Effect Of Hydrochloric Acid Research Articles

Effect of hydrochloric acid and citric acid with ultrasound processing on characteristics of superfine-ground pectic polysaccharides from okra (Abelmoschus esculentus L.) peel

The structural properties and biological activities of okra pectic polysaccharides (OPs) were impacted by various extraction methods. Based on commonly grinding (40, 100 meshes) and superfine grinding okra powders, two extraction solvents (hydrochloric acid, HA; citric acid, CA) were used firstly. Next, the extraction yield, physical and chemical properties, molecular structure and functional properties of OPs were analyzed by non-ultrasonic treatment and ultrasound-assisted superfine grinding method. The outcomes demonstrated that the extraction yield of OPs rose as the particle size of the powder decreased. HA-OPs had higher molecular weight (Mw), apparent viscosity and emulsification ability than CA-OPs. CA-OPs had higher esterification degree (DE), solubility and total sugar content, and higher amounts of rhamnogalacturonan-I (RG-I) segments. Compared with OPs without ultrasound-assisted extraction, ultrasound-assisted superfine grinding extraction exhibited higher sugar content, antioxidant capacity, emulsification ability, lower Mw, DE and apparent viscosity. Finally, the correlation between structure and function of OPs was further quantified. The antioxidant capacity was positively correlated with RG-I content, and negatively correlated with DE and Mw. The emulsification ability was mainly positively correlated with the GlcA of OPs. This study provides a theoretical basis for the development of OPs foods with clear structure-function relationship, which would be instructive for the application of OPs in food and cosmetics.

TiO2-UV detection under different types of acids and rinsing process for films preparation

Titanium dioxide (TiO2) films were prepared by the sol–gel method under different types of acids. Effect of hydrochloric acid (HCl), nitric acid (HNO3) and nature-based solutions (NBS) under ultraviolet (UV) detection of films were investigated. Films were coated by dip coating on glass substrate. Moreover, TiO2 films were compared properties on water rinsing (Ri) and without rinsing (WRi) processes. The phase structure of prepared samples was characterized by means of X-ray powder diffraction (XRD). The results confirm that films were highly crystalline anatase TiO2 and free from other phases of titanium dioxide. For the optical property, the transmittance (%T) observed sharp rise in the violet-ultraviolet transition region and a maximum transmittance of ~80%. Photocurrents were measured under UV intensity of 260 mWcm–2 and DC bias voltage of -20 – 20 volts (V). The results observed that currents increased as bias voltage increased. Current - Voltage (I-V) curves observed different slopes under the different of acids and rinsing process. The photocurrent of TiO2-NBS-Ri was greater than TiO2-HCl-WRi and TiO2-HNO3-WRi of 10 and 20 times; respectively. These findings suggest that the significant effect of the acid and rinsing process on crystalline, morphological, optical, and electrical properties of nanostructured TiO2 films would be useful for applying the device in UV photoelectric detection.

Temperature and Molarity Effects on the Synthesized Zircon Crystal Cells

A study was carried out on the effect of hydrochloric acid (HCl) temperature and molarity during the dissolution process on the crystal cell of ZrSiO4 of zircon powders derived from zircon sand mined in Kereng Pangi, Central Kalimantan. The study is a continuation of the previous work and is aimed at associating the process and structural parameters of the zircon phase in the product. The synthesis was started with a well-established route in our laboratory, i.e., magnetic separation and milling for 2 hours, but the subsequent leaching using the HCl step was carried out at varying temperatures and concentrations. The temperature variations used were 80°C, 90°C, and 100°C, while the molar variations of HCl were 0.5 and 2 M. Then, the various products were further leached using 7 M sodium hydroxide (NaOH) to yield zircon powders subjected to X-ray diffraction (XRD) investigation. The XRD data analysis using Rietica software found that at the concentration of 0.5 M, the increasing temperature decreased in zircon cell volume but increased the tetragonality parameter c/a. However, opposite results occurred at the concentration of 2 M HCl. In general, we found that the impurity levels in the zircon powders may be associated with its cell volume and tetragonality parameters, i.e., the more the quartz content in the zircon powder, the smaller the zircon cell volume and tetragonality.

