典型硅酸盐细菌和真菌对钾长石动态溶蚀效果对比研究

Comparative study on dynamic dissolution of potassium feldspar by typical silicate bacteria and fungi

以典型硅酸盐细菌Paenibacilluspolymyxa和Agrobacterium tumefaciens及真菌Aspergillus niger为试验菌株,采用摇瓶培养试验,通过测定发酵培养液中细菌浓度、pH值、浸矿上清液中K、Si、Al的质量浓度以及钾长石被菌株作用前后的SEM和XRD分析,比较了这三种典型种类微生物对钾矿物的动态溶蚀效果。结果表明:真菌的生长周期较硅酸盐细菌的短,且具有更高的产酸能力,但硅酸盐细菌的对数生长期相对较长,其在培养液中具有更高的细菌浓度,产生胞外多聚物的能力更强;三株菌种对钾长石均有一定的风化分解能力,Paenibacilluspolymyxa的溶蚀效果最好,浸出液中的K_(2)O、SiO_(2)、Al_(2)O_(3)的质量浓度最高可达2.30 g/L、6.55 g/L、5.20 g/L,其次为Aspergillus niger和Agrobacterium tumefaciens;但真菌释放钾长石中的K、Al、Si的速率最快,浸矿周期最短,综合效率最高。分析认为,真菌对矿物的溶蚀效果主要受有机酸酸解和络解作用机制的影响,而硅酸盐细菌对矿物的风化分解能力则主要受胞外多聚物络解作用机制的控制。

The dynamic corrosion effects of typical silicate bacteria Paenibacillus polymyxa and Agrobacterium tumefaciens and fungus Aspergillus niger on potassium feldspar were comparative analysed by measuring the concentration of bacteria in fermentation medium,pH value,mass concentrations of K,Si and Al in leaching supernatant,and SEM and XRD analysis of potash feldspar before and after being subjected to bacterial strains.The results show that the growth period of fungus is shorter than that of silicate bacteria,and the fungus has higher acid production capacity,but silicate bacteria have longer logarithmic growth periods,higher bacterial concentrations in their culture media,and stronger abilities to produce extracellular polymers.Paenibacillus polymyxa has the best corrosion effect on feldspar,the mass concentrations of K_(2)O,SiO_(2) and Al_(2)O_(3) in the leaching solution are up to 2.30 g/L,6.55 g/L and 5.20 g/L,followed by Aspergillus niger and Agrobacterium tumefaciens.However,the rates of K,Al and Si in potassium feldspar released by fungus is the fastest,its leaching period is the shortest,so the fungus has higher comprehensive leaching efficiency than the other two strains.It is concluded that the corrosion effect of fungus on minerals is mainly influenced by the mechanism of organic acidolysis and complexation,while the ability of silicate bacteria to decompose minerals is controlled by the complexation mechanism of extracellular polymers.