Study On Cr Leaching Behavior Of Cast Stone Material Prepared From Stainless Steel Slag Containing Cr

China is paying more and more attention to ecological and environmental protection,and the resource treatment of a large amount of solid waste generated in the industrial production process is particularly important.For example,the stainless steel industry,the electroplating industry,the chromium salt industry,etc.,the long-term accumulation of chromium-containing solid waste generated during the production process not only causes the waste of land resources,but also the hexavalent chromium formed after the Cr element is oxidized will cause serious harm to the environment..Cr₂O₃ in the slag is often used as one of the raw materials of silicate products,and Ca F₂is also a good nucleating agent.Therefore,this article uses stainless steel slag and a variety of oxides to mix appropriate proportions under different sintering conditions to explore the preparation of cast stone materials with anorthite phase as the main crystal phase,and evaluate the loss on ignition,corrosion resistance,hardness,etc.After analysis,it will be tested in accordance with the national solid waste toxicity leaching standards and under acid-base neutral conditions,different solid-to-liquid ratios,different immersion times,different p H,different chromium content,and immersion experiments under different temperature conditions,and Determine the Cr content in the leaching solution and the p H value of the solution after leaching to study its leaching mechanism.The experiment uses the thermodynamic software Fact Sage to calculate a reasonable proportion of ingredients.Add a certain amount of Ca O,Al₂O₃,Si O₂,Cr₂O₃,Ca F₂,etc.to the stainless steel slag to adjust the appropriate ratio to prepare the chromium-containing cast stone material and control its main crystal phase It is an anorthite phase,in order to explore the effect of consolidation and leaching of Cr under this mineral phase.Several groups of cast stone materials with different conditions are obtained through different heat treatments,and the phase composition is analyzed,and the microscopic morphology changes are observed.It is found that the heat treatment at 1400°C for 6 hours is a relatively good heat treatment method,which is used for sintering preparation.Cast stone materials with different amounts of Cr₂O₃ are added and their physical and chemical properties are measured.The hardness is between 6-7,which meets the requirements of cast stone.The corrosion resistance is measured according to the corrosion resistance standard of the cast stone industry,and its acid resistance is measured to be 98%Above,alkali resistance above 99%,which is higher than natural stone.According to the national standard（HJ557-2010）,the prepared chromium-containing cast stone material was subjected to a toxicity leaching test,and the leaching amount of Cr was in accordance with the national standard,far less than the required1.5mg/L.By investigating its leaching behavior,it is found that the leaching amount of Cr increases with the increase of the solid-liquid ratio;it first increases to the highest leaching amount with time,and then tends to stabilize;the Cr content of the leaching solution is very obvious as the temperature rises The increase.Under the condition of strong acid（p H=1）,the leaching amount should be significantly higher.Comprehensive leaching experiments,it is found that the leaching amount in an alkaline environment is slightly higher than that in an acidic environment under the same conditions.The p H of the leached solution tends to be weakly alkaline.The Cr element exists in the form of Cr O₄^2-and Cr（OH）₃ in the alkaline environment,and the Cr element exists in the form of Cr²⁺,Cr³⁺and Cr₂O₇^2-in the acidic environment.