What are the different types of mining mixing tanks and how to choose the right one

Main Types and Working Principles of Mining Mixing Tank

In practical mining applications, the selection of a Mining Mixing Tank depends on pulp viscosity, particle settling velocity, and process requirements for mixing intensity. Below are the detailed analyses and technical parameter comparisons of several mainstream types.

Flat Bottom Mining Mixing Tank

This is the most common structure, suitable for standard pulp conditioning before flotation operations. The motor drives the main shaft, which rotates the umbrella-shaped impeller at the bottom. The impeller flings the slurry outward, creating negative pressure at the tank bottom, causing the slurry to enter through the suction port and form a circulating flow field. It offers a simple structure, easy installation, and low cost.

Cone Bottom Mining Mixing Tank

The bottom of the tank is designed as a cone, which facilitates the concentration of high-density particles toward the center. It completely solves the "dead zone" problem that may exist in flat-bottom tanks, making it particularly suitable for processing coarse-grained, easily settled heavy minerals.

Lifting Mining Mixing Tank

The impeller not only provides mixing but also features specific blade angles and a draft tube structure that gives it pump characteristics. It can lift the slurry to a certain height for discharge while mixing. This is very useful in processing plants where the building height is insufficient to transport slurry by gravity.

Aeration Mining Mixing Tank

It utilizes a hollow shaft design or air injection ports below the impeller to force air into the tank during mechanical agitation. This enhances gas-liquid-solid three-phase contact and is often used for pulp pre-oxidation or special pre-flotation treatments.

Technical Parameter Comparison of Mining Mixing Tank Types

Factors Affecting Circulation Efficiency

In the design of a Mining Mixing Tank, the circulation ratio is the key measure of performance. For the lifting type, the lift height and rotation speed follow a quadratic relationship. To significantly increase lift, speed or diameter must increase, which also accelerates the wear rate of liners.

Core Components of Mining Mixing Tank

The efficient operation of a Mining Mixing Tank depends on the design and material selection of its internal core components, which directly affect flow distribution and service life.

Impeller System

The impeller is the heart of the Mining Mixing Tank. Umbrella Impellers generate strong radial flow for uniform mixing, while Propeller Impellers generate axial flow with large circulation volumes to prevent sedimentation. Materials usually consist of carbon steel covered with high-wear-resistant rubber or polyurethane. For corrosive slurries, 316L stainless steel or titanium alloys are used.

Baffles

Baffles are installed vertically on the inner wall of the tank, usually 3 to 4 pieces. They eliminate the circular motion and central vortex, converting tangential flow into axial and radial flow to force the slurry to churn up and down for deep mixing.

Transmission and Reduction System

A Mining Mixing Tank requires high torque and low speed. Cycloidal pinwheel or gear reducers are typically used to maintain speeds between 100 and 300 rpm.

Draft Tube

In large or deep tanks, a draft tube guides the slurry vertically downward into the impeller zone, increasing the circulation radius and preventing short-circuiting flow.

Component Materials and Technical Parameters

Critical Design Parameter: D/T Ratio

The ratio of impeller diameter (D) to tank diameter (T) determines the mixing nature. A D/T of 0.25 to 0.35 is for high speed and high shear, suitable for chemical dispersion. A D/T of 0.35 to 0.50 is for low speed and high circulation, suitable for homogenization with lower energy consumption.

Key Technical Parameters and Selection Guide

Scientific selection of a Mining Mixing Tank ensures no bottom accumulation. Selection is based on flow rate, solid density, particle size, and retention time.

Retention Time

Retention time determines the effective volume. The formula is Volume = Flow Rate * Retention Time * Safety Factor. The safety factor is usually between 1.1 and 1.2.

Power and Motor Calculation

The slurry density must be considered for motor load. The higher the density, the greater the torque required. Rotation speed must stay above the Critical Suspension Speed to prevent dead zones at the tank edges.

Selection Parameters by Application

Maintenance and Operation Essentials

Startup and Shutdown Procedures

No-load Startup: It is strictly forbidden to start the tank when it is filled with settled slurry. Before long-term shutdown, empty the slurry and rinse the bottom and impeller with fresh water to prevent solid caking.

Wear Monitoring

When the impeller diameter wears more than 10% of its original size, discharge volume drops significantly. Check for peeling or bulging of the rubber lining to prevent acidic slurry from corroding the steel tank structure.

Troubleshooting

FAQ

Why is the impeller of a Mining Mixing Tank usually umbrella-shaped?

Answer: The umbrella design generates strong radial centrifugal force, creating a local turbulent zone at the bottom, which is vital for re-suspending settled heavy minerals.

Does increasing rotation speed always improve mixing?

Answer: No. Excessive speed causes power consumption to surge and increases wear. It can also break long-chain chemical molecules, negatively affecting flotation.

How to choose rubber lining thickness?

Answer: Generally, wall lining is 6 to 10 mm, while the impeller and impact zones at the bottom should be increased to 15 to 20 mm.

What causes severe vibration in a Mining Mixing Tank?

Answer: Usually caused by impeller imbalance, a bent main shaft, or poor alignment of the coupling.

How to handle bottom buildup in the mixing tank?

Answer: Check if the impeller installation is too high or if the motor speed has dropped due to loose drive belts.