Production Capacity Of Vibrating Screen

Vibro screen manufacturer will share this article with you.

The more products you plan to sort, the more surfaces you need to filter. The most immediate symptom of a screen that is too small is that its effectiveness is reduced because it cannot let so many particles pass through the holes.

On the other hand, the smaller the size to be sorted, the more surface is required, because the smaller the hole, the less the number of products that can pass.

Vibration frequency of vibrating screen

As a general rule for large classification, low-frequency and large-amplitude vibrations are best, while fine-classified high-frequency and small-amplitude vibrations are best. In other words, if the particle is large, a slow and wide movement is better, in this case the particle jumps are few but large, if it is small, it is smaller than many jumps but smaller. This is a problem that the particles do not pass through several single jump holes.

The importance of correct feeding

In the screen, as in any sorter, it is necessary to use the width of the entire work surface from the beginning. If the product falls on the screen surface "piled", the particles at the top of the pile will not touch the screen or the screening element until the pile is vibrated and disappears. When this happened, it had already crossed half of the earth's surface. In other words, we wasted the surface and caused a very important production loss. At the same time, the area where the piles are located will also be severely worn, and additional maintenance costs will follow. It also increases the risk of clogging, especially for low-density products, if the pile is much higher. This is meaningless, it is impossible to accept for correct screening.

This is why it is necessary to pay attention to the implementation and design of the pipes that dump the product on the screen, and use auxiliary means such as vibrating distributors when necessary.

Good screen and bad screen

A good vibrating screen must be reliable, minimize wear and maintenance, and have strong vibration like any vibrating screen: the more vibrating, the better, that is, the higher the production efficiency.

On the other hand, most "bad" screens are not really bad, but not suitable for use: if the product is wet and sticky, it will stick to the metal screening element instead of the polyurethane screen. If dry and fine, the screen should be dust-proof. If you are screening large and heavy particles, the screen should be very strong. If it is very sturdy and used with a good product, it will consume more power and maintenance costs than required.

The combinations are endless, and a good choice, suitable for use at the beginning, will save the user from having to remember this machine again in his life, or at least until he needs to install another screen.

The Importance Of Coal Washing

Coal washing is actually an important step in coal preparation. When washing the coal, non-coal materials and unnecessary raw materials are washed from the original ore. Through the coal washing plant, qualified products will be reached.

Why is coal washed(the importance of coal washing)?

The raw coal is mixed with many impurities during the mining process, and the quality of the coal is also different. The internal ash content of the coal is small, but the internal ash content is large. The products produced after coal washing process are generally divided into meteorites, medium coal, grade B clean coal, and grade A clean coal.

By washing coal, the cost of coal transportation can be reduced and the utilization rate of coal can be improved. Clean coal is an energy source generally used as fuel, and the fine coal in bituminous coal is generally used for coking.

The main reasons for coal washing are as follows:

1. Improve coal quality and reduce coal pollutant emissions

Coal washing can remove 50% to 80% of ash and 30% to 40% of total sulfur (or 60% to 80% of inorganic sulfur) in coal. Burning coal can effectively reduce soot, SO2 and NOx.

Emissions, washing 100 million tons of thermal coal can generally reduce 600,000 to 700,000 tSO2 and remove 16Mt of meteorites.

2. Improve coal utilization efficiency and save energy

The improvement of coal quality will significantly increase the efficiency of coal utilization.

Studies have shown that: coking coal ash content is reduced by 1%, iron-making coke consumption is reduced by 2.66%, and iron-making blast furnace utilization rate is increased by 3.99%; the use of washed anthracite to produce ammonia can save 20%;

For every 1% increase in coal ash used for power generation, the calorific value will decrease by 200~360J/g, and the standard coal consumption per kWh will increase by 2~5g; when industrial boilers and kilns burn coal, the thermal efficiency can be increased by 3%~8%.

3. Optimize product structure and improve product competitiveness

The development of coal washing is conducive to the transformation of coal products from a single structure, low quality to multiple varieties and high quality, and to achieve high-quality products.

