1.Project Background and Challenges
1.1 Overview of the Sand and Gold Extraction Project in Nigeria
In a sand and gold extraction project in a river area in Nigeria, a Henan customer faced a typical construction challenge: initially, the river was dry, requiring a crane to dredge sand until the water level rose. However, traditional cranes were inefficient, costly, and unable to meet the demand for sustained, large-scale sand transport.
1.2 Analysis of Specific Customer Requirements
The customer required sand to be pumped to a 20-meter-high vibrating screen with a processing capacity of 100 cubic meters per hour, relying on on-site generator power. This requirement placed stringent demands on the equipment’s power, lift, and reliability.
2.Solution and Equipment Configuration
2.1 Core Equipment Selection
For this application, we recommended an 8-inch submersible sand extraction pump (model NSQ400-25-75), equipped with a sand extraction platform, electric winch, control cabinet, and sand discharge hose. This pump has a flow rate of 400 cubic meters per hour, a head of 25 meters, and a power of 75 kilowatts, perfectly matching customer needs.
2.2 Equipment Package
The motor and pump body are coaxially submersible, allowing for direct underwater operation without the need for a fixed pumping station, significantly reducing infrastructure costs. The complete package includes:
Sand extraction platform (twin-body pontoon structure)
Electric winch (for adjusting the pump depth)
Control cabinet (with integrated motor protection)
Sand discharge hose (DN200, wear-resistant)
3.Working Principle of Submersible Slurry Pump
3.1 Basic Working Principle
A submersible slurry pump is a hydraulic machine with a coaxial motor and pump submerged in the medium. Its operation is based on the centrifugal principle: When the motor drives the impeller to rotate, the centrifugal force throws the material toward the impeller edge and pushes it through the pump casing flow channel to the outlet pipe. 3.2 Unique Design Features
Unlike ordinary water pumps, this submersible slurry pump incorporates a stirring impeller at the bottom, which sprays accumulated sludge into a mixture of water and solid particles. This design enables the pump to achieve high-concentration delivery without auxiliary equipment.
3.3 Safety Protection System
The unique sealing device effectively balances the internal and external pressures of the oil chamber, maximizing the reliability of the mechanical seal. The motor also incorporates multiple protection measures, including overheat protection and water ingress detection, to ensure long-term safe operation under harsh operating conditions.
4.Detailed Equipment Technical Parameters
4.1 Main Performance Parameters
For this project, we recommend an 8-inch submersible sand pump. Its main parameters are as follows:
Flow rate: 400 cubic meters/hour
Head: 25 meters
Motor power: 75 kW
Outlet diameter: 200 mm
Particle capacity: up to 5 cm
4.2 Materials and Manufacturing Process
The pump’s flow path is made of high-chromium wear-resistant alloy (such as Cr26), offering excellent wear resistance and a large flow channel. It is suitable for conveying media containing large solid particles, such as mud, slurry, and gravel.
5.Core Performance Advantages Analysis
5.1 Excellent Wear Resistance
The flow path is made of high-hardness, high-chromium cast steel, offering wear resistance 4-8 times that of ordinary materials. At a sand content of 30-40%, the impeller’s service life can reach over 3 months, significantly reducing downtime and replacement frequency.
5.2 High-Efficiency Mixing Function
In addition to the main impeller, an independent mixing impeller is used to mix sediment, silt, and ore slurry deposited on the bottom of the water into a slurry for extraction. This ensures high-concentration delivery even in densely deposited areas.
5.3 Strong Environmental Adaptability
The motor is submersible, eliminating suction range limitations, resulting in a high suction rate and more thorough desilting. The unit can be submerged up to 50 meters, requiring only a minimum submergence depth to submerge the motor.
5.4 Significant Energy Savings
Direct submersible operation reduces transmission losses and saves over 15% in energy compared to traditional sand pumps. This advantage is particularly significant for sites that rely on generator power.
6.Application Scenarios and Case Studies
6.1 Wide Range of Applications
Submersible slurry pumps are widely used in a variety of applications:
Dredging, sand extraction, and sewage disposal in rivers, lakes, reservoirs, and ports
Draining silt, mud, sewage, and impurities in construction projects
Transporting tailings, slag, and slurry from beneficiation plants
Ore dressing, gold panning, and iron ore extraction
6.2 Philippine Iron Ore Project Demonstration
In October 2012, a Fujian customer used similar equipment (NSQ400-40-90) to extract iron ore off the coast of Luzon Island, Philippines. Project data showed: the conveying conditions were a horizontal distance of 600 meters and a vertical height difference of 8 meters; operating efficiency was a stable sand content of 30-40% and an iron ore output of 30 tons per hour; and durability was a three-month impeller lifespan under high-intensity operation.
6.3 Nigeria Localized Application Case
Slurry pump technology has also been successfully employed in a similar lithium mining project in Nigeria. In April 2023, Jizhong Equipment’s Shigong Pump Company successfully won a bid for a Nigerian lithium mining project with a total contract value of over 2 million yuan, demonstrating the value of this type of equipment in the African mining industry.
7.Operation and Maintenance Key Points
7.1 Equipment Startup Specifications
To ensure long-term and stable operation of submersible slurry pumps, the following operation and maintenance key points must be observed: Before startup, check the correct direction of rotation (clockwise when viewed from the drive end). Confirm that the motor is filled with clean lubricating oil and that the mechanical seal assembly is properly assembled.
7.2 Operational Concentration Control
Concentration is controlled by adjusting the submersion depth. The impeller directly contacts the sediment surface, making concentration control more precise.
7.3 Daily Maintenance Plan
Regularly check the cable for wear and ensure that safety devices such as overheat protection and water ingress detection are functioning properly. Wearing parts (such as the impeller and mixing impeller), even if made of wear-resistant materials, must be replaced according to the service life schedule. 7.4 Fault Handling Mechanism
The control cabinet features a built-in motor protector that detects common faults such as phase loss, overload, leakage, and water ingress during operation. It automatically shuts down when the current exceeds 115% of the set value, preventing equipment damage.
8.Return on Investment and Economic Analysis
8.1 Initial Investment Analysis
Although the initial investment for a submersible slurry pump may be higher than that of traditional equipment, its total lifecycle cost (TCO) is significantly superior: It eliminates the need for a fixed pump house and transmission, reducing equipment investment by 30%. The simplified overall equipment eliminates the need for auxiliary mixing or injection devices, reducing total unit investment.
8.2 Operating Cost Optimization
Direct submersible operation reduces transmission losses, saving over 15% in electricity compared to traditional sand pumps. This energy saving benefit is significant for projects with long annual operating times.
8.3 Maintenance Cost Control
The wear-resistant design extends the replacement cycle for wearing parts and reduces downtime. The modular design facilitates on-site replacement of wearing parts, typically taking no more than two hours. 8.4 Improved Production Efficiency
Compared to traditional dredging methods, pumping efficiency can be increased by 3-5 times, significantly shortening project cycles and creating greater economic benefits for customers.
Authored by
Tai’an OCEAN Pump Co., Ltd
Alina.Liu
Email: Oceanpump15@tsbeng.com
WhatsApp: +86 17354610320
