【作者】 韩晓玲；

【导师】 王春光；

【作者基本信息】 内蒙古农业大学 ， 农业机械化工程， 2010， 博士

【摘要】 目前矿物质微量元素舔块(以下简称矿物舔块)成型主要采用压制生产工艺,有关生产工艺的研究,无论是在理论方面还是在试验方面,研究成果都比较少。而矿物舔块由于它特有的营养作用和产品特点,是适合我国养殖方式和畜牧业发展的新型节粮饲料,受到许多大型牧场和广大牧民的欢迎。国内,矿物舔块生产规模最大的工厂坐落在我区,其产品与国外产品比较,一些品种在营养方面超过了国外产品,但是产品品质不好,生产成本高,致使产品价位低,企业利润不高。为了提高国内产品的竞争力,本论文着眼于矿物舔块单向压制成型的生产工艺,主要做了以下工作:1.基于颗粒体最紧密堆积理论的颗粒级配试验研究。针对我区矿物舔块生产的实际情况,经过筛分把原料分成三个级别:粒径在2mm-4.75mm称为大颗粒;粒径在0.05mm-2mm称为中颗粒;粒径小于0.05mm的称为小颗粒。然后以压缩比、压坯密度、抗压强度为试验指标分别在60MPa、70MPa、80MPa、90MPa下压制成型,通过方差分析得到最佳颗粒级配为大颗粒含量20%-25%,中颗粒含量40%-60%,其余为小颗粒含量,同时分析了颗粒级配对压缩比、压坯密度和抗压强度的影响规律。2.颗粒级配的相关性分析。包括颗粒级配与压缩比的相关性、颗粒级配与抗压强度的相关性和颗粒级配与各试验指标之间的相关性。3.颗粒级配与压坯密度多元回归分析。压坯密度的多元线性回归方程为:y=1.631+0.003x1+0.083x2-0.051x4(压力x1、大颗粒含量x2、小颗粒含量x4、压坯密度y)。4.矿物舔块压制成型的正交试验研究。通过方差分析和趋势图分析得到:以压坯密度和抗压强度为主要试验指标选定最优工艺条件为填充量150g,颗粒级配大颗粒、中颗粒和小颗粒的比例为20%/50%/30%,压力100MPa。5.矿物舔块压制成型过程中含水率与1%粘结剂的关系。综合考虑耐水性、压坯密度和抗压强度,添加1%-1.5%水分合适,高压成型时含水率宜取高一些,低压成型时含水率宜取低一些。6.工程应用试验研究。分别对不添加粘结剂未进行颗粒级配、添加1%粘结剂未进行颗粒级配、添加1%粘结剂进行颗粒级配的三种矿物舔块生产方案进行对比试验,结果表明添加粘结剂并进行颗粒级配的矿物舔块其耐水性、压坯密度和抗压强度等性能显著提高。最优工艺参数为颗粒级配按大颗粒含量、中颗粒含量、小颗粒含量为20%-25%/40%-60%/15%-40%;含水率为1%-1.5%;压力根据现有设备选择高压压制成型,填充量根据反刍动物舔食量和生产效率综合考虑选择低填充量(目前广泛应用5kg)。7.矿物质舔块压制成型过程的数值模拟。以非线性大变形弹塑性有限元理论为基础,借助有限元软件Msc.Marc 2007,对圆柱形矿物舔块的单向压制成型过程进行有限元模拟,重点分析矿物舔块在压制过程中的密度分布、位移及应变分布,并研究颗粒体材料压制成型过程中的变形和致密规律;颗粒体与模壁之间的摩擦对密度分布的影响;数值模拟可以预测成型件成型后的尺寸,并与试验结果进行对比,一致性较好。此外,保压可提高压坯密度,改善密度分布不均匀性,保压时间30s为宜。更多还原

【Abstract】 The mineral microelement licking block (to hereinafter referred to as mineral licking block) to formed mainly uses the press forming at present. Whether in theory or in the test, the research results about production process are quite few relatively. Moreover, the mineral licking block as a result of its unique nutrition function and the product characteristic, becomes a new thrifty feed which suits the development of our country’s feeding culture and livestock, and receives many large-scale pastures and general herdsman’s welcome. The largest plant of the production of mineral licking block is located in my district at home. Some varieties of its products are more nutritious than foreign products, but high production costs, poor product quality, low prices and small profits. In order to improve the competitiveness of domestic products, this paper focuses on one-way compaction production process, mainly to do the following:1. Based on the closest packing theory of granular materials, grain composition test of the mineral licking block was done according to the actual situation of production. First of all, the material was divided into three levels: diameter of 2mm-4.75mm as large particles; diameter of 0.05mm-2mm as middle particles; particle size less than 0.05mm as small particles according to the results of the screening material. Then, took the compressed ratio, the compacted density and the compressive strength as test index; Took them press forming under pressure 60MPa、70MPa、80MPa、90MPa respectively, and the optimal grain composition was the large particle content of 20%-25%, the middle particle content of 40% -60%, the rest of the small particle content through the analysis of variance. At the same time, the rule of the grain composition to compression, coMPacted density and compressive strength were investigated.2. The correlation of the grain composition, include between grain composition and compressed ratio, between grain composition and compression strength and between grain composition and the entire test index was investigated.3. The regression between grain composition and the compacted density was investigated. The multivariate linear regression equation of the compact density is y=1.631+0.003x1+0.083x2-0.051x4( the pressure x1, the large particle content x2, the small particle content x4 and the compacted density y).4. The press forming of the mineral licking block was investigated with orthogonal test method. Through variance analysis and trends diagram analysis, the optimal technological parameters were filling quantity 150g, grain composition 20%/50%/30% and pressure 100MPa.5. The relationship between water content and 1% of the binder on press forming of the mineral microelement licking block was studied. Water content 1%-1.5% is right considering water resistance, compacted density and compressive strength comprehensively. Moreover, press forming with high pressure takes higher water content and pressing forming with low pressure takes lower water content.6. Engineering application test, three kinds of mineral licking block production scheme comparison test was taken, the material without any binder, the material with 1% binder without grain composition and the material with 1% binder for grain composition. The results showed that water resistance, compact density and compressive strength performance had improved significantly with the material adding binder for particle composition. The optimal parameters was grain composition by large particle content, the middle particle content and the small particle content 20-25% / 40% - 60% / 15% - 40%, water content 1%-1.5%, the higher pressure according to the existing equipment, and the lower filling quantity based on ruminant lick appetite and production efficiency (now widely 5kg).7. The press forming process of mineral licking block was simulated with nonlinear large deformation elastoplastic finite element method (FEM). The unidirectional press forming process of the cylindrical mineral licking block was visualized with FEM software Msc.Marc 2007. The density distribution, the displacement and strain distribution, particles deformation and dense rule and the influence to density distribution from the friction between particles and die wall, upper punch and bottom punch was studied primarily. The simulation resultst can forecast the size of the green compact, and had good consistency with the experimental results. In addition, pressure upkeep can improve the compacted density and the density distribution non-uniform, and the advisable pressure upkeep time is 30s.更多还原