Effect of hydrochloric acid and hydrofluoric acid treatment on the morphology, structure and gamma permeability of 2D MXene Ti3C2Tx electrodes

ABSTRACT Two-dimensional (2-D) materials have attracted tremendous interest once discovered due to their unique physical and chemical properties. One of the critical application areas of the 2-D materials is the production of electrodes for batteries. The electrodes can be produced in different ways. In the present study, in order to create MXene powders required in the manufacturing of electrodes, several acids and mixing times have been tested. The structural characteristics of these materials have been analyzed by scanning them under electron microscopes (SEM and FE-SEM), using the X-ray diffraction (XRD) method, the Fourier Transform Infrared (FTIR) Spectroscopy, and Transmission Electron Microscope (TEM). From these analyses, the morphological changes due to different etching acids and mixing time has been determined and discussed. In addition to the structural characterisation, the gamma radiation absorption properties of MXene electrodes have been examined with the typical experimental setup equipped with 3 × 3 NAI(Tl) detector. The linear and mass attenuation coefficients of them have been determined. The effect of different acid treatments and the mixture times on the gamma absorption properties has also been discussed.

In Vitro and In Vivo Investigation on the Effectiveness of Alginate-Based Gastric Mucosal Protective Gel.

Objective To investigate the feasibility and effectiveness of an alginate-based gastric mucosal protective gel on the gastric ulcer. Methods (1) In the physical protection model, after GES-1 cell attachment add the gel to transwell chamber, add different concentrations of HCl to the gel. Absorbance was measured to assess proliferation and images of the cells migrating into the wound were taken; then the migration rate of the cells was quantified by comparing images. (2) In the gastric ulcer model, excise the gastric mucosal of SD rats; the gel and fixative were applied on the artificial ulcer immediately. Dissect rats after 10 days, and calculate the wound healing rate and analyzed histology changes. Results The effect of hydrochloric acid on cells in the lower layer was significantly reduced after the use of gastric mucosal protection gel. The protective gel had an isolation effect on different concentrations of acid. A number of GES-1 were significantly higher than those in the control group at 24 h to 72 h (P < 0.01). The migration was observed compared with the control group. The average healing rate of ulcer in the gel group was about 50%, and the control group was about 30%. Inflammation occurred in all wound regions after ten days. In the gel group, inflammatory infiltration depth was lower than that of the control, and part of SD rats' new muscle layer appeared without inflammatory infiltration. The connective tissue proliferation promoted tissue repair. In the control group, necrosis marginal, mucosal hyperplasia, marginal lymphocyte aggregation, and bleeding were observed. Conclusion This novel gel mainly has an isolating and shielding effect to prevent the wound from being exposed to gastric acid for a long time, and it can reduce the inflammatory reaction on the wounds to promote the healing of the ulcer. The gastric mucosal protective gel cannot only promote the speed of wound healing but also improve the quality of wound healing.

The effect of hydrochloric acid and sodium hypochlorite on fracture resistance of orthodontic self-cure acrylic base

The effect of hydrochloric acid and sodium hypochlorite on fracture resistance of orthodontic self-cure acrylic base

Effect of Hydrochloric Acid on Seed and Seedling Properties in Melon Seed Extraction

Kavun tohumu çıkarılırken meyve eti, plasenta ve tohum etrafındaki jelimsi tabakadan arındırılması gerekmektedir. Bu işlem için yaygın olarak kullanılan fermantasyon yöntemine alternatif olarak bazı kimyasalların kullanılması zaman ve işgücü tasarrufu sağlamaktadır. Bu çalışmada hidroklorik asit uygulamasının kavun tohumlarındaki ekstraksiyon işlemini kolaylaştırıcı, zaman kazandırıcı etkileri ile çimlenme, çıkış ve fide büyümesi üzerine etkileri incelenmiştir. Bitkisel materyal olarak Sena F1 kavun çeşidine ait tohumlar kullanılmıştır. Tohumlar çekirdek evinden çıkarılarak etraflarındaki jelimsi madde, bir miktar meyve eti ve plasenta ile beraber %1, 5, 10, 15, 20 konsantrasyonlarındaki hidroklorik asit (HCl) çözeltileri içerisinde 5, 10, 20, 30 dakika süreyle bekletilmiştir. Uygulamaların, tohum çimlenme oranı ve hızı, çıkış oranı ve hızı üzerine etkileri ile fidelerde bitki boyu, yeşil aksam yaş ağırlığı ve hipokotil boyu üzerine etkileri değerlendirilmiştir. Bu çalışmayla kavunda yüksek dozda hidroklorik asit ile ekstraksiyonda doz ve bekletme süresi belirlenmiştir. Çalışmanın sonuçlarına göre HCl kullanımında tohumların kolay ayrıldığı bu bağlamda klasik fermantasyon yöntemine göre zamandan ve işgücünden kazanç sağlandığı görülmüştür. Kavun tohumlarının hidroklorik asit ile ekstraksiyonunda, yüksek tohum çıkış oranı ve yeterli fide gelişimi dikkate alındığında düşük asit konsantrasyonunda %1 HCl - 20 dakika veya kısa bekleme süresi tercih edilirse %5 HCl-5 dakika uygulamalarının önerilebileceği belirlenmiştir.

