Research into Technology of Bao Steel's Pickling Tension Leveler

According to the survey of Bao Steel's pickling tenstion leveler,the technology of the tension leveler is analysed systematically.In order to solve the problem which hinders the production,the given technological parameters of this leveler have been improved and good results achieved.

Characterization and recycling of nickel- and chromium-contained pickling sludge generated in production of stainless steel

Pickling sludge generated during the neutralization of pickling wastewater with calcium hydroxide in stainless steel pickling process was characterized using X-ray fluorescence spectrometry, X-ray diffractometry, scanning electron microscopy, thermogravimetry and differential scanning calorimetry, etc. The major compositions of pickling sludge are CaF2, CaSO4, Me（OH）, （M： Fe, Cr, Ni）, and the content of CaF2 is high in the sludge. The melting point of pickling sludge is about 1350℃ and the viscosity is about 0.14 Pa.s at 1450 ℃, which are comparatively lower than those of normal refining slag. After heat treatment, the contents of sulfur and fluorine in the pickling sludge were reduced, confirming the thermal decomposition of sulfate in the sludge. Fluorine in the sludge is reduced by the gaseous SiF4 and A1F3 generated through the reactions of CaF2 with SiO2 and Al2O3. The preliminary results from the reduction test indicate that the sulfur content in the steel is not affected by the presence of sulfur in the sludge. The recovery of nickel is about 40%, and the chromium content changes marginally due to the protective atmosphere under the reduction condition of chromic oxide. The pickling sludge is a potential auxiliary material for the production of stainless steel.

Two-stage treatment process of pickling wastewater in the cold-rolling production of stainless steel

Based on the characteristics of pickling wastewater in the cold-rolling production of stainless steel, a new processing route, featuring source sludge reduction, wastewater two-stage treatment, heavy metal-contained sludge and calcium salt sludge separating recovery, was proposed. As shown by the research results, after the two-stage process treatment, the effluent water can steadily reach the emission standards, the sludge yield can be decreased by more than 8% ; within the heavy metal-contained sludge, the recovery rates of Fc,Cr and Ni can either reach or surpass 95% ,and the total content ofF and S can drop to around 3%. Therefore,the sludge in the front part can be used as ferric dust. In the calcium salt sludge ,the recovery rate of F can either reach or surpass 85% ,and the total contents of Fe,Cr and Ni can fall below 0.5%. So the sludge in the rear part can be used as fluorgypsum or fluorite. Meanwhile,the results of the analysis on heavy metals leaching toxicity and morphologic distribution indicate that the two kinds of sectionalized sludge are not classified as hazardous wastes, which have a stable behavior and better utilization values compared with the former mixed- sludge.

Synthesis of Fe_3O_4 Magnetic Powder from Spent Pickling Liquors

Spent pickling liquors pose a serious environmental problem in most industrialized countries, mainly owing to their corrosive properties and their ferrous iron and hydrochloric acid content. In this paper, spent pickling liquor was used as an inexpensive raw material to prepare Fe304 magnetic powder via an oxidation method. Being able to recover the dissolved iron from spent pickling liquors would not only salvage a valuable material but also render the effluent environmentally benign. The structure of the Fe_3O_4 magnetic powder was characterized by X-ray diffraction. The morphology and size were characterized by scanning electron microscopy and transmission electron microscopy. Their magnetic properties were tested at room temperature by a vibrating sample magnetometer. In addition, the saturation magnetization of Fe_3 O_4 products can be further enhanced to 96.1 emu/g after purification.

Acid-pickling plates and strips speed control system by microwave heating based on self-adaptive fuzzy PID algorithm

Double self-adaptive fuzzy PID algorithm-based control strategy was proposed to construct quasi-cascade control system to control the speed of the acid-pickling process of titanium plates and strips. It is very useful in overcoming non-linear dynamic behavior, uncertain and time-varying parameters, un-modeled dynamics, and couples between the automatic turbulence control (ATC) and the automatic acid temperature control (AATC) with varying parameters during the operation process. The quasi-cascade control system of inner and outer loop self-adaptive fuzzy PID controller was built, which could effectively control the pickling speed of plates and strips. The simulated results and real application indicate that the plates and strips acid pickling speed control system has good performances of adaptively tracking the parameter variations and anti-disturbances, which ensures the match of acid pickling temperature and turbulence of flowing with acid pickling speed, improving the surface quality of plates and strips acid pickling, and energy efficiency.

Does acid pickling of Mg-Ca alloy enhance biomineralization?

