地浸采铀工程工艺水余热供暖回灌水防冻技术研究

Study on Anti-freezing Technology of Water Waste Heat for Heating and Recharging of In-situ Leaching Mining of Uranium

中国某地浸采铀工程采用工艺水余热供暖,经过换热后工艺水温度4℃左右,需要经过长距离的室外管道输送后回灌。项目所在地为寒冷区,最大冻土层深度2.4 m,室外最低温度-32℃,为解决回灌水冻结问题,现场对冻土层温度进行监测。试验结果表明:土壤层距地面0.5、1.0、1.5、2.0、2.4 m处最低温度分别是-7.4、-4.5、-1.6、-0.5、0.0℃;管道周围土壤形成的以管道为中心的"冻融圈"可以防止管道内输送液体在短时间内冻结。通过对比4种管道埋设方案,推荐本项目中回灌水管道采用浅埋敷设不保温方案,施工简单,运行时不会完全冻结,安全可靠,节约工程投资。

In a in-situ leaching mining of China, process water waste heat exchange is adopted for heating. After heat exchange, process water temperature is about 4 ℃, which needs to be refilled after long-distance outdoor pipeline transportation. The project is located in a cold zone, with a maximum depth of 2.4 m in the permafrost and an outdoor minimum temperature of-32 ℃. In order to solve the problem of recharging water freezing, the temperature of the permafrost is monitored on site. The results showed that the lowest temperature of the soil layer at 0.5, 1.0, 1.5, 2.0 and 2.4 m from the ground was-7.4,-4.5,-1.6,-0.5 and 0 ℃, respectively. It was found that the soil around the pipeline formed a "freezing-thawing ring" centered on the pipeline, which could prevent the liquid transported in the pipeline from freezing for a short time. Through the comparison of the four embedding schemes of pipelines, it is recommended that the recharging water pipeline in this project should be laid in shallow burial without thermal insulation scheme, which is simple in construction, will not be completely frozen in operation, safe and reliable, and will save engineering investment.