猪粪与磷石膏配合施用对菱镁矿粉尘污染土壤化学性状的影响

辽宁省菱镁矿煅烧产生的粉尘对土壤污染越来越严重,但目前关于菱镁矿粉尘污染土壤的改良机理并不清楚,为此采用大石桥市菱镁矿粉尘重度污染土壤进行盆栽试验,研究了猪粪与磷石膏配合施用对菱镁矿粉尘污染土壤化学性状的影响。结果表明,施用磷石膏、猪粪与磷石膏配合施用可降低土壤pH幅度为0.3～0.6,增加水溶性钙镁比值(Ca2 /Mg2 )幅度为1.57～3.02。单施猪粪、猪粪与磷石膏配合施用增加了土壤中速效氮、磷、钾的含量。单施猪粪对土壤pH和Ca2 /Mg2 影响不显著,单施磷石膏增加了土壤中速效磷含量,施用猪粪与磷石膏可以有效地改善菱镁矿粉尘污染废弃地的土壤化学性状,且以两者配合施用的效果最好。     

Effect of Two Magnesium Fertilizers on Leaf Magnesium Concentration,Yield, and Quality of Potato and Sugar Beet

Twelve field experiments were conducted to study the impacts of calcined magnesite and Kieserite fertilizers on yield, quality and leaf concentrations of magnesium (Mg) in potatoes and sugar beet. The rate of Mg applied was 60 kg Mg ha^?1, and the experiments were realized in six locations for both crop species. There were clear increases in leaf Mg concentration and yield of both crops resulting from application of Mg fertilizers. Mean increase in leaf Mg concentration and crop yield for both species were more pronounced with Kieserite than with calcined magnesite. Sugar concentrations of sugar beet and dry matter yield of potatoes were, however, influenced only slightly by the Mg fertilizers. It seems that superiority of Kieserite to calcined magnesite is related to higher Mg solubility of Kieserite. Use of Mg fertilizers with higher solubility helps to avoid the risk of Mg deficiency and subsequent losses in yield and economic returns.     

Influence of calcined alum on the hydration and hardening performance of anhydrite

The influence of calcined alum on the hydration process, the structure and intensity of hardened anhydrite, the degree of solution supersaturation, and other properties are investigated by determining setting time, hydration rate and hydration temperature increases in combination with analyzing the microstructure and intensity of hardened paste. The alum action mechanism also is revealed. The results indicate that calcined alum is a highly active excitant for anhydrite. Calcined alum can reduce setting time, increase the hydration process and intensity of anhydrite, and refine crystals. Calcined alum improves the hydration and solution performance of anhydrite and sulfate radical concentration. This subsequently raises the degree of dihydrate gypsum supersaturation. Anhydrite hydration and solution, and the spontaneous homogeneous nucleation and growth of dihydrate gypsum crystals are all accelerated.     

促释型轻烧氧化镁的养分释放特性及其对番茄生长的影响

 【目的】探讨促释型镁肥的养分释放特性、肥效及其作用机理。【方法】采用连续抽提、盆栽试验和X射线粉末衍射仪分别测定镁肥的水溶性镁释放量、番茄果实重量与生物量、镁肥的结构。【结果】连续抽提表明,促释型轻烧氧化镁水溶性镁每次的释放量高于轻烧氧化镁（第5次除外）,6次累积释放量是轻烧氧化镁的1.10倍。盆栽试验结果表明,促释型轻烧氧化镁处理的果实重量和生物量均高于轻烧氧化镁处理和硫酸镁处理;施镁肥处理的叶片镁、硫含量显著高于CK（无镁肥）,促释型轻烧氧化镁处理的番茄叶片镁含量显著高于轻烧氧化镁处理和硫酸镁处理;施镁处理的植株中的镁含量显著高于CK（无镁肥）,硫的含量没有显著性差异;番茄生物量与叶片、植株中的镁含量相关系数是0.8975、0.8715;X射线衍射分析结果显示,促释材料改变了轻烧氧化镁的结晶状态,促进了轻烧氧化镁中镁的释放。【结论】与轻烧氧化镁相比,促释型轻烧氧化镁的水溶性镁含量、生物量均提高。     