The mechanical and physical properties of biodegradable magnesium(Mg)alloys make them suitable for temporary orthopaedic implants.The success of these alloys depends on their performance in the physiological environment.In the present work,surface modification of Mg-Ca binary alloy by acid pickling for better biomineralization and controlled biodegradation is explored.The corrosion rates of nitric and phosphoric acid treated samples were analysed by conducting electrochemical corrosion tests.In vitro degradation behaviour was studied using immersion test in simulated body fluid(SBF).The sample surfaces were characterized using scanning electron microscope(SEM),energy dispersive X-ray spectroscopy(EDS),Fourier transform infrared spectroscopy(FTIR)and X-ray photoelectron spectroscopy(XPS).It is seen that acid pickling leads to significant improvement in biomineralization and develop in situ calcium phosphate(Ca P)coating on the sample surfaces.In addition,the treated samples recorded a reduced degradation rate in the SBF compared to untreated samples.Thus,acid pickling is suggested as an effective surface treatment method to tailor the biomineralization and degradation behaviour of the Mg-Ca alloy in the physiological environment.

One-step pickling-activation before magnesium alloy plating

A one-step pickling-activation process was proposed as an environmental friendly pretreatment method in phosphate-permanganate solution before electroplating on magnesium alloys. The effects of pickling-activation on qualities of coating were assessed by adhesion and porosity testing of copper plating. The interfacial reactions between specimen and solution were analyzed with SEM,EDX and XRD. The results show that the developed process of pickling-activation can equalize the potentials on substrate surface. The compacted zinc film can be obtained by zinc immersion after treating magnesium alloy in the pH 4-6 phosphate-permanganate solution for 3-5 min. The adhesion and corrosion resistance of copper plating are enhanced. The one-step pickling-activation can replace the existing two-step process of acid pickling and activation which contains a great deal of chromium and fluorine. The procedure of surface pretreatment is simplified and the production environment is improved.

Study on the simulated pickling of 443NT medium chrome ferritic stainless steel

The oxide scale structure of 443NT hot-rolled strips was analyzed. The pickling of 443NT stainless steel was simulated via the 6σ experimental design. The results indicate that parabolic relations exist between the pickling scores and some of the pickling influencing factors, such as the nitric acid density, the hydrofluoric acid density and the pickling temperature. Effective pickling of 443NT can be achieved by controlling the pickling processing parameters with the HNO3 density ranging from 80 g/L to 180 g/L ,the HF density from 20 g/L to 40 g/L and the pickling temperature from 45 ℃ to60 ℃.

Mechanism underlying the formation of cloud-shaped defects in 304 stainless steel after hot-rolled annealing and pickling

It is highly imperative to understand the mechanism underlying the formation of cloud-shaped defects in stainless steel to reduce the defect incidences. This study investigated the defect microstructure by SEM, simulated pickling in the laboratory, and performed structure analysis of oxide scales after hot rolling. Results show that the cloud-shaped defects in 304 No. 1 surface （after hot-rolled annealing and pickling） cause the pickling chromatic aberration between the honeycomb-shaped grains of the Cr-depleted layer and the smooth grains of the stainless steel matrix, which is formed in the case of insufficient pickling. The chromatic aberration is related to the uneven oxide scales formed before pickling. With the improvement of pickling capacity, it is possible to completely pickle the Cr-depleted layer and eliminate the cloud-shaped defects.

A new acid pickling process for copper alloys

The cleaning process of removing oxides on the surface of copper alloy sheetswas investigated systematically. Through optimizing, a perfect process was selected that is fit forremoving oxides on the surface. By acid pickling, all kinds of copper oxides are removedcompletely, furthermore, no poisonous gases are given out and a smooth and clean surface of copperalloys is obtained. At present, the process is applied successfully in the copper-processingindustry.

Analytical Method to Monitor Industrial Pickling Baths Initially Constituted by HF, HNO₃

The present study couples the acid/basis titration and the ICP analysis in order to monitor the concentrations of nitric and hydrofluoric acids, and presents into baths used to pickle alloys of titanium or stainless steel, largely employed in the aeronautic industry. The pickling of the alloys releases various metallic cations able to react with HF in order to lead to metal-fluoride complexes and free H+, the last being able to react with the basis. In this study, it was determined: the most significant correlations providing the number of the protons released by the complexation of the metallic cation by the fluoride. The proposed method based on: 1) these correlations;2) the titration pH = f(VKOH) curves;and 3) the content of metallic cations determined by ICP, enables the monitoring of the content of HNO3 and HF into the pickling bath. Assuming that one bath was used for one type of alloy (alloys of Titanium for example, or alloys of stainless steel), then the proposed method appears providing reliable concentration values of both acids as well as metallic cations.

