Papers by Author: Rui Ying Bai

Abstract: Magnesium slag was used to produce cement clinker replacing part of limestone and sandstone with 11% content. The results show that the magnesium slag can significantly improve the grindability and burnability of Portland cement raw materials. The 28d compressive strength of this clinker is 58.9MPa and the physical performance can satisfied the requirements of 52.5 strength grade according to GB 175-2007.

Abstract: The particle characters and their physical properties of vertical roller mill finish grinding cements were studied in this paper. The difference with roller press-ball mill combined grinding products was also analysis. The results were shown that the particle size of the vertical roller mill finish grinding cements was more evenly distributed at the comparative average size. The proportion of the particles under the 3um and on 60um has fallen off a little; the average circularity and slenderness ratio were nearly same with combined grinding process, but the proportion of high circularity particle is lesser, and the particle shape were slightly inferior with the cement produced by combined grinding process; the physical properties were nearly same with the combined grinding cement except the longer setting time. So the cement produced by vertical roller mill finish grinding process is satisfied for the usability requirements.

Abstract: The influence of air content on compressive strength of C20，C30，C40 and C50 concrete was investigated in this paper. The result shows that this relationship varied with concrete strength grade. For C20~C40 concrete, the air content increases with addition of air entraining agent, while a maximum air content value appears for C50 concrete. The compressive strength of C20 decrease slightly with the air content, on the other hand, that of C40 significantly decreases relatively.

Abstract: The paper analyzed some problems of general chemistry teaching in independent college, and pointed that teaching reform should be carried out according to the independent college training goal. Teaching plans should be worked out according to training goal, teaching methods should be reformed, experimental course should be enhanced, general chemistry course should combine with professional feature, contact of the theory and practic should be payed great attention. Through the teaching reform, the general chemistry teaching level of independent college can be enhanced practically.

Abstract: A modified Tessier sequential extraction procedure was employed to investigate the speciation of Cr in cement products. The amount of Cr in extracting solution was determined by atomic absorption spectrophotometer and extraction residue was analyzed based on the results of XRD, SEM and EDS. The distribution of Cr in cement was discussed also. Cr existing as species exchangeable or bound to carbonates increases with curing age gradually.

Abstract: The magnesium slag is discarded from production of magnesium metal from dolomite. However the magnesium slag is slaked in some factories by means of sprinkling water to prevent from dust pollution. The possibility of slaked magnesium slag (SMS) to play a role of raw material and blend for portland cement was investigated by experiments of raw mix preparation, clinker calcining and property determination of cement pastes and mortars. The results revealed that SMS was still reactive. The raw mix with SMS was of excellent burnability that would contribute to energy saving. As a raw material, SMS can be used for calcining clinker of good quality; and as a blend it is suitable for production of ordinary portland cements. Because the magnesium slag is slaked, SMS has no problem on soundness. Higher strength of cement can be obtained in form of binary blends consisting of SMS and ground granulated blast-furnace slag or fly ash.

Abstract: It is in great request to substitute foamed concrete for organic thermal insulating materials that are inflammable and liberate virulent gases on burning. In current study, felsite powder (powdery magnetite mill tailings) was used as filler and Solvay distiller waste (DW) was used as hardening accelerator for foamed concrete. The results showed that the strength and strength-to-density ratio of foamed concrete in cement-felsite powder system is much higher than those in cement-sand system and cement-lime-sand system. The Solvay distiller waste, suspending agent and polypropylene fiber can improve performances of foamed concrete such as cohesion and strength. DW can reduce shrinkage in forming process of foamed concrete.