high pressure grinding rolls main view
hihigh pressure grinding rolls side view
hpgr installed for ore grinding
hydraulic station for HPGR

    Long-term work practice shows that the energy consumption and wear part consumption of the crushing process are significantly lower than those of the grinding process, so more crushing and less grinding is an important principle that should be adhered to in the material crushing process. High pressure grinding rolls or HPGR is such a kind of equipment that uses this principle for crushing operations.

    HPGR has been widely used in fine crushing of metal ore beneficiation plants, crushing in cement industry, granulation in chemical industry and fine grinding of pellets to increase specific surface area. It can replace the fine crushing operation, realize more crushing and less grinding, improve system production capacity, save energy and reduce consumption, and have high reliability.

    Served Industries:  Metallurgy, Mining, Cement, Chemical, etc.
    Common material: iron ore, limestone, cement clinker, ceramic materials, diamond, gold ore, copper ore, etc.

    Working Principles

     

    principle of high pressure grinding rolls

    The material is fed by the feeding device between two rollers rotating in opposite directions, and the rollers exert a large extrusion pressure on the material.

    The first is that the irregularly shaped large material blocks are subjected to point contact pressure, which reduces the overall volume of the material and tends to be dense, and moves down with the rollers. At the same time, the material is also changed from point contact pressure to line contact pressure, making the material more dense. With the sharp increase of material density, the internal stress also rises rapidly. When the material passes through the minimum gap between the two rollers, it will be subjected to greater pressure, making the internal stress of the material exceed its compressive strength limit. At this time, cracks begin to appear inside the material and continue to expand, causing the material to break from the inside. , forming small cake-like pieces that shatter when moved. In the next process, it is broken down using only a small amount of energy.

    Due to the relatively weak force at the joints between different minerals in the ore, cracks are more likely to occur in these parts during the crushing process of the high-pressure roller mill. The degree of monomer dissociation was significantly higher.

    Rolled material:

    • Grain size highly reduced
    • Micro crack created
    • Grindability raises

    Structure and Main Components

    structure drawing of HPGR

    1. Fixed roll 2. Feeding chute  3. Floating roll  4. Lubrication oil station 5. Motor 6. Reducer 7. Coupling  8. Hydraulic station

    Rolls

    Roll can be the type of built-up welding, compound or inlay.

    Built-Up Welding Compound Inlay
    Material Cement raw meal, cement clinker, etc. Material with low hardness Cement raw meal, cement clinker, etc. Ores with relatively high hardness Ores with higher hardness
    Roll cost relatively low relatively high high
    Service life (h) 8,000 30,000/10,000 20,000
    Running cost relatively low medium low
    Texture Built-Up Welding roll surface for HPGR Compound roll surface for high pressure grinding rolls Inlay roll surface

    Transmission part

    Through hydraulic coupling, the universal connector is connected with the motor. Smooth start, and the reducer adopts planetary gear transmission.

    Lubracation

    Open lubrication.

    Advantages

    1. In comparison to conventional crushing and grinding methods are reached through increase of capacity in combination with – potential benefits to the separation kinetics of downstream processes such as floatation and leaching as consequence of residual micro-cracks generation in the crushed product of low energy requirements, increase of valuable product yield and efficiency of grinding, low space requirements and high availability.
    2. Significantly improve the efficiency crushing and grinding system, reduce electric cost and steel ball consumption in ball mill.
    3. Solid structure, wearable roll surface, high efficiency.
    4. Great crushing ratio, high availability, flexible configurations, cost-effective, meet capacity of 20-1800t/h.

    Applications & Materials

    • Medium, fine and superfine grinding of loose materials
    • In the mineral processing industry, it is arranged in front of the ball mill as a pre-grinding equipment or forms a mixed grinding system with the ball mill
    • Oxidized pellet industry to replace damp mill
    • Industries such as building materials and refractories for grinding cement clinker, limestone and bauxite, etc.
    • Key application in the liberation of diamonds, primary crushing of gold and iron ore and regrinding of concentrate for pellets production. And industries as copper, nickel, zinc, vanadium and molybdenum ores, bauxites and many more.

    Qiant conditions for stable work

    1. Reasonable feeding particle size forms a dense material layer
    2. A certain material pressure ensures that the material is fed into the roller room stably
    3. When crushing, it has sufficient crushing force (varies with different materials)

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