Innovative surfactant of Gemini-type for dissolution mitigation of steel in pickling HCl medium

A new surfactant of Gemini-type,N,N'-((phthylbis(oxy))bis(ethane-2,1-diyl))bis(N,N-dimethyldodecan-1-aminium bromide)is prepped&confirmed.The dissolution suppression impact of the new compound on steel is performed in 1 mol·L^(-1)HCl environment by means of chemical and electrochemical methods.The prepared surfactant is an agreeable dissolution inhibitor for steel.The mitigation efficacy rises with the quantity of the compound.The surfactant belongs to inhibitors of mixed-type.The adsorption of the synthesized compound followed the Langmuir's model.The negative magnitudes of bothΔG_(ads)^(θ) andΔH^(adsθ)indicate that the adsorption process proceeds from its own accord and exothermic.The mechanism of adsorption is elucidated by scanning microscopy.It is established that the transfer resistance(R_(ct))value rose,where the value of the phase element(CPE)reduced with the amount of synthesized inhibitor.According to the experimental data arrived by surface tension measurements,the prepared compound is a powerful active agent at the air/water boundary.

Macroscopic,thermodynamic,kinetic and microscopic study of nitric acid pickling of Elektron 21(EV31A)magnesium alloy

The study of pickling of the EL21T6 substrate in a nitric acid bath firstly provided knowledge of the influence of the different experimental parameters(concentration of acid,temperature and stirring of the solution)in relation to the etching rate.This experimental part led to the choice of standard pickling(T_(bath)=25℃,moderate stirring(250 rpm),[HNO_(3)]=1.20 mol/L,duration of 2 min)so as to obtain constant removal of material,even after several uses of the pickling bath.SEM observations also confirmed that in these operating conditions,pickling concerns both the grains of the matrix and the precipitates of type Mg3(Nd,Gd),leading to uniform removal of material from the surface.Working from a number of assumptions,thermodynamic and chemical kinetic studies then allowed a pickling mechanism to be proposed and led to obtaining values for the corresponding kinetic parameters(order of reaction,constant of mean rate,activation energy)to be obtained.

Study on the Corrosion inhibitor and Fog Suppressor for Chemical Pickling of Iron and Steel

A new type of corrosion inhibitor and fog suppressor composed of Nitrogen-containing alkaloid,water-soluble butadiene lower polymer, and inorganic electrolyte has been investigated by gravimetric and electrochemical method. Effects or this chemicals on pickling rate and hydrogen penetration into iron and steel material in 50～150 g/L HCI or/and H2SO4 solutions at 20～70℃ temperature were examined. The amount of acid fog escaping from the surface of air-liquid was determined by chemical titration. The results indicate that the efficiency of inhibition and suppression depends on film properties by which mean a barrier film on the interface of bare mild steel/solution or an unsolvable liquid membrane as hydrophibic effect.In present work the film-forming mechanism by in situ and chemistry-mechanics effect is also discussed.

抑制活菌泡菜贮藏过程中品质劣变的研究

目的:研究活菌泡菜产品在贮藏流通过程中由微生物引起的产品品质变化,开发延长泡菜贮藏期的新方法。方法:对从泡菜中分离鉴定出来的8种乳酸菌,在不同pH培养基条件下检测各种乳酸菌生长速度。对8种乳酸菌进行产气测定。在发酵前添加泡菜汁、嗜酸乳杆菌、植物乳杆菌、木糖醇等,在不同温度条件下发酵和贮藏,对泡菜的色泽进行评分,对酸度、混浊度、挥发性物质进行测定。结果:在pH 4.5时,植物乳杆菌是优势菌,其次是短乳杆菌。在pH 4.0~3.0时,嗜酸乳杆菌是优势菌,其次是植物乳杆菌,主要产气菌是短乳杆菌、假肠膜明串珠菌、坏发酵乳杆菌。pH 4.0~4.5时,主要产气菌是短乳杆菌。在pH 3.5时,主要是坏发酵乳杆菌产气。在pH 3.0时,不容易产气。发酵前添加2 mL/L 1×10~5CFU/mL植物乳杆菌和20 mg/g木糖醇,可显著延长常温和低温下泡菜的贮藏期和货架期。结论:1×10~5CFU/mL植物乳杆菌和20 mg/g木糖醇处理,显著抑制常温贮藏泡菜的总挥发物积累,抑制泡菜的异硫氰酸烯丙酯、萘类积累,有利于维持原初气味特征。

