基于活性氧化镁的碳化砌体生产技术研发
发布时间：2019-03-01 21:30
【摘要】：目前,我国砌体主要有烧结粘土砖、蒸压硅酸盐砖和混凝土空心砌块,由于粘土砖的生产破坏了大量的耕地资源,我国在十几年前就提出了“禁粘”。蒸压硅酸盐砖和混凝土空心砌块相对来说对耕地资源破坏较小,但是其中的主要原料——硅酸盐水泥(波特兰水泥)存在严重的环境问题:(1)资源和能源消耗严重。我国水泥工业每生产1吨水泥熟料平均需要消耗0.11吨标准煤、0.13吨粘土和0.95吨石灰石,且是一个不可逆的过程,即不可持续。(2)二氧化碳排放和大气污染严重。水泥生产过程中会释放出大量的二氧化碳,平均每生产1吨水泥需向大气排放0.95吨的二氧化碳,水泥工业排放的二氧化碳占世界人为排放二氧化碳的10%左右,除了二氧化碳之外,在水泥的生产过程中,还有大量的粉尘、烟尘以及二氧化硫、氮氧化物、氟气等有毒气体排入大气中,对环境造成很大的污染。另外,水泥制品需要一定的养护时间,一般需要一个月以上才能达到设计强度、承受荷载。针对上述技术问题,本研究使用活性氧化镁来替代传统硅酸盐水泥,用于砌块的固化剂,通过碳化技术,使得活性氧化镁反应生成碱式碳酸镁,来增加砌块的抗压强度及耐久性能,同时对试块进行微观测试,并分析其碳化机理。主要的试验过程和成果如下:(1)通过室内试验,在实验室通过小型搅拌机将骨料、活性氧化镁和水搅拌均匀,然后通过制样机制作小尺寸砌体试样。试样经过短期养护后,移到小型碳化养护箱中对试样进行碳化,然后进行抗压强度测试和碳化程度测试(即二氧化碳的吸收率,通过化学中和法确定)。通过设计多种试验方法,比较测试效果,得出活性氧化镁碳化砌块的最佳配比为:砂37%,碎石53%,粉煤灰3%,普通水泥3.5%,活性氧化镁3.5%;最佳碳化环境为:湿度60%,温度20℃,20%CO_2;最佳成型方式:10MPa压力成型;最佳水灰比为1.0。(2)在(1)的基础上,选取最优碳化砌体,按照国家相关标准规范进行干湿循环、冻融循环等耐久性测试,并与常规水泥砌体进行对比。活性氧化镁碳化砌块在碳化3d达到甚至超过80%抗压强度,碳化14d就能够达到其最大抗压强度,相对于普通水泥砌块养护28d节约了一半的时间,且活性氧化镁碳化砌块的抗压强度是普通水泥砌块的2-3倍,且其耐久性优于常规水泥砌体。(3)在(1)、(2)的基础上,选取典型的碳化砌体试样进行微观化学测试,初步计划进行的试验包括X射线衍射(XRD)、扫描电镜(SEM)、热重分析(TGA)等,分析试样的碳化反应机理,以及碳化产物与环境的相互作用机理。结果表明:活性氧化镁碳化反应生成了三水合碳酸镁和碱式碳酸镁,有效填充了砌块内部的孔隙,且碳化产物为网状的微观结构,具有非常强的胶结能力,这些是活性氧化镁碳化砌块强度高的原因。(4)在室内试验的基础上,采用最优的碳化砌体原材料,在工厂研发相应的生产设备和工艺,进行商业碳化砌体的试制,并按照国家相关标准检测砌体质量,综合评价其经济和环境效应,为推广应用奠定基础。结果表明:相对于普通水泥砌块,活性氧化镁作为砌体固化剂可以减少约48.1%能耗和50.53%CO_2排放,且具有较大的社会经济效益。
[Abstract]:At present, there are mainly sintered clay brick, autoclaved silicate brick and concrete hollow block in our country. Because the production of clay brick has destroyed a lot of cultivated land resources, our country put forward the "forbidden stick" more than a decade ago. Autoclaved silicate bricks and concrete hollow blocks have relatively little damage to the cultivated land resources, but the main raw materials _ Portland cement (Portland cement) have serious environmental problems: (1) resources and energy consumption are serious. The average consumption of 1 ton of cement clinker in China's cement industry needs to consume 0.11 tons of standard coal, 0.13 ton of clay and 0.95 tons of limestone, and is an irreversible process, that is, unsustainable. (2) Carbon dioxide emission and atmospheric pollution are serious. a large amount of carbon dioxide can be released during the production process of the cement, and an average of 1 ton of cement is produced to discharge 0.95 tons of carbon dioxide to the atmosphere, the carbon dioxide emitted by the cement industry accounts for about 10 percent of the carbon dioxide in the world, and in addition to the carbon dioxide, in the production process of the cement, There are also a large amount of dust, smoke, sulfur dioxide, nitrogen oxides, fluorine gas and other toxic gases into the atmosphere, causing great pollution to the environment. In addition, a certain curing time is required for the cement product, and the design strength can be met for more than one month, and the load can be borne. in the light of the technical problem, the active magnesium oxide is used for replacing the traditional silicate cement, the curing agent for the building block is used for producing basic magnesium carbonate through the reaction of the active magnesium oxide through the carbonization technology, the compressive strength and the durability of the building block can be increased, At the same time, the test block was micro-tested and its carbonization mechanism was analyzed. The main test procedures and results are as follows: (1) The aggregate, active magnesium oxide and water are uniformly stirred by a small mixer in a laboratory by a laboratory test, and then a small-sized masonry sample is produced by a