Applications and Technical Process Analysis of Flotation in Modern Mineral Processing

Froth flotation technology, as the core process in modern mineral processing industry, has become an indispensable technical method in the field of mineral processing due to its outstanding separation efficiency and extensive adaptability. This article will thoroughly analyze the basic principles of flotation, main process flow types, and complete process equipment configuration, providing systematic technical reference for mining practitioners.

Flotation Principles and Industrial Applications

Froth flotation is essentially a substance separation method using air bubbles as carriers, with its core principle based on separating different minerals according to their surface property differences. In professional mineral processing, flotation technology offers significant advantages:

- High Separation Precision: Particularly suitable for processing fine-grained materials, enabling efficient separation of mineral particles at the micron level

- Wide Application Range: Not only dominates non-ferrous metal beneficiation (over 80% of non-ferrous metal ores utilize flotation processes) but is also widely applied in ferrous and non-metallic mineral separation

- Strong Process Adaptability: Through adjustments to reagent systems and process parameters, can accommodate processing requirements for different ore types

The foundation of flotation technology lies in the differences in mineral surface properties. In their natural state, mineral surfaces can exhibit hydrophobicity (easily attach to bubbles) or hydrophilicity (difficult to attach to bubbles). The flotation process utilizes or artificially enhances these differences to achieve selective enrichment of target minerals in a gas-liquid-solid three-phase interface system. By adding various flotation reagents (collectors, frothers, regulators, etc.), mineral surface properties can be selectively controlled to enhance selective separation effects.

Analysis of Major Flotation Process Flows

Based on differences in ore characteristics and separation requirements, modern mineral processing plants typically employ the following typical flotation process flows, each with specific applicable conditions and technical features:

Preferential flotation is a process method that separates multiple valuable minerals in raw ore sequentially according to their flotation differences. The significant characteristics of this process are:

- Technical Route: First float minerals with the strongest flotation properties, gradually adjust flotation conditions, and recover other minerals sequentially

- Applicable Conditions: Especially suitable for processing ores with significant differences in flotation performance between different minerals, coarse mineral particle size, or high valuable mineral content

- Process Advantages: Relatively simple flow, lower reagent consumption, good selective separation effect

Bulk flotation is a process method that first simultaneously floats and enriches multiple valuable minerals in raw ore, then separates the mixed concentrate. This process has the following characteristics:

- Technical Route: First perform bulk flotation to obtain mixed concentrate containing multiple valuable minerals, then achieve separation of various minerals through secondary separation

- Applicable Conditions: Mainly used for processing low-grade polymetallic ores or complex ores with valuable minerals tightly intergrown with gangue

- Process Advantages: Can effectively improve recovery rates, suitable for processing difficult-to-separate ores, relatively flexible particle size requirements

Partial bulk-preferential flotation combines bulk flotation and preferential flotation, reflecting the technical characteristics of both processes:

- Technical Route: First preferentially float some valuable minerals, then recover other valuable minerals, and re-separate the initially floated mixed concentrate

- Applicable Conditions: Suitable for raw ores containing several valuable minerals with similar flotation properties but different flotation conditions, such as copper-molybdenum, copper-lead, copper-zinc, lead-zinc, and other complex polymetallic ores

- Process Advantages: Combines advantages of both bulk flotation and preferential flotation, flexible process flow, strong adaptability

Equal-flotability flotation is a process method that divides minerals to be recovered into easy-floating and difficult-floating portions based on similarities in flotation properties, treating them separately:

- Technical Route: Perform flotation separation in order of easy-floating and difficult-floating minerals, applying differentiated flotation conditions for minerals with different flotation properties

- Applicable Conditions: Suitable for processing complex polymetallic sulfide ores containing both easy-floating and difficult-floating minerals, such as lead-zinc ores containing sphalerite with different flotation properties

- Process Advantages: Classified processing improves selectivity, beneficial for improving recovery rates of difficult-floating minerals

Branch-series flotation is a complex process that divides raw ore pulp into multiple branches and processes them through specific series connections:

- Technical Route: Divide raw ore pulp into two or more branches, combining the froth product from rougher flotation of the former with the raw ore pulp of the latter, forming specific "series" configurations

- Applicable Conditions: Suitable for large mineral processing plants, especially for complex ore processing requiring secondary or higher flotation series

- Process Advantages: Improves processing capacity of the concentrator, beneficial for efficient separation of complex ores

Flash flotation is an innovative process that promptly recovers valuable minerals that have been sufficiently liberated during the grinding process:

- Technical Route: Install flash flotation components in the grinding circuit to quickly recover liberated valuable minerals, preventing over-grinding

- Applicable Conditions: Mainly applicable to non-ferrous metal sulfide ore beneficiation, especially for processing ores containing precious metals with uneven particle size distribution

- Process Advantages: Implements the "recover as early as possible" principle, reduces valuable mineral losses from over-grinding, improves recovery rates

The flotation block process is a specialized process that optimizes flotation time based on specific mineral particle characteristics:

- Technical Route: Uses shorter flotation times to preferentially recover portions of minerals with the fastest flotation speeds, achieving rapid pre-enrichment

- Applicable Conditions: Suitable for separating rough concentrates or middlings requiring regrinding where target mineral particle size distribution is uneven

- Process Advantages: Improves mineral processing efficiency, reduces energy consumption, optimizes the overall beneficiation process

Flotation Process Flow and Equipment Configuration

A complete flotation process flow typically includes crushing, grinding, flotation, dewatering, and other stages, with each stage closely linked to form a systematic processing flow:

- Process Purpose: Crush large raw ore blocks to a particle size suitable for grinding

- Main Equipment: Jaw crushers, cone crushers, vibrating screens, feeders, belt conveyors

- Technical Key Points: Typically employs multi-stage crushing combined with closed-circuit screening to ensure uniform particle size of crushed products

- Process Purpose: Grind crushed products to the particle size required for flotation, achieving sufficient mineral liberation

- Main Equipment: Ball mills, spiral classifiers or hydrocyclones

- Technical Key Points: Typically employs closed-circuit grinding, with classifier overflow serving as flotation feed and underflow returning to the ball mill for regrinding

- Process Purpose: Selectively enrich target minerals through air bubbles, achieving mineral separation

- Main Equipment: Conditioning tanks, various flotation machines (mechanical agitation, pneumatic, column, etc.)

- Technical Key Points: The flotation process typically includes roughing, cleaning, and scavenging stages, with appropriate reagent systems configured according to ore properties

- Process Purpose: Reduce moisture content in concentrate for subsequent processing or direct sale

- Main Equipment: Thickeners, filter presses, dryers

- Technical Key Points: Thickener overflow water is typically returned to the production system for recycling, improving water resource utilization

Based on years of mineral processing practical experience, the Zexin Mining Technical Team notes that efficient flotation processes depend not only on rational process design but also on precise operational control and adaptive parameter adjustments. In practical applications, the most suitable flotation process flow should be selected based on ore properties, processing scale, and product requirements, with continuous optimization adjustments to achieve optimal balance between mineral processing indicators and economic benefits. With the continuous development of mineral processing technology, the application of intelligent control systems, new efficient flotation equipment, and environmentally friendly flotation reagents will further enhance the separation efficiency and environmental friendliness of flotation processes.