As a high-efficiency flocculant, PAM is inferior to other flocculants. Adding HPAM to the mineral suspension, and under the action of ultrasound, will produce a highly effective flocculation effect. The flotation fluid used for coal can accelerate deposition and agglomeration, and used for coal mining can increase the mining rate and reduce energy consumption. The use of HPAM in the hematite-quartz mixture can perform selective flocculation, and the strong intermolecular binding force between the HPAM polymer and the molecular surface of the hematite powder can be used to separate the quartz powder.
In 1976, Japanese scholars used the massive PAM containing Ti ((OH), to be crushed, and then extracted metal uranium from seawater. In 1979, they used Fe(OH)2, Zn(OH), etc. PAM copolymer to adsorb Cat, Metal ions such as Ni* and Cu* have been successful.
In 1983, Yanchaoyeu of Taiwan, China, and others synthesized PAM-Radium Phosphate Resin, which effectively separated metal ions such as Cs', Co?', Ce". In 1988, Japan subsequently synthesized PAM-tin phosphate resin for use in seawater. Extract metal ions, the exchange capacity for Na* and L* is 0.5molL (dry resin).
In the mining industry, an effective method must be used to separate mineral solids from water or aqueous solutions. In many beneficiation processes, if there is no effective flocculation, the heavier inorganic solids will fall to the bottom of the settler for a long time, and the smaller particles will be suspended in the supernatant liquid, such as the standing solution. These particles may be suspended for several days before they settle down. The efficiency of filtration and dehydration selection is also severely reduced due to the presence of a small amount of particles in the supernatant. Now, these fine particles can settle down quickly by using PAM. When PAM is added to this kind of aqueous dispersion, the individual particles in the suspension tend to aggregate, forming heavy aggregates, and settle down quickly, and the upper dispersion becomes a clear liquid. In order to obtain a good flocculation effect, there is an optimal flocculant depth, and excessive stirring will also cause decoagulation. This is due to the destruction of the agglomeration between the particles exposed to the fresh surface, allowing more polymer molecules to stick to themselves. It is difficult to form new flocs at a concentration greater than the optimum. Because most of the surface of a single particle has already been covered by polymer. There are only a few places where new adhesions are formed between the particles. Another problem in the mining industry occurs during the settling process in the leaching box. This box is equipped with stirring, but even if the stirring stays for a short period of time, the coarse particles fall to the end, clogging the pipeline and clogging around the stirring blade, resulting in stirring. When restarting, the blades or drive shaft will be destroyed. Adding a small amount of PAM can relieve it in a wide pH range. At this time, small particles and large particles settle together from the suspension, so that lumps will not be concentrated at the bottom of the box, so the stirring is easy to start, and the pipeline is easy to remove.
One of the earliest applications of PAM is uranium extraction. Almost all paving ore is extracted by leaching the ore in an acid or sulfonate solution. After multi-stage filtration and sedimentation, the leaching residue is separated from the liquid, which is one of the main processes for uranium extraction.
There is a liquid-solid separation problem when thickening the leached mine slurry and precipitating sodium salts from the production solution. In the thickening process of the concentrate before leaching, PAM treatment is very effective. It can increase the filtration speed by 4 times.
When the acid leach liquor is filtered, the PAM treatment can also greatly improve the capacity of the filter, reduce the cost of the flocculation process, and increase the recovery of uranium. After leaching, many mines use alkali to precipitate uranium from the production solution, and PAM treatment can also improve, Thickening and filtration rate. When leaching gold ore with cyanide, PAM treatment can increase the sedimentation rate during the thickening, filtering and decanting of the slurry.
The hot dipping liquid of boron ore contains a lot of impurities such as clay. Adding PAM can promote its sinking and improve the efficiency of filtration and concentration. At present, the application of polyacrylamide in the coal washing industry in my country is more and more widespread. The sedimentation and filtration of pulverized coal and sludge are the main issues related to economy and pollution control in coal washing operations. PAM often helps to reduce clay pollution, reduce pipeline blockage, and pump maintenance. The use of PAM also helps to obtain a relatively clean top effluent. In water-deficient areas, closed-circuit circulation options can also be used to achieve higher production capacity and water saving rates. It can also economically recover pulverized coal and increase the filtration rate. The main aspects of PAM application in coal washing are the concentration of clean coal and tailings and the dewatering of clean coal and tailings.