JUSTIFICATION OF THE INNOVATIVE METHOD OF PRELIMINARY PROCESSING OF FISH RAW MATERIALS

The scientific article presents experimental data on the possibility of modification of the generally accepted traditional technology of pre-heat treatment of freshwater fish raw materials in the production of canned fish by developing an innovative method - dehydration with hydrochloric acid. Technological and rheological features of the muscle tissue of the object of study - silver carp, which is the most important object of aquaculture and commercial fish farming in Ukraine and in many other countries, require the use of pre-heat treatment. This technique is required to remove moisture from muscle tissue by denaturing sarcoplasmic proteins when the temperature rises above 95 C. Due to the high specific heat of fish muscle tissue, heat treatment is energy intensive and, consequently, not cost effective.&#x0D; In connection with the above promising direction of modification of preliminary heat treatment of raw materials of the fish industry in the production of canned fish should be the development and implementation of a new innovative energy-saving method of processing semi-finished products in the design of modern fish processing enterprises.&#x0D; The paper presents data on the effect of hydrochloric acid on the properties of muscle tissue of silver carp. This directional regulation of the moisture holding capacity in the direction of its reduction is possible by shifting the pH to the isoelectric point of muscle tissue proteins.&#x0D; The influence of such technological parameters as mass fraction of hydrochloric acid in the treatment solution, hydromodule (solution: raw material), temperature and duration of the process on the change of active acidity of muscle tissue of fish raw materials, and, accordingly, moisture binding capacity was established. Accordingly, the following technological parameters of the process were determined: mass fraction of hydrochloric acid - 0.1%, processing temperature 20–25°С, hydraulic module - 1:10, processing duration - 30 minutes. The introduction of the developed technological parameters of the innovative method of pre-treatment creates conditions in which the active acidity of muscle tissue is as close as possible to the isoelectric point of most fish proteins, which in turn provides minimum values of moisture binding capacity.&#x0D; Based on the obtained data, a technological method of pre-processing of fish raw materials in the production of canned fish has been developed, the use of which allows to completely eliminate energy-intensive thermal operation from the technological cycle, and accordingly significantly increase economic efficiency

Effects of Hydrochloric and Acetic Acid Modification on the HTAB and K+ Adsorption Characteristics of Natural Zeolites

In this study, the effects of hydrochloric acid (HCl) and acetic acid (HAc) modification on the hexadecyl trimethyl ammonium bromide (HTAB) and K+ adsorption characteristics of a natural zeolite were investigated. Electrokinetic evaluations showed that HCl had a more prominent effect on zeta potential compared to HAc. Additionally, the pH regulation behavior of the acid-modified samples was found to differ from the natural zeolite sample and it was in agreement with the results of zeta potential measurements. It was clear that the acid modification processes positively affected the surface properties and improved the cation exchange capacity (CEC) of natural zeolite. The results for the adsorption studies showed that the adsorption density of zeolite increased at elevated HTAB and K+ concentrations. Moreover, following the zeta and pH profile results, a considerable difference in the adsorption ability between natural and acid-modified zeolite samples is present in terms of HTAB and K+ adsorption characteristics. It was concluded that acid modification can be used in the enhancement of the adsorption ability of zeolites.

Анализ применения кислотных составов в высокотемпературных карбонатных коллекторах

The use of hydrochloric acid treatment goes back a century. For the first time the company “Ohio Oil” applied acid for formation stimulation in 1895, and the patent for acidizing limestone was obtained by the company "Standard Oil". However, with a significant increase in production volumes, it turned out that acid solutions caused very strong corrosion of downhole equipment. Therefore, the hydrochloric acid treatment method had not been used for 30 years. The discovery by John Grib of “Dow Chemical” in 1931 – slowing down the effect of hydrochloric acid on the metal with arsenic – made it possible to return to this method, and three years later “Halliburton Oil Well Cementing” began to practice acidizing on an industrial scale. As the analysis of the field material has shown, there are many technologies with the use of modified acids intended for acidizing, which are characterized by a high degree of success. Nevertheless, according to the estimates of different authors, the treatments success varies in the range from 60 to 80%, and for repeated treatments – less than 50 %. The urgency degree of the problems associated with acid treatment of the bottomhole formation zone and the tendencies of its development was investigated. Analysis of patent information according to the International Patent Classification for 17 years (from 1997 to 2013 inclusive) for Russian patents and for 15 years (from 1999 to 2013 inclusive) – for American ones showed stable activity of Russian organizations, while foreign organizations showed in this respect a significant growth of interests and achievements. Foreign experts mainly investigated the modeling of acid treatment [6–11], while Russian specialists were more inclined towards service support of acid treatment. It was revealed that there were no methods for calculating the risks of falling out of heavy oil components during acid treatment, depending on the geological and physical conditions of the target.

