微波干燥湿法炼锌中和铁渣实验研究

湿法炼锌产出的中和沉铁渣作为重要的二次资源,含有大量的铁、锰、锌等有价金属,具有较高的综合回收利用价值。回收有价金属前需对中和铁渣进行脱水预处理,基于回转窑干燥法存在干燥时间长、干燥效率低、二次污染等问题,本文开展了微波干燥湿法炼锌中和铁渣实验研究,考察了微波功率、物料量对中和铁渣温升行为的影响,表明微波干燥湿法炼锌中和铁渣是可行的;实验考察了微波功率、物料量和干燥时间对中和铁渣脱水率的影响。研究结果表明：在一定程度上,中和铁渣脱水率与干燥时间和微波功率成正比,与物料量成反比。实验控制微波功率为1000W、物料量为50g、微波干燥时间为9min时,中和铁渣脱水率达98.55 %;X射线衍射、红外光谱分析展示微波干燥中和铁渣自由水脱除较为完全,但仍含有部分的结晶水;扫描电镜分析显示微波干燥较常规干燥更为均匀;与常规干燥工艺相比,微波干燥具有干燥时间短、水脱除率高、干燥均匀、清洁无污染等优势。     

微波辐射干燥氟化铝的工艺研究

介绍了微波干燥的原理和主要特点，研究了利用微波辐射干燥氟化铝工艺，探讨了微波功率、微波辐射时间、物料质量、物料厚度对氟化铝脱水率的影响。实验的最佳条件为微波功率2．0kW、干燥时间80s、物料质量400g、物料厚度2．0cm。实验结果表明，利用微波辐射干燥，氟化铝含水质量分数小于1％，且干燥时间短、能耗低，实验为工业化提供了必要的参考数据。     

微波干燥八水氢氧化锶的研究

提出了利用微波干燥八水氢氧化锶的新工艺,探讨了主要影响因素对样品相对脱水率的影响,其优化干燥条件为：物料质量50g、物料厚度5mm、微波干燥时间3min、微波功率950W,此时八水氢氧化锶的相对脱水率达到99．95％;与常规电加热干燥相比,微波干燥时间仅为常规干燥时间的1／40,而且微波干燥的最大相对脱水率提高了5．35％。     

微波辐射干燥硫酸钠的工艺研究

研究了利用微波干燥硫酸钠的工艺 ,并分析了微波功率、辐射时间、物料质量和物料厚度对硫酸钠脱水率的影响     

响应曲面法优化硫酸铵微波干燥工艺

对微波干燥硫酸铵的新工艺进行研究,探讨了干燥温度、微波干燥时间、物料质量、物料厚度等因素对硫酸铵相对脱水率的影响.并在单因素实验的基础上,以硫酸铵的相对脱水率为响应值采用响应曲面中心组合设计,对硫酸铵的微波干燥工艺参数进行了优化.所获得的优化实验条件:干燥温度86.05℃,微波干燥时间190.50 s,物料质量102....     

微波-过氧化氢工艺处理含Cu-EDTA废水

采用微波-过氧化氢工艺处理含Cu-EDTA废水,考察反应时间、初始pH、H₂O₂投加量、微波功率以及共存物质等因素对该工艺处理效能的影响,并分析了氧化作用机制。结果表明,在初始pH为3,H₂O₂投加量为41 mmol·L^-1,微波功率为210 W时,1.57 mmol·L^-1Cu-EDTA反应10 min后,Cu和TOC去除率分别高达97.0%和60.7%,出水电导率低至1.8 mS·cm^-1,产泥量仅为0.15 g·L^-1。NO₃^-的存在对Cu-EDTA的氧化降解过程无明显影响,而Cl^-、H₂PO₄^-和酒石酸对反应过程有一定的抑制作用。该工艺下反应4 min后Cu-EDTA基本氧化为中间产物,并在4～6 min内急剧降解,最终形成小分子羧酸类物质、NH₃-N和无机碳。反应过程沉淀产物主要以CuO形式存在。相比Fenton工艺,该工艺在氧化效能、出水电导率及产泥量等方面有显著优势。     

一种高效节能的沉积物微波干燥法

水体沉积物具有含水率高的特点,对沉积物的微波干燥条件进行正交实验,发现20 L微波炉最佳干燥沉积物投放质量为20 g,干燥14 min后可达到恒重,微波烘干法干燥时间和能耗只占到传统烘箱烘干法1%~3%。随功率增加,样品脱水率呈增加趋势,微波功率分别在480 W、640 W、800 W时,同一样品的脱水率分别为38.25%±2.49%、42.30%±3.90%、44.96%±2.04%,并对相关原因进行了探讨,认为结晶水和有机物是造成差异的主要原因。     

