Study On Waterproofing Anhydrite Products

The anhydrite resources of our country are very abundant. In recent years, the domestic and international experts have made great break-through on the study of clotted capability of anhydrite, which made it possible for anhydrite to be used in more fields. Anhydrite products are lacunaris materials, proning to absorb water. The water absorbed by anhydrite products can make crystalloid touch point to be dissolved and separated out again, deceasing the intensity of the anhydrite products. The main purpose of this study is to research how to decrease the absorbing water rate of anhydrite products, improve the intensity of anhydrite products and expand the range of application of anhydrite.In this study, liquid paraffin and rosin are used as raw materials, Tween-20 and Span-80 as emulsifier, SDBS as assistant emulsifier. And the synthesis conditions of modified paraffin emulsion is optimized through orthogonal experiments. When the HLB value of emulsifier is 11, the dosage of emulsifier is 15%, the speed of stir is 600r/min, the ratio of water and oil is 3:1, the time of reaction is 15min and paraffin and rosin that is mixed by the ratio of 3:2 are prepared modified paraffin emulsion at 65℃by the techniques of normal air pressure and reversion, we can obtain a kind of emulsion which have the character of a sort of blue and white liquid with the particle diameter range from 0.1 to 1μm, the felting strength of 1350N and the lower viscosity of 0.2Pa·s.Added in as waterproofing agent, modified paraffin emulsion can be joined into anhydrite products. The softening coefficient of anhydrite products is 0.58 and the absorbing water rate of anhydrite products is 17.5% when the ratio of emulsion and water is 3:20. Compared with the ratio of emulsion and water which is 1:5, the softening coefficient of anhydrite products has changed little, but the inchoate and final coagulate time of anhydrite has been reduced for 5min and 5.5min separately, i.e. 12min and 16.5min. So not only the waterproofing capability of anhydrite products can be effectively improved, but also the clotted capability is enhanced, when modified paraffin emulsion is used as waterproofing agent of anhydrite productsThis thesis, based on above research, further studies the effect of cement, slag and pulverous coal on waterproofing capability and clotted capability of anhydrite products. The results show that it is limited for cement slag and pulverous coal to improve waterproofing capability and clotted capability of anhydrite products, since the absorbing water rate of anhydrite products is still above 20%. But the compressive strength of anhydrite products increases greatly. The softening coefficient of anhydrite products is 0.77 when the content of pulverous coal is 15% and the content slag is 25%. These three components can reduce the absorbing water rate of anhydrite products and enhance its intensity, because they can increase the density of anhydrite products in varying degrees.