-liquid phase area and the slurry viscosity. In a certain particle size range, increasing the grinding fineness can increase the leaching speed. The fineness of the grinding fineness not only increases the grinding cost, but also increases the viscosity of the slurry, thereby increasing the diffusion resistance.
The concentration of the leaching reagent is one of the main factors affecting the leaching speed. Since the concentration of the reagent on the surface of the ore is small, the leaching speed mainly depends on the initial concentration of the leaching reagent, and the initial concentration is higher. The leaching speed is greater. The amount of leaching reagent is mainly determined by factors such as the consumption of the leaching reaction, the remaining concentration, and the liquid-solid ratio of the slurry.
The liquid-solid ratio of the leached pulp affects both the leaching reagent consumption and the viscosity of the slurry, thereby affecting the leaching efficiency and subsequent treatment. Increasing the slurry-to-solid ratio can reduce the viscosity of the slurry, which is beneficial to slurry agitation, transportation, solid-liquid separation, and high leaching rate. However, the consumption of the leaching agent will be increased, and the amount of subsequent processing will be large.
Stirring can reduce the thickness of the diffusion layer and increase the diffusion coefficient. The leaching speed and leaching rate of the stirring leaching are often higher than the leaching leaching. However, the stirring strength must be appropriate.
When other conditions are constant, the leaching rate increases as the leaching time increases, but too long a time will reduce the productivity of the equipment.
In addition, physical properties (such as permeability, porosity, etc.), chemical composition and structural structure of mineral raw materials also have a great influence on the leaching rate.
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