盐泥颗粒热风干燥特性及动力学模型

为优化盐泥颗粒干燥设备及结构参数，搭建热风干燥实验装置对盐泥颗粒进行热风干燥实验，研究不同风温、风速和堆积厚度对盐泥颗粒热风干燥特性的影响。对不同条件下的干燥特性曲线，通过比较决定系数R²、卡方x²和标准误差ESME等指标，评价5种常用干燥动力学模型对干燥曲线的拟合结果。结果表明：Midilli模型可以预测盐泥颗粒热风干燥过程水分的变化规律，模型预测的干燥曲线与实验干燥曲线有较高的拟合度。盐泥颗粒热风干燥过程中干燥速率逐渐下降，热风干燥特性与风温和堆积厚度密切相关。当温度从50℃增加到80℃时，有效水分扩散系数由2.038 39×10^-9 m²·s^-1增加到8.137 643×10^-9 m²·s^-1。     

微波干燥锰碳合金球的响应曲面法优化

为了研究微波干燥锰碳合金球新工艺过程,确定各因素对脱水率的影响情况,得到优化工艺参数,文中采用响应曲面法中心组合设计对工艺过程进行设计并分析了干燥温度、干燥时间、物料质量及其交互作用对相对脱水率的影响,建立了关于相对脱水率的数学模型。方差分析表明,干燥温度、干燥时间对相对脱水率有较显著影响,建立的数学模型拟合度良好,获得优化工艺参数:干燥温度90℃,干燥时间176 s,物料质量150.61 g,相对脱水率达到93.96%。实验验证表明,实际值与模型预测值相差0.71%,干燥后锰碳合金球的含水质量分数为0.26%,达到炼钢用锰碳合金球的水分指标。研究表明:模型预测结果可靠有效,应用响应曲面法优化得到微波干燥锰合金球的工艺条件合理可行,为工业化应用提供必要的工艺参数。     

电渗透/Fe-过硫酸盐氧化协同强化污泥深度脱水

利用电渗透和高级氧化技术,采用自制实验装置对城市污水处理厂的脱水污泥进行了脱水研究,系统研究了过硫酸盐投加量、铁盐与过硫酸盐比例、电压梯度、脱水时间和污泥厚度对污泥脱水的影响。结果表明,电渗透-高级氧化复合技术可以改善污泥的脱水性能,在污泥样品为140 g、过硫酸盐投加量为100（mg·g DS）^-1、Fe²⁺与过硫酸盐比例为1：1、机械压力为17.59 kPa、控制初始电压为11 V·cm^-1时,污泥的含水率可以降低至60%以下,与单独使用电渗透技术相比,泥饼具有更好的均匀性,便于后续的运输和安置。     

微波辅助浸取废弃电路板中铅锡锑

浸取废弃电路板中铅、锡、锑等金属的主要方法是利用传统加热辅助湿法冶金, 但通常耗时长、效率低。为了解决这一问题, 本文提出了一种用微波代替传统加热方式、辅助湿法冶金浸取金属的新方法。结合氧化熔炼技术的原理, 采用微波辐射废弃电路板粉末, 探索了以下几个因素对金属浸出率的影响:氧化浸取过程中的NaNO₃用量、NaOH用量、微波功率、微波辐射时间、Na₂S浸取过程中的水用量、微波辐射时间。在实验研究基础上得到的最佳工艺条件为:氧化浸取过程中NaNO₃与金属粉末的质量比为3, NaOH与金属粉末的质量比为5, 微波功率为800W, 微波辐射时间为6min;Na₂S浸取过程中液固比为3, 微波辐射时间为20s;此时铅、锡、锑的浸出率分别是92.37%、94.4%、88.13%。较之传统氧化熔炼技术, 该方法反应速率加快, 金属浸出率提高, 产生废液少, 具有方便高效、绿色环保的特点。     

微波干燥玉米籽粒的试验研究

针对玉米热风干燥中存在的问题。运用自制的微波干燥试验设备。采用不同的质量比功率和加热时间及配套的工艺流程。研究了玉米微波干燥特性及干燥条件对干燥品质、能耗的影响；分析了微渡干燥玉米过程中单位质量功耗、温度、平均失水速率与玉米籽粒发芽率、爆腰率和淀粉得率的关系；确定了影响微波干燥玉米的工艺参数和玉米微波干燥的合理工艺流程。研究结果表明：玉米微波干燥主要处于恒率干燥阶段，应用微波技术既能快速而经济地对玉米籽粒进行干燥，又能保持其种用价值，且有利于改善其品质。     

Energetic Analysis of Drying Biological Materials with High Moisture Content by Using Microwave Energy

One of the most important parameters in the drying process is the efficiency of energy transfer. Although it is well known that the absorbed component of the referred energy in the dehydration process under microwave conditions is theoretically lower—especially during the falling rate period of drying—by an order of magnitude than that of convective drying, the real efficiency of energy transfer in the microwave field depends on numerous—partly unknown—factors. In this study, the most significant relations between the energy transfer efficiency and the drying parameters were investigated. During the experiments, two power levels were used to study the effects of domain variables in apple, potato, and onion dehydration processes. The results showed that variations in microwave power level played an important role in overall drying kinetics.

