1. Function and significance (1) Improve the selectivity of interaction between minerals and collectors and improve the flotation properties of pulp.
Mechanism: When regulating and controlling the action of collectors and minerals, strengthen or weaken the action of the collector on minerals, thereby increasing or decreasing the floatability of minerals and improving the selectivity of the flotation process.
The role of the collector: to improve the hydrophobicity of the mineral.
Reasons for using conditioner:
A, a variety of useful minerals symbiosis (associated), and floatability close, using a modifier to improve selectivity.
The principle of flotation: First, priority flotation: inhibition - flotation - activation - flotation;
Second, mixed flotation: flotation - suppression - flotation.
B. Harvesting flotation after mineral activation.
C. Flotation specific conditions: for example: the effect of PH value.
(2) Adjustment and influence of the modifier on the flotation foam:
A. The modifier affects the dispersion of the bubbles and the strength of the bubbles.
For example, pine oil foaming agent, under the adjustment of CuSO4, Na2S, NaCN, etc., the thickness of the foam layer is reduced, and the specific foaming agent can prolong the bubble life under the action of a specific adjusting agent.
B. The adjusting agent colloidal particles on the liquid-gas interface affect the flotation activity.
Regularity: The adhesion of fine colloidal particles to the surface of the bubble can activate the flotation process, and the growth of excessively large colloidal particles will inhibit the flotation process.
Reason: The fine rubber particles promote the rupture of the granules of the ore particles and the bubble layer, and squeeze the water molecules in the cracks to accelerate the thinning and cracking of the hydration layer. The oversized rubber particles occupy the surface of the bubbles, making the bubbles "armor" and hindering. Contact and adhesion of the ore particles to the bubbles.
Application: Control the growth rate of the rubber particles.
C. Effect of the adjusting agent on the adhesion speed of the ore particles to the bubble.
The activator can shorten the adhesion time of the ore particles to the bubble (contact---thinning---breaking---attachment), and the inhibitor can prolong the time of the mineral particles to adhere to the bubble. Acids and bases also affect the adhesion time of certain minerals to bubble attachment.
2. Main mode of action (1) Directly on the surface of minerals.
A. The conditioning agent acts on the mineral surface in an ion, molecular or colloidal state, or competitive adsorption occurs to enhance or weaken the interaction of the collector with the mineral surface.
B. Adjusting the dissolution of the mineral surface to enhance or reduce the number of active particles adsorbed by the collector on the mineral surface, causing the collector to adsorb on the surface of the mineral or desorb from the surface.
(2) It acts in the pulp.
Role: Adjust the ion composition or the pH of the medium.
A. Formation of insoluble salts precipitates or formation of stable complexes to eliminate or reduce the adverse effects of poorly soluble ions on flotation.
B. The adsorption of harmful ions in the slurry by substances with large adsorption capacity.
C. Adjust the pH of the slurry. It has many effects on the flotation process.
3. Classification of adjustments (classified by function)
(1) Inhibitors: A large class of regulators that weaken or destroy the interaction of collectors with minerals.
Commonly used: lime, water glass, sodium sulfide, sodium cyanide.
(2) Activator: A class of regulators that promote the interaction of collectors with minerals.
Commonly used: calcium sulfate, calcium chloride, platinum chloride, acid, alkali.
(3) pH adjuster: a class of agents that adjust the pH of the pulp.
Commonly used: inorganic acids, alkalis.
(4) Dispersant and flocculant:
Description: relativity, multiplicity.
Second, inhibition and inorganic inhibitors 1. Inhibition (1) role and significance:
It destroys and weakens the adsorption of minerals on the collector, enhances the hydrophilicity of the mineral surface, and thus reduces the effect of mineral floatability---inhibition. Inhibitory agent---inhibitor----inorganic, organic inhibitor.
Significance: Improve the role of collectors and increase selectivity.
Concentrate on the quality and variety of industrial raw materials have become increasingly demanding, and the choice is difficult to select the mine and complex multi-metal ore is increasing, and the reduction of mineral reserves, factors such as changes in mining methods, in the research and development of various In addition to collectors with high selective effects, minerals should be given significant attention to the research and application of inhibitors to guide production practices.
(2) Mode of inhibition and specific mode of action:
A. Form a hydrophilic film or colloidal particles on the surface of the mineral. Secondly, the collector is competitively adsorbed on the surface of the mineral, and is mutually displaced, so that the trap is desorbed from the mineral surface or hinders the adsorption of the collector, and both may occur simultaneously.
B. Dissolving a hydrophobic coating film formed on the surface of the mineral by a collector.
C. Dissolving the mineral surface active particles or activated membrane which is easy to act with the collector.
D. Removing activated ions from the slurry.
Description: diversity of methods, diversity of roles.
