Technology Research On Optimal Utilization Of Cold Rolled Stainless Steel By-product Sludge

Nowadays cement industry faces a severe reality and challenges, for various industrial by-products and the low-quatity raw materials which also provide a chance that turn it into a green industry. This paper mainly focus on the recycle utilization of stainless steel rolling dewatered sludge, and carries the research from two directions of relative technology, take the sludge as a raw material into the cement system and take the measure of thermal activation to make the sludge as an active addition of cement. Based on getting the chemical constitute and physical properties, I begin the research with investigating different sludge volume,three rate value and calcining temperature on the quantity of alkali cement clinker and the affected laws of the properties. The research tells that the sludge has significant influences on clinker minerals, at the optimal volume, it can obviously decrease the harmful function of the alkali on the formation and the quantity of clinker, promote the clinker mineral crystals, especially C3S, better formed, and sintering quantity optimized, then improve corresponding mechanical properties. And the reason is that beside some irony component, there also are some F Cr and Ni which have good mineralization that drop the eutectic temperature definitely, increase the high-temperature liquid volume, decrease the viscosity, all which can make up the disadvantageous influence of alkali on the sintering circumstance, remarkably improve the conditions of clinker sintering. But when the addition volume is excessive, the rate of the liquid phase is too high and the viscosity is too low that destroy the balance condition of C3S crystal formation, cause the massive appearance of block, both of which are harmful for the formation and improvement of clinker minerals. In this paper, we set the optimum calcining parameters range of alkali clinker:KH0.93, SM2.7, IM1.4, sludge addition volume 5.41%, calcining temperature 1400℃. The thermal activated treatment technology of sludge indicates that with the calcining temperature rises to 900℃, the hydration activity of the sludge increases distinctly, however, to the contrary, if to 1000℃, the activity decreases severely. The reason is that if the burning temperature is below 500℃, some minerals in raw sludge deforms which warps the micro structure, and inner energy increases, but the structure is so loose that the absorptive capacity is very high, when mixed with cement, species need much water, causes hydration slurry structure hard compact, absolute strength not so good; when the temperature rises to 700℃, the structure destroys more forward, so does the system inner energy and the hydration activity, all what cause the samples strength increased obviously; compared with calcined at 900℃, the sludge has the highest activity, not just because the origin structure decomposes fully, also part solid phase reactions have occurred, which produces some new masses with hydration activity and the system inner structure becomes density which decrease the needed water volume, all these express that as an addition of cement the sludge has nice hydration property; at the treatment of 1000℃, more new substances are formed, but some of them such as kaynite and calcium fluorosilicate have not water hard activity, which makes the sludge system's hydration activity drop seriously and manifest as an inert material. So we have to control the proper thermal treatment temperature for better hydration activity of the sludge. In the condition of this paper, the thermal temperature range is between 700℃and 900℃. In accordance with relative standards(HJ557-2009,GB/T15337-2008 and GB5085.3-2007), we carry on the leaching-out toxicity testing of the different ages cement samples mixed 30%sludge, all the results(Cr&Ni) are low the state standard limitation of 5mg/L, which indicates the sludge is good environmentally friendly as a cement addition.The above researches tell that the sludge could be made into high-quality alkali clinker as an addition under proper procedures; the sludge could be used as cement clinker addition under thermal activated treatment between 700℃and 900℃. This can not only recycle the utilization of the sludge, avoiding the "second pollution", but also improve the quality of alkali cement, and find a new technological way of comprehensive utilization of the sludge and high-alkali low-quality raw materials.