Related Question about Phosphate Processing
2019-06-01 20:20:40xinhai
Phosphate refers to the general term of phosphate minerals which can be used economically. It is an important chemical mineral raw material. It can be used to make phosphate fertilizer, also can be used to make yellow phosphorus, phosphoric acid, phosphates and other phosphates, which can be used in medicine, food, matches, dyes, sugar making, ceramics, national defense and other industrial sectors.
In industry, the main phosphate mineral extracted from phosphorus is apatite, followed by sulfur, phosphorus, aluminum strontium, struvite and bluestone.
About 95% of the phosphorus in nature is concentrated in apatite.
Using different surface properties of phosphate minerals and impurity minerals, flotation agents are used to float phosphate minerals to achieve separation. This operation is called positive flotation.
The other is to float an impurity mineral and sink a phosphate mineral, called reverse flotation.
In order to make the separation more effective, it is often necessary to add inhibitors to inhibit the rise of certain minerals.
Concentrate can be obtained by thickening, filtering and dewatering the pulp containing phosphate from the flotation machine.
Phosphate ore has no fixed molecular formula and fixed crystal structure. It belongs to noncrystalline. Phosphate usually shows oolitic structure, sometimes binding, globular and power shapes and so on. It is a kind of fine dispersed phase apatite with colloidal structure which is difficult to process.
Phosphorite ore beneficiation processes involves in all ore dressing methods which include Scrubbing and removing mud, flotation method, roasting and digestion method, heavy medium separation method, photoelectric mineral processing method, biological treatment method and combined mineral processing technology.
Crubbing and removing mud of phosphorite ore beneficiation processes has been mature. But the practice shows that it is limited in improving the grade of phosphorite and a large of tailing produced has not been taken advantage of. At present, this method is combined with flotation and the phosphorite among the tailing can be recovered by the flotation method.
The flotation method is widely suitable among all the phosphorite ore beneficiation processes. By the different nature of phosphorite, it can be divided into positive flotation, flotation (positive and negative), double reverse flotation.
Roasting and digestion method of phosphorite ore beneficiation processes is mainly used in the carbonate phosphorite rock. It has many features such as simple process, fine index, professional operation process and high roasting energy saving.
Heavy medium separation method of phosphorite ore beneficiation processes has such advantages as simple process, low cost, easy operation and less pollution ans so on. But the fine particles are difficult to recover, so this method is usually used as the pre-election process for phosphorite ore.
The principle of photoelectric mineral processing of phosphorite ore beneficiation process is based on the difference of the useful minerals and gangue minerals to separate. It has many advantages such as no waste water and environmental pollution, simple structure of equipment, easy maintenance and low cost. But it has high requirement for the water content of the feeding material.
The principle of biological treatment of phosphorite ore beneficiation process is taking advantage of the microorganism growing in the phosphorite ore and producing sulfuric acid to dissolve the phosphorite ore. It has many advantages as low costs and lean ore processing and so on. But it need long time to leach the concentration.
Combined mineral processing technology phosphorite ore beneficiation process has strong pertinence. It can simplify the processes and reduce the energy consumption, reagent consumption and recover the associated metal. It is the trend of the phosphorite ore beneficiation process.
The reasons for hard flotation are:
① Micro-fine phosphate ore’s surface energy is large, in some condition, mirco-fines with different components would form non-selective agglomeration, surface forces cause agglomeration, also causes micro-fine adhere to the coarse surface and become mirco-fine cover influence flotation.
② As micro-fine particles have a large specific surface area and surface energy, higher drug adsorption capacity, lower selective adsorption, surface solubility increased, "inevitable ion" in the pulp raised, at the same time, as the mirco-fine particles has light weight, and can be Susceptible to mechanical entrainment of water and foam mechanical entrainment.
③ Mirco-fine phosphate ore has low adhesion efficiency with the bubble, it can decrease the bubble capture capability, at the same time, mirco-fine would adhered to the bubble cause the bubble “armor” and influence the bubble carrying capacity.
