In the ore beneficiation process, the purpose of the classification operation is to effectively separate the coarse and fine particles, avoid the over-crushing of fine minerals and make the coarse minerals return to the grinding mill for regrinding. The classification effect will directly affect the production capacity of the grinding mill, the effect of finished products, the concentrate grade, and recovery rate in the subsequent separation operation.
At present, the mineral spiral classifier and hydrocyclone separator are two kinds of commonly used classification equipment in concentrators. Before selecting, we need to know the difference between mineral spiral classifier and hydrocyclone separator, then choose the suitable one accordingly.
Use the table of contents below to navigate through the guide:
The common mineral spiral classifiers include spiral classifiers and submerged spiral classifiers. The mineral spiral classifier is usually used for coarse-grained classification, and its diameter of overflow size is generally greater than 0.15mm. The submerged spiral classifier is suitable for the fine classification, whose overflow size is generally less than 0.15mm. Compared with the two kinds of spiral classifiers, the hydrocyclone separator has a better classification effect when treating the fine-grained materials (the range of separation size is generally 0.3-0.01mm).
Generally, the classification efficiency and product accuracy of the hydrocyclone separator are lower than that of the spiral classifier. A large part of the reason is that the hydrocyclone separator will change the final discharging position when the pressure is not up to the standard.
The mineral spiral classifier rotates at a low speed through the spiral and stirs the pulp, so the fine particles are suspended to the top and flow to the overflow weir, the coarse particles sink to the bottom and are transported to the discharge port by the spiral as the return sand, while the hydraulic cyclone needs to discharge the material on the side opposite the inlet port. Once the pressure is not up to standard, the material layer will appear disorderly, resulting in the material cannot be discharged from the discharge port. However, this is not absolute. When the classification size is very fine (such as 0.037mm), the classification efficiency of the hydrocyclone separator is significantly higher than that of other classification equipment.
It is obvious that the occupied area of hydrocyclone separator is significantly smaller than that of the spiral classifier. Generally, the hydrocyclone covers only 1/30-1/50 of the area of the spiral classifier.
The requirement of equipment occupied area limits the application of spiral classifier to some extent.
The mineral spiral classifier has the advantages of simple structure, stable operation, and easy operation. Its simple operation process and stable working state not only greatly reduce the cost of maintenance and replacement, but also ensure the construction time so that the classification of the operation is more guaranteed. Relatively speaking, the operation of the hydrocyclone separator is more complicated, and the ore feeding pressure, concentration, and particle size will affect its classification index, so its operation accuracy is required to be high.
In terms of equipment investment, the price of hydrocyclone is lower than that of spiral classifiers. In addition to its own equipment, a series of necessary auxiliary equipment is needed for hydrocyclone, such as distributor, valves, pumps, etc., which corresponding increase a part of the equipment investment.
In terms of equipment maintenance, the main wear parts of hydrocyclone separator are lining and overflow pipe. The frequency and degree of wear are caused by the material size, shape, solid content, and other factors. Therefore, the service life and maintenance cost can be obtained accurately only in the practice of the actual plant. The maintenance of mineral spiral classifier is mainly the replacement of spiral lining and other routine maintenance.
In general, the equipment investment cost of the spiral classifier is higher than that of hydrocyclone.
Classifier equipment works in close liaison with grinding equipment in the mineral processing production line, they jointly provide the appropriate size of the ore (material) for the separation operation. The selection of mineral processing equipment is not a unilateral decision, which is the result of comprehensive consideration. In production, it is suggested to choose single or multiple classification equipment according to the related equipment selection given by the mineral processing test.