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用砂、粘土和水进行的混砂试验已经得到了关于配砂机理及其影响因素的许多数据。用新材料制备型砂的关键是粘土和砂粒的粘结。只是在有足够的附着力时,砂粒才被均匀的粘土层包围,并在砂粒接触表面之间形成键桥。型砂的各种性能,例如造型性、抗冲刷及抗结疤的能力,到那时将达到最高水平。不断的混砂将进一步加强附着力,并因此改善型砂的湿压强度,但是不易改变其他性能。为了使加入的新砂获得适宜的粘性,就要在粘土和砂粒之间进行具有相当大混合力的强烈混砂。这种混合力由辗轮的搓研,或者由快速运动的混砂部件的搅拌产生。使用新材料,累积混砂获得的每1％膨润土含量的湿压强度约为4牛顿/厘米~2。该值是用一般混砂方法所得值的两倍多。在砂处理系统中的充分混砂,每1％膨润土将达到约3牛顿/厘米~2。在使用具有低破碎作用的混砂机时,加料次序特别重要。因此最好的加料次序是砂、水、膨润土。强度增长在很大程度上决定于砂粒的表面性质,以及附着和分散成分,例如焙烧过的粘土的存在。通过测定混好型砂的湿压强度评价膨润土,必须考虑到提高附着力因素的作用,但是这种评价与膨润土的性质无关。在结论中,提到的一些混砂特性对选择用于砂处理系统的混砂机,是重要的。
Sand mixing tests with sand, clay and water have yielded many data on the mechanism of sand mixing and its influencing factors. The key to making sand from new materials is the bonding of clay and sand. Only when there is sufficient adhesion, the grit is surrounded by a uniform layer of clay and a bond bridge is formed between the grit contact surfaces. The various properties of sand, such as styling, scour resistance and resistance to scarring, will reach their highest levels by then. Continuous sand mixing will further enhance the adhesion, and thus improve the wet sand compressive strength, but not easy to change other properties. In order to obtain the proper viscosity of the new sand added, intense mixing of sand with considerable mixing between the clay and the sand is required. This mixing force is created by the rubbing of the wheel, or by the agitation of the quick-moving sand mixing unit. With new materials, the wet compressive strength per 1% bentonite content obtained by cumulative sand mixing is about 4 Newtons / cm2. This value is more than twice the value obtained with the usual sand mixing method. Adequate sand in the sand treatment system, each 1% bentonite will reach about 3 Newton / cm ~ 2. In the use of sand mixer with low crushing effect, the feeding order is particularly important. So the best feeding sequence is sand, water, bentonite. The strength increase depends to a large extent on the surface properties of the grit and the presence of adhering and dispersing ingredients, such as calcined clay. The evaluation of bentonite by measuring the wet compressive strength of mixed sand has to take into account the effect of improving the adhesion, but this evaluation has nothing to do with the nature of the bentonite. In conclusion, some of the sand characteristics mentioned are important for the choice of sand mills for the sand treatment system.