Slurries are a blend of liquids and solids. Often used for transporting large quantities of solids that have undergone particle reduction processes, these materials are added to water or other liquids to allow them to be pumped away via a slurry pump. It’s a much more cost-efficient means for moving bulk solids after processing, including for abrasive substances. Slurry pumps are commonly used in many of these applications.
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There are two basic types of slurry that abrasive slurry pumps are designed to transport. Non-settling slurries contain very small particles that remain suspended in the liquid, making it more viscous. Settling slurries contain solids that tend to sink to the bottom of fluids, except when agitated. Regardless of the type, materials within a slurry are often abrasive. Slurry pumps that handle such abrasive material need certain characteristics to transport material most effectively.
What is an Abrasive Slurry?
An abrasive slurry usually entails a mixture of insoluble solid material within water, so settling slurries tend to be more abrasive. Slurry pumps are utilized in various applications, including cement manufacturing, digging boreholes for wells, drilling for gas and oil, generating electricity, maritime dredging, material processing industries, mining operations, and tunnel construction. This will often entail the use of a slurry pump connected to piping.
For example, the raw ingredients for cement used in construction are brought in solid form to a cement plant, where these ingredients are then ground down and mixed with water utilizing piping within the plant before the cement is transported to where it’s needed. In contrast, during dredging operations, solids are dredged up with water and transported away from the area, with the slurry taken away via a pipeline to a disposal site. Theoretically, any solid can be transported in this manner, but pumps must be significantly more robust for a more abrasive slurry.
There are four basic classifications for abrasiveness in slurries, which are:
- Class 1: Least abrasive (clean and uncontaminated liquids)
- Class 2: Somewhat abrasive (contaminated water or other fluid)
- Class 3: More Abrasive (slurries like those containing clay or gypsum)
- Class 4: Most Abrasive (heavy slurries like those containing emery dust or mixtures used in lapping)
With larger particles and more abrasive particles, slurry pumping operations require more specialized pumps that can perform under harsher conditions. Without the correct pump for an abrasive slurry, parts like wear rings, shaft seals, pump impellers, mechanical seal faces, and lip seals are likely to wear much more quickly.
Industries That Utilize Abrasive Slurry Pumps & Their Applications
Depending on the industry and application, slurry pumps that handle abrasive materials can be considerably diverse in their design.
Industries that utilize abrasive slurry pumps include:
- Agriculture: Used for transferring water and crop irrigation, slurry pumps are also used for the management of weeds, removing animal waste, and cleaning sediment from ponds.
- Chemical processing: For fluids that are both corrosive and abrasive, slurry pumps used by the chemical processing industry transport acids, bases, and other solutions, as well as gels and syrups.
- Construction: Slurry pumps are often used for transporting concrete, grout, and mortar, as well as for cleaning up construction sites.
- Flood control: As flood waters contain suspended solids, slurry pumps are often used as an emergency response to flooding in agricultural, commercial, industrial, and residential areas for bypassing sewage and removing stormwater.
- Gas and oil drilling and refining: Often needing to handle a thick and abrasive slurry, pumps in the petroleum industry are used for applications such as fire suppression in refineries, handling mud from drilling operations, and transporting water in oilfields.
- Mining: Needing to withstand media that are particularly corrosive or abrasive, slurry pumps for mining operations are used to transfer water with sediment for such applications as dewatering gravel and sand quarries, settling pond containment, or emergency pumping.
- Power generation: For applications like transporting coal ash, slurry pumps are employed to remove waste within power plants.
- Waste: Handling contaminants from agricultural waste from manure lagoons or those used by municipalities to pump sewage to plants makes these sorts of slurries potentially hazardous, for which slurry pumps are particularly suitable.
- Wetland management: Land conservation activities to protect habitats like wetlands use slurry pumps to dewater habitats to prepare for migrating birds, flood habitats for hunting and fishing activities, mitigate storm surges, and manage other environmental conditions.
Regardless of how corrosive or abrasive the material they transport, slurry pumps are designed to handle conditions common to the industries in which they’re used.
Types of Abrasive Slurry Pumps
Pumps are imperative to production in many processing industries that work with abrasive material. Slurry pumps – like any type of pump – help move fluids from an area with high pressure to one that’s low, by the laws of fluid dynamics. The pump types involved in transporting slurries differ according to the application. They’re used for various beneficiation processes in the mining industry to improve the value of mined materials, many of which are abrasive. Slurry pumps are also used for processing fertilizers or the disposal of ash in thermal power plants. Regardless of the application, the pumping of abrasive slurries will remain an important aspect of many industries for decades to come.
