ICP-AES法测定磷矿浆烟气脱硫剂固液相中硫含量的研究

SO₂是大气主要污染物,与雾霾的形成有直接关系,烟气脱硫是保护环境、减少雾霾的有效措施。磷矿浆法烟气脱硫是一种以磷矿浆为吸收剂的新型脱硫方法。采用电感耦合等离子体原子发射光谱(ICP-AES)法测定磷矿浆烟气脱硫剂固液相(磷矿粉、磷矿浆脱硫液和脱硫渣)中硫含量。在选定了较灵敏的硫分析线后,探讨了ICP光谱仪工作条件对分析结果的影响,同时研究了样品预处理方法以及共存元素对硫测定结果的影响。分别用三种不同的方式对磷矿粉、磷矿浆脱硫液和脱硫渣样品进行前处理,确保样品溶解完全。选用181.973 nm光谱线为分析线,避免共存元素的光谱干扰。选择仪器的入射功率为1 300 W,观测高度为12 mm,雾化气流量为0.65 L·min-1,泵进样量为1.5 mL·min-1。在光谱仪最佳分析条件下,利用该方法测定磷矿粉、磷矿浆脱硫液及脱硫渣中硫的含量,其检出限为0.000 38%,加标回收率在89.5%～104.5%之间,相对标准偏差(RSD)≤2.30%,同时与硫酸钡重量法进行对比实验,结果基本吻合,相对偏差≤3.88%,该方法简便快捷,精密度和准确度较高,适用于磷矿浆脱除烟气SO₂的科研及生产中。     

超声波对木瓜蛋白酶催化活性影响的机理研究

木瓜蛋白酶经适当参数的超声波处理后酶活力提高。超声处理后酶的米氏常数Km变小,最大反应速率Vm也减小。超声处理后酶的紫外吸收光谱不变,荧光发射光谱也不改变,而差示光谱出现明显的正峰和负峰。研究结果表明,超声波处理后,木瓜蛋白酶的构型没有改变,而构象发生了变化。本文讨论了超声波影响木瓜蛋白酶活性的可能机理。     

双低频超声处理偶氮类染料模拟废水的研究

对用双低频超声波处理偶氮染料活性艳红X-3B模拟废水进行了实验研究。探讨了不同超声波之间的功率搭配和超声波探头之间的距离对处理效果的影响。实验表明双频超声降解效果优于单频超声，双频超声存在最佳功率搭配。在给定的实验范围内，两个超声波探头之间的最佳距离为1．5cm，US／Fenton处理污染物的效果（η值为94．90％）高于US与Fenton处理效果之和7．1个百分点。通过UV-Vis分析，观察到活性艳红X-3B处理60min后基本被矿化。     

功率超声在废水处理中的应用

采用不同强度和频率的超声波，对几种生物难降解的有毒污染物（苯胺，硝基苯）废水进行超声处理，实验表明，降解效果主要取决于超声波在反应液中的声强及处理时间，同时，若辅以通氧气或加入催化剂，处理效果更好，这就为设计相应的超声废水处理设备提供了实验基础。     

PEG6000溶液超声化学反应机理的初步研究

采用不同电功率的超声波处理了聚乙二醇(PEG6000)溶液。凝胶渗透色谱(GPC)分析超声处理后的PEG溶液发现,当超声电功率超过250W时,PEG分子量随超声波作用强度的增大而减少,随超声波作用时间的延长而增大;在电功率超过250W超声波作用下,傅立叶红外光谱(FT-IR)分析表明,组成PEG的单体没有明显改变,但是,羟基含量分析表明,PEG固体样品中的羟基含量有所减少。结合实验结果,根据高分子化学、有机化学和超声化学中相关理论对PEG超声化学反应机理进行了探讨,认为:当超声波作用于PEG溶液时,同时存在有PEG的缩水聚合反应和自由基降解反应,当频率为20-25kHz、电功率为250-600W的超声作用于PEG6000溶液时,缩水聚合反应占主导地位。     

