Test Of Mechanical Properties Of Electrolytic Manganese Residue And Stability Analysis Of Tailings Pond

Manganese residue is a solid waste discharged from the production of metallic manganese in the electrolytic manganese industry.With the rapid development of the electrolytic manganese industry,how to deal with manganese residue has become a huge challenge when enterprises face safe production and environmental protection.In particular,the raw material of our country's electrolytic manganese industry is rhodochrosite,which mainly contain Manganese Carbonate.The grade is low.The average grade of manganese ore is only 13%-15%.Every 1 t of electrolytic manganese products produced will produce 10 t?12 t of manganese residue.Manganese residue is accumulated on the surface to form the manganese residue reservoir.The manganese residue reservoir is similar to the tailings reservoir.It not only occupies a lot of land,but also involves safety and environmental issues.The safety requirements of the manganese residue reservoir in my country are implemented in accordance with the technical standards of the tailings storage.A large amount of sulfuric acid and ammonium nitrate(NH₄NO₃)are added in the production process of electrolytic manganese,cause to high concentration of sulfate and ammonia nitrogen in the manganese residue.The sulfate in the manganese residue is easily dissolved and lost due to the infiltration of atmospheric rainfall,which causes the porosity of the manganese residue to increase,reduces its mechanical properties,and threatens the safety of the manganese residue reservoir.Ensuring the production safety of the manganese residue reservoir has become a bottleneck restricting the healthy development of the electrolytic manganese industry.Therefore,it has great significance to research on the engineering mechanical properties of manganese residue and analysis the stability of the manganese residue reservoir I order to the safe production of electrolytic manganese enterprises.At present,there are few research results on the engineering mechanical properties of manganese residue.And these properties of manganese residue are related to the safety of the manganese residue reservoir.Because the manganese residue contains easily soluble salts.The test conducted in accordance with the used national standard"Geotechnical Test Regulations"(GB/T50123-2019)can not get correct results obviously.So,at the basis of summarizing the related research results of natural saline soil,the author chooses"World Manganese Capital"-Chongqing Xiushan's manganese residue as the sample.The author has carried out a series of studies on the composition and content of easily soluble salts in manganese residue and the engineering mechanical properties of manganese residue.At the same time,taking the Longjingcao manganese residue reservoir of Xiushan Jiayuan Mining company as an engineering case,the dynamic and static stability of the manganese residue reservoir was calculated and analyzed.The results achieved are as follows:(1)We obtain the composition and content of the easily soluble salt in the manganese residue and the cleaning and desalting method The main components of easily soluble salts in manganese residue are sulfate minerals such as aluminum sulfate and calcium sulfate.The content is 10.64%?13.98%.So manganese residue belongs to super saline soil.Due to the influence of the crystal water contained in the soluble salt,the drying temperature for testing the moisture content of the manganese residue should be set at 55?and the duration of 4 d.(2)The loss of soluble salts in manganese residue will have a significant impact on its engineering mechanical properties.In terms of consistency performance,the liquid plastic limit of desalted manganese residue is greater than that of original manganese residue.In the permeability test,the permeability coefficient of the original manganese residue sample will gradually increase with the loss of soluble salt and the conductivity of the leachate will gradually decrease.As the dry density of the sample increases,the initial permeability coefficient of the manganese residue gradually decreases,and it takes longer for the permeability coefficient to increase to the maximum value with the dissolution of soluble salts.In terms of compressibility,the consolidation coefficient of the desalted manganese residue is larger than that of the original manganese residue,but the compression modulus is reduced.(3)We obtain the the stress-strain curve and change law of manganese residue.The triaxial compressive stress-strain curve of manganese residue can be divided into initial deformation stage(linear strain hardening stage),strain stabilization stage and nonlinear strain softening stage.The strain softening characteristics of manganese residue under high confining pressure are more obvious.The Duncan-Chang model can better describe the change law of the stress-strain curve of manganese residue.In terms of shear strength,the values of c and?(c'and?')of manganese residue increase with the increase of dry density,and decrease with the loss of soluble salt.The change of dry density has a greater influence on the c and c',but a smaller influence on the?and?'.(4)We obtain the dynamics characteristics of manganese residue.Under the same conditions,the dynamic strength of the desalted manganese residue has decreased,and the seismic performance has been weakened.Both the original tailings and desalted tailings with the confining pressure increases,the number of vibrations required for the specimen to be destroyed gradually increases when they have the same density.As the dry density increases,the number of vibrations required for the specimen to be destroyed gradually increases.The typical hysteresis curve of manganese residue can be divided into three stages.In the initial stage,the stress is larger but the strain is smaller,the area of the hysteresis loop gradually increases,and the shape is basically the same,showing a concentric ellipse.With the increase of the number of vibrations,the growth of dynamic stress slows down,the dynamic strain gradually increases,the hysteresis loop continues to increase and the dynamic stress peak appears.The hysteresis loop ellipse will become wider and larger.As the number of vibrations increases,the peak dynamic stress has passed and gradually decreased,while the dynamic strain continues to increase.It can be seen that the hysteresis loop gradually becomes shorter and wider,backward to the strain axis,and the area gradually decreases.The initial dynamic shear modulus of manganese residue increases with the increase of the effective consolidation confining pressure,and increases with the increase of the dry density.The dynamic shear modulus of manganese residue decreases with the increase of dynamic shear strain,and increases with the increase of confining pressure.Besides,the greater the confining pressure,the smaller the decay rate of the dynamic shear modulus.(5)We obtain the dynamic and static stability results of the manganese slag dam of Longjingcao manganese slag reservoir.using Geo-Studio software and choosing to simplify the Bishop method,the stability of the manganese slag dam body was calculated and analyzed.The results show that the safety factor of the manganese slag dam under the two working conditions meets the requirements of the national regulations and is rich,which is beneficial to the later heightening and expansion of the manganese slag silo.Using time history analysis method and selecting two seismic waves,the seismic response and dynamic stability of the manganese slag dam were calculated and analyzed.The results show that:When the seismic waves acts.The maximum horizontal acceleration in the dam body occurs near the crest of the dam in the initial stage and the front end of the accumulation dam.The horizontal deformation of the dam is mainly towards the downstream of the dam.As the height increases,the displacement gradually increases.The largest horizontal displacement is near the top of the accumulation dam.The minimum safety factors of the dam under the action of seismic waves are all greater than 1.0,indicating that the manganese slag reservoir is safe under the action of earthquakes.