2. Basic requirements for inhibitors:
(1) High selectivity;
(2) The inhibition is easy to eliminate;
(3) No chemical reaction with the collector;
(4) Cheap and easy to obtain, economical and practical, non-toxic, low toxicity and no pollution to the environment.
3. Common inhibitors (self-study).
Third, activation and activator 1. Activation (1) role and significance:
Activation: It promotes and enhances the interaction of minerals with collectors and improves the floatability of minerals. This agent - activator.
Applicable conditions: A, the target and the collector are not active. ---"promote"
B. The process needs to activate the object to be suppressed. ---"resurrection"
Significance: Like inhibitors, it is important to achieve effective separation of various minerals and to promote the development of flotation technology.
(2) Spontaneous activation Minerals spontaneously undergo activation in mineral deposits or in mining and sorting operations due to interaction with mineral solubility.
For example: oxidation, floating water.
Nature: A, unpredictability; B, uncontrollable; C, harmful to the flotation process.
(3) Purposeful activation According to the activity of the target and the collector is not strong, or even does not act, the activation of activation can be purposefully added to an activator.
A, pre-activated, pre-selective activation treatment, harvesting.
B. Vulcanization Pre-activation of specific non-ferrous metal oxide minerals.
It is activated by a soluble sulfide (sodium sulfide) to form a metal sulfide film which acts on the surface of the object with a collector (xanthine).
C. Revitalization Activates the surface of the inhibited mineral.
(4) Activation mode A. Dissolve the inhibitor film on the mineral surface, contaminant or dissolve the mineral lattice frame to expose the fresh surface or active particles.
B. Forming a living film on the surface of the mineral that is insoluble and beneficial to the action of the collector.
C. The activated ions adsorb on the surface of the mineral to form or enhance the properties of the mineral surface and the collector.
D. Change the ion composition in the slurry. Reduce the concentration of harmful ions and eliminate harmful effects. Play the flotation activity of the collector. The influence of ion composition is complex, and the specific situation is analyzed.
E. Adding a mineral lattice reduces the solubility of the mineral.
4. Pulp pH and pH adjuster 1. The natural PH value of the pulp and the role of the pH adjuster:
(1) Natural pH: the pH of the mineral suspension when no flotation agent is added.
Cause: When the fine particles of various minerals are partially hydrolyzed in aqueous solution, the ability to produce H+ or OH- ions is different, or the difference in the ability to adsorb H+ or OH- ions from the solution, there is a natural pH value.
Impact: (1) PH value required for flotation process; (2) continuity of process.
(2) The role and significance of the pH adjuster:
A. directly or indirectly affecting the floatability of minerals;
B, affecting the flotation activity of the agent;
C, affecting the ion composition in the slurry;
D. Affect the dispersion and agglomeration of the slurry.
2. Impact on the flotation process:
(1) Impact of floatability:
A, electrical;
B, conditions of the pulp, sorting conditions;
C. Promoting the formation of an activated film.
Overall: affecting the dissociation or adsorption properties of the mineral surface and thus affecting the surface electrical properties;
Affects the composition and structure of the adsorbate on the mineral surface, which in turn affects the total hydrophobic and hydrophobic effects of the surface.
(2) Effect on the flotation activity of the agent:
A. adjusting the concentration of collector ions in the slurry;
B. Adjust the ion concentration of the inhibitor and the reducing agent.
(3) Change the ion composition in the slurry to eliminate or reduce the harmful effects of inevitable ions in the slurry.
(4) Affecting the dispersion or agglomeration of the slime.
There are three basic types of fixed bed reactor: (1) axial adiabatic fixed bed reactor. The fluid flows through the bed along the axial direction, and there is no heat exchange between the bed and the outside world. (2) radial adiabatic fixed bed reactor. The fluid flows through the bed along the radial direction. Centrifugal flow or centripetal flow can be adopted. There is no heat exchange between the bed and the outside world. Compared with axial reactor, radial reactor has shorter flow distance, larger cross-sectional area and smaller fluid pressure drop. But the structure of radial reactor is more complicated than that of axial reactor. The above two forms are adiabatic reactors, suitable for the reaction heat effect is not large, or the reaction system can withstand adiabatic conditions caused by the reaction heat effect of the temperature changes. (3) The tubular fixed-bed reactor is composed of multiple reaction tubes in parallel. The catalyst is arranged in the tube or between the tubes, and the heat carrier flows through the tubes or tubes for heating or cooling. The diameter of the tubes is usually between 25 ~ 50mm, and the number of tubes can be as many as tens of thousands of roots. The tubular fixed bed reactor is suitable for the reaction with high thermal effect. In addition, there is a reactor composed of the above basic forms in series, called a multistage fixed bed reactor.
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