碱激发−水热法活化某超细钼尾矿制备硅钾土壤调理剂

Preparation of Potassium−Silicon Soil Conditioner from Ultrafine Molybdenum Tailings by Alkali Activation−Hydrothermal Method

  • 摘要: 针对某超细钼尾矿常规用于制备建材时难度大、综合利用率低的特点,提出了碱激发−水热法联合制备土壤调理剂的技术途径,以钼尾矿、生石灰、秸秆为原料,KOH为激发剂,在水热条件下制备土壤调理剂。研究了KOH质量浓度、尾矿与石灰质量比、秸秆与尾矿质量比、混合干料与碱液质量体积比、水热反应时间、水热反应温度等因素对可溶性Si和K元素产生量的影响。结果表明,在KOH浓度为0.5 mol/L、尾矿与石灰质量比为1∶0.8、秸秆与尾矿质量比为1∶70、混合干料与碱液比为100 g∶300 mL、水热反应时间为9 h、水热反应温度为180 ℃的条件下,制备的土壤调理剂可溶性Si、K含量分别为8.9 %、6.85 %,满足《硅钙钾镁肥》(GB/T 36207—2018)中Si和K元素指标要求。在碱激发−水热法的联合作用下,尾矿中的硅铝酸盐矿物发生解聚和缩聚反应,激活Si、K、Al等元素的反应活性,所制备的土壤调理剂样品中可溶性Si、K元素含量符合国标要求;生成了网络结构,具备较强的吸附性能。该研究成果将对我国钼尾矿的减量化、资源化以及农业生产的可持续发展具有重要意义。

     

    Abstract: In response to the challenges of high difficulty and low comprehensive utilization rate when conventionally using ultrafine molybdenum tailings for the preparation of building materials, a technical approach combining alkali activation and hydrothermal method to prepare soil conditioners has been proposed. Molybdenum tailings are used as the main raw material, with quicklime, KOH, and others as activators to prepare soil conditioners under hydrothermal conditions. The study investigated the impact of factors such as the mass concentration of KOH, the mass ratio of tailings to lime, the mass ratio of straw to tailings, the mass−volume ratio of mixed dry materials to alkaline solution, hydrothermal reaction time, and hydrothermal reaction temperature on the production of soluble Si and K elements. The results showed that under the conditions of a KOH concentration of 0.5 mol/L, a mass ratio of tailings to lime of 1 : 0.8, a mass ratio of straw to tailings of 1 : 70, a mass−volume ratio of mixed dry materials to alkaline solution of 100g : 300mL, a hydrothermal reaction time of 9 hours, and a hydrothermal reaction temperature of 180 ℃, the prepared soil conditioner had soluble Si and K contents of 8.9 % and 6.85 %, respectively, meeting the requirements for Si and K elements in "Silicon−Calcium−Potassium−Magnesium Fertilizer" (GB/T36207—2018). Under the combined action of alkali activation and hydrothermal method, the silicate minerals in the tailings undergo depolymerization and condensation reactions, activating the reactivity of elements such as Si, K, and Al. The prepared soil conditioner samples meet the national standard requirements for soluble Si and K elements; they form a network structure with strong adsorption capacity. This research outcome will be of great significance to the reduction, resource utilization of molybdenum tailings in China, and the sustainable development of agricultural production.

     

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