Study On Steady Technology Of Sewage Zero Drainage In Aluminium Industry

Industrialized development causes the water resources to be intense day by day, reasonably duplicating the water is a important way to solve the problem.For saving water,simultaneously reducing the environmental pollution,many industrial enterprise had implemented the wastewater zero drainage project.China Aluminum Guizhou Subsidiary Company (hereafter referred to as the Guizhou Aluminum Manufacturer) is the frist to implement the industry wastewater zreo drainage in the aluminum production and processing profession.Research objective is to determine factor of pipeline scaling and corrosion, find influence of sensitive indicators to water quality and stability, put forward the stable solution to the water quality and do testing and certification through Guizhou Aluminum Plant recycling water quality tests and studies. So that production of recycled water will meet the water quality requirements to ensure that water equipment is not easily blocked,corrosion,scaling and influented by sensitive index fluctuations, and ensure that production of the normal operation of long-term stability.In the piece experiment,metalline pieces were hanged in main pipelines of the alumina plant, the power plant and the thermal power plant,then scaling and corrosion situation of the three plants were compared in the end.Main water harmful of the alumina plant lied in the pipeline scaling, main water harmful of the thermal power plant lied in the pipeline corrosion,while those of power plant didn't have obvious corrosion and scaling phenomenon.According to piece experiment and scale test results,alumina plant scale sample shows the main pipeline scale is carbonate,and identifid the main reason for scaling is high alkalinity in alumina water and high hardness of the water added.The solution is to collect the original and added water of alumina together into the sedimentation tank, then be treat. Test determined coagulant is PAC with amount of 6mg/L,flocculant is Si-sodium with dosage of 10 mg/L,reaction time is 60S. On this basis, the original sedimentation tank is partly transformed to ramp setting tank,the foreside supplements micromesh reaction zone,the after portion sets up ramp sedimentation wall,so ability and treatment effect of sedimentation tank is improved.Water analysis of the thermal power plant demonstrated reuse water in thermoelectricity including high corrosive sulfate radical ion,while the rmoelectricity pulp rowing water also had destructd attrition function to the pipeline.Considering the thermal power plant have already took steps on new craft transformation,and the new craft could eliminate the sulfate radical from the source,so processing target is to guarantee the thermoelectricity water quality not to worsen for 2 years. Experimentation determined is to use the thermoelectricity reuse water to flush the ash,then they will back for processing again, in order to elimination the sulfate radical ion by changing it into deposit.Quality of the power plant reuse water is relatively good, only the chloride ion content is upper.The highly concentrated chloride ion is caused by calcium chloride using in the processing of carbon factory roasting waste water. Experimentation determined to use milk of lime to replace the calcium chloride in eliminating the fluorine, raw material milk of lime can provide by the alumina plant, thus origin convenience is reliable and the expense is reduced. The experimentation result demonstrats it is feasible, quantity of milk of lime is 20t/d, fluorine elimination rate achieves up to 80%.After the implementation of zero drainage, the entire system water volume needs to redistribute and achieve the balance optimization.East according to various factory districts water volume change, adopts west the water to adjust the measure, the eastern zone reuse water supplements to the alumina plant then to recycle.