Based on the recorded data, we determined the typical energy efficiency factors for microwave drying of apple, potato, and onion. The specific energy consumption was calculated to compare the energy efficiency of a single measurement series. It was evident that by applying higher power levels, the energy utilization was more efficient. Furthermore, we theoretically proved and experimentally showed the nonthermal effects of the microwave energy.     

响应曲面法漂白紫胶微波-真空干燥工艺研究

为提高漂白紫胶产品质量及生产效率,采用微波-真空干燥漂白紫胶研究了不同压强、微波功率和干燥时间对漂白紫胶产品颜色指数和含水率的影响,用响应曲面法（RSM）设计试验并建立了该工艺条件的拟合方程。结果表明,拟合方程的拟合度较高,所建立的数学模型可以用于描述漂白紫胶的微波-真空干燥。漂白紫胶微波-真空干燥的最优条件：干燥压强为3.0 kPa,微波功率为795 W,干燥时间为30 min。在优化条件下进行了验证实验,得到了颜色指数为0.9、含水率为0.028 9kg水/kg干料的产品。     

COMBINED CONVECTIVE-MICROWAVE DRYING OF AGAR GELS: INFLUENCE OF MICROWAVE POWER ON DRYING KINETICS

The use of microwave energy in the drying of deformable material such as gel considerably reduces drying time and enables the control of retraction in the sample. A further advantage is that no hot spots are produced, allowing a dry product of superior quality to be obtained.The aim of this work has been to determine the kinetics of the convective-microwave drying process of agar gel plates. For this purpose, we developed a pilot closed loop, computer-controlled apparatus of convective-microwave drying, that enables the drying air conditions to be changed and the microwave power to be supplied over a wide value range. The equipment also records the sample surface temperature by means of an infrared thermometer. The drying curves obtained for plane geometry present four different drying phases: an initial phase where a rapid increase in the drying rate and in the surface temperature can be observed, as well as a constant rate phase that ends in the so-called convective critical moisture content, a first falling rate phase that concludes in the microwave critical moisture point, and finally a second falling rate phase. Combined convective-microwave drying enables a considerable reduction in drying time compared to convective drying, the time required being inversely proportional to the microwave power supplied. The empirical equation that best represents the kinetics is of the Page type. The absorbed volumetric power in terms of the moisture content was experimentally estimated, with the experimental data fitting an empirical equation.     

Microwave Drying of Wood Strands

Characteristics of microwave drying of wood strands with different initial moisture contents and geometries were investigated using a commercial small microwave oven under different power inputs. Temperature and moisture changes along with the drying efficiency were examined at different drying scenarios. Extractives were analyzed using gas chromatography/mass spectrometry (GC/MS). The results showed that the microwave drying process consisted of three distinct periods (warm-up period, evaporation period, and heating-up period) during which the temperature, moisture change, and drying efficiency could vary. Most of the extractives were remnant during microwave drying. It was observed that with proper selections of power input, weight of drying material, and drying time, microwave drying could increase the drying rate, save up to 50% of energy consumption, and decrease volatile organic compound (VOC) emissions when compared with the conventional drying method.     

Study on preparation and desulfurization characteristics of biomass activated carbon by microwave heating CO2 activation method

Taking soybean straw rich in nitrogen-containing functional groups as the raw material precursor, combined with the special advantages of microwave heating, microwave heating technology is applied to the pyrolysis and activation process of soybean straw. The pyrolysis solid product is used as the activation raw material, and CO₂ is used as the activator to study the preparation of activated carbon, in order to prepare the biomass activated carbon with high desulfurization performance. First, the optimal activation level was obtained by orthogonal experimental design and range analysis. Then, the effects of microwave power, CO₂ flow rate and activation time on the yield, pore structure and desulfurization performance of activated carbon were investigated by single factor experiment. The optimal activation conditions were selected by comparative analysis: microwave power 900 W, CO₂ flow rate 0.10 L/min, activation time 20 min. Under these conditions, the yield of activated carbon is 76.3%(mass), the SO₂ adsorbance quantity is 112.56 mg/g, specific surface area is 466.28 m²/g. Compared with pyrolytic carbon, activated carbon has larger specific surface area and more abundant pores and significantly improved desulfurization performance.