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为研究我国东北地区典型气候条件对采矿废石酸性排水的影响,以辽宁省本溪市红透山铜矿废石为研究对象,探讨了干-湿循环和冻-融循环作用对采矿废石风化产酸的影响。黄铁矿(FeS2)在废石中的平均质量分数为23.51%,是主要的产酸硫化矿物。利用自制淋溶试验设备开展了为期120 d(共计20次)的冻-融循环、干-湿循环及淋溶试验,对不同试验条件下铜矿废石淋溶液的pH值、酸度、电导率以及Ca2+、Mg2+、SO2-4、总Fe及Cu2+质量浓度进行了测试分析。结果表明,相对于干-湿循环作用而言,单纯的冻-融循环作用不会对废石的风化产酸产生明显影响。试验过程中冻-融循环作用下废石淋溶液的pH值基本维持在5左右,干-湿循环作用下废石淋溶液的pH值则保持在4.5左右。由于风化产酸程度较高,干-湿循环作用下黄铁矿风化所形成的总Fe、SO2-4质量浓度分别为冻-融循环下的8.5倍和1.6倍;Cu2+的质量浓度约为冻融循环条件下Cu2+质量浓度的5.2倍。冻-融循环及干-湿循环条件下,氧气及水分穿透黄铁矿外“包裹层”的时间分别为60 d和80 d。因此,与南方相对温暖湿润的气候类型相比,我国东北地区冰冻期长、丰水期短的气候类型可在一定程度上抑制废石风化产酸的形成。
In order to study the influence of the typical climatic conditions in northeastern China on the acid drainage of mining waste rock, a study was made on the waste rock of Hongtoushan copper mine in Benxi City, Liaoning Province. The effects of dry-wet and freeze-thaw cycles on the mining waste rock weathering Acid production. Pyrite (FeS2) in waste rock average mass fraction of 23.51%, is the main acid-producing sulfide minerals. The freeze-thaw cycles, dry-wet cycles and leaching tests were carried out for 120 days (20 times in total) using self-made leaching test equipment. The pH value, acidity, conductivity As well as Ca2 +, Mg2 +, SO2-4, total Fe and Cu2 + concentration were tested and analyzed. The results show that, compared with the dry-wet cycle, the simple freeze-thaw cycle does not affect the acidification of waste rock significantly. The pH value of the waste rock leaching solution under the freeze-thaw cycle was maintained at about 5 during the test. The pH value of the waste rock leaching solution under the action of the dry-wet cycle was kept at about 4.5. Due to the high degree of weathering and acidification, the total Fe and SO2-4 mass concentrations formed by the weathering of pyrite under the wet-dry cycle were 8.5 and 1.6 times higher than those in the freeze-thaw cycle respectively. The mass concentration of Cu2 + 5.2 times the mass concentration of Cu2 + in the melting cycle. Under the conditions of freeze-thaw cycle and dry-wet cycle, the time for oxygen and water to penetrate the outer layer of “pyrochlore” outside the pyrite was 60 d and 80 d, respectively. Therefore, compared with the relatively warm and humid climate types in the south, the climatic types with long freezing period and short wet season in northeastern China can restrain the weathering and acidification of waste rock to a certain extent.