Research On Preparation And Performance Of Steel Slag Source Thermal Storage Material

Steelmaking is one of the most developed and widely covered heavy industries in the world.Far from reducing the total steel production,in the last 10 years the total produced steel amount has experienced an increase of around 5 % every year.However,this production activity means one of the biggest by-products of high-temperature operation,extraction and refining of metals:the production of steel slag.Moreover,Steel slag is alkaline and will produce a water leachate with a basic p H of approximately 11.Even if steel slag is officially classified as non-hazardous waste in Europe,landfilling steel slag should not be regarded as a long-term solution for waste treatment,and a new market should be identified to recycle 100 % of this material.Therefore,this article uses steel slag as the raw material,and first carries out an acid extraction experiment on the steel slag with 1 M acetic acid,and then uses the obtained leachate and residue to prepare three different types of heat storage materials(sensible thermal energy storage,latent thermal energy storage and thermochemical thermal energy storage),(1)Using 10 wt% acetic acid solution in a 70 ? water bath,the calcium chloride and Magnesium oxide is compounded with the leachate of dried and high-temperature treated,and the calcium oxide conversion rate of the prepared composite steel slag source thermochemical thermal storage material is as high as 97.39 %,and there is no obvious decline in the ten-cycle experiment,which is maintained at about 96.59 %.This is about 6.84 times higher than the highest calcium oxide conversion rate of commercial calcium oxide.(2)The residue after high temperature treatment at 900 ? was pressed into a block,and the sensible thermal storage material of steel slag source with good thermal stability within1000 ? and a thermal conductivity of 1.022 W/m K at 300 ? was obtained.(3)Latent heat is 60.19 J/g,supercooling degree is 8.3 ?(reduced by 3.9 ? compared to pure solar salt),and thermal conductivity is 0.788 W/m K(compared to 0.52 W/m K of pure solar salt,an increase of about 55.1 %)steel slag source latent thermal storage material is prepared by mixing the residue of 900 ? high temperature treatment with solar salt in a mass ratio of 5:5,pressing into a block and sintering.