Factors Affecting the Flotation of Scheelite at Room Temperature

01Effect of ore properties on room temperature flotation of scheelite

The following mainly introduces the effects of mineral composition, embedded particle size and mineral surface properties on flotation. In actual production, it is necessary to analyze and determine the influencing factors according to the specific situation.

1. Mineral composition: Low-grade scheelite is often associated with quartz, mica, calcite, fluorite and other minerals. The symbiotic relationship between these minerals and scheelite will directly affect the flotation effect. Among them, fluorite and scheelite have similar physical and chemical properties, which can easily cause the problem of poor selectivity in the flotation process.

2. Embedded particle size: The embedded particle size of scheelite determines the selection of grinding particle size range, because the surface area of mineral particles with too fine particle size increases, resulting in increased consumption of flotation reagents, and at the same time, it will increase the loss of tungsten ore and affect its recovery rate. Too coarse mineral particles will reduce flotation efficiency and affect the grade of concentrate. Reasonable selection of grinding fineness is crucial to improving flotation effect.

3. Ore surface properties: The degree of oxidation and contamination on the surface of low-grade tungsten ore will affect the flotation effect at room temperature. The surface of scheelite will form tungstate or other insoluble substances after oxidation. These compounds will affect the collector's collection of minerals. Adding an activator to the slurry or adjusting the pH value of the slurry will improve the situation.

02Effect of flotation reagents on room temperature flotation of scheelite

The types of flotation reagents involved in the flotation of scheelite include collectors, inhibitors, activators, frothers, etc. The following will introduce the effects of these four flotation reagents on flotation.

1. Collector: Collector is the decisive factor affecting the floatability of minerals. Commonly used collectors for scheelite flotation include fatty acids, sulfonic acids, etc. Different collectors have different selectivity for scheelite and gangue minerals. In production, they need to be selected and optimized according to the properties of the ore.

2. Inhibitors: In order to improve the flotation efficiency of scheelite, inhibitors are added to inhibit the flotation of gangue minerals. Common inhibitors include water glass, oxalic acid, phosphates, etc. Water glass can be used to inhibit silicate minerals, and oxalic acid can be used to adjust the surface potential of minerals and improve the interaction between scheelite and collectors.

3. Activator: Activator is mainly used to improve the floatability of scheelite. The activators for scheelite flotation are ammonium carbonate and ammonium sulfate. These agents can not only change the surface properties of the mineral, but also make the mineral easier to combine with the collector, thereby improving the flotation effect.

4. Frothing agent: The type and dosage of the frother will affect the stability and selectivity of the foam. Common types of frothers include pine oil, MIBC, etc. Adding an appropriate amount of frother to the pulp can improve the recovery rate of the mineral, but excessive amounts will lead to increased foam and affect the separation effect.

03Optimization of room temperature flotation of scheelite

The process parameters in flotation of scheelite involve grinding fineness, pulp concentration, flotation time and flotation equipment.

1. Grinding fineness: Reasonable grinding fineness improves the flotation efficiency of scheelite. The best grinding fineness for scheelite flotation is -74μm, with a content of about 70%. Too much or too little fineness will reduce the flotation effect.

2. Pulp concentration: Pulp concentration mainly affects the collision probability between mineral particles and the effect of reagents. The appropriate pulp concentration is generally 25-35%. Too high increases the viscosity of the pulp and increases the difficulty of flotation. Too high pulp concentration will reduce the flotation efficiency.

3. Flotation time: If the flotation time is too short, the scheelite is not fully recovered. If the time is too long, the gangue minerals may enter the concentrate and affect the grade. Generally speaking, the best time for scheelite flotation is 8 to 15 minutes.

4. Flotation equipment: The type of flotation machine and its operating parameters (such as aeration volume, stirring intensity, etc.) have a direct impact on the flotation effect. Appropriate aeration volume can enhance the combination of minerals and foams and improve the recovery rate; moderate stirring can evenly disperse the minerals and improve the effect of the collector.

04Effect of water quality conditions on room temperature flotation of scheelite

Water quality conditions mainly include pH value and water hardness.

1. pH value: The pH value of the pulp affects the action mode of the reagent and the floatability of the mineral. The optimal pH value for scheelite flotation is generally 7-9. Too high or too low will affect the flotation effect. Methods for adjusting the pH value include adding regulators such as lime, sulfuric acid, and sodium carbonate to the pulp.

2. Water hardness: Because calcium ions and magnesium ions in the water will react with the collector and reduce the effect of the reagent, add an appropriate amount of water softener or increase the amount of collector when the water quality is hard to improve the flotation efficiency.

05Effect of operating conditions on room temperature flotation of scheelite

1. Temperature: Although it is room temperature flotation, changes in ambient temperature will still affect the effect of the reagent. For example, when the temperature is low, the solubility of fatty acid collectors decreases, affecting the flotation effect. Therefore, under low temperature conditions, the amount of collector can be appropriately increased or a collector with better solubility can be used instead.

2. Agitation intensity: Agitation intensity affects the uniformity of the slurry and the dispersion of the reagent. Appropriate agitation helps the reagent to fully contact the mineral and improve the flotation effect, but excessive agitation may destroy the foam and affect the flotation recovery rate.

The room temperature flotation of scheelite is affected by many factors. The recovery rate and grade can be improved by optimizing the flotation reagent, grinding fineness, slurry pH value and equipment parameters. Reasonable flotation process (such as roughing-fine-sweeping) and optimized combination of series or parallel flotation machines can improve enrichment efficiency and reduce energy consumption. Xinhai Mining fully considers the characteristics of ore in the design of scheelite beneficiation, combines advanced flotation technology and optimization measures to achieve efficient separation, and provides reliable guarantee for the comprehensive recovery and utilization of scheelite resources.