Coking Wastwater Coal Washing And Impact Floatability Of Coal

Coking industry is the most serious water and environmental pollution one of the industries, the treatment of coking wastewater treatment technology focus only on the development of end to coking wastewater discharge standards for the purpose for a long time. With the diminishing capacity of water environment and the ecological requirements of increasingly stringent, need development, research and application of new biological wastewater treatment process and coking wastewater reuse technology. The topics according to circular economy concept, using coal-based industrial chain of the different requirements on water quality, making a big circle idea:Coal washing and other reasons due to evaporation of water generated tons of coal consumption for the 0.2m3/t of coal (in closed loop as standard), to accept the coking wastewater reuse provides an effective space. The coking wastewater treatment supply water for washing, the introduction of coal preparation plant closed circulation system, use of coal adsorption treatment and flocculation treatment waste water biodegradable pollutants in coking wastewater to achieve zero discharge of a cycle of new technology. Closed water circulation system development and utilization of coal washing plant coking wastewater to achieve zero discharge of a cycle of new technology, need to examine whether the coking of adverse effects of water on the flotation. Coking wastewater by two out of three major pollutants in water analysis and conclusion, using two kinds of coking coal on the simulated secondary effluent wastewater adsorption properties of the major pollutants of wastewater in the determination of rate of microbial hydrophobic pollutants adsorbed on the surface properties of coal and coal can affect the impact of floating, we can draw the following conclusions:(1) The adsorption removal rate of organic pollutants by coke is slightly higher than the fei coal's, adsorption capacity of coal (-0.5mm) is between 0.1094～0.1544 mg/g. The adsorption of phenol with coke is consistent with the Freundlich adsorption isotherm, and the quinoline is fit with the Langmuir adsorption isotherm, but the adsorption of quinolineis more in line with the Freundlich isotherm on fei coal. Adsorption reaction of organic pollutants is well conformed to the characteristics of second-order reaction kinetics on different types and particle size of pulverized coal, R2=0.990±0.008.The adsorption process is controlled by liquid film diffusion. The rate constant equation In k=188.54e-11.64/(RT) and activation energy Ea=11.64kJ/mol may be obtained under different temperatures by the phenol has been adsorpted on coke.(2) In biochemical treatment of waste water, hydrophobicity and hydrophilicity of microorganisms, from a secondary sedimentation tank, has a significant effect on the deep treatment and recycle of reclaimed water. After compared three kinds of extracting agent, selected optimum bacilli and the best ratio of extracting agent, then the optimum separation conditions were determined. The results showed that capacities of carbon tetrachloride adsorbed micro-organisms were all strong, and micro-organisms could maintain stability in the interface of carbon tetrachloride-water and the carbon tetrachloride layer for a long time. Controlling the concentration of test micro-organisms were basically the same, the best ratio of bacilli and extractant was 2.67 (bacilli:extractant= 12ml:4.5ml). Using low-speed centrifugation (1000r/min,10min) as separation conditions. Main microbial hydrophobic in the actual coking wastewater had been determined, moreover the infrared spectra of microorganisms had been analyzed, proved this method is simple and feasible. It describes the study of hydrophobicity of nitrifying bacteria (NFB) and denitrifying bacteria (DFB) under different pH value, temperature and growth cycles using extraction-turbidimetry to determine hydrophobic percentage of microorganisms. Variation of Zeta potentials and sedimentation of coal particulates in coal suspension was investigated at various conditions of the coal particles absorbed with different hydrophobicity of the microorganisms. The study shows that the hydrophobic percentage of microorganisms varies with pH, temperature, growth cycle, and inactivation of the microorganisms. The NFB appear to be hydrophobic with hydrophobic percentage over 60% while the DFB are hydrophilic with hydrophobic percentage less than 20%.(3) Hydrophobic variation tendency in the coal surface, surface potential and flotability were investigated to study by wetting speed of oil and water (OHR), Zeta potentialand after pulverized coal adsorbed main contamination such as ammonian, phenol, quinoline, and microbe in this paper.Analysis the change of coal surface properties after it adsorbed single pollutant revealing the mechanism of pollution:Zeta potential had a significant change of coal-water system after adsorption of pollutants, Zeta potential was-17.27mv without adsorption, after adsorption of pollutants and micro-organisms, Zeta potential were-21.88mv/-26.62mv (nitrobacteria),-25.21mv/-29.47mv (quinoline),-27.39mv/-32.58mv (phenol),-32.13mv/-38.53mv (ammonian) and -38.80mv/-43.40mv (denitrifying bacteria). The electro-dynamic study on Zeta potentials of coal particulates in coal suspension indicates the coal particles absorbed preferably by the microorganism instead of the other minerals. Absolute value of the Zeta potential of coal particles considerably increases when DFB absorb on their surfaces. The microorganisms are also functioning as a flocculant to flocculate coal particles in the coal suspension to promote sedimentation of the coal slime. The surface hydrophobicity of coal has been increased by adsorbing nitrifying bacteria and quinoline in surface. When coal adsorbed the amount of ammonian, phenol over a certain adsorption respectively, the negative impact of coal surface hydrophobicity was revealed relatively. While coal adsorbed denitrifying bacterium, its surface hydrophobicity deteriorated obviously. Infrared spectroscopy indicated characterization analyzed indicating that the effect of pollutants on the surface of hydrophobic mainly rested with the performance including hydrophilicity, hydrophobicity of the material itself.(4) Cell flotation tests showed the higher the concentration of phenol and ammonia in wastwater, coal and ash yield a corresponding increased in flotation perfect indicators also tended to decline, but to a certain drug dosage of flotation, ammonia, phenol, the yield of the coal and ash effects small, by changing the dosage of flotation reagent and the ratio of ammonia nitrogen could coking coal floatability of impact ignored. Quinoline on the positive effects of coal flotation in the same drug dose, the higher the concentration of quinoline wastewater, flotation perfect indicator was rising, increase 3-4 percentage points; coal ash balanced case, the fine coal production rate increased slightly. Showed that the flotation of coal quinoline positive effect that the foregoing results:coal adsorption quinoline can improve the surface hydrophobicity of coal. Coking coal in the water adsorption nitrifying bacteria and denitrifying bacteria, the flotation concentrate yield and ash change varies. Containing nitrifying bacteria in raw water, the coal ash, the ash is less than clear water flotation and flotation improve the indicators increased with the bacterial concentration increased; and denitrifying bacteria to the contrary, denitrifying bacteria contained in raw water, the concentrate yield decreased with the increase of bacteria concentration, coal ash has increased gradually. Description beneficial nitrifying bacteria adsorption of coal flotation, denitrifying bacteria are on the floatability of coal have an adverse effect.