The effect of hydrochloric acid (HCl) on permanent molars: A scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS) study

It is well established that acid disposal is a potentially effective method used by criminal syndicates to hinder the identification of victims. This study documents the effects of continuous immersion in hydrochloric acid (HCl, 37%) on molars using macroscopic analysis, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). The goal of this study is to aid in distinguishing visually unrecognizable fragments of dental remains when drastic changes in morphology have occurred as a result of acid exposure. Macroscopic, SEM, and EDS analysis were conducted on seven maxillary molars before and after HCl treatment. Molars reduced in weight relative to the length of time immersed in HCl and the dissolution time was over 40 hours longer than reported in previous studies, at just over 66 hours. SEM and EDS analysis showed acid-treated teeth exhibited morphological patterns such as cracking and layering visible at high magnification. Calcium/phosphorous ratios fell within the expected range of 1.6-2.5, indicating that HCl-treated teeth are still identifiable as osseous or dental tissue even when not visually identifiable as teeth. This is the first study to present SEM images of molar cementum before and after immersion in HCl and to present EDS results. This information can assist researchers and investigators in determining the presence of dental tissue in a forensic context associated with acid disposal.

Study of surface properties of aqueous solutions of sodium dodecyl sulfate in the presence of hydrochloric acid and heavy metal ions

The surface properties (equilibrium and kinetic studies) and adsorption characteristics of sodium dodecyl sulfate (SDS) at the liquid−air interface were presented. The effects of hydrochloric acid and heavy metal ions addition on some surface properties of SDS were studied. The equilibrium surface tension and critical micelle concentration (CMC) were obtained. Moreover, the adsorption parameters were calculated using the Szyszkowski equation. The kinetics of SDS adsorption was examined, and the diffusion coefficients as well as the micellar dissociation constant were calculated. As it was found both hydrochloric acid and heavy metal ions decrease the CMC values in all presented cases. The dynamic surface tension of the systems under discussion decreases with the increasing time and the higher the decrease is, the higher the surfactant concentration is. The SDS adsorption is controlled by diffusion. The value of diffusion coefficients decreases with the increasing surfactant concentration.

Development of the coupled elastoplastic damage constitutional model of acidized shale gas formation based on experimental study

Since the focus of shale reservoir exploration and exploitation have shifted to deeply buried formations, the high breakdown pressure becomes an obstacle for massive hydraulic fracturing. Pre-acidizing is an effective way to reduce the breakdown pressure, at the same time it causes the plastic deformation that affects the shale fracability. In order to evaluate the acidizing effect on rock mechanical deformation, experimental and numerical approaches were conducted in this paper. A series of experimental studies on the effects of hydrochloric acid on the micro-structure and rock mechanical properties of shale samples was conducted for analyzing the mechanism of acidizing. A damage elastoplastic constitutive model for acidized shale was proposed to simulate the nonlinear deformation and damage process caused by the acidizing effect and pressure. The model input parameters were interpreted from the experimental data. This constitutive model based on plastic mechanics and damage mechanics was verified through good correlation between the numerical simulation results and the experimental data. This model is practical because its parameters are easy to acquire from the conventional indoor experimental data and it could be embedded into the hydraulic fracturing model conveniently.

Effects of Hydrochloric Acid and Formic Acid Decalcification on Breast Tumor Biomarkers and HER2 Fluorescence In Situ Hybridization.

