Flotation: Pulp Depth & PH Value

The adjustment of flotation pulp includes pulp depth, PH value, etc., The depth and PH value will affect the flotation effect. In the flotation process, pH value has many effects on mineral flotation and is an important factor affecting flotation indexes. Following we will discuss the adjustment of pulp depth and PH value.


Pulp Depth

Slurry depth refers to the weight or series of solid minerals and liquid (water) in the slurry. Concentrators usually express the ratio of liquid to solid or solid depth, and coal preparation plants use solids. The common flotation depths are shown in the following table:


Ore Type Flotation Cycle Rough Selection Concentration
Scope(%) Average(%) Scope(%) Average(%)
Dense Sulfide Ore Copper, iron sulfide 28-40 34 10-30 20
Lead and Zinc Ore Lead flotation 30-40 35 10-30 20
  Zinc flotation 20-30 25 10-25 18
Infiltrate polymetallic ore Copper flotation 18-33 25 10-23 16
  Pyrite and gold flotation 18-40 29 18-30 24
  Lead flotation 25-35 30 15-20 18
coal*   20-22 21 15-18 16
Molybdenum Sulfide Ore Molybdenum flotation 40-48 44 16-20 18

*The concentration is the concentration during the flotation of slime


The flotation depth of the concentrator is closely related to the overflow depth of the classifier. Generally, the roughing depth is the same as the overflow depth of the classifier, and the overflow depth is related to the fineness required by the mill. If the abrasive grains are required to be fine, the overflow is thin; On the contrary, the overflow will be thick. The concentration of scanning is always thinner than that of rough selection. When the particle size of the flotation material is finer, the concentration should be thinner. The influence of slurry concentration on flotation is mainly manifested in the aeration of the slurry, the concentration of the reagent in the slurry, and the production volume.


  1. The influence on the amount of inflation

The aeration amount of the flotation machine varies with the concentration of the pulp, and both too thick and too thin pulp will cause the aeration to deteriorate.


  1. Concentration of agent

Under the condition of a certain dosage, when the slurry concentration is large, the chemical concentration is also high. Therefore, the slurry concentration can be used to appropriately reduce the dosage. In the low-concentration sorting, the dosage should be increased appropriately. Therefore, the high-concentration float When you choose, you can save the amount of medicine.


  1. Production volume

The slurry concentration increases. If the volume and productivity of the flotation machine remain unchanged, the residence time of the slurry in the flotation machine can be relatively extended, which is beneficial to increase the recovery rate. On the contrary, if the flotation time remains unchanged, increase the slurry concentration. The productivity of the flotation machine can be improved.


Generally, the slurry concentration is thinner, the recovery rate is low, but the quality of the concentrate is good, so thicker slurry is used for roughing, and thinner slurry is used for beneficiation. The concentration of sweeping is generally determined by the roughing concentration and does not need to be adjusted. In addition, when the particle size of the material is relatively coarse and the particle size is large, a thicker slurry is often used; on the contrary, a thinner slurry can be used.



The PH value of the pulp

The PH value of ore pulp is one of the important factors to control the flotation process. It not only affects the surface properties of minerals but also enables various flotation reagents.


  1. Effect on the surface properties of minerals PH value has a great influence on the electrical properties of mineral surfaces.

As mentioned above, when PH>mineral zero electric point, the mineral surface is negatively charged; when PH<zero electric point, the mineral surface is positively charged, and the electrical properties of the mineral surface affect the coverage of the fine mud on it and the physics of the agent. Adsorption plays an extremely important role.


  1. The efficacy of the medicament and its effect on the surface of minerals

Most of the collectors used in flotation are ionic. The dissociation of the reagent directly affects the flotation effect, and the PH value is closely related to the degree of dissociation. In order to improve the use effect of the reagent, the pH value of the slurry should be in accordance with the reagent The PH value range that can produce more ions is consistent. For example, the flotation of non-ferrous metal oxide ore with amines is mostly carried out in an alkaline medium. Some medicines are easy to decompose under a certain pH value and make them ineffective, such as xanthate, which dissociates in water to form xanthate radicals, which are hydrolyzed to form xanthogenic acid. Xanthogenic acid is a weak acid, which is extremely in an acidic medium. Easy to decompose, the lower the PH value, the faster the decomposition, resulting in the failure of xanthate.


It is introduced in the contact curve that under a certain reagent concentration, adjusting the PGH value of the slurry can inhibit the minerals or smoothly perform flotation. Therefore, in order to make the agent fully exert its effectiveness, control the effect of the agent and the surface of the mineral, and make the flotation process proceed smoothly, the PH value of the pulp should be properly adjusted during flotation. When various ores are sorted, the appropriate PH value range is shifted over time. According to the experience of long-term production practice, the pH value of common sulfide ore flotation is shown in the following table:


Ore type


Concentration PH Value Ore type


Concentration PH Value
Copper mine 9.5-11.8 Copper Cobalt Ore 10-11
Copper pyrite 9.0-11.5 Lead-zinc mine 7.1-12
Copper molybdenum ore 10-11.5 Copper-lead-zinc mine 7.2-12
Copper molybdenum ore 7.8-9.5 Molybdenum Sulfide Ore 8.5