In actual production, we always take some measures to strengthen mirco-fine phosphate ore flotation.
① Adding a dispersant to prevent micro-fine particles coagulate each other to ensure adequate dispersion.
② Use appropriate micro-fine phosphate ore flotation reagent to make the surface hydrophobic selectivity hydrophobilizing.
③ Make micro-fine phosphate ore selective flocculation, increased size to facilitate the flotation, so we usually use hydrophobic flocculation, flotation and selective flocculation carrier route.
④ Decrease flotation bubble size. In order to achieve microbubble flotation, we can choose the appropriate frother or microbubble flotation column, etc.
At present, the researches on phosphate ore flotation mainly force on flotation process and flotation reagent. Flotation reagent has a crucial role in phosphate flotation indexes. According to application, flotation reagent can be divided into: collector, frother, modifier (Inhibitors, activators, and media modifier), flocculant and dispersant. As phosphate, calcite, dolomite belongs to same mineral and chemical nature, so phosphate ore has same flotation with those ores, so we must use inhibitors. At present, the inhibitor we use and researched is inorganic acids inhibitors and organic acid addition salts with inhibitors.
Inorganic acids inhibitors. It mainly has phosphoric acid, sulfuric acid silicon fluoride, phosphate, alizarin red and so on, the research shows that the alizarin red inorganic acids inhibitors could inhibit apatite, dolomite in Sorting calcite system, apatite – calcite.
Organic acid addition salts with inhibitors.it is complex with inorganic salts (copper, cobalt, nickel, iron, lead, heavy metal salts) and oxalic acid, tartaric acid and other organic, take use of principle that phosphate mineral salts has a better adsorption of metal salt than carbonates salts, it make mineral salt surface charged with positive electrolyte, then organic complexes complexed to make hydrophilicity, then use general fatty acids collector can realize sorting in the natural pH conditions.
Phosphate mining equipment are choose by its nature. Scrubbing and desliming process is suitable for high degree weathering ore, but it will has a low grade and recovery phosphate concentrate ore; gravity separation has less pollution and has good indexes of coarse phosphate particle , but it is not suitable for fine particle size ore. Flotation process is the main process, it is suitable for processing the complex ore and has good flotation indexes. Gravity and magnetic and flotation process is suitable for the ore with useful associated minerals, it will have a high utilization, but the process is complex, sometimes it need off-treatment. Microbial treatment method is suitable for the ore with complex nature and low grade, it has good leaching effect but it takes several months. The new method such as dry electrostatic separation method, magnetic cover method and selective flocculation method, though has good indexes in the lab, it is not applied in the production. So we have rare use those method in our production.
Secondly, we also considerate the cost of choosing phosphate mining equipment. The phosphate ore has more complex mining equipment, the price is higher. Generally, flotation cost higher than other process. When we really need the flotation, we should take the mixing flotation method to decrease the regent and flotation equipment cost. When consider the dressing cost, we should consider the fixed costs, liquidity costs and earnings to maximize the benefits.
What Kind of process should been used to phosphates. The following is the ore beneficiation process. The aim of the ore beneficiation process is achieve the enrichment of the phosphate which has achieved the monomer dissociation. Flotation process is usually used in the phosphate ore. Usually the flotation process includes the Single reverse flotation, positive flotation, flotation (positive and negative), double reverse flotation. Usually, the phosphate rock contains the associated metals such as iron ore which is worth of recovering.
At this moment, the magnetic separation can be added to the process to recover the useful associated metal. The common flotation principles are: preferential flotation process, mixed flotation process, partial flotation process and equal floating process. For the phosphate with low grade, the mixed flotation process is commonly used: the phosphate ore and the useful minerals can be floated firstly and then they will be separated. This process method can save the flotation reagent, reduce the flotation cells and lower the flotation costs.
Uganda 720 tpd Phosphate Processing
Ore Characteristic: high phosphorus tailings in magnetic separation plant, -200 mesh accounts for 50%
Processing Solution: Desilting - a section of closed circuit grinding - one coarse one sweep two fine flotation - concentrate dehydration process