Experimental Study On Mix Proportion And Performance Of Lead-Zinc Slag Powder Foamed Concrete

Lead-zinc slag is an industrial waste discharged from the lead-zinc smelting industry in the process of smelting lead-zinc ore,and then treated by water quenching process to form a glass containing Si,Ca,Al and other elements.At present,the accumulation of lead-zinc slag in China is large,and the treatment and utilization of lead-zinc slag is an urgent problem to be solved.In this study,lead-zinc slag was ground into lead-zinc slag powder by ball mill,and its particle size analysis test,toxicity leaching test and X-ray diffraction test were carried out.The raw materials are lead-zinc slag powder,Portland cement,grade II fly ash,sulphoaluminate cement after grinding and sieving.Industrial hydrogen peroxide is used as chemical foaming agent,supplemented by basalt fiber and water reducing agent.Foam concrete is prepared by chemical foaming,and macro and micro experimental studies are carried out.Through the single-doped experimental study of raw materials,the optimal dosage range of each factor is determined.The effects of fly ash content,lead-zinc slag powder content and water-binder ratio on the compressive strength,flexural strength,water absorption and thermal conductivity of lead-zinc slag powder foam concrete were analyzed by orthogonal test.The optimal mix ratio of lead-zinc slag powder foam concrete was determined by range analysis and variance analysis.The composition and hydration reaction mechanism of lead-zinc slag powder foam concrete were analyzed by X-ray diffraction test.The internal microstructure of lead-zinc slag powder foam concrete was analyzed by scanning electron microscopy.Finally,the relationship between dry apparent density and porosity of lead-zinc slag powder foamed concrete was analyzed by image analysis method,and the test results were fitted.The results show that:（1）When the content of lead-zinc slag powder is between10%and 30%,the compressive strength and flexural strength of the specimen are higher.When the fly ash content is between 10%and 20%,the compressive strength and flexural strength of the specimen are higher.Considering the influence of specimen strength,setting time and test environment,the optimum content of sulphate aluminium cement is 20%.When the length and content of basalt fiber are 6mm and0.3%respectively,the compressive strength of the specimen is the highest.When the water-binder ratio is between 0.50 and 0.60,the compressive strength of the specimen is the highest.（2）The optimal mix ratio of lead-zinc slag powder foam concrete is A₂B₁C₁,that is,the fly ash content is 15%,the lead-zinc slag powder content is 10%,and the water-binder ratio is 0.5.The 28d compressive strength,28d flexural strength,water absorption and thermal conductivity of lead-zinc water slag powder foam concrete with the optimal mix proportion are 2.73MPa,1.81MPa,19.1%and 0.149W/（m.K）respectively.（3）Microscopic test analysis shows that the hydration reaction of lead-zinc water slag powder foam concrete occurs,and the hydration products are C-S-H,Ca（OH）₂and AFt.The hydration reaction degree of lead-zinc water slag powder foam concrete in the optimal proportion group is the best and the strength is the highest.The internal microscopic structure of lead-zinc slag powder foam concrete is more uniform.Basalt fibers overlap in the cement matrix to form a dense skeleton,thereby enhancing strength.The results of image analysis show that the dry apparent density of lead-zinc slag powder foamed concrete is inversely correlated with the porosity,and the correlation is good.