改性磷石膏免烧透水砖的制备与性能

Preparation and Properties of Phosphogypsum Modified Burning-free Permeable Bricks

为了拓展磷石膏的资源化利用,进一步实现我国绿色可持续发展的目标,利用磷石膏作为原材料制备免烧透水砖。试验分析了改性磷石膏对免烧透水砖关键指标的影响规律及作用机制。首先对改性磷石膏免烧透水砖原材料的试验方案进行设计,通过体积法进行配合比设计优化,计算得到透水砖初步配合比,并以磷石膏pH值、磷石膏球磨时间及聚合物乳液掺量为改性磷石膏的影响因素,通过正交试验设计,以占胶凝材料总质量30%的改性磷石膏为主要原料,采用静压成型工艺制备透水砖,进行了力学性能和透水性能试验,并对试验结果进行了极差分析及因素水平分析。结果表明:磷石膏pH值是改性磷石膏免烧透水砖劈裂抗拉强度的主要影响因素,其次分别是磷石膏球磨时间和聚合物乳液掺量;磷石膏球磨时间是改性磷石膏免烧透水砖透水系数的主要影响因素,其次分别是磷石膏pH值和聚合物乳液掺量;改性磷石膏免烧透水砖原材料最佳配合比为:磷石膏的pH值为10,磷石膏球磨时间3 min左右及聚合物乳液掺量2%。经生产验证,批量生产抽样实测改性磷石膏免烧透水砖的28 d劈裂抗拉强度为3.57 MPa,透水系数为2.1×10^(-2)cm/s,满足标准要求。

In order to expand the resource utilization of phosphogypsum and achieve the goal of green and sustainable development in China, burning-free permeable bricks are prepared by using phosphogypsum as raw material. The influence rule and mechanism of modified phosphogypsum on the key indicators of burning-free permeable bricks are analyzed after test. First, the experimental scheme for raw materials of the modified phosphogypsum non-burning permeable brick is designed. The mix proportion is optimized by volume method, and the preliminary mix proportion of permeable bricks is calculated. Taking the pH value of phosphogypsum, the ball milling time of phosphogypsum and the content of polymer emulsion as the influencing factors of the modified phosphogypsum, through orthogonal experimental design, using the modified phosphogypsum accounting for 30% of the total mass of the cementitious material as the main raw material, the permeable bricks are prepared by the static pressure forming process, the mechanical properties and permeable performance tests are carried out, and the range analysis and factor level analysis on the test result are carried out. The result shows that the pH value of phosphogypsum is the main factor affecting the splitting tensile strength of burning-free permeable bricks modified with posphogypsum, followed by the ball milling time of phosphogypsum and the amount of polymer emulsion;(2) the optimum mix proportion of the raw materials of burning-free permeable bricks modified with posphogypsum is obtained as follows: the pH value of phosphogypsum is 10, the ball milling time of phosphogypsum is about 3 min, and the content of polymer emulsion is 2%. Through production verification, the 28 d splitting tensile strength of burning-free permeable bricks modified with posphogypsum measured in batch production is 3.57 MPa, and the water permeability coefficient is 2.1×10^(-2)cm/s, which meets the requirements of the standard.