A paper on ultrafine grinding equipment for non-metallic mineral powders

In the field of non-metallic ore, typically the particle size distribution of the product is referred to as ultra-fine powder d97≤10μm products, including micro-nano powder material, and the corresponding processing technique called ultrafine grinding.

1, first come to understand the superfine crushing technology

Since there are certain requirements for the particle size and gradation of ultrafine powders in various industrial sectors, the general ultrafine pulverization technology includes a pulverization process that reduces the particle size to "ultrafine" and makes the ultrafine powder "specific". Fine grading technique for particle size distribution.

2, common superfine crushing equipment

Classification from processing methods, there are dry superfine pulverizing equipment such as jet mill, high speed mechanical impact mill, rotary mill, roller mill, etc. There are wet pulverizer grinding and stripping machine, sand mill, high pressure homogenizer, colloid mill, etc. There are also agitating ball mills , vibrating ball mills, rotary barrel ball mills, planetary ball mills, etc., which are available for both wet and dry.

(1) Jet mill

Jet mill, also known as jet mill or energy jet mill, is a mechanical device that uses super high-speed airflow or superheated steam to superfinely crush solid materials. It is one of the most important superfine crushing equipment. Thanks to the internal grading function and the external grading device, the jet mill can process powder products with d97=3-5μm, and the output ranges from tens of kilograms to several tons per hour. The product of jet pulverization also has the characteristics of narrow particle size distribution, smooth particle surface, regular particle shape, high purity and high activity.

Mechanical impact type ultra-fine grinding machine (mechanical impact grinding) refers to a rotating body (rod, hammer, blade, etc.) that rotates at a high speed around a horizontal or vertical axis to cause intense impact, impact, shearing, etc. on the material. An ultrafine pulverizing device that smashes particles by creating a strong impact collision between the wall or the fixed body and the particles. Which are widely used in coal-based ultra-fine kaolin, calcite, marble, talc, pyrophyllite medium hardness metallic mineral pulverization.

At present, the ultra-fine roll mills used in the industry include centrifugal ring roll grinding and roller grinding, etc., which are mainly composed of a body, a main shaft, a boring plate, a grinding ring, a grinding ring bracket, a grinding ring, a split ring, and a grading wheel.

(1) Sand mill

The sander is another type of agitator or bead mill. Named for the initial use of natural sand and glass beads as grinding media. Sand mills can be divided into open and closed types, each of which can be divided into vertical and horizontal.

The abrasive stripper is actually a disc agitator or sander. During operation, the slurry is fed into the grinding and peeling cylinder through the feeding pump system. The cylinder is provided with a certain amount of stripping medium. The transmission mechanism drives the stripper (plate) to rotate at a high speed, and the stirring and dispersion of the stripping disc are used to make the slurry The solid particles are ground. Particles meeting the fineness requirements are free to flow out of the discharge port and collect with the slurry upward through the screen.

The colloid mill uses a pair of fixed grinding bodies (stators) and a high-speed rotating grinding body (rotor) to produce strong shearing, friction, impact and the like, so that the material to be treated passes through the gap between the two grinding bodies. Under the action of the above-mentioned forces and high-frequency vibration, it is pulverized and dispersed. There are three types of vertical, vertical and horizontal models.

The high-pressure homogenizer utilizes the cavitation effect when the pressure of the high-pressure jet falls, so that the material is crushed by high-speed impact, bursting and shearing. The high-pressure homogenizer has both pulverizing effect and homogenizing effect.

5, dry and wet dual-use superfine crushing equipment

(1) Vibration mill

Vibrating mill is a fine grinding and ultra-fine grinding device that uses grinding media (spherical and rod-shaped) to impact, rub, shear and so on the material in a high-frequency vibrating cylinder. It can be used for dry crushing. Can be used for wet pulverization.

The vibration mill adjusts the amplitude of the vibration. Vibration frequency, media type and media size allow for the processing of different materials, including high hardness materials and various fineness products. The average particle size of the product can reach about 1 μm.

Agitating mill (stirring mill) refers to a type of ultra-fine grinding equipment consisting of a stationary cylinder filled with grinding media and a rotary agitator.

The agitating grinder mainly stirs the grinding medium by the agitator to generate irregular movement, and applies impact or impact, shearing, friction and the like to the material to pulverize the material.

Ball mill, also known as ball mill crush. Due to its simple structure, the ball mill occupies a very important position in the field of superfine pulverization. The main working principle of the ball mill is to drive the material to be crushed by grinding and grinding with various grinding materials (such as rods, balls, etc.) of various materials and shapes loaded in the cylinder by a rotating body. Ball mills can be divided into ordinary horizontal ball mills, horizontal counter-rotating ball mills, vibrating ball mills, centrifugal ball mills, planetary ball mills, etc. according to their different movement modes.

1) Ordinary horizontal ball mill

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