Advantages and disadvantages of spiral classifiers and hydrocyclones

Both spiral classifiers and hydrocyclones belong to mineral processing classifiers.It is widely used in metal and non-metallic mineral processing plants.Today I will introduce the advantages and disadvantages of these two grading equipment.

Spiral classifier is a kind of mechanical classifier, which consists of a U-shaped sink, a spiral device, a transmission device, a lifting mechanism, and a supporting bearing.

The working principle of the spiral classifier is: after grinding, the ore slurry is discharged from the ore feed port of the spiral classifier into the U-shaped groove. After the spiral device continuously rotates and agitates the ore slurry, the light and fine particles are suspended on the surface of the ore slurry, overflowing from the overflow weir, and the coarse and heavy particles settle to the bottom of the groove, which is transported by the spiral device to the ore discharge port and re-enters the grinding machine for grinding.

There are generally two classification methods for spiral classifiers. One is to divide into single-spiral classifiers and double-spiral classifiers according to the number of spiral shafts; the other is to divide into low-weir type, high-weir type and sunken type according to the height of the overflow weir.

Hydrocyclone is a kind of extension equipment that uses centrifugal force. It is mainly composed of a ore supply pipe, a tapered container, a cylindrical shell, a sand discharge nozzle, and an overflow pipe.

The working principle of the hydrocyclone is: the ore slurry enters the cylinder of the cyclone in the tangent direction through the ore supply pipe at an inlet pressure of 0.5-2.5kg/cm2, that is, it rotates in the device and generates great centrifugal force. Under the action of centrifugal force, the thicker slurry particles are thrown towards the wall of the device, descending with the spiral line, and discharged by the sand discharge nozzle; the finer ones, together with the water, form an ascending spiral flow in the center of the vertebral body and are discharged through the overflow pipe.

The advantages of hydrocyclones are: simple structure, no moving parts; small size, small footprint; large processing capacity per unit area, easy operation and maintenance, low cost; high grading efficiency and sorting accuracy; less slurry residence quantity and time; and the advantages of supporting large ball mills are more obvious.Of course, hydrocyclones also have their shortcomings, such as the slurry needs to be transported by pump head, stable working pressure, high requirements for the particle size and concentration of the slurry, and more serious wear and tear.

Compared with hydrocyclones, the outstanding advantages of spiral classifiers are: reliable work; easy to operate; stable grading area, fine overflow particle size can be obtained; large sink slope, easy to form artesian sand return with the grinder, etc., The disadvantage of spiral classifiers is relatively bulky; low grading efficiency; the spindle is easy to break and maintenance is extremely inconvenient; the bearing at the bottom of the overflow is poorly sealed; it is not easy to obtain a finer graded overflow fineness, especially when the overflow particle size of 0-0.074 mm is required to account for more than 90%, it is difficult to meet this requirement.