Research On Alkali-activated Phosphorous Slag Cementitious Material

Environmental protection has become a global focus. For the purpose, Kyoto Protocal took effect on 16 February 2005. In building material production, green technology obviously means green building material. During the manufacture process of Portland cement, which consumes large energy, causes severe pollutions. It doesn't meet the requirement of green building material. Phosphorous slag is a by-product from the production of yellow phosphorous. It was reported that at least more than 5,000,000～6,000,000 ton phosphorous slag was discharged annually in China, and large amount of phosphorous slag was exposured to atmosphere, which not only occupied land and caused pollution on environment due to P and F elements in phosphorous slag, but also resulted in the waste of natural resource. Phosphorous slag containing silicon oxide and aluminum oxide have potential activity. Making use of them as primary material of cemented material not only releases the load on ecological condition, but also can replace part of cement, which displays waste-utilized and low power waste function. So that it is essential to make the best of phosphorous slag.CaO and SiO2 are great composition of phosphorous slag. Mostly amorphous glass phase reaches 90% of phosphorous slag by cooled apace. Its uses are limited in admixture for cement or mineral admixture for concrete, which can not make full use of its potential activity. Chemical compositions, phase compositions and structures of phosphorous slag are analysed by chemical analyse, XRD, and NMR measurements. The results show that its chemical compositions are closed the blast furnace slag, all of them content glassy substance as the main phase, and their structures are likeness. Firstly granulated phosphorous slag by mechanism activation, and then choosing proper alkali activators, the alkali-activated cemented material which contains no clinker and can normally hydrate and harden in natural conditions is made up. The activator dosage of sodium silicate calculated as Na₂O is 5～7%. As...