硅酸盐细菌的筛选、鉴定和对铝硅酸盐矿物的作用研究

为了获得能够对高硅铝土矿具有生物脱硅作用的硅酸盐细菌,通过亚历山大洛夫无氮培养基从野外采集的土壤样品中分离得到30株固氮解钾细菌。经与矿物的作用实验,选出脱硅能力较高的细菌。经过菌落形态学特征、显微镜染色观察、16S rRNA序列分析,确定该菌株为胶质类芽孢杆菌,并命名为BM-4。实验结果表明BM-4对硅酸盐矿物有一定的脱硅效果,更有利于层状结构硅酸盐矿物的脱硅。该菌株对高岭土和一水硬铝石有较强的吸附、絮凝和浮选作用。单矿物浮选试验结果表明BM-4在高岭土表面的吸附可将高岭土的浮选回收率从50%提高至75%,而对一水硬铝石的吸附可将其浮选回收率从49%降至27%。一水硬铝石:高岭石=5:1的混合矿物采用改进的哈里蒙德浮选管进行浮选试验,矿物的Al/Si由3.05升至8.6,氧化铝的回收率为83%。这说明,研究筛选出的胶质类芽孢杆菌BM-4对层状硅酸盐矿物有较好的溶蚀脱硅效果。通过对矿物表面的吸附,提高高岭土在浮选过程中的浮选回收率,降低一水硬铝石的浮选回收率,能够从两矿的混合体系中通过浮选的方法除去高岭石,提高铝土矿的铝硅比,从而实现应用生物浮选方法用于铝土矿预脱硅的的可能性。     

铝土矿中铝的物相分析方法

铝在地壳中约占7.5%,是常见元素之一,它几乎只成为含氧化合物和铝硅酸盐存在。铝的氧化物是铝硅酸盐经风化水解后转变成为三水铝矿,一水硬铝石及一水软铝石等水化程度不同的氧化铝矿物或氢氧化物,通常称这类矿物为铝土矿。但铝土矿中经常伴生有高岭石等的铝硅酸盐,如广西某铝土矿中除高岭石外还含有绿泥石和水白云母,     

硫化矿捕收剂的研究进展

综述了硫化矿捕收剂的合成及浮选应用,混合捕收剂与组合用药的应用现状,捕收剂在硫化矿表面的作用机理。研究捕收剂分子结构和它们与矿物表面的作用机理,为硫化矿物新药剂的分子设计、开发与应用提供了理论指导。     

硫化矿捕收剂的研究进展

综述了硫化矿捕收剂的合成及浮选应用,混合捕收剂与组合用药的应用现状,捕收剂在硫化矿表面的作用机理。研究捕收剂分子结构和它们与矿物表面的作用机理,为硫化矿物新药剂的分子设计、开发与应用提供了理论指导。     

非硫化矿捕收剂的研究进展

综述了非硫化矿捕收剂的合成及应用现状,以及捕收剂在矿物表面的作用机理,重点介绍了羟肟酸和阳离子反浮选捕收剂的应用。研究捕收剂与矿物表面的作用机理,为非硫化矿新药剂的开发和应用提供理论指导。     

纳米粒子浮选捕收剂的研究进展

传统的油类捕收剂在回收微细粒煤、低阶煤和氧化煤等难浮煤泥方面效果不佳，研发新型高效的浮选药剂和浮选工艺是当前必须突破的难题。纳米技术作为一种前沿技术，在矿物加工领域展现出广阔的应用前景，并受广泛关注和探索。探讨了将纳米粒子作为矿物浮选捕收剂的研究进展，重点介绍了新型的疏水性纳米粒子的设计、合成及其在浮选中的应用现状。其中，包括阴离子和阳离子聚苯乙烯纳米粒子以及具有更好选择性吸附效果的功能化纳米粒子。这些纳米粒子具有优良的浮选性能，可以有效回收难浮煤泥和微细粒矿物资源。讨论了纳米粒子与矿物界面的微观相互作用机理。纳米粒子的尺寸和表面性质对其与矿物之间的相互作用具有重要影响。阴离子和阳离子聚苯乙烯纳米粒子具有疏水性，可与煤泥中疏水矿物发生作用，增强其浮选性能。而功能化纳米粒子通过表面改性，使其与特定矿物具有更好的选择性吸附效果。了解微观相互作用机理有助于优化纳米粒子的设计和合成，提高其在矿物浮选中的应用效果。最后，针对新型纳米粒子捕收剂的研究方向提出建议，推动纳米技术的快速发展和矿物浮选领域不断进步，为矿业行业带来新的活力与机遇。     

摩洛哥沉积磷酸盐的选矿 第三部份 选择性浮选客回收

对摩洛哥Mera-el-Arech矿石在哈利蒙管中作了浮选方解石和磷酸盐鲕石的研究,所用的药剂是阴离子捕收剂(油酸钠、十二烷基磺酸盐)和一种阳离子捕收剂(十二烷基胺盐酸盐)。试验结果表明,在适当的捕收剂浓度和PH值范围内可得到选择性回收。通过含有变量方解石的人为混合料的浮选可以验证纯矿物表面性能的守恒。从含18％P_2O_5矿石可得到含35％P_2O_5的磷酸盐精矿(接近鲕粒成分)。此外,这项工作使个们了解捕收剂对方解石和碳酸盐——磷灰石的吸附机理。     

细重晶石的浮选研究

对重晶石的浮选研 究,曾研究了油酸钠对 重晶石的吸附机理,及 以油酸钠为捕收剂时重晶石的浮游性。试验中将重晶石与地开石(一种高岭土矿物)以1:1的混合样进行浮选分离,并对深泽选矿厂经水力旋流器分级的细重晶石进行浮选回收,均取得研究成果。 ①据油酸钠对重晶石的吸附机理,在矿浆浓度低时,因油酸离子和硫酸离子的交换吸附,在矿物表面形成油酸钡化学吸附层。     

磷块岩浮选新捕收剂CCLS

开发新型高效浮选药剂是提高分选指标、降低精矿成本的有效途径。CCLS的研制成功,可以加速磷块岩矿石的开发和利用。 一、新型捕收剂的构思 1、国内外研究实践表明,两种或两种以上捕收剂混用会产生协同效应。由于矿物在成矿或破碎过程中表面的不均匀性,对同一捕收剂也有不同的吸附能力;而不同的捕收剂对表面状态相似的矿物也有不同的吸附能力。因此,如果将两种或两种以上相互匹配的捕收剂混用,则有可能获得矿物浮游所需的最佳吸附密度和强度。使在矿物表面的物理吸附和化学吸附兼而有之,获得更佳的浮选捕收性和选择性。     

改性水玻璃和捕收剂KC_2对萤石与方解石、石英浮选分离的作用效果

通过对萤石、方解石和石英进行浮选试验、药剂吸附量测定以及红外光谱分析,研究了改性水玻璃和捕收剂KC_2对萤石与方解石、石英浮选分离的效果及作用机理。结果表明,捕收剂KC_2在萤石和方解石表面均发生较强的化学吸附,而在石英表面吸附量很小;分别使用改性水玻璃和水玻璃这两种抑制剂进行浮选试验发现,改性水玻璃对方解石的抑制效果较好。改性水玻璃在方解石表面发生强烈的化学吸附,对KC_2体系中方解石的浮选产生抑制,这有利于萤石与方解石、石英的浮选分离。     

A comparative study of drying methods on physical characteristics,nutritional properties and antioxidant capacity of broccoli

Abstract

Broccoli is considered one of the attractive raw materials for dehydrated vegetables owing to its high nutritional value. However, information about how drying methods affect the physicochemical and nutritional properties of broccoli is limited. In this study, broccoli pieces were subjected to freeze drying (FD), hot air drying (HAD), microwave vacuum drying (MVD), vacuum drying (VD), MVD combined with HAD (MVD?+?HAD), and MVD combined with VD (MVD?+?VD). Quality attributes of dehydrated broccolis were contrasted in terms of color, texture, volume shrinkage, nutritional components, antioxidant activity, and rehydration capacity. Results demonstrated that FD better preserved the nutrients while HAD displayed the worst effect. The combination of MVD?+?HAD and MVD?+?VD resulted in higher retention of nutritional compositions, better antioxidant activity, and lower energy consumption than that of HAD. Furthermore, combined drying processing exhibited similar rehydration capacity but lower hardness compared to that of HAD.     

Design and Control of Heterogeneous Azeotropic Distillation for Separating 2‐Methylpyridine/Water

In industrial processes, 2‐methylpyridine/water mixtures can be separated via the conventional heterogeneous azeotropic distillation (HAD) using benzene as entrainer. 2‐Methylpyridine and water can form a heterogeneous azeotrope by themselves, based on which an improved HAD process is proposed. This allows for reducing the total operating cost and total annual cost (TAC) by more than one‐tenth compared with the conventional HAD process. Two different control structures were established for the enhanced HAD process. The results indicate that applying the feedforward ratio controllers to the control structure can handle the feed disturbances and maintain product purities with smaller transient deviations and shorter settling times.     

Visualization of crust formation during hot-air-drying via micro-CT

Abstract

Nowadays, hot-air-drying (HAD) is the most common process for the production of dried fruits and vegetables till now. It is well known that HAD has a big influence on product structure leading to effects like shrinkage or case-hardening. While shrinkage has already been documented throughout the drying process, case-hardening or the formation of a crust has only been shown for the dried product. In this study, a three-step approach consisting of a HAD-, a freezing-, and a freeze-drying step is used to show the development of a crust of carrot discs throughout a HAD process. With this method, the crust structures created during HAD were preserved and could be analyzed in a dry state with cone-beam micro-CT measurements. Crust thickness increased significantly during HAD and crust formation started before a relative moisture content of X/X₀ = 0.5.     

Red pepper (Capsicum annuum L.) drying: Effects of different drying methods on drying kinetics,physicochemical properties,antioxidant capacity,and microstructure

Results of an experimental study are presented and discussed for pulsed vacuum drying (PVD), infrared-assisted hot air-drying (IR-HAD), and hot air-drying (HAD) on drying kinetics, physicochemical properties (surface color, nonenzyme browning index, red pigments, rehydration ratio, water holding capacity, and ascorbic acid), antioxidant capacity (ferric reducing antioxidant power and 2,2-diphenyl-1-picrylhydrazyl radical scavenging capacity), and microstructure of red pepper. As expected, the drying time decreased with an increase in drying air temperature, IR-HAD needed the shortest drying time, followed by HAD and PVD. The effective moisture diffusivity (D_eff) of red pepper under PVD, HAD, and IR-HAD was computed to be in the range 1.33–5.83?×?10^?10, 1.38–6.87?×?10^?10, and 1.75–8.97?×?10^?10 m²/s, respectively. PVD provided superior physicochemical properties of dried red pepper compared to samples dried by HAD and IR-HAD. In detail, PVD yielded higher rehydration ratio, water holding capacity, red pigment and ascorbic acid content, brighter color, lower nonenzyme browning index, and comparable antioxidant capacity compared to samples dried by HAD and IR-HAD at the same drying temperature. Furthermore, PVD promoted the formation of a more porous structure, while HAD and IR-HAD yielded less porous structure. The current findings indicate that PVD drying has the potential to produce high-quality dried red pepper on commercial scale.     

The Eyes Absent Proteins: Unusual HAD Family Tyrosine Phosphatases

Here, we review the haloacid dehalogenase (HAD) class of protein phosphatases, with a particular emphasis on an unusual group of enzymes, the eyes absent (EYA) family. EYA proteins have the unique distinction of being structurally and mechanistically classified as HAD enzymes, yet, unlike other HAD phosphatases, they are protein tyrosine phosphatases (PTPs). Further, the EYA proteins are unique among the 107 classical PTPs in the human genome because they do not use a Cysteine residue as a nucleophile in the dephosphorylation reaction. We will provide an overview of HAD phosphatase structure-function, describe unique features of the EYA family and their tyrosine phosphatase activity, provide a brief summary of the known substrates and cellular functions of the EYA proteins, and speculate about the evolutionary origins of the EYA family of proteins.     

Rehydration and Sensory Properties of Dehydrated Russet Potatoes (Solanum tuberosum) Using Microwave Vacuum,Heated Air,or Freeze Dehydration

Russet potatoes (Solanum tuberosum) dehydrated by microwave-vacuum (MVD), heated air (HAD), and freeze drying (FD) were compared by measuring color, texture, rehydration properties, and sensory properties. Scanning Electron Microscope (SEM) images were taken to observe cell damage in the dried potatoes. The MVD potatoes remained intact following rehydration and retained suitable textural and color properties based upon sensory evaluation. The FD potatoes became friable and lost color. Sensory panelists preferred MVD, FD, and HAD in that order. MVD can provide consumers with a dehydrated product that has characteristics similar to or better than those dried by HAD or FD.     

钝化工艺对HEDP镀铜层耐蚀性的影响

采用盐水浸泡试验、硝酸点滴试验以及电化学测试方法,研究了苯并三氮唑、苯并三氮唑与Cr(Ⅲ)复配、苯并三氮唑与铈盐复配、Cr(Ⅵ)以及HAD无铬钝化工艺对HEDP镀铜层耐蚀性的影响。结果表明,经苯并三氮唑复配钝化液钝化处理后,钝化膜耐蚀性较单一的苯并三氮唑钝化稍有提高,但均不及Cr(Ⅵ)钝化处理,而经HAD无铬钝化处理后,钝化膜耐硝酸点滴时间最长,在3.5%Na Cl溶液中的Rct最大,icorr最小,耐蚀性明显优于Cr(Ⅵ)钝化处理。     

微波干燥和热风干燥对金萱茶叶品质影响

将微波干燥和热风干燥应用于新鲜金萱茶叶的干燥,在3个不同的微波功率（350 W,470 W,800 W）和4个不同的空气温度（70 ℃,80 ℃,90 ℃,100 ℃）下,研究了干燥参数即微波功率或温度对干燥时间、失水量的影响,同时还考察了茶叶中茶多酚总量和儿茶素含量的变化、干茶叶的复水性。实验得出,与热风干燥相比,微波干燥的时间缩短了76%～95%,而且干燥后的茶叶有很好的复水性,但干燥后茶多酚总量少于热风干燥;同时随着功率增加,微波干燥时间由11 min降为6 min,随着温度升高,热风干燥时间由127 min缩短为45 min。这两种方法的茶叶干燥动力学模型均满足Page’s半经验公式。     

Drying and Quality Characteristics of Shredded Squid in an Infrared-Assisted Convective Dryer

Drying is one of the most common methods for processing and preserving squids. A novel forced convective dryer based on infrared heating was developed with an online temperature control. By setting the drying medium temperature of 50°C, we studied the effects of infrared wavelength and air velocity on drying characteristics of the shredded squid and qualities of dried squid products. We also compared it with the conventional hot-air drying (HAD) and advanced microwave vacuum drying (MVD). The infrared heating rate increase was faster than that of HAD. The heating and drying at the wavelength of 2.5–3.0 µm were more effective than those at the infrared wavelength of 5.0–6.0 µm. Specific energy consumption linearly increased with the air velocity. Microstructure observation showed that the infrared-dried rehydrated sample displayed a muscle fiber structure similar to the fresh sample. The infrared-dried squids had less drying shrinkage, brighter color, and better rehydration capacity than HAD products. Their sensory qualities were better than HAD and MVD products. Above all, infrared drying with wavelength of 2.5–3.0 µm and air velocity of 0.5 m/s was suggested as the best drying condition for squids in this study.     

浮选柱结构参数对锶的浮选率影响的研究

研究了浮选柱浮选法对锶的浮选。考察了在锶最优浮选条件下浮选柱的高度、直径、布气室、微孔发泡器型号及柱形变化对浮选柱浮选法的影响。通过实验可知,浮选柱直径、发泡器、布气室、球型浮选柱都对锶的浮选率都有很大的影响;而浮选柱高度对浮选率的影响不大,但是在相同条件下,合适浮选柱高度可以缩短浮选时间;当选择合适的尺寸和球形柱,锶的浮选率最高可以达到97%。