Study On Preparation And Mechanical Properties Of Alkali Leaching Of Lead Zinc Slag Geopolymer Paste

Alkali leaching lead-zinc slag is an industrial waste discharged from the alkali leaching-electrolysis process.Many accumulated alkali leaching lead-zinc slag occupies a large amount of land,resulting in waste of resources,but also caused great pollution to the environment,bringing great potential safety hazards to the environment.Geopolymer is a new type of cementitious material developed in recent years.It uses silicon-aluminium material as the main raw material and has three-dimensional network structure,so it has a strong fixation effect on heavy metals such as lead.Based on the study of alkali leaching lead-zinc slag,the geopolymer material was prepared directly by using it.The optimum mix ratio of strength of alkali leaching lead-zinc slag was obtained under different factors through experiments.The influence of temperature activation on strength of alkali leaching lead-zinc slag was further investigated and optimized tests were carried out.Its specific contents are as follows:(1)Experimental studied on direct preparation of geopolymer from alkali leaching lead-zinc slag.The effects of water-solid ratio,sodium silicate modulus and alkali activator dosage on the mechanical properties of geopolymer prepared directly from alkali leached lead-zinc slag were studied through experiments.The optimum water-solid ratio,sodium silicate modulus and alkali activator dosage were determined to be 0.35,1.2 and 40%.(2)Experimental studied on slag content of direct preparation of geopolymer from alkali leaching lead-zinc slag.The geo-aggregation performance of the alkali leaching lead-zinc slag is general.If it meets the requirement of cement grade 32.5,the maximum content of the alkali leaching lead-zinc slag is 23%.It has no obvious advantage in engineering application.It is necessary to improve the reactivity of the alkali leaching lead-zinc slag in order to further improve the performance of the products.(3)Studied on Preparation of geopolymer by calcination and activation of alkali leaching lead-zinc slag.The reactivity of calcined alkali leached lead-zinc slag is obviously improved,and its 28-day flexural and compressive strength is increased by 35% and 44% respectively when the optimum calcination temperature is 750 C,compared with the 28-day flexural and compressive strength of geopolymer prepared directly from alkali leached lead-zinc slag under the same process conditions.According to the grade requirement of cement 32.5,the content of slag should not exceed 40% when the geopolymer prepared from alkali leaching lead-zinc slag is activated.