Biomarker analysis of metastatic breast carcinoma (MBC) is routinely recommended by ASCO/CAP guidelines, and establishing a diagnosis of MBC often requires immunohistochemistry (IHC). The reliability of breast tumor biomarkers and breast-specific markers on decalcified tissues has not been extensively studied. We performed IHC studies on breast tumors exposed to hydrochloric acid (HCl) and formic acid (FA) decalcification solutions, and HER2 fluorescence in situ hybridization on a subset of these tumors to establish a protocol for handling bone specimens with suspicion for MBC. Fifteen fresh cases of primary breast carcinoma and 8 HER2+ paraffin-embedded core biopsy cases were studied. Fresh tissue was divided into 5 fragments to approximate a bone core biopsy. One fragment (control) was fixed in 10% neutral buffered formalin. The remaining fragments were also exposed to FA or HCl decalcification for 1 or 5 hours. All fragments were embedded in 1 block and tested with an IHC panel. The known HER2+ cases were exposed to either 1 or 5 hours of FA, and HER2 fluorescence in situ hybridization was also performed. Results were interpreted as follows: H-scores for estrogen receptor, progesterone receptor, and GATA-3 were assigned from 0 to 300; HER2, cytokeratin 7, gross cystic disease fluid protein-15, Pax-8, TTF-1, cytokeratin 20, and mammaglobin were scored from 0 to 3+; and Ki67 from 0% to 100%. Mean scores were compared using the t test or Wilcoxon test for paired samples. No significant differences in mean score were seen between NF and 1 hour FA for any IHC immunoreactivity. After 5 hours of FA, only Ki67 average score was significantly less than NF. Mean scores for estrogen receptor, progesterone receptor, HER2, Ki67, and GATA-3 were significantly lower than NF in the tissue after either 1 or 5 hours of HCl. Mean scores for gross cystic disease fluid protein-15, mammaglobin, and cytokeratin 7 staining were not significantly lower than NF after 1 or 5 hours of HCl.

Effect of Hydrochloric Acid on Resin Cement Microleakage in Zirconia-Reinforced Lithium Silicate Crowns

Effect of Hydrochloric Acid on Resin Cement Microleakage in Zirconia-Reinforced Lithium Silicate Crowns

Purification of Metallurgical-Grade Silicon by Acid Leaching

Purification of metallurgical-grade silicon (MG-Si), used in many applications such as the medical industry, polymer industry and the solar cells manufacturing. Removal of impurities from MG-Si is critical in these applications. The MG-Si studied in the present research contained various iron, calcium, and aluminum impurities. The hydrometallurgical purification method with different types of acids as solvents was chosen to refine MG-Si. Effects of hydrochloric acid, hydrofluoric acid, sulfuric acid, nitric acid in combination with each other as a solvent for purification of MG-Si were investigated. Additionally, the effects of temperature and particle size of MG-Si were evaluated. In this study, in comparison with previous studies, samples with a larger particle size (in the range of 53 to 300 microns), less refining time (1 to 6 h) and relatively higher temperatures (30 to 70 ∘C) were studied. The results indicated that the highest purity of MG-Si was achieved by HCl (25%) + HF (5%) and followed by HCl (25%) + H2SO4 (30%), HNO3 (25%) + HCl (25%), HNO3 (5%) and H2SO4 (25%), respectively. It was also found that with particle size 53μm, applying a temperature of 50 ∘C for 6 h resulted in high efficiency and purity (99.96%) of MG-Si.

The effect of hydrochloric acid on microstructure of porcine (Sus scrofa domesticus) cortical bone tissue

We evaluated the degradation of cortical bone tissue by hydrochloric acid (HCl) since intentional bone decalcification in a forensic context has not been studied on a histomorphological level. We used 70 pig metatarsal bones split into subsamples and immersed in one of three concentrations of acidic solutions (0.5M, 1M, 2M HCl) for two and four hours. We analyzed the cortical thicknesses on transversal cross-sections, thicknesses of the three histomorphologically distinct zones present in acid-immersed bones, and number and area of crystals present in one of the zones. Furthermore, we analyzed the ratio of calcium to phosphorus (Ca:P). We observed a division of the cortical bone cross section into three distinctive zones: demineralized matrix (DM) in the periosteal part of bone, middle contact zone (CZ), and mineralized matrix (MM) in the endosteal part of bone. With increasing acid concentration and time of immersion (from 0.5M HCl for 2h to 2M HCl for 4h), the thickness of DM increased by 67%, the thickness of CZ increased by 56%, and the thickness of MM decreased by 32%. The Ca:P ratio in the contact zone of acid-treated samples did not change significantly with changing acid concentration and time of immersion. The Ca:P ratio of the CZ decreased by 10% when compared to the Ca:P ratio of MM in acid-treated samples. Moreover, we observed crystals on the outer periosteal border of the DM zone, in the CZ, and in the MM Haversian/Volkmann’s canals. The size and number of the crystals in the CZ of acid-treated bones increased with acid concentration and time of acid immersion. Moreover, we also observed significant differences in all analyzed properties between anatomical regions. Due to varying reactions to acid immersion among anatomical regions, bone micro-degradation should be observed separately for each region.

Synthesis of large pore sized ordered mesoporous carbons using triconstituent self-assembly strategy under different acidic conditions and ratios of carbon precursor to structure directing agent

This study was aimed at the synthesis of ordered mesoporous carbons with large pores. