The flotation process takes place in the medium water, while the water used for flotation changes with time and place. The composition of water has a great influence on flotation, and the quality of floating water must be emphasized. Floating water can be divided into the following categories according to different situations:
Soft water
Most rivers and lakes are soft water and are the most used water in the flotation process. It is characterized by relatively low salinity, generally less than 0.1% salt, polyvalent metal ions less.
The hardness of water is usually measured by the amount of Ca 2+ and Mg 2+ ions in water. The total hardness of water can be converted as follows:
Total hardness of water = [Ca 2+ ] / 20.04 + [Mg 2+ ] / 12.16 (mmol / L)
Wherein [Ca 2+ ], [Mg 2+ ]-Ca 2+ , the concentration of Mg 2+ ions in water, mg/L.
1mmol/L is called once.
The calculation standards for hardness in different countries are different. Therefore, the hardness is marked with ×× hardness. After conversion, 1 milligram hardness = 2.804 German hardness = 3.511 British hardness = 50.045 American hardness. The water in Shenyang is about 3.6 milligrams of hardness.
2. Hard water
Water with a hardness greater than 4 is collectively referred to as hard water. Hard water can be divided into: 4-8 degrees medium hard water; 8-12 degrees is the hardest water. Hard water contains more polyvalent metal cations, such as Ca 2+ , Mg 2+ , Fe 2+ , Ba 2+ , Sr 2+ , etc., and there are many corresponding anions, such as HCO 3 - , SO 4 2- , CI - , CO 3 2- , HSiO 4 - and the like. Hard water is detrimental to the flotation of fatty acid agents because Ca 2+ , Mg 2+ ions consume the collector and are often destroyed by the selectivity of the process. When such iron ore flotation, Ca 2+ activates quartz and silicate gangue minerals. Thus, its harmful effects must be eliminated before flotation. The general method of adding soda to make an insoluble precipitate. Softening of hard water, chemical and physical. The chemical method is a method of converting some harmful metal ions into precipitation or adsorption, such as using sodium carbonate, sodium hydroxide or the like. The ion exchange method has wide adaptability. According to different requirements, different types of exchange resins can be selected to achieve the required purpose. Both electromagnetic treatment and ultrasonic treatment can be used as a means of softening water.
3. Salt water
Sea water and some lake water are salt water. They are characterized by a high salt content, generally 0.1% to 5%. Salt water is used for flotation and is of great significance to coastal mines or the salt lake area. Naturally hydrophobic minerals such as coal , float in salt water, or even without drugs. For example, a coal well water contains the following ions (mg/L), Na + -1789.6, CI - -2141.3, Mg 2+ -28.4, SO 4 2 - 131.6, which can be obtained well without flotation when using flotation coal. index of. And the flotation speed is 60% higher than ordinary fresh water. [next]
When a lead-zinc ore flotation, the water did not affect the flotation of lead, lead concentrate grade, impurity, and recoveries were similar flotation with fresh water, but the water flotation of zinc, there is some impact, making increasing the amount of reagent, such as lime, sulfuric acid copper were increased. At the same time, the gangue is also relatively easy to float, and it is necessary to add water glass. The grade and recovery rate of zinc concentrate are lower than those of freshwater flotation. When using seawater flotation, attention should be paid to the corrosive effect of seawater on equipment.
4. Backwater
The use of backwater is getting more and more attention. Whether it is environmental protection, or from the point of view of conservation and industrial water, the use of recycled water is necessary.
The characteristics of flotation backwater are that it contains more organic and inorganic agents and its composition is more complicated. The effect of backwater on the flotation process must be considered when using it. If it is used improperly, it will affect the sorting effect. The flotation reagent in the backwater is sometimes 50-100 times higher than the fresh water. The use of the backwater can save the flotation reagent. It has been proved that the flotation of the single metal ore is simpler, such as copper- nickel- sulfur flotation. At the time, all the water is used, which can reduce the dosage of the agent: 17% alkali and 23% xanthate.
When sorting polymetallic ore, the recycling of backwater is more complicated. The process of mixing and separating after the flotation of sulfide ore is convenient for utilizing the return water. For example, the overflow after dewatering of the lead-zinc mixed concentrate and the clarified water of the tailings can be returned to the front process for reuse. In the case of more complicated conditions, in principle, the wastewater discharged from the same circuit is suitable for returning to the same circuit. The use scheme of the backwater and the proportion of use must be determined through experiments.
Adjustments are often required before returning water. Because there are not only excess chemicals in the backwater, but also solid materials, especially fine-grained sand, which is harmful to flotation. Generally, the content of solid particles in water that is recycled is not more than 0.2 to 0.3 g/L. For this reason, the natural clarification or coagulant method is often used to flocculate and settle the fine mud. The coagulants used are: lime, lime and ferrous sulfate (lead sulfate). When it is not desired to have Ca 2+ in the circuit, aluminum sulfate can be used alone as a coagulant. If the pH of the return water is too high, acid treatment may be added if necessary.
202 Stainless Steel Cut Wire Shot
Longlived 202 Stainless Steel Cut Wire Shot, also named 202 Stainless Steel Shot, is made from high quality 202 stainless steel.
Benefit from great quality and material, Longlived 202 Stainless Steel Shot has an excellent anti corrosion characteristic. Its chemical composition is as below:
|
C
|
Si
|
Mn
|
P
|
S
|
Ni
|
Cr
|
N
|
|
0.78
|
0.76
|
15
|
0.032
|
0.001
|
4.06
|
14.36
|
0.01
|
Longlived 202 Stainless Steel Shot is widely used on stainless steel die casting parts, aluminium die casting parts for copper alloy casting parts and other non-ferrous alloy casting parts for surface treaning of shot blasting.
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