Horizontal Slurry Pump
Horizontal pumps are suitable for highly abrasive material. Slurry pumps of this type are suitable for moving highly concentrated slurries containing either large or fine particles that can corrode components and piping. Horizontal slurry pumps are used for coal mining, metal processing, and power generation applications. With a horizontally positioned pump shaft, these abrasive slurry pumps utilize robust and wear-resistant material.
Vertical Slurry Pump
When the pump shaft is instead positioned vertically, it’s known as a vertical slurry pump. These types of pumps usually deal with slurries that contain high concentrations of material, containing coarse particles that corrode rather than just those that are strictly abrasive. Slurry pumps with vertical shaft placements are generally classified as submerged or submersible. Submerged slurry pumps generally only have their pump head placed under the surface of the slurry, while submersible slurry pumps have the motor and other components submerged. Generally, submerged vertical slurry pumps are used for applications like cement manufacturing, dye-making, municipal wastewater treatment, and paper mills. Submersible vertical slurry pumps are often used for purposes like dredging rivers, extracting sand, metal processing, and power generation.
Centrifugal Slurry Pump
The centrifugal slurry pump is the most common pump type for slurries, though there are numerous iterations. This type of slurry pump utilizes centrifugal force caused by a rotating impeller, which transfers energy to the slurry, much like centrifugal pumps for transporting water and other similarly flowing liquids. When pumping an abrasive slurry, pumps of this type should be chosen based on ease of maintenance, impeller design and size, materials being transported within the slurry, and shaft seal type. Not only do centrifugal slurry pumps need to handle wear from an abrasive slurry, but pumps also often need to consider corrosion and erosion. Their impellers must be heavier and wider so larger particles can get through. Meanwhile, the materials from which they’re made also need to withstand abrasion, corrosion, and erosion from the solids within the slurry.
Selecting the Right Abrasive Slurry Pump for an Application
Design is particularly important when handling materials that are corrosive and abrasive. Slurry pump impellers are particularly vulnerable to corrosive and abrasive slurries. If a pump isn’t designed correctly, it’s more likely to get clogged by slurry or sludge, so centrifugal pumps with tight tolerances around their impellers wear quickly when pumping a corrosive or abrasive slurry. Pumps can also lose suction when used for such applications, which can lead to longer periods of unplanned downtime, along with the expenses for maintenance and replacement components.
It's important to consider the slurry being pumped to steer clear of such avoidable repairs. Choosing the right pump for the application also leads to safer working conditions for those who work with them. Perhaps the most important reason for any business that requires an abrasive slurry pump is that it lasts much longer, which translates to reduced costs for repair and replacement.
For handling abrasive material, slurry pumps are often classified according to application:
- Cyclone feed: Similar to those used in both tailings transfers and for hydro-transport, cyclone pumps are used in hard rock mining to scalp and separate solids throughout processing by particle size, as well as for dredging operations.
- Flotation froth: The air in froth can cause problems with pump performance, so a special type of slurry pump that can remove air from the froth should be used in these cases.
- Hydro-transport: These types of slurry pumps are used to move material via water and are often used for dredging.
- Tailings transfer: As tailings tend to contain finer particles that are abrasive, slurry pumps like these are used in hard rock mining, transferring ore or mud along with chemicals used in the mining process.
When selecting a slurry pump, considerations should include efficiency, flow rate, output, and pressure. Additionally, the rate at which the pump is fed is critically important, with an optimal feed rate augmenting energy efficiency and extending the pump’s lifespan. The material properties and size of solid particles should also be considered, and the flow path’s durability as determined by the concentration of solids within the slurry.
How a slurry flows depends on its characteristics. Though none flow identically, wear patterns will differ depending upon the flow system used. Wear from an abrasive slurry pumped through a specific type of system needs to consider numerous factors, including special regulatory requirements necessary when handling specific materials. All these aspects must be considered when selecting the best pump for transporting an abrasive slurry.
Contact the Pump Experts
One of the great advantages of modern pumps is the sheer variety of designs which are available.
The basic design is simply a hydraulic mechanical device that transfers different fluids from one position to another. Yet there are almost endless variations available on this simple theme.
The main types of pump
There are two main categories of pump: Centrifugal and positive displacement both of which break down into sub-categories. Centrifugal pumps include vertical and horizontal designs for low to medium viscosity liquids.
The positive displacement pump category includes diaphragm, gear, peristaltic, progressing cavity, piston and vane pumps.