超声法测量高浓度矿浆两相流粒径分布和浓度

研究了超声衰减谱法和超声多次回波反射法测量高浓度矿浆两相体系粒径分布和浓度。实验测量了多个浓度下硫矿浆在3～6 MHz频率下的声衰减谱,结合反演算法由实验数据计算得到矿浆两相流粒径分布。同时测量了不同浓度下硫矿的声阻抗值,由超声多次回波反射法计算得到浓度。粒径分布与浓度测量得到的结果与标准配置值较为吻合,表明超声法适用于高浓度矿浆两相流粒径分布和浓度的在线检测。     

超声波水处理性能的实验研究

本文采用传热实时监测方法,以一定频率28 kHz的超声波对冷却水进行处理,考察了超声作用下水质硬度、水温变化对处理效果的影响。结果表明,超声波具有比较明显的阻垢作用,在低硬度下有较高的阻垢率,并使过程的传热系数显著提高,同时超声波能够抑制硬度水中Ca~(2+)的析出。     

快速制取人体组织病理切片的超声波法

本文介绍了用超声波方法快速制妈人体组织病理切片的基本原理，实验步骤和试验结果。结果表明，用超声波处理后快速制取的病理切片完全怀可常规石蜡切片相媲美，在临床外检快速病理诊断应用上，超声处理仪有可能取代价格昂贵的恒温式冷冻切片机。     

高炉炉墙测厚的信号处理

超声波反射法应用于高炉炉墙测厚时,高炉内部环境高温高噪声的特点,造成超声回波信号被噪声湮没的问题;针对这一问题,研究了超声波在金属介质中传播的机理,分析了超声回波信号信噪比下降的原因以及实验数据时域和频域的特征,设计改进了高炉炉墙测厚的超声波发射电路和信号调理电路;采用加热炉模拟高炉200~1 000 ℃温度环境,对直径40 mm、长度1.2 m的铁棒进行测厚实验;经实测,改进的发射电路发射的超声信号强度增大,回波处理电路处理后超声回波信号信噪比明显提高、峰值清晰可辩,解决了噪声湮没回波信号的问题,提高了高炉炉墙测厚的测量精度,对高炉的高产、顺产和延长炉龄具有实际意义。     

新仪器,新设备

超声矿浆粒度仪是一种借助于超声衰减值的测量来测定矿浆粒度的设备,为国内各金属矿山选矿生产中急需的重要检测仪表.冶金部作为一项重要科研课题而下达给马鞍山矿山研究院.1985年起中国科学院声学所参与合作攻关,以解决关键的声学问题.经过近两年的艰苦努力,终于取得了较满意的结果.采用微计算机操作,可同时实时地测出矿浆的粒度和浓度.在我国首次独立自主地研制成了定名为“CLY-1     

Study on ultrasound-assisted oxidative desulfurization for crude oil

The existence of sulfur compounds in crude oil will bring many problems such as corrosion, catalyst poisoning and pollution to the petroleum processing process. Therefore, how to reduce the sulfur content as much as possible in the process of crude oil processing has become an important research topic in the petroleum processing industry. In this paper, ultrasonic-oxidative desulfurization is studied. The effects of reaction temperature, reaction time, amount of oxidant and demulsifier on desulfurization rate are investigated. And the effect of oxidative desulfurization and single oxidative desulfurization under ultrasonic treatment are compared. It is found that the addition of ultrasonic treatment can enhance the desulfurization effect of desulfurizer, the desulfurization efficiency can be increased by about 10% under ultrasonic treatment (100 W, 70 kHz); ultrasonic wave plays an auxiliary role in the system, it can promote heterogeneous reactions, improve the activity of oxidants, and promote the degradation of macromolecular compounds. Finally, physical desulfurization, chemical desulfurization and biological desulfurization technologies are compared.     