There are many coal consumers in my country, and the requirements for coal quality and variety are constantly increasing. In some cities, the sulfur content of coal is below 0.5% and the ash content is below 10%.

If coal is not developed, it will not be able to meet market demand.

4. Reduce production waste

Because the coal-producing area is far away from the economically developed and rich coal resource areas, the coal transportation volume is large and the transportation distance is long.

The average transportation distance of coal is about 600 kilometers. After washing, the coal can remove a large amount of impurities and wash 100Mt raw coal, can save 9600Mt-km capacity.

What Is a Vibrating Screen?

Also referred to simply as a screen, a vibrating screen consists of a vibrating chassis that supports one or several surfaces or screen elements inside.

The screen serves to classify different particle sizes from bulk products in a continuous process. The inlet material (raw material) is pushed from the part where the screen is fed to the other end, and the particles are separated according to their size, shape or density. There is also a vibrating screen loaded by the center, and the product moves in the radial direction to the outer output.

For the correct advancement of product, the process must be continuous. If the screen surface is horizontal, it is due to vibration. Most screens have a certain inclination, and the advancement of the product is due to a combination of gravity and vibration.

Screening element

The screening element is a flat surface or a slightly curved surface with perforations of a certain size, so that when the product is poured in bulk on the element, it only passes through those particles whose size is smaller than the perforation size.

The screening element can be a metal or nylon wire mesh, passing through a rod between the materials, a metal sheet with circular, square or hexagonal perforations, or a more or less hard rubber or polyurethane perforated sheet.

The type of element is selected according to the application, nature of the product, the size and shape of the particles, abrasion resistance, adhesion, humidity and temperature.

A screen can have several screen elements on the top of each screen to form different floors. In this case, the floor with larger holes is placed on the upper part, while the members with smaller and smaller holes are installed in turn on the lower floor slab. In this way, each particle is trapped between the floor where the cutting point (opening) is larger than the particle and the floor where the cutting point is smaller.

Screening efficiency with vibrating screen is much higher

The traditional non-vibrating screen is composed of a fixed mesh with a large inclination angle. When vibration is introduced, the product vibrates and the particles jump on the screen surface without sliding. Each jump is an attempt by a particle to pass through a hole. If the machine vibrates, the probability of this happening is much greater. In other words, the effect is much greater.

When a particle jumps and falls again, it can do so in a hole or an area without holes. If the screening element is a wire mesh, the particles can fall on the wire or on another particle without squeezing through the hole through which it should pass. This is why the efficiency without a screen is 100%, because it requires an infinite number of jumps, so that all smaller particles, that is, holes, will leak.

The concept of screening efficiency is very clear: it is the weight of the particles actually filtered through the holes divided by the percentage of the total particles that should be sieved.

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Why Should Coal Be Washed?

Coal from coal mine is a complex material mixture with multiple physical properties. In addition to coal itself, this mixture also contains rocks, sand and various minerals. Therefore, coal must be cleaned before being sold to consumers. The cleaning process includes a series of steps, and finally produces products that are particularly suitable for specific consumer needs. The earliest of these steps is crushing and sorting. These two processes can reduce coal to the form required by consumers.

The coal washing plant has improved the coal washing process and quality, thereby increasing the price. Coal washing technology also helps reduce emissions from combustion.

How to wash coal?

There are two main coal preparation methods, one is density separation and the other is froth flotation. Both processes depend on the fact that the particles from which the coal sample is made have different densities. For example, when water is added to the sample, the particles will sink to different depths according to their density. In this way, the various components of the sample can be separated from each other.

Purpose of coal washing equipment:

1. Reduce water and energy-intensive coal production

The coal washing program includes factory installation and independent modules to optimize beneficiation capacity. In other words, this means maximizing the ore recovery rate while using less water, energy or other consumables in the process.

Another important feature is water conservation. By enhancing water conservation, zero discharge of wastewater and reducing carbon emissions, this solution helps to achieve a more sustainable process.

2. A more sustainable process helps reduce operating costs

To meet the needs of customers for greater flexibility and efficiency in terms of sustainability. Our philosophy is to provide comprehensive solutions for the industry.

Structural characteristics of coal washer:

1. Standard length valve body can be used, and the combined shape can be selected according to needs.

2. Coal washing technology-the use of CNC pneumatic valve, high degree of automation of coal washing.

3. Coal preparation method-double-amplitude pulsed water flow, good bed stratification effect and high clean coal yield.

The Relationship Between Slurry Pump Life And Correct Use(2)

(2) Ensure that the pump runs under the allowed slurry material. When using it on site, ensure that the density of the slurry and the largest particle size are within the range specified by the slurry pump model. Excessive density will cause excessive friction between the slurry and the pipe wall, which will damage the parts in severe cases. If the particles exceed the maximum allowed by the pump, the pump may vibrate, directly causing damage to the flow parts.

(3) When using a slurry pump, install a high-pressure air pipe in the feed pipe to prevent the deposit of slurry materials before the pump is started. Avoid running the pump without closing the high-pressure air pipe, otherwise it will cause high-pressure air in the slurry. Due to the low inlet pressure of the pump, the gas in the feed pipe expands rapidly. After entering the high-pressure zone through the impeller, the protective plate and the volute cause impact and aggravate wear.

(4) Avoid using a slurry pump when the filling height is insufficient. Otherwise, the absolute pressure of the suction slurry may be less than or equal to the vaporization pressure at the site temperature. A part of the liquid in the slurry will vaporize and form bubbles, thus cause cavitation. Therefore, it is necessary to ensure the liquid level in the suction pool.

(5) The shaft seal water supply of the slurry pump cannot be interrupted. Most slurry pumps are equipped with a shaft seal water device to ensure the pump body shaft seal. Ensure that the water in the device is sufficient.

3. Maintenance of slurry pump

Timely and correct repairs and maintenance can maximize the service life of the slurry pump.

(1) Adjust the gap between the slurry pump impeller and the guard plate or pump casing. This gap has been adjusted before leaving the factory, but after a period of use, due to wear and other reasons, the gap between the impeller and the guard plate or the pump casing will inevitably change. The size of the gap has a direct effect on the slurry flow rate. After the gap increases, the flow rate decreases, that is, the operating efficiency of the slurry pump decreases. Due to the unavoidable axial movement of the pump during operation under actual working conditions, the gap cannot be infinitely small, and the gap should be adjusted to the minimum required by the assembly of the slurry pump. Regularly observe the flow rate of the pump. If the slurry density is constant, if the gate must be opened to make the flow rate normal, it means that the gap of the pump has increased. You can grasp the regular adjustment rule through daily production and make timely adjustments.

(2) Adjust and repair the unevenly worn pump parts in time. The flow rate at the inlet of the pump is low, and it is prone to wear faster than the upper part of the feeding nipple of the pump and the lower part of the front guard plate. According to the actual working conditions on site, the position can be rotated in time to make all parts wear evenly and lifespan be extended.

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The Relationship Between Slurry Pump Life And Correct Use(1)

 Slurry pump suppliers will share this article with you.

Slurry pumps are widely used due to their low energy consumption and high efficiency. Because of the different usage habits and maintenance methods of various manufacturers, the service life of the pump is different.

1. Reasons for wear of slurry pump

The impeller, guard plate, volute and other parts are the main parts of the slurry pump, and are also the most easily worn parts. Frequent maintenance is required in daily work. By consulting the information and combining the actual situation on the site, the reasons for the wear of the slurry pump can be divided into:

1.1 Erosion

In the normal operation of the slurry pump, the slurry (tailings) impacts the surface of the impeller, guard plate, volute and other parts at a fast speed, causing damage to the pump. Cutting, deformation fatigue and cutting deformation composite wear are three manifestations of erosion wear. The difference lies in the different wear surfaces of failed parts.

1.2 Cavitation

During the operation of the slurry pump, cavitation is prone to occur at the part behind the impeller inlet. When the absolute pressure of the pumped slurry is less than or equal to the vaporization pressure at the site temperature, some of the liquid in the slurry will vaporize. Thereby forming bubbles. When these bubbles flow with the slurry, they will shrink sharply to collapse when they reach the high pressure. After the bubbles have condensed and disappeared, the slurry will quickly fill the pores and strongly impact the conditional surface, causing a part of the pump surface material to fatigue and peel off, and finally causing wear.

1.3 Abrasion

Pharmaceutical additives make the slurry delivered by the slurry pump acidic or alkaline. Such slurry will inevitably corrode the impeller, guard plate, volute and other flow parts of the slurry pump. Abrasion is the combined effect of corrosion and erosion.

In addition to the above three types of wear mechanisms, the service life of the slurry pump is also related to the casting material and design structure of the pump itself.

2. Correct use of slurry pump

(1) When the pump is about to stop running, it should run for a period of time with clean water to remove the slurry in the pipeline to prevent materials from depositing in the feed pipe and volute, otherwise the following situations will occur:

(a) The pump is crushed and cannot be started when it is used again.

(b) Larger shaking will occur when restarting, because the deposited material produces eccentric force during the rotation of the impeller.

(c) The sedimented material blocks the feed pipe.

What Is Coal Cleaning?

Coal that comes from a mine is an intricate combination of materials with a big selection of physical homes. Along with the coal itself, items of rock, sand, and different minerals are contained in the blend. Therefore, before coal can be offered to consumers, it needs to be cleaned. The cleaning procedure contains a number of steps that leads to a product that is especially suited to the requirements of certain customers. Among the earliest of these steps is crushing and also sizing, two processes that reduce the coal to a form required by the customer.
The following action in coal prep work is a washing or cleaning step. This step is essential not just to meet consumer demands, but likewise to make certain that its burning will certainly adapt environmental criteria.
Coal washing is achieved by one of two major procedures, by density splitting up or by froth flotation. Both procedures rely on the truth that the particles of which a coal sample are made have different thickness. When water, for instance, is contributed to the sample, particles sink to numerous depths depending upon their densities. The various parts of the sample can hence be divided from each various other.
Sometimes, a fluid besides water may be utilized to accomplish this separation. In a heavy tool bathroom, as an example, a mineral such as magnetite or feldspar in carefully divided form may be mixed with water, creating a liquid tool whose density is significantly above that of distilled water.
A number of devices and also systems have been developed for extracting the numerous elements of coal once they have been separated with a water or hefty tool therapy. Among the oldest of these devices is the jig. In a jig, the column of water is preserved in a consistent up-and-down movement using a circulation of air. Clean coal particles are carried to the top of the jig by this movement, while larger refuse bits sink to the bottom.
An additional technique of extraction, the cyclone, contains a tank in which the functioning liquid (water or a heavy tool) is kept in a constant round motion. The tank is constructed so that lighter clean coal fragments are thrown out of one side, while much heavier refuse particles are expelled via the bottom.
Drinking tables are one more extraction approach. As the table shakes back and forth, particles are separated by size, creating tidy coal at one end as well as waste products at the other.
In cylindrical separators, a coal blend is fed into a rotating column of air that tosses the much heavier waste fragments outward. They layer the internal wall of the cyndrical tube and fall to the bottom, where they are drained. The clean coal bits stay in the facility of the air column as well as are drawn off at the top of the cyndrical tube.
Froth flotation procedures depend upon the production of small air bubbles to which coal fragments adhere. The amount of absorption onto a bubble depends not only on a bit's density, but also on particular surface area features. Splitting up of tidy coal from waste materials can be achieved in froth flotation by differing aspects, such as pH of the service, time of treatment, particle shapes and size, rate of oygenation, solution thickness, as well as bubble dimension.

In the coal washer procedure, the washability characteristics of coal are applied:
To find the loved one convenience for separation of coal from the refuse.

To find the performance of coal cleaning.
To characterize the type and quantity of contaminations.
To gather the information for creating a separation plant.