煅烧对白云石治酸效果及其钙镁释放动力学特性的影响

针对中国土壤普遍酸化,而用石灰治理会导致土壤板结,用碱性工业废弃物治理又有二次污染风险等问题,该研究在低温煅烧工艺下,研究了白云石颗粒大小、煅烧时间对白云石碱度、微结构、钙镁释放动力学特征的影响,旨在为开发既能治酸改土又能供应钙镁养分的白云石煅烧工艺提供理论依据。研究提出了总碱度和短期累积碱度2个概念。结果表明:粒径从0.15到3 mm的白云石,经过1 h煅烧后,总碱度增加了78%、短期累积碱度提高了1 100倍。粒径为1～3 mm的煅烧白云石在煅烧1～3 h后钙镁的释放速率快慢的规律一致,以煅烧2 h后释放速率最快。钙、镁释放曲线可用Parabolic、一级动力学、Richards和Bertallanffy方程进行拟合。其中Bertallanffy修正方程最适于描述煅烧白云石CaO释放的规律;Richards和Bertallanffy修正方程适于定量描述MgO的释放规律。由此可见,白云石煅烧后具有较高治酸潜力(总碱度)又有较大的治酸强度(短期累积碱度),并且能促进钙镁的释放,钙镁供肥量可用Richards和Bertallanffy修正方程预测预报。就粒径1～3 mm的白云石而言,煅烧1 h是增加其总碱度的经济煅烧时间,但是促进其快速裂解、提高其治酸强度和钙镁有效性的最佳煅烧工艺是850℃和2 h。     

EFFECT OF CALCINED SHALE ON TNE PORE STRUCTURE OF CEMENT PASTE

By means of the test the pore strticture of cement pastes incorporating calcinedshale,the results show the effect of calcined shale on the pore sturcture of cement pastes.and the ef-fect of calcined shale on the strength of cement pastes with the changing of pore structure. The workprovides an experimental and theoretical basis for the usage of pozzolanic admixture.     

轻质菱苦土木丝板蒸压机理的研究

轻质菱苦土木丝板是一种具有环保、装饰等功能的新型建筑材料。传统的冷压法和热压法压制的木丝板的各项性能均不理想。本文采用蒸压法来制备轻质菱苦土木丝板,并借助XRD、SEM微观手段来研究分析其蒸压机理。结果表明:通过蒸压方法制备的木丝板表面结构稳定,吸湿性和木丝板的力学性能较好。     

菱镁矿区土壤质量退化研究

Fourteen soil properties in 17 sampling sites were analyzed to study the soil degradation in a magnesite mining area in Haicheng City,Northeast China.Such areas have hitherto received little attention.The current practices of magnesite mining in this area resulted in degradation of soil quality and specifically led to an increase in soil pH,the ratio of magnesium to calcium,bulk density,clay dispersibility,total magnesium and equivalent calcium carbonate and a decrease in surface soil porosity and available phosphorous.The soil quality in the areas affected by intensive mining activity was obviously worse than that of areas far away from the mine.Four factors were identified and "magnesium factor","pH factor" and "fertility factor",involving 13 soil properties,explained 82% of the total variance in the entire data set.Discriminant analysis showed that the total magnesium,water-soluble calcium and available phosphorous were the most sensitive indicators for soil quality.     

石灰石和菱镁矿对酸化森林土壤修复作用的研究

以重庆铁山坪马尾松林下典型的酸化土壤为修复介质,将土壤溶液pH值和主要阴阳离子浓度作为测试指标,对石灰石和菱镁矿这2种化学修复剂的修复效果进行了为期1a的野外实验研究.结果表明:与未投加修复剂的土壤相比,投加石灰石和菱镁矿后土壤溶液的pH值和相应阳离子(Ca²⁺或Mg²⁺)浓度显著上升,而且无机单体铝(Al_i)浓度明显下降,从而起到了缓解土壤酸化并降低其对植被危害的效果.但是,修复剂的投加导致NO₃^{-相似文献}