Phosphorus is an important raw material for the production of phosphate fertilizer, yellow phosphorus, phosphoric acid, phosphide and other phosphate products, and is a non-renewable and alternative resource. The reserves of phosphate rock resources in my country are relatively large, but more than 70% of them are low-grade and lean ore, which cannot be industrialized only by the scrubbing process. At present, medium and low-grade phosphate rock resources are mainly used for enrichment, and the flotation effect of phosphate rock depends on the interaction between mineral particles and air bubbles in the water medium, among which flotation reagents are particularly important.
Commonly used flotation processes for phosphate ore beneficiation are: positive flotation, reverse flotation, first positive then reverse flotation, first reverse then positive flotation and double reverse flotation.
1. Positive flotation process of phosphate rock
The process is to grind the phosphate rock until the monomer is dissociated, add water to the slurry to adjust the concentration to a certain concentration, use a specific collector to enrich the useful phosphorus minerals in the foam product, and use a specific agent to inhibit the silicon in the phosphate rock. gangue minerals such as salts and carbonates. Commonly used flotation agents are "S", "L", "sulfonated phenol tar", "F" series of inhibitors.
The process is suitable for siliceous or calcium-siliceous phosphate rock, endogenous apatite, and sedimentary phosphate rock. The technological process is simple, the impurity removal effect is good, and the content of impurities such as Me and Fe can be effectively reduced. But the energy consumption is high and the beneficiation cost is high.
2. Phosphate rock reverse flotation process
In this process, inorganic acid is generally used to adjust the pH of the pulp to a certain range (pH=4.0 to 5.0), and a specific collector is used in a weakly acidic medium to enrich the dolomite into the foam product, and the phosphorus minerals remain in the tank. Commonly used flotation reagents are mainly inorganic acid regulators, modified fatty acid collectors, sulfate modification of fatty acids, or addition of auxiliary agents during their saponification process to improve their water solubility, temperature resistance, collection performance and Optional.
This process is generally suitable for the separation of phosphorus minerals and dolomite gangue minerals, and the exclusion rate of dolomite gangue minerals can reach 70% to 80%. The process does not require heating, and can be carried out at low temperature and normal temperature, which reduces energy consumption and saves costs.
3. Phosphate ore first positive and then reverse flotation process
The process is to first use inorganic alkali to adjust the pulp to weak alkalinity, use a specific collector to enrich the useful phosphorus minerals in the foam product, and leave the silicate gangue minerals in the tank to remove, and the foam is positive flotation. Concentrate, then add inorganic acid to adjust the pulp to weak acidity, positive flotation concentrate (regrinding or non-grinding), and then use collector to enrich carbonate impurities, and leave useful phosphorus minerals in the tank to obtain Reverse flotation concentrate, the main purpose of reverse flotation is to remove MgO impurities in phosphate concentrate. Commonly used are inorganic bases and inorganic acid modifiers, XM-10, water glass and sulfur-phosphorus mixed acid inhibitors.
This process is suitable for the treatment of siliceous phosphate ore, and the grade of phosphate concentrate obtained is higher than that of single positive or reverse flotation, and the combination of positive and negative can effectively improve the processing performance of phosphate concentrate, but the cost of reagents is high, which is not suitable for concentrators. The recycling of water resources has caused great difficulties.
4. Phosphate ore reverse first and then positive flotation process
In this process, the carbonate gangue is first floated with a collector in an acidic medium to obtain an anti-floating concentrate, and then the second-stage grinding is performed until the siliceous gangue is decomposed, and the phosphate rock is floated in an alkaline medium. material to obtain positive floating concentrate.
This process is suitable for low-grade silicon-calcareous collophanites. The process does not require heating and has low energy consumption, but the circulating water needs to be treated separately, which has a great impact on production.
5. Double reverse flotation process of phosphate rock
In this process, inorganic acid is generally used to adjust the pulp to weak acidity, and a part of dolomite gangue is enriched by fatty acid collectors, and then quartz minerals are enriched by fatty amine collectors. Phosphorus minerals in the tank are the final concentrate. Commonly used flotation reagents are inorganic acid modifiers, fatty acid and fatty amine collectors.
This process is mainly suitable for the treatment of mixed phosphate rock with low content of siliceous gangue and carbonate. Especially for the separation of dolomite and quartz-like gangue minerals. It can realize low and normal temperature flotation, with simple process, low energy consumption, simple pharmaceutical system and few types of pharmaceuticals. However, the amine collectors used in this process are cationic collectors, which will produce viscous foam, poor selectivity, and are more sensitive to ore slime. This makes the process more complicated.
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