prototype. After short-term curing, the sample is moved to a small-scale carbonization curing box for carbonization, and then the compression strength test and the degree of carbonization are tested (i.e., the absorption rate of carbon dioxide is determined by the chemical neutralization method). By designing a variety of test methods and comparing the test results, the optimum proportion of the active magnesium oxide carbonized block is as follows:37% of sand,53% of broken stone,3% of fly ash, 3.5% of common cement and 3.5% of active magnesium oxide; the optimum carbonization environment is: humidity 60%, temperature 20 鈩，
本文编号：2432820
[Abstract]:At present, there are mainly sintered clay brick, autoclaved silicate brick and concrete hollow block in our country. Because the production of clay brick has destroyed a lot of cultivated land resources, our country put forward the "forbidden stick" more than a decade ago. Autoclaved silicate bricks and concrete hollow blocks have relatively little damage to the cultivated land resources, but the main raw materials _ Portland cement (Portland cement) have serious environmental problems: (1) resources and energy consumption are serious. The average consumption of 1 ton of cement clinker in China's cement industry needs to consume 0.11 tons of standard coal, 0.13 ton of clay and 0.95 tons of limestone, and is an irreversible process, that is, unsustainable. (2) Carbon dioxide emission and atmospheric pollution are serious. a large amount of carbon dioxide can be released during the production process of the cement, and an average of 1 ton of cement is produced to discharge 0.95 tons of carbon dioxide to the atmosphere, the carbon dioxide emitted by the cement industry accounts for about 10 percent of the carbon dioxide in the world, and in addition to the carbon dioxide, in the production process of the cement, There are also a large amount of dust, smoke, sulfur dioxide, nitrogen oxides, fluorine gas and other toxic gases into the atmosphere, causing great pollution to the environment. In addition, a certain curing time is required for the cement product, and the design strength can be met for more than one month, and the load can be borne. in the light of the technical problem, the active magnesium oxide is used for replacing the traditional silicate cement, the curing agent for the building block is used for producing basic magnesium carbonate through the reaction of the active magnesium oxide through the carbonization technology, the compressive strength and the durability of the building block can be increased, At the same time, the test block was micro-tested and its carbonization mechanism was analyzed. The main test procedures and results are as follows: (1) The aggregate, active magnesium oxide and water are uniformly stirred by a small mixer in a laboratory by a laboratory test, and then a small-sized masonry sample is produced by a prototype. After short-term curing, the sample is moved to a small-scale carbonization curing box for carbonization, and then the compression strength test and the degree of carbonization are tested (i.e., the absorption rate of carbon dioxide is determined by the chemical neutralization method). By designing a variety of test methods and comparing the test results, the optimum proportion of the active magnesium oxide carbonized block is as follows:37% of sand,53% of broken stone,3% of fly ash, 3.5% of common cement and 3.5% of active magnesium oxide; the optimum carbonization environment is: humidity 60%, temperature 20 鈩，
本文编号：2432820
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