氯化钾替代氯化钠对腌渍黄瓜品质的影响

近几年,低盐化逐渐成为代的饮食需求,在人们的健康生活中变得越来越重要,低盐化腌渍蔬菜的研究已经成为健康饮食的研究热点。该研究的目的是利用氯化钾替代氯化钠发酵黄瓜,不仅能够减少钠元素的摄入,而且能够丰富黄瓜的加工利用方式。通过研究发现,钾元素对黄瓜发酵过程中产生的危害人体健康的亚硝酸盐具有一定的抑制作用,10%和20%替代组的含量最低,最低为1.13~2.61 mg/kg,均远低于国家标准20 mg/kg,通过跟踪测定分析得出30%氯化钾替代发酵效果最佳。因为腌菜制品容易产生的有害物质亚硝酸盐可能存在食品安全问题,因此该试验得到的钾元素替代方法可以在发酵上避免这种可能性,保证发酵黄瓜制品的安全性。

传统酸菜发酵乳酸菌多样性及其功能特性研究进展

酸菜是以大白菜、卷心菜为主要原料,主要通过乳酸菌发酵而成的发酵食品,由乳酸菌发酵的酸菜具有独特的风味和积极的健康效果;乳酸菌也产生香气成分、细菌素和胞外多糖,这些成分有助于酸菜的质地、味道和保质期的提高;乳酸菌菌群结构交替变化,不同阶段发挥不同的作用,对酸菜品质、风味及安全性有很大的影响;酸菜富含蛋白质、碳水化合物、矿物质、维生素,因此食用酸菜有良好的益处;乳酸菌可以减少和降解酸菜中生物胺、亚硝酸盐和真菌毒素,从而降低了许多健康风险发生。基于此,本文综述了国内和国外酸菜乳酸菌的生化作用、多样性和益生性,乳酸菌分泌的代谢产物和风味,食用酸菜对健康的益处和酸菜存在的潜在风险,以期为传统发酵酸菜品质提升和筛选潜在益生菌菌株提供依据。

三次发酵技术提升工业化四川泡青菜风味的研究

目前工业化四川泡青菜大多采用两次发酵工艺结合脱盐、巴氏杀菌生产商品化酸菜的技术,以解决芥菜季节性收获和酸菜常年销售的问题。文章立足于工业化四川泡青菜的加工过程,研究了两次发酵后的半成品泡青菜经过脱盐后的风味损失,并设计了三次发酵进行风味优化。GC-MS与HPLC测定结果表明,脱盐后的泡青菜特征香味物质种类减少,相对含量降低,有机酸含量显著降低。经第3次发酵后,新增了酸类物质,赋予其草本香及酸香,并产生具有发酵果香和花香的己酸乙酯、辛酸乙酯,同时异硫氰酸酯类物质的相对含量降低,泡青菜的特征香味得到提升,自然发酵香味突出;有机酸总量提高12.69%,酸味更加柔和与醇厚;乳酸菌含量从234×10^(2)CFU/g提高到298×10^(3)CFU/g。该研究为工业化泡青菜自然发酵风味的提升提供了数据与工艺参考。

浓度直读法快速测定市售腌菜中的硝酸盐和亚硝酸盐含量

该研究探讨建立一种快速检测硝酸盐和亚硝酸盐含量的方法。结果表明,pH为2~6时,加入1 mL氨基磺酸溶液消除NO 2-的干扰,在此基础上,用浓度直读法测定5种市售腌菜中硝酸盐和亚硝酸盐含量,其亚硝酸盐含量在2.76~67.5 mg/kg之间,硝酸盐含量在37.58~149.7 mg/kg之间,回收率在91.0%~110.0%之间。与GB 5009.33-2016第二法相比,经F检验和t检验,二者结果之间无显著性差异。与国标法相比,该方法具有操作简单、无需进行复杂计算、测定速度快、仪器便于携带等优点,适用于腌菜中亚硝酸盐及硝酸盐含量的测定。

酸皮基磷光型碳点的制备及防伪应用

以浸酸山羊皮为碳源、硼酸为硼源,采用热解法制备了磷光型碳点(P-CDs)。探讨了浸酸山羊皮含量、反应pH、反应温度和反应时间对P-CDs余辉时间的影响。采用有机元素分析仪、SEM、EDS、TEM、FTIR、XRD对样品进行了表征,并评价了P-CDs的防伪应用。结果表明,在浸酸山羊皮含量(以3 g硼酸为基准,下同)4.10%、反应pH为7、反应温度为225℃、反应时间为7.5 h的条件下,制备的P-CDs的余辉时间达到12s;该材料的最佳发射波长为520 nm,对应明亮的青绿色余辉。P-CDs平均粒径为4.42 nm,具有典型的石墨结构,硼原子成功地掺入到碳点中,形成了C—B、B—O等共轭链结构,稳定了三重激发态,延长了余辉时间。