多源固废基固碳矿用材料制备及多场景利用关键技术

Key technologies for preparation and multi scene utilization of multi-source solid waste based carbon fixation mining materials

  • 摘要: 冶金工业生产与煤炭资源开发过程中产生了大量难以有效利用的固废,并伴随地表沉陷、固废堆存及高碳排放等一系列问题。为实现“煤矿减损化开采−固废功能化利用-CO2低碳化处置”目标,本研究创新性地提出了CO2矿化多源固废制备固碳矿用材料及多场景利用关键技术。以改性镁−煤基固废(包括改性镁渣、粉煤灰、煤矸石)为例,采用直接矿化法在地面将其矿化制备固碳矿用材料,以适应矿山多场景的应用需求。系统分析了固废直接矿化的工艺及其关键影响因素,制备了改性镁−煤基固废固碳矿用材料,研究了不同液固比条件下改性镁−煤基固废固碳矿用材料的基础性能(流动性能、强度性能、固碳能力)及其固碳机制。结果表明:液固比大于0.23时材料满足充填流动性能要求,且28 d抗压强度最高可达6.18 MPa;直接矿化搅拌10 min的矿化效率达到50.7%。针对多源固废基固碳矿用材料的多场景利用问题,提出了包括“固碳矿用预制件、固碳膏体充填开采、固碳矿用材料用于采空区治理、固碳充填材料用于矿井降温”在内的多场景利用关键技术。基于固碳矿用预制件,提出了高强低渗储库墙构筑技术及巷道掘进底板铺设一体化技术装备;在矿井膏体充填开采的基础上,创新性地提出了房柱式采煤固碳充填煤柱回收技术及冶金−煤基固废固碳充填材料的高效制备与充填应用一体化装备。此外,在采空区治理的应用方面,还需研究CO2在固废材料中的吸附−扩散机理、注浆材料与环境的多场耦合机制及CO2高效吸收搅拌反应装置,建立“采空区危险源监测−固废矿化注浆材料治理−注浆效果评价”等应用体系。本研究为大宗冶金−煤基固废的合理处置和CO2的高效封存提供了有益参考,对于推动双碳目标的实现及煤矿区由“零碳”向“负碳”的转型发展具有重要意义。

     

    Abstract: During the production of metallurgical industry and the development of coal resources, a large number of solid wastes that are difficult to be effectively utilized are produced, accompanied by surface subsidence, solid waste stockpiling and high carbon emissions. In order to achieve the goal of "coal mine loss reduction mining-functional utilization of solid waste-CO2 low-carbon disposal", this study innovatively proposed the key technologies of CO2 mineralization multi-source solid waste preparation of carbon fixation mining materials and multi scenario utilization.Taking the modified magnesium coal based solid waste (including modified magnesium slag, fly ash and coal gangue) as an example, the direct mineralization method was used to mineralize it on the ground to prepare carbon fixation mining materials, so as to meet the application requirements of multiple scenarios in the mine. In this paper, the process of direct mineralization of solid waste and its key influencing factors were systematically analyzed, and the modified magnesium coal based solid waste carbon fixation mining materials were prepared. The basic properties (flow performance, strength performance, carbon fixation ability) and carbon fixation mechanism of the modified magnesium coal based solid waste carbon fixation mining materials under different liquid-solid ratios were studied.The results show that when the liquid-solid ratio is greater than 0.23, the material meets the backfill flow performance requirements, and the maximum 28 day compressive strength can reach 6.18 MPa; The mineralization efficiency of direct mineralization mixing for 10 minutes reached 50.7%. Aiming at the problem of multi scene utilization of multi-source solid waste based carbon fixation mining materials, this paper puts forward the key technologies of multi scene utilization, including "carbon fixation mining prefabricated parts, carbon fixation paste backfill mining, carbon fixation mining materials for goaf treatment, and carbon fixation backfill materials for mine cooling". Based on the carbon fixation mine prefabricated parts, the integrated technology and equipment of high-strength and low-permeability reservoir wall construction technology and roadway excavation floor laying are proposed; On the basis of paste backfill mining in the mine, this paper innovatively puts forward the room and pillar coal mining carbon fixation backfill coal pillar recovery technology and the integrated equipment of efficient preparation and backfill application of metallurgical coal based solid waste carbon fixation backfill material. In addition, in the application of goaf treatment, it is also necessary to study the adsorption diffusion mechanism of CO2 in solid waste materials, the multi field coupling mechanism between grouting materials and the environment, and the CO2 efficient absorption mixing reaction device, and establish the application system of "goaf hazard monitoring-solid waste mineralization grouting material treatment-grouting effect evaluation". This study provides a useful reference for the rational disposal of bulk metallurgical coal based solid waste and the efficient storage of CO2, and is of great significance to promote the realization of the dual carbon goal and the transformation and development of coal mining areas from "zero carbon" to "negative carbon".

     

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