浅谈双盘磨精浆机打浆的功率控制器

为了提高造纸机供浆流程的打浆匀度,目前在双盘磨精浆机打浆设备控制上都积极采用一种恒功率控制的电器设备,以下简称PRC控制器.该设备有着许多优良特点,以下就使用过程作些浅谈.

三种晚熟甜橙冷磨精油挥发性及主体香气成分的比较分析

为研究重庆主栽晚熟甜橙精油的挥发性及主体香气物质的组成含量特点,采用顶空固相微萃取-气质联用技术和香气活度值(odor activity values,OAV)分析奥林达夏橙、五月红甜橙和晚熟血橙的果皮冷磨精油(cold-pressed oil,CPO)。3个品种中分别鉴定出53、54和52个挥发性物质,其中D-柠檬烯含量普遍较低;奥林达CPO醇酚类、醛酮类含量更高,五月红和晚熟血橙CPO含较高的萜类物质。OAV分析表明,3种CPO的主体香气贡献物质包括对伞花烃、癸醛、己醛、壬醛和芳樟醇等30个成分,体现柑橘香、花香、油脂香等8类主要香气属性;奥林达CPO中花香、脂香和甜香类物质OAV较高,晚熟血橙CPO中松香和木香类物质OAV较高。本地区3个晚熟甜橙冷磨油的主体香气属性各具特点,适合加工不同类型的低萜精油,提升晚熟甜橙的产品附加值。

精切代磨技术的发展与应用

随着人们对环境保护意识不断增强及科技进步,绿色加工技术随之产生。精切代磨技术就是在此背景下产生并得到迅速发展,本文详细论述了其产生、发展及目前国内外的应用情况。同时对精切代磨技术的发展前景与展望作了简单的介绍。并指出了研究精切代磨技术现阶段存在的问题和未来的研究重点。

粗精再磨工艺在某高铜镍比矿石选矿中的研究及应用

本文通过对某硫化铜镍矿的矿石性质调查发现,随着矿石深度开采,矿石中铜镍品位的变化明显,铜镍比由原来的0.64提升到现在的0.9左右。随着铜镍比的增加,一段粗精矿的铜镍品位呈现下降趋势,对一段粗选精矿进行单体解离度分析发现铜镍矿物的单体解离度不够是造成精矿品位降低的主要原因。因此,对一段粗精矿进行磨矿细度、药剂添加等工艺条件的小型试验研究,试验结果表明:(1)相对于其他细度条件,在粗精矿再磨后,细度为-0.043 mm/ 80%和添加丁黄药20 g/t条件下,产生的铜镍精矿的产率、铜镍品位和回收率较高;(2)在粗精矿再磨后不添加捕收剂条件下,随着细度的增加,得到的铜镍精矿产率降低,镍品位和回收率也降低,原因可能是由于磨矿过程中有用矿物表面发生脱药所致;(3)闭路试验结果表明:相对于粗精矿不再磨(细度-0.043 mm /69%),在粗精矿再磨后(细度-0.043 mm /80%)和再磨后添加丁黄药20 g/t条件下,产生的精矿产率提高0.64个百分点,镍品位和回收率分别提高0.63个百分点和4.61个百分点,铜品位和回收率分别提高0.57个百分点和5.54个百分点。通过粗精矿再磨工艺工业应用实践可知:相对于应用前,产生的精矿镍品位和回收率分别提高了0.81个百分点和2.94个百分点,铜品位和回收率分别提高了0.30个百分点和5.85个百分点,同时,精矿中氧化镁含量满足冶炼厂对产品的要求。

45淬硬钢的精切代磨加工

从几个方面对45淬硬钢的精车、精铣加工性能进行了分析,证实了精切代磨是干式切削加工的一种重要加工方式。

编辑的功夫:精雕细磨

提高期刊编校质量需要编辑的精雕细磨。现今,编校质量下降和编辑的责任感和文化素养的缺失关系很大。要做到精雕细磨,应注重编辑细节。提高和完善编辑自身修养是精雕细磨之基础,完善编辑制度是精雕细磨之保障。

导轨安装面精铣代磨工艺可行性研究

介绍了采用数控龙门铣代替导轨磨床对磨床床身导轨进行加工的工艺可行性研究,分析了磨床导轨的设计精度和加工工艺流程,详细介绍了在磨削试验的基础上对磨床床身导轨面经采用数控龙门铣铣削后的精度检查的方法,并作了铣削和磨削的精度对比,通过改变切削参数的试验,达到了设计图纸的要求。研究结果表明,采用数控龙门铣替代导轨磨对磨床床身导轨表面的加工方法可行,可以推广应用。

巧妙设计 精打细磨 ——基于翻转课堂生物学科课内翻实践的研究

大数据时代,翻转课堂席卷了教育界。各个地区各个学科踊跃参与,开发研究适合自身的模式。经过两年的实践,本教师针对所授生物学科的课内翻模式小有心得。

慢磨出好课——教学《用字母表示数》磨课感悟

好课多磨，在磨课的过程中，教师不仅要养成质疑思考的习惯，而且要关注在合作互助中深入的思考，更要提升自身理论研究、外力引领的反思内化能力，并以此为导航系统，把准方向，驶入专业化成长的快车道!应该：磨透教材；磨就学生；磨锐方法；磨精语言。

弹性盖板针布磨针形状对梳理效果的影响

为了控制弹性盖板针布梳针出现平顶或圆顶,提高弹性盖板针布的加工质量和梳理质量,分析弹性盖板针布梳针平顶出现的原因及其对梳棉生条质量的影响,对以相切、相切、半径作圆和以起点、终点、半径作弧两种压磨方式下的梳针弧形半径、弧形针尖后角与平顶长进行对比,得出梳针弧形半径与平顶长的控制范围,分析砂带压磨与砂轮压磨磨针工艺,提出弹性盖板针布磨针的4种方案并进行优选,将改进磨针工艺后的弹性盖板针布在不同纤维、不同厂家进行纺纱实践。指出:梳针弧形半径R大于0.60mm、平顶长b不大于0.075mm的尺寸临界区,对减少和消除弧形针尖平顶或圆顶有利;改进磨针工艺后的弹性盖板针布棉结、杂质显著降低,梳针弧形针尖的穿刺锋利度有效性延长6个月,为弹性盖板针布产品梳理周期的进一步提高提供了理论依据。

Effect of milling time on carbothermic reduction of ilmenite

A systematic investigation on the effect of milling time on carbothermic reduction of ilmenite was carried out by a combination of thermal analysis, X-ray diffraction（XRD）, scanning electron microscopy（SEM） and particle size analysis. It was shown that the graphite crystalline structure was easily destroyed along the（002） crystal plane during milling process. The particle size of ilmenite/graphite mixture was largely decreased and a fully mixed composite structure was obtained after milling for 4 h at high milling intensity. Milling exerts positive effect on the decreasing temperatures of ilmenite reduction and gradual deoxidizing of titanium oxides was completed.

Study on the new materials for fiberboard refiner plate of defibrator

Defibrator is a very important machine in the wood industry for producing fiberboard. The refiner plates are the key parts of defibrator that directly act with the wood, and broken easily. The working life of the refiner plates is of significance to the wood industry. It may affect refining quality, production efficiency, and power consumption. In this paper, the abrasion resistance of the refiner plate made of different materials, the stainless steels and high chromium cast irons, were tested and compared. The results showed that abrasion resistance of refiner plate made of high chromium cast irons was better than that of the stainless steel materials. Although the two kinds of materials have the same compositions, their abrasion resistances have ap-parent difference. The main reason is that the material microstructures have very important effects on their performance. The refiner plates made of developed high chromium cast irons don抰 demand the complex heat treatment. This can simplify the producing process, save the cost of production, decrease labor strength, and increase the production efficiency.

高位浆箱在高档薄页纸打浆中的作用

高位浆箱已普遍使用在抄纸车间短流程中,起到稳定浆压的作用。而在浆间使用高位浆箱,不仅能提供给精浆机一个稳定的浆压,同时还可以起到连续兼循环打浆的作用,给操作控制带来极大的方便,打浆质量也容易得到保证。

Recovery of iron from waste ferrous sulphate by co-precipitation and magnetic separation

Magnetite concentrate was recovered from ferrous sulphate by co-precipitation and magnetic separation. In co-precipitation process, the effects of reaction conditions on iron recovery were studied, and the optimal reaction parameters are proposed as follows： n（CaO）/n（Fe2＋） 1.4：1, reaction temperature 80 ℃, ferrous ion concentration 0.4 mol/L, and the final mole ratio of Fe3＋ to FJ＋ in the reaction solution 1.9-2.1. In magnetic separation process, the effects of milling time and magnetic induction intensity on iron recovery were investigated. Wet milling played an important part in breaking the encapsulated magnetic phases. The results showed that the mixed product was wet-milled for 20 min before magnetic separation, the grade and recovery rate of iron in magnetite concentrate were increased from 51.41% and 84.15% to 62.05% and 85.35%, respectively.

张家口崇礼县磷铁公司铁尾矿中磷的浮选回收试验

张家口崇礼县磷铁公司铁尾矿中主要回收元素为磷,含磷矿物主要为有磷灰石,脉石矿物主要为钙镁硅酸盐。试验采用一次粗选粗精矿再磨,四次精选浮选流程,在再磨细度-0.074 mm为70%左右,碳酸钠3500 g/t,水玻璃用量1000 g/t,氧化石腊皂800 g/t用量条件下,获得了磷精矿品位及回收率分别为34.34%、75.81%的较好指标。

Elbow precision machining technology by abrasive flow based on direct Monte Carlo method

The investigation was carried out on the technical problems of finishing the inner surface of elbow parts and the action mechanism of particles in elbow precision machining by abrasive flow.This work was analyzed and researched by combining theory,numerical and experimental methods.The direct simulation Monte Carlo(DSMC)method and the finite element analysis method were combined to reveal the random collision of particles during the precision machining of abrasive flow.Under different inlet velocity,volume fraction and abrasive particle size,the dynamic pressure and turbulence flow energy of abrasive flow in elbow were analyzed,and the machining mechanism of particles on the wall and the influence of different machining parameters on the precision machining quality of abrasive flow were obtained.The test results show the order of the influence of different parameters on the quality of abrasive flow precision machining and establish the optimal process parameters.The results of the surface morphology before and after the precision machining of the inner surface of the elbow are discussed,and the surface roughness Ra value is reduced from 1.125μm to 0.295μm after the precision machining of the abrasive flow.The application of DSMC method provides special insights for the development of abrasive flow technology.

综合回收某铜钼矿中钼的试验研究

针对某铜钼矿的矿石性质,确定了"铜钼混选—粗精矿再磨—铜钼分离"工艺,采用常规药剂制度,实验室获得的闭路试验指标为铜精矿品位30.40%、铜回收率93.94%,钼精矿品位46.51%、钼回收率74.89%。与原工艺相比,在铜品位大幅提高的情况下,铜回收率提高了8.94个百分点,综合回收了品位大于45%的钼精矿。

Analysis and optimization of drilling parameters for tool wear and hole dimensional accuracy in B_4C reinforced Al-alloy

Cutting parameters were evaluated and optimized based on multiple performance characteristics including tool wear and size error of drilled hole. Taguchi＇s L27, 3-level, 4-factor orthogonal array was used for the tests. It is shown that generally abrasive wear and built up edge （BUE） formation were seen in the tool wear, and the comer wear was also of major importance. Flank wear of the cutting tool was found to be mostly dependent upon particle mass fraction, followed by feed rate, drill hardness and spindle speed, respectively. Among the tools used, TiAlN coated carbide drills showed the best performance with regard to the tool wear as well as hole size. Grey relational analysis indicated that drill material was the more influential parameter than feed rate and spindle speed. The results revealed that optimal combination of the drilling parameters could be used to obtain both minimum tool wear and diametral error.