摘要
【目的】研究固体废矿富硒煤矸石制备硒肥的资源化利用技术。【方法】以世界硒都恩施的煤矸石废矿为原料,分别进行了活化剂(弱碱性物质Na2CO3)、活化时间、活化温度和料液比的单因素6水平试验,测定硒活化率,每个因素筛选出3个水平,采用响应面优化方法进行计算,最终确定富硒煤矸石中硒的活化工艺参数。采用IR光谱、TG热重法对煤矸石活化前后官能团键合、热效应进行表征分析。用活化煤矸石硒肥与养殖场粪肥以1∶1、2∶1、3∶1、和4∶1的比例分别混合后发酵一个月,制备4种活化煤矸石硒有机肥(简称硒有机肥),以煤矸石硒肥和发酵粪肥作两个对照,以大蒜为试材进行了田间试验。收获后测定了土壤和大蒜鳞茎中的总硒、有机硒含量。【结果】单因素试验确定的4个因素用于响应面优化的范围,活化剂Na2CO3的浓度为10%、20%和30%;活化时间为2.5、3.5、4.5 h;活化温度为75℃、85℃和95℃;料液比(g/mL)为1∶5、1∶10、1∶15。经过响应面优化计算,当原料粒径为0.038 mm时,最优工艺条件为活化剂的浓度22%、活化时间3.9 h、料液比1:9 g/mL、活化温度85℃。应用此参数活化的煤矸石固体硒肥pH约为7.6、最大活化效率为81.24%。IR光谱曲线显示,Na2CO3的加入破坏了煤矸石中硒与其它的金属、非金属等元素间的弱作用力及网络原子原有的结晶态,使得硒基团解脱束缚,成为活性硒。由TG(thermal gravimetric)及DTG(derivative thermogravimetry)曲线可知,煤矸石活化前后的热稳定性有较大变化。活化前样品的DTG曲线出现两个峰,而活化后只在100℃前出现一个峰,且失重情况较活化前弱。因此,活化后的煤矸石硒肥热稳定性更好。活化后煤矸石的硒含量为170.82 mg/kg,制备的4个比例煤矸石硒有机肥的硒含量依次为85.41、113.88、128.05、136.66 mg/kg。在等硒量试验下,5个处理大蒜鳞茎中硒的含量依次为1.033、1.306、1.480、1.382、1.355μg/g,均显著高于未施硒肥对照组的0.005μg/g(P<0.05)。硒肥处理大蒜鳞茎中有机硒比例均在99%以上,高于未施硒肥对照组的60%。硒有机肥处理大蒜吸收硒的效果优于煤矸石硒肥,并以煤矸石固体硒肥与家禽粪2∶1比例混合配置的煤矸石硒有机肥的吸收硒效果最优。【结论】Na2CO3活化富硒煤矸石的最佳工艺条件为活化剂的体积质量分数22%、活化时间3.9 h、料液比1∶9 g/mL、活化温度85℃。在该条件下,煤矸石中硒的活化率可高达81.24%,且煤矸石硒肥的热稳定性更好。将煤矸石硒肥与畜禽粪混合发酵,可以大大提高大蒜对硒的吸收量,其中有机硒的比例非常高,故有机肥与活化煤矸石硒肥以1∶2比例混合发酵制备煤矸石硒有机肥是活化煤矸石硒的有效方法。
【Objectives】The technology of producing Se fertilizer was studied using Se-rich coal gangue from solid waste ore.【Methods】The tested coal gangue was from Enshi,where was famous for rich of Se in the environment,and grounded to pass 0.038 mm for the experiment.Preliminary experiments were conducted with 6 levels of each single factor for the activation of Se,and three levels of each were accordingly selected for the following response surface optimization,which would give the optimal activation parameters eventually.The IR spectroscopy and TG thermogravimetry methods were employed to observe and analyze the activating and thermal effects of the bonds of Se with other metals before and after the activation in the coal gangue.The activated coal gangue was then blended with farm manure in ratio of 1∶1,2∶1,3∶1 and 4∶1,and fermented for one month to make activated coal gangue selenium organic fertilizers(organic Se fertilizer).A garlic field trial was conducted using the four organic Se fertilizers as treatments,and pure activated coal gangue Se and farm manure as controls.The total and organic Se contents in the garlic bulbs were measured at harvest.【Results】The single factor levels obtained from the single factor experiments were 10%,20%and 30%for Na2 CO3,2.5 h,3.5 h and 4.5 h for the activation time,75℃,85℃and 95℃for the activation temperature,and 1∶5,1∶10 and 1∶15 for solid-liquid ratio(g/mL).The optimized activation condition by the response surface optimization were Na2 CO322%,the activation time 3.9 h,the solid-liquid ratio 1∶9 g/mL and the activation temperature 85℃.Under the condition,the pH of the activated coal gangue was 7.6,and the maximum activation rate of Se was about 81.24%,and the active Se content was 170.82 mg/kg.Through the IR spectroscopy image,it could be seen that the bonds between Se and other symbiotic metal and nonmetal elements were broken,and the original crystalline network were broken too,indicating the Se in the coal gangue was unleashed.The derivative thermogravimetry curve had 2 peaks before activation within 100℃,while only 1 peak left near 100℃after activation,the weightlessness situation was weaker than the non-activated as well,indicating the improved heat stability of the coal gangue.According to the Se content in the activated coal gangue,the Se contents in the prepared 4 Se organic fertilizers were roughly 85.41,113.88,128.05 and 136.66 mg/kg in turn.The total Se contents of the garlic bulbs applied with the coal gangue fertilizer and the four Se organic fertilizers were 1.033,1.306,1.480,1.382,and 1.355μg/g,respectively,which were all significantly higher than that in the noneselenium fertilizer control(P<0.05).The organic Se rate of the garlic bulbs in the five fertilizer treatments reached 99%,which was higher than the 60%of the control.The four Se organic fertilizers produced significantly higher Se contents in garlic bulbs than the activated coal gangue did,with the highest Se content by the 2∶1 ratio mixed Se organic fertilizer.【Conclusions】The optimum process conditions of coal gangue using Na2CO3 as activator are:the Na2CO322%,activation time for 3.9 h,the solid-liquid ratio of 1∶9 g/mL at 85℃.Under the condition,the activation ratio of Se can be as high as 81.24%,and with good thermal stability.The preparation of Se organic fertilizer made by co-fermentation of farm manure and activated coal gangue can greatly increase the efficiency of the activated Se,and the optimum effect is under the mix ratio of 1∶2.
作者
刘信平
吴少尉
张驰
LIU Xin-ping;WU Shao-wei;ZHANG Chi(College of Chemistry and Environment Engineering,Hubei Minzu University,Enshi 445000,China;College of Biological Science and Technology,Hubei Minzu University,Enshi 445000,China)
出处
《植物营养与肥料学报》
CAS
CSCD
北大核心
2020年第8期1526-1535,共10页
Journal of Plant Nutrition and Fertilizers
基金
国家自然科学基金项目(21461009,81402225,21565013)
恩施州科技计划研究与开发项目(D20160059)。
关键词
富硒煤矸石
活化煤矸石硒肥
活化条件
煤矸石有机硒肥
硒肥效应
Se-rich coal gangue
activated coal gangue selenium fertilizer
activation condition
Se organic fertilizer
Se fertilizer efficiency