This all means that whatever industry you work in, whatever the application you’re involved in or the material you wish to pump, there will be a unit which is specifically designed to meet your requirements.
In fact, one of the most versatile pump designs around is the peristaltic pump. They are easy to set up and can be operated and regularly maintained without needing any special training.
The widest range of applications
The peristaltic pump is a real workhorse able to easily transfer a wide cross section of fluids from ink, glues and food, to pastes, sludges, slurries, chemicals and cement across a spectrum of viscosities from 1cst right up to 50,000cst.
What’s more, peristaltic pumps are tailor-made for applications requiring the movement of liquids which are gaseous, volatile or very abrasive.
Peristaltic pumps are the best for abrasive transfers – here’s why
1. Gentle pumping action
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The slow pump speed and gentle squeezing pump action are much gentler than the high-speed rotation of other pump types.
These enable peristaltic pumps to comfortably handle the most abrasive of slurries from biogas, mining or dewatering activities, as well as other flows which contain sharp particles or debris.
Remarkably, this easy peristaltic pumping action is not only perfect for handling the most abrasive flows. It’s also ideal for transferring shear-sensitive fluids and preventing damage to solids or delicate materials.
2. No direct contact
Peristaltic pumps are great for handling abrasive fluids because they minimise direct contact between the pump's components and the fluid, which stays inside the tube. This keeps wear and tear to a minimum and reduces the risk of clogging or damage from abrasive particles.
They do this by employing a flexible hose or tubing that contains the fluid, removing the need for valves, seals or impellers that are likely to suffer abrasion.
3. Non-clog, hardwearing and run dry
Peristaltic pumps can easily accommodate solids as large as the internal diameter of the hose, and due to the gentle pumping action, lack of compressed air or valves they don’t clog.
In addition, the pump’s simple design, rugged construction and tough, hardwearing tube, plus the absence of any valves and seals means it can work without fluid and not suffer any damage. In short, peristaltic pumps can run dry and are ideal for abrasive, dry or viscous sticky liquids which would damage other pump designs.
4. Abrasion-resistant tubing
The material of the flexible hardwearing tube or hose can be specified according to the particular abrasive qualities of the fluid to be pumped. This will help to ensure its longevity and durability.
Moreover, advanced hose designs can even incorporate additional and enhanced abrasion resistance, extending service intervals and reducing the need for costly maintenance.
5. Contamination prevention
The fluid being pumped stays within the hose or tubing throughout the transfer process. This completely prevents any contamination from any outside sources and stops the fluid from leaking into the pump itself, stopping its operation and possibly causing damage.
6. Energy efficiency
Compared to other pump designs like centrifugal or diaphragm pumps, peristaltic pumps can offer big energy savings, particularly when working at lower speeds.
This is down to their gentle pumping action which compresses the hose or tubing containing the fluid, which in turn reduces friction and energy usage. In addition, roller design of peristaltic pumps have extremely low starting torque, and have the ability to run at very low speeds -from 1rpm very efficiently requiring less energy.
The perfect application - abrasive grout transfer at a power plant facility
Leading UK pump supplier, North Ridge Pumps were contacted earlier this year by a large construction company. They were looking to source two grout transfer pumps for a new power plant which was being built.
Industrial grout is a composite material usually made of sand, cement and water, and often contains small amounts of epoxy resin or other materials to give it more durability and chemical resistance.
Like domestic grout used in DIY, it also fills gaps. But in industrial settings it’s useful for a whole range of applications in construction, factory environments, industrial processing plants and other locations.
So what’s the best kind of pump for grout transfer?
Yes, a peristaltic pump. The simple design of the peristaltic pump makes it perfect for handling abrasive industrial grout. The rugged mix of sand, cement and assorted solids in grout is no problem for these pumps. In fact, they can comfortably handle a heavy solids content.
What’s more, these units are tailor-made for projects where the grout transfer pumps may be out of action for long periods.
What was the exact specification for this client?
This construction project required abrasive grout transfer up to 15 bar and 3 tonnes an hour. To meet the project brief, North Ridge Pumps supplied the client with two of their brand new RBT-40 pumps.
As well as the two abrasive grout pumps, they also supplied the client with a spare set of hoses and enough lubricant to make sure that they had spares for at two years continuous service.
If you have an application which requires the transfer of viscous fluids or dense slurries containing solids, and aren’t sure of the best solution, talk to North Ridge Pumps to see how they can help.
Contact us to discuss your requirements of Medium Abrasion Slurry Pump. Our experienced sales team can help you identify the options that best suit your needs.