Study On Preparation Of Microbial Oxidant By Embedding Technology Of Sodium Alginate-hydrolyzed Polyacryamide Gel

With the development of industrial production, the demand of mineral resources is increasing, and the mining scale became more and more large. Deep、low grade and complex ore body has gradually became the main mining processing object. Aiming at these mining object, the traditional mining method is difficult to achieve the production requirement of safety、economic efficiency and environmental protection. Relative to the traditional mining method, microbial leaching technology has more advantages Biological preparation is the key to the microbial leaching technology.In this experiment, the carrier is the two hybrid materials of sodium alginate polyacrylamide and added polyethylene glycol 400(PEG) which easily dissolves in water as the hole agents with Ca Cl2 and aluminum citrate as crosslinking agent, fixed Acidithiobacillus ferrooxidans bacteria by the embedding method and constructing fixed bed bioreactor to produce oxidant Fe3 + preparation of microorganisms. In order to prepare microbial oxidation agent with high oxidation ability the main research content of this experiment are as follows:(1) By condition experiments, the best embedding condition of Acidithiobacillus ferrooxidans bacteria are selected as follows: the concentration of sodium alginate is 2.5%, polyacrylamide’s concentration is 0.4%, polyethylene glycol 400’s concentration is 2%. The maximum oxidation rate of immobilized Acidithiobacillus ferrooxidans Fe2+ prepared under this condition is 2.863g·(L·H)-1. Acidithiobacillus ferrooxidans bacteria in Gel ball of value-added ratio can reach 1.51 times. The immobilized Acidithiobacillus ferrooxidans bacteria which is reused 15 days is still kept good oxidation.(2) The optimum immobilization conditions of the embedded Acidithiobacillus ferrooxidans is preparing a lot of gel microspheres, then loaded to homemade fixed bed bioreactor, through the conditions to obtain the optimum operation condition for fixed bed bioreactor are as follows: Air flow rate is 1.4 L·min-1, initial p H is 2.0, the outer reactor temperature jacket water temperature is 32 ℃, initial concentration of Fe2+ 8.5 g·L-1, the dilution rate is 0.6 h-1. The reactor under the condition of the continuous operation, got the biggest oxidation rate of Fe2+ 2.97 g·L-1·h-1, 3.38 times that of free bacteria Acidithiobacillus ferrooxidans. The reactor started to run continuously, the oxidation ability of Fe2+ decreases slightly, by cleaning the reactor material after precipitation, oxidation capacity of immobilized Acidithiobacillus ferrooxidans bacteria will be restored, experiments show that the fixed bed bioreactor has good stability. The finial experiment shows that immobilized bacteria Acidithiobacillus ferrooxidans for the first order reaction rate constant k of Fe2 + is 0.39 h-1.