Effect of ultrasonic standing waves on flotation bubbles

Ultrasonic flotation was an effective method to float fine coal. In this study, the effects of the standing waves with different frequencies on ultrasonic flotation were investigated. The dynamic processes of bubble and coal-bubble were revealed by a high-speed camera. The results showed that under the action of Bjerknes force, bubble aggregates were formed within 450 ms and coal bubble aggregates were formed within 20 ms. The bubble aggregates were statistically analyzed by image processing method. The number of aggregates and small bubbles in the ultrasonic field at 100 kHz was greater than those at 80 and 120 kHz. Besides, 100 kHz ultrasonic flotation achieved the highest yields of clean coal (35.89%) and combustible recovery (45.77%). The cavitation bubbles acted as either a “medium” or an “inclusion”, entrapping and entraining the coal particles in the flotation pulp. It promoted the aggregation of bubbles with coal particles, so the flotation efficiency was effectively improved in the presence of ultrasonic standing waves.     

Ultrasound-assisted oxidative desulfurization of bunker-C oil using tert-butyl hydroperoxide

This work investigated the ultrasonic assisted oxidative desulfurization of bunker-C oil with TBHP/MoO₃ system. The operational parameters for the desulfurization procedure such as ultrasonic irradiation time, ultrasonic wave amplitude, catalyst initial concentration and oxidation agent initial concentration were studied. The experimental results show that the present oxidation system was very efficient for the desulfurization of bunker-C oil and ～35% sulfur was removed which was dependent on operational parameters. The application of ultrasonic irradiation allowed sulfur removal in a shorter time. The stronger the solvent polarity is, the higher the sulfur removal rate, but the recovery rate of oil is lower. The sulfur compounds in bunker-C oil reacted with TBHP to produce corresponding sulfoxide, and further oxidation produced the corresponding sulfone.     

Design of a flotation cell equipped with ultrasound transducers to enhance coal flotation

Ultrasonic treatment is widely used for surface cleaning during physical, chemical and physico-chemical processes in mineral processing. Several research papers and a few industrial applications about the subject suggest that the mechanism behind the positive effect of ultrasound for mineral processing and especially flotation is due to formation of cavitation by ultrasonic energy. Within this study, coal floatability is investigated by use of a specially designed flotation cell equipped with ultrasound transducers with different power, frequency and geometry. The results indicate that ultrasonic treatment during coal flotation positively affects the quality and quantity of the properties of floated coals while using of lesser amounts of reagent than a conventional flotation system.     

A review of effects and applications of ultrasound in mineral flotation

Ultrasound technology is widely applied in the flotation process. From the perspective of the theory of ultrasound, this article explains the effects and applications of ultrasound in the flotation process. To obtain a clear understanding of ultrasonic effects, we observe the phenomena of ultrasound using a high-speed camera and a CCD camera, and investigate potential applications in flotation. From these different phenomena, the ultrasonic effects are classified into three types of effect: the transient cavitation effect, stable cavitation effect, and acoustic radiation force effect. Based on these effects, the applications of ultrasound to mineral flotation are reviewed, including slime coating removal, oxidation film removal, desulfuration, tiny bubble generation, flotation reagent dispersion, and aggregation. In addition, the ultrasonic equipment and treatment methods applied in flotation are classified and compared based on their characteristics. Finally, we propose some potential directions in the study of the stable cavitation effect and acoustic radiation force effect, which are important, but are seldom mentioned in previous reports.     

Effect of the ultrasonic standing wave frequency on the attractive mineralization for fine coal particle flotation

Froth flotation for mineral beneficiation is one of the most important separation techniques; however, it has several challenges for processing fine and ultrafine particles. Attractive mineralization between particles and bubbles by ultrasonic standing wave (USW) is a novel and high-efficiency method that could assist fine particle flotation. Frequency is an important ultrasound parameter, whose effectiveness mechanisms on the attractive mineralization did not compressively address. This study explored the effect of the USW field with various frequencies on the fine coal flotation for filling this gap. Herein, a high-speed camera and a focused beam reflectance measurement (FBRM) were used to analyze three sub-processes of the attractive mineralization, including the microbubbles’ formation, the conventional flotation bubbles (CFBs)’ dispersion, and the particles’ movement. It was found that the maximum flotation metallurgical responses were obtained under the highest examined USW frequency (600 kHz). However, the flotation outcomes by a low USW frequency (50 kHz) were even lower than the conventional flotation tests. Observation and theoretical calculation results revealed these results were originated from the influence of frequency on the carrier bubbles’ formation and the action of the secondary acoustic force during USW-assisted flotation. These outcomes demonstrated that frequency is a key factor determining the success of attractive mineralization for fine particles’ flotation.     

Study on removing calcium carbonate plug from near wellbore by high-power ultrasonic treatment

In this paper, the effects of ultrasonic wave on the removal of inorganic scaling and plugging in cores and the influence of the key wave field parameters, process parameters and core physical parameters on the plugging removal efficiency are systematically studied. The main dynamic mechanism of ultrasonic plugging removal is also systematically analyzed. Results show that the transducer frequency, transducer power, ultrasonic treatment time and initial permeability of core have great influence on the effect of ultrasonic scale removal. When the cumulative treatment time of ultrasonic wave exceeds 60 min, the recovery rate of core permeability tends to be stable. Best effect can be achieved when processing for 80–120 min cumulatively; the plugging removal effect is improved with the increase of ultrasonic transducer power and ultrasonic frequency, but the effect of plugging removal is not obvious with the further increasing of them. In addition, it is proved that the effect of removing calcium carbonate plug from near wellbore by hydrochloric acid solution is slightly better than that by ultrasonic treatment alone. Finally, the micro dynamic mechanism of removing inorganic scale plug by high-power ultrasonic treatment is discussed in view of ultrasonic inorganic scale body crushing, ultrasonic cavitation, ultrasonic friction, ultrasonic peristaltic transport operation and ultrasonic fracture-making and permeability-increasing effect.     

Ultrasound-assisted oxidative process for sulfur removal from petroleum product feedstock

A procedure using ultrasonic irradiation is proposed for sulfur removal of a petroleum product feedstock. The procedure involves the combination of a peroxyacid and ultrasound-assisted treatment in order to comply with the required sulfur content recommended by the current regulations for fuels. The ultrasound-assisted oxidative desulfurization (UAOD) process was applied to a petroleum product feedstock using dibenzothiophene as a model sulfur compound. The influence of ultrasonic irradiation time, oxidizing reagents amount, kind of solvent for the extraction step and kind of organic acid were investigated. The use of ultrasonic irradiation allowed higher efficiency for sulfur removal in comparison to experiments performed without its application, under the same reactional conditions. Using the optimized conditions for UAOD, the sulfur removal was about 95% after 9 min of ultrasonic irradiation (20 kHz, 750 W, run at 40%), using hydrogen peroxide and acetic acid, followed by extraction with methanol.     

Ultrasonic treatment improves the performance of starch as depressant for hematite flotation

In this study, ultrasonic treatment was introduced to enhance the depressive performance of starch in the reverse flotation separation of fine hematite from quartz. It was found that after ultrasonic treatment, starch was not only able to impart a higher surface wettability of hematite, but also better reduced the degree of entrainment of fine hematite, both of which alleviated the loss of hematite to the froth. Flocculation tests together with starch property characterization were conducted to understand the underpinning mechanism. It is interesting that ultrasonic treatment of starch led to stronger and more selective flocculation of hematite, which accounted for the reduced entrainment loss of fine hematite and benefited the concentrate Fe grade. It was also found that ultrasonic treatment enhanced the dissolution and acidity of starch with a simultaneous increase in the content of amylose, which in turn could contribute to the improved depression and selective flocculation of hematite.