静水和滴水条件下碳酸盐岩溶解与主要元素释放规律初步研究

Preliminary research on dissolution of carbonate rocks and major element release under the conditions of stagnant water and dripping water

为进一步了解在静水和滴水条件下碳酸盐岩溶解与主要元素释放规律,文章选取在贵阳市花溪区贵州大学南校区、将军山、花溪水库三地分别采集的白云岩、灰质白云岩、石灰岩三类碳酸盐岩石为样本进行静水浸泡和动水滴溅试验,测定了静水与滴水条件下碳酸盐岩石的钾、磷、钙、镁四种主要元素的溶解量,结果表明:(1)在相同室温25℃,浸泡时长到达20 d时,白云岩中四种元素溶解量均为最高,钾元素溶解量为0.001 38μg/cm^3、磷元素溶解量为0.000 6μg/cm^3、钙元素溶解量为199.75μg/cm^3、镁元素溶解量为70μg/cm^3,且三种碳酸盐岩石的钙元素溶解量分别为白云岩199.75μg/cm^3,灰质白云岩148.42μg/cm^3,石灰岩137.88μg/cm^3,远远高于其他三种元素的溶解量;(2)经过不同温度浸泡24 h后,三类碳酸盐岩石中钾元素的溶解量随温度的升高而增大,并且在10~20℃条件下钾元素溶解速率最大,但温度的变化对于磷元素的溶解量影响不大;岩样养分含量中白云岩的钾元素与石灰岩的磷元素含量最少,但是随着温度的升高,它们的溶解量却是最大的;(3)静水浸泡状态下白云岩中元素的溶解量多数较高,而在动水滴溅状态中除白云岩的镁元素比石灰岩和灰质白云岩的镁元素溶解量高,试验的其他三种元素钾、磷、钙元素中都是石灰岩溶解量高;在动水滴溅的作用下,随着滴溅时间的增加,石灰岩的钙元素溶解量仅1h的滴溅时间就增加了2.55倍,超过了白云岩的钙元素溶解量。

To further understand the dissolution of carbonate rock and the release of the major elements under the different conditions of stagnant and dripping water, three types of carbonate rock samples, i.e. dolomite, calcite dolomite, and limestone, were collected from Guizhou University South Campus in Huaxi district of Guiyang City, Jiangjun hill and Huaxi reservoir, respectively, to conduct the tests of soaking them in stagnant water and splashing them by dripping water. The dissolution of four major elements potassium （as K）, phosphorus （as P）, calcium （as Ca） and magnesium （as Mg） for each type of rock under each condition were measured. The results showed that： （1） at the same temperature 25 ℃, when soaking for 20 days, the highest dissolved amount on all four elements occurred in dolomite, i.e. K-0. 00138 μg/cm^3, P-0. 0006 μg/cm^3 , Ca-199.75 μg/cm^3 and Mg-70 μg/cm^3. Also, the dissolution of Ca were the highest in all three types of carbonate rocks, i. e. 199. 75 μg/cm^3 in dolomite, 148. 42 μg/cm^3 in calcite dolomite and 137.88μg/cm^3 in limestone, which was far higher than other three elements. （2） When soaking at different temperatures, the dissolution of K increased with temperature in all three types of carbonate rocks. At the temperature between 10 ℃ and 20 ℃, the dissolution rate of K reached to the maximum, while the dissolution of P showed very little response to temperature change. In terms of the constituent contents in the samples, K in dolomite and P in limestone had the lowest value; however, their dissolution was the largest when temperature increases. （3） Under the condition of rock soaking in stagnant water, the dissolution of most elements in dolomite was higher than other two types of carbonate rock. However, under the condition of splashing by dripping water, the dissolution of Mg was higher in dolomite than in calcite dolomite and lime- stone while the dissolution of all other three elements was higher in limestone. Under the condition of dripping water, with the increase of dripping time, the dissolution of Ca had increased by 2. 55 times in one hour, which far exceeded the dissolution of Ca in dolomite.