Coal, as the so-called industrial food, plays an indispensable role in the development of the national economy. Affected by the development of new energy technologies and economic development and policies, in recent years, the growth of coal consumption as an energy source has slowed down, but the production and consumption are still at a historical high, and the production and sales are still very large.
Whether in the process of production or use, coal carbon will produce a mixture of water and fine coal powder, such as coal washing wastewater in the coal industry, coal sludge water in coal preparation plants, washing wastewater in coal-fired power plants, etc. The main characteristics of these coal washing wastewater mixtures Water Treatment Chemicals are as follows:
First, the turbidity is high, the solid particle size is fine, the surface of the solid particle is more negatively charged, due to the repulsion between the same charge and the influence of gravity and Brownian motion, so that these particles remain dispersed in the water;
Second, due to the interaction between the interface of solid particles in coal slime water (such as adsorption, dissolution, combination, etc.), the nature of coal washing wastewater is quite complex, which not only has the properties of suspension, but also has the properties of colloids.
Third, the sludge resistance is large, the filtration water is poor, and the pressure filtration dehydration is difficult
Therefore, the coal wastewater is particularly stable, it will not settle naturally for a few months, it is difficult to clarify naturally, after precipitation, the supernatant still contains a large number of black liquid suspended solids such as coal slime, and contains various additives and heavy metals and other harmful substances in the production and processing process, so it is very difficult to deal with. If the waste water is not discharged according to the standard, it will cause water pollution, siltation, coal slime loss, not only cause environmental damage and waste of resources, but also cause huge economic losses. The quality of wastewater treatment seriously affects the development of coal industry. Therefore, in the face of coal washing wastewater, it is of great significance to develop corresponding new products and new technologies.
In view of these characteristics of coal washing wastewater, we have concluded the following coal washing wastewater treatment methods through a large number of experiments:
First of all, add lime or calcium carbide slag to the wastewater (the composition is calcium oxide), neutralize the negative charge in the wastewater, destroy the stability of the water body, and achieve the purpose of mud-water separation.
Secondly, flocculant (polyacrylamide) is added. The sedimentation rate of suspended solids in wastewater treated with calcium oxide is very slow, and it is difficult to achieve complete precipitation, which takes a long time, because polyacrylamide has a long molecular chain with different groups on the molecular chain, and the long molecular chain can attract suspended particles to collide with each other and adsorb to form large floc sedimentation. Therefore, the addition of polyacrylamide can increase the sedimentation rate and achieve complete and rapid separation of mud and water. According to years of experience, coal washing wastewater treatment generally uses anionic polyacrylamide or non-ionic polyacrylamide, there are also a few use of cationic polyacrylamide. It is recommended that when using flocculants, we must first do the selection of flocculants to avoid unnecessary waste.
Characteristics of polyacrylamide flocculation products:
1, can quickly form large flocculent, the amount of sludge is small and the flocculation settling speed is fast; Dissolves quickly and thoroughly, without any soluble matter (fish eye); Dissolve the powder product for about 60 minutes; Economical and practical, small dosage, good effect, high dehydration rate.
2, low operating cost, low dose can have an effective effect and high dehydration performance, very economical; Excellent filtration and dewatering improve the dewatering effect of the sludge.
3, automatic feed, easy to handle. Product selection can be specially used for high viscosity aqueous solution state, is a good flow viscous gel system.
Special attention should be paid to:
The addition amount of polyacrylamide solution is the key link in the treatment of coal slime wastewater. Appropriate addition method and dosage will help to improve the flocculation effect. Usually according to the selected treatment process and properties of slime water through the test to determine.
If the amount of polyacrylamide is too large, the sedimentation rate of coal slime will slow down, the concentration overflow will easily exceed the standard, and the required circulating water index can not be guaranteed, so that the index of coal washing products is difficult to control stably.
If the amount of polyacrylamide is too much, although it speeds up the sedimentation rate of coal slime, it is easy to cause the concentration of concentrated bottom flow is too high, and the polyacrylamide content in the bottom flow increases, resulting in the bottom flow transportation and pressure filtration production difficulties, and the coal cake is not easy to fall off when the coal cake is discharged by the filter, which increases the labor intensity of the operator, reduces the work efficiency, causes the waste of chemicals, and increases the production cost. Therefore, the test to determine the appropriate amount of polyacrylamide can not only improve the flocculation effect and effectively treat the coal slime wastewater, but also play an important role in the quality and production efficiency of coal and reduce the production cost.
Henan Hongze Environmental Protection Technology Co.. is a professional polyacrylamide R & D, production, sales and service in one of the supply chain resource integration company, with cationic polyacrylamide, anionic polyacrylamide, non-ionic polyacrylamide, zwitterionic polyacrylamide and
Polyaluminum Chloride， emulsion series products, can provide you with our best solutions and a full range of services. Welcome to inquire or online message.
Henan Hongze Environmental Protection Technology Co., Ltd
