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.

We are slurry pump suppliers. If you are interested in our products, please feel free to contact us.

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.