Energy Consumption in Comminution of Mica with Cavitation Abrasive Water Jet

We have studied the efficiency of energy consumption in the comminution of mica powder with cavitation abrasive water jet technology. The energy required to create new surfaces in the comminution of mica powder with cavitation abrasive water jet was calculated,in order to estimate its efficiency of energy consumption. The particle size distribution and the specific surface area were measured by applying a JEM-200CX transmission electron microscope and an Autosorb-1 automatic surface area analyzer. The study results show that the efficiency of energy consumed in creating new surface areas is as high as 2.92%,or 4.94% with the aid of cavitation in the comminution of mica powder. This efficiency will decrease with an increase in the number of comminutions. After three comminutions,the efficien-cies will become 1.91% and 2.29% for comminution without cavitation and with cavitation,respectively. The abrasive water jet technology is an effective way for comminution of mica powder.

Pre-treatment of rocks prior to comminution--A critical review of present practices

It has been an established fact that comminution processes, crushing and grinding, are most energy intensive processes which account for more than half of the total energy consumed in mineral industries.Various alternative pre-treatment methods have been tried by experts around the globe. Although these methods yielded positive results in terms of reduction in energy consumption in crushing and particularly, in grinding operations at laboratory scale, their industrial application still remains an unresolved issue and challenge. Present review paper describes each one of these methods along with outcome of earlier studies and issues that need to be addressed through further rigorous experimental investigation.It also suggests the direction in which future studies can be carried out to meet the primary objective of making comminution processes more energy efficient than today they are.

Application of the fractal theory for evaluating effects of coal comminution by waterjet

Comminution of coal to ultrafine sizes by high-pressure waterjet provides a novel method for preparation of coal-water fuels for next generation,near-zero emission electric power generation.The particle size distribution(PSD)of ground coal is a key parameter in the preparation of slurries as it determines the settling behavior of the particles and viscosity of the coal-water mixture.There are several methods available for representation and evaluation of particle size analysis data.However,fractal theory provides a means by which the entire PSD of comminuted materials can be quantified by using of a specific and exact value.In this paper,a volume-based fractal model was deduced to characterize the PSD of the coal which is ground in a specially designed comminution cell.During the size reduction process,the inlet pressures up to 276 MPa were used.

Numerical simulation of high voltage electric pulse comminution of phosphate ore

Numerical simulation of the electrical field distribution helps in-depth understanding of the mechanisms behind the responses and the benefits of the high voltage pulse comminution. The COMSOL Multiphysics package was used to numerically simulate the effect of ore compositions in this study. Regarding phosphate ore particles shape and composition, the effects of mineral composition, particle size, particle shape and electrodes distance were investigated on the electrical field intensity and distribution. The results show that the induced electrical field is significantly dependent on the electrical properties of minerals,the feed particle size and the location of conductive minerals in ores. The angle of material contact surface with the discharge electrode is also an important factor in the intensity of electrical field. Moreover,it is found that the specific liberation effect at the disintegration of phosphate ore by electrical pulses is due to the locality of the electrical field at the interface of mineral components of the phosphate ore aggregates with different permittivities. However, the intensity of the electrical field increases with sharpening the contact angle. Besides, the electrical discharge in the samples is converted to the electrohydraulic discharge across the surrounding water by changing the distance between the discharge electrode and sample surface.

Research on Calculation Models of Coal Comminution Energy Consumption

在总结粉碎功耗规律的研究进展的基础上，分析了单一粒度颗粒的粉碎功耗预测理论，介绍了粉碎功耗理论的3种著名假说体积假说、面积假说、裂缝假说及其修正计算方法，并进行了比较，描述了粉碎功耗计算的通用关系式和近年来提出的新机制，包括原生裂纹假说、突变理论及分形理论等；进而针对具有复杂粒度分布物料的粉碎功耗，将给料与产品粒度分布作为参数引入能耗计算中，获得了当粒度分布分别满足G．S分布、R—R分布、分形分布时的各种粉碎功耗理论预测结果。此外，还列出了部分常用的粉碎功耗经验关联式并进行了比较。文中提出在研究煤的粉碎功耗规律时，采用Walker计算式结合分形粒度分布或R-R分布的能耗模型及Morrell经验式是可行的。

Comminution of Mica by Cavitation Abrasive Water Jet

The comminution of mica with an abrasive water jet is mainly based on three knids of effects, that is, high-speed collision, cavitating effect and shearing effect. Cavitation abrasive water jet was applied for the comminution of mica because cavitation abrasive water jet can make full use of the three effects mentioned above. Besides high speed impacting among particles,cavitation and shearing were also enhanced due to the divergent angle at the outlet of the cavitation nozzle.A JME-200CX transmission electron microscope was used for observing the size distribution of particles.Variance analysis on the experimental results indicates that the effect of cavitation is much more significant than that of collision.The effect of pressure on comminution results becomes less with the decrease of the particle size.

Computational Comminution and Its Key Technologies Applied to Materials Processing Procedure

A new concept named computational comminution is proposed in thispaper, which is different from the traditional studies on materialsprocessing procedure such as the study based on theoretic models, thestudy based on experiment models, which is based on informationmodels. Some key technologies applied to mate- rials processingprocedure such as artificial neural networks, fuzzy sets, geneticalgorithms and visualization techn- ology are also presented, and afusing methodology of these new technologies is studied. Applicationin the cement grinding process of Horomill shows that results in thispaper are efficient.

A CONTINUOUS DAMAGE APPROACH TO RELATIONSHIP BETWEEN SIZE REDUCTION AND ENERGY CONSUMPTION DURING ORE COMMINUTION

Based upon the aspect of continuous damaging,the process of ore comminution may be des- cribed as the growth and propagation of the microcracks in the ore grains under external load- ing,and a theoretical expression has been developed on the relationship between the grain size distribution and the total energy consumption during entire ore comminution process.The en- ergy consumed totally may be considered consisting of two portions,i.e.with fresh crack sur- faces growth and with crack propagation.The proposed expression seems to be an advance over previous conventional ones,especially that from the viewpoint of energy distribution.

STUDY ON ULTRAFINE COMMINUTION AND ITS MECHANISM OF HARD KAOLIN

The comminution mechanism of hard kaolin from Enshi District in China Hubei Province is investigated through applying comminution theory and basing on the ore properties of the kaolin. The technique and effectiveness of comminution are introduced according to the practice of ultra-fine comminution with impact comminutor. The results show that the circuit comminutor unit has advantages of simple technological process, being easily controlled, high effectiveness and so on.

ANALYSIS OF DISSIPATIVE STRUCTURE IN MATERIAL COMMINUTION

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Effect of cavitation on comminution of mica powder

The cavitation abrasive water jet was used in the comminution ofmica. By applying a cavitation nozzle in the abrasive water jetsystem to enhance the effect of cavitation and friction, bettercomminution results were obtained. The JME-200CX transmission elec-tron microscope was used for observing the size distribution ofparticles. As using cavitation abrasive water jet, the relativecomminution effect is raised by more than 25/100 compared with usingabrasive water jet only. It can be concluded that the effect ofcavitation is much more significant than that of impacting in thecomminution of mica.

EXPERIMENTAL STUDY ON ULTRAFINE COMMINUTION IN THEORY OF VERTIGINOUS CURRENT OF BULK MATERIAL

Experiment about ultrafine comminution in theory of vertiginous current of bulk material has successfully performed by a lately developed vertical shaft centrifugal autogenous grinder. The results of tested several materials are analyzed, moreover. the comminution mechanism and the affecting factors of ultrafine comminution are analyzed.

Effects of Ultrafine Comminution on the Dissolution of Active Ingredients from Compound Feed Additive of Strobilanthes cusia

[Objective] The research aimed to explore the effects of comminution technology on the dissolution of active components from compound feed additive of Strobi/anthes cusia. [Method] Using active component adenosine in principal herb S. cusia and chlorogenic acid in minister drug Lonicera japonica Thunb. as dissolution indices,the effects of ultrafine comminution on the dissolution degree of compound feed additive of S. cusia were analyzed. [ Result] The dissolution degree of adenosine and chlorogenic acid in ultra micro particles were obviously higher than that of common particles. Ultrafine comminution could significantly quicken the dissolution rate of adenosine and chlorogenic acid in compound feed additive of S. cusia, shorten the extraction time, avoid the breakage of active components in long-time extraction process,and meanwhile saved the energy greatly. [ Conclusion] The ultrafine comminution technology could obviously increase the dissolution degree of active components in compound feed additive of S. cusia.

COMPRESSIVE COMMINUTION MECHANISM OF PARTICLE BEDS

Granular material mechanics,finite element analysis and crushing theory are applied to study the compressive comminution mechanism of particle beds in this paper.This is a new method by which we have established an equivalent model of granular material,determined the values and distributions of contact forces and discovered a crushing law.The model has been tested on the newly designed equipment and proved to be correct.Some new characteristics and laws of compressive comminution of particle beds have been found.

DESCRIPTION OF G-S PARTICLE SIZE DISTRIBUTION OF ROCK COMMINUTION WITH FRACTAL GEOMETRY

The fractal model of rock comminution is presented with Mandelbrot's fractal geometry.The results show that it is difficult for those with only a linear similarity ratio to fit practical situations.The comminution prob ability of the central part should be considered so the geometric meaning of the constant in Gaudin-Schuhmann's distribution function can be explained more clearly.

COMMINUTION CIRCUIT FOR LARGE CONCENTRATOR

This paper provides a summary of the current comminution circuit and its development trend,focusing the discussion on the comminution circuit selection for the No.3 concentrator with 60000 t/d througput in the Dexing Copper Mine.Based on the large amount of information and data on autogenous grinding tests and conventional grinding practices in the Dexing Copper Mine,the comparison results for various comminution circuits as well as the authors suggestions for the comminution system are presented.

Influence of the Hydriding Cycles on U-IOMo Alloy Comminution Process

Hydriding-dehydriding process has been widely employed to comminute uranium alloys. Developments have been made to improve this process because it is a cheaper way to obtain powder of uranium alloys compared to the other methods, such as atomization. This work presented an innovative comminution process of U-10Mo alloy in laboratory scale where a Sievert type equipment was utilized and only hydriding cycles were employed without repetition of the dehydriding procedure. Experiments of comminution of the U-10Mo alloy were carried out by employing alloy samples which were submitted to different heat treatment conditions and, subsequently, to different hydriding cycles. The heat treatments considered were hot rolled at 800 ℃, homogenization at 900 ℃ or 1,000 ℃ and aging at 520℃. It was observed that the number of hydriding cycles and heat treatment conditions have influenced the particle size distributions. Samples that were hot-rolled, homogenized at 1,000 ℃ and aged, and comminuted with five cycles of hydriding have produced powders with particle size distribution more uniform with the major quantity of particles in the range from 50μm to 200 μm while the other conditions have obtained a great quantity above 200 μm.

支架外固定与钢板内固定治疗桡骨远端粉碎性骨折的Meta分析

目的:外固定支架和钢板内固定作为桡骨远端粉碎性骨折的常用治疗方法,在临床上各有利弊。系统评价外固定支架与钢板内固定治疗粉碎性桡骨远端骨折的临床疗效及安全性,为桡骨远端骨折中西医结合诊疗指南研制提供论证依据。方法:系统检索PubMed、Web of Science、Embase、Cochrane Library、中国知网、中国生物医学文献数据库、维普和万方数据库,纳入2013年10月至2023年10月发表的关于外固定支架和钢板内固定治疗粉碎性桡骨远端骨折的随机对照试验文献,按照纳入标准和排除标准筛选文献,使用Review Manager进行文献质量评价和Meta分析。结果:(1)纳入8篇文献,其中中文文献4篇,英文文献4篇、总样本量648例,外固定支架组328例,钢板内固定组320例;(2)术后3个月,钢板内固定组的背伸、掌屈、旋后范围优于外固定支架组;术后12个月,钢板内固定组的握力、掌倾角、掌屈、旋前和旋后范围优于外固定支架组;钢板内固定组在术后感染方面优于外固定支架组,其余结局指标两组差异均无显著性意义。结论:现有8项证据表明,在粉碎性桡骨远端骨折的治疗方式选择上,外固定支架与切开钢板内固定都有良好的治疗效果,综合其他因素钢板内固定更胜一筹,但是对于一些高度严重的粉碎性桡骨远端骨折、骨质较差、严重污染的开放性骨折以及软组织肿胀而无法进行切开手术的特殊患者,外固定支架才是首选。此次研究结果具有局限性,未来还需要开展更多高质量、大样本、多中心的随机对照试验研究,另外需重视远期疗效、其他次要指标的观察,补充优化当前研究结果。

纤维带与无头加压螺钉治疗第1,2跖骨近端粉碎性骨折Lisfranc损伤

背景:Lisfranc韧带是维持足部横弓与纵弓的重要结构,Lisfranc损伤为一种严重的中足损伤。Lisfranc韧带损伤是复杂的,其治疗以及首选的固定方法有争议。目的:比较钢板联合Suturetape与钢板联合无头加压螺钉治疗第1,2跖骨近端粉碎性骨折Lisfranc损伤的短期疗效。方法:回顾性分析东莞市中医院骨七科2019年1月至2022年6月因第1,2跖骨近端粉碎性骨折Lisfranc损伤患者48例,其中25例采用钢板联合Suture tape固定(观察组),23例采用钢板联合无头加压螺钉固定(对照组)。术前参照影像学资料,根据Myerson分类系统进行分型;术后随访根据骨折愈合时间、目测类比评分、美国足踝外科学会标准评估足功能恢复情况,并对两组术后并发症进行比较分析。结果与结论:①两组患者均顺利完成手术并获得随访,随访时间12-36个月,平均(18.0±5.42)个月;②两组患者手术时间、术中出血量比较差异均无显著性意义(P>0.05);③观察组较对照组骨折愈合时间稍长,差异有显著性意义(P<0.05);④术后3,6,12个月随访,观察组较对照组目测类比评分明显降低(P<0.05);⑤术后6,12个月,观察组术后各时间点随访足功能AOFAS评分较螺钉组明显改善(P<0.05),且均较术前显著提高(P<0.05);⑥术后观察组出现1例创伤性关节炎,对照组出现1例切口感染、1例螺钉断裂及2例创伤性关节炎,两组比较差异无显著性意义(P>0.05),考虑与样本量偏少有关;⑦提示对于第1,2跖骨近端粉碎性骨折Lisfranc损伤,实施钢板联合Suture tape内固定治疗Lisfranc关节损伤效果可靠,可改善患者足关节功能,且具有手术创伤小、术后并发症少、远期医源性创伤性关节炎风险低的优势,较无头加压钉更有利于足功能的恢复。

Maillard Products Formed from Chicken Fat Oxidants and Amino Acids Act as a Flavor Enhancer in Comminuted Chicken Products

Lipid oxidation and degradation are generally recognized as unfavorable reactions in food processing. However, lipids can be utilized to produce meat-like flavorings through reaction with amino acids after degradation to carbonyls such as aldehydes and ketones. The fatty acids in chicken fat mainly comprise palmitic acid, oleic acid and linoleic acid. After being heated at 120 ~C for 3 h, the degraded carbonyls of chicken fat were reacted with cysteine, alanine, glycine and thiamine to form a chicken-like flavoring. The key aromatic components of the flavoring were identified by GC-MS. In the overall volatile profile, 22 kinds of compound were detected, among which 2-furanmethanol was formed by the Maillard reaction, 1-（2-furanyl）-ethanone by cyclization and 2,4,6-trimethyl-l,3,5-trithiane by the Strecker degradation of cysteine. Dihydro-2-methyl-3（2H）-furanone, dihydro-2-methyl- 3（2H）-thiophenone, 2-acetyl-lH-pyrroline and 4-methyl-5-thiazoleethanol were the degradation products of thiamine. The prepared chicken flavoring was added to comminuted chicken product （CCP）. GC-MS analysis and sensory evaluation showed that the flavor and odor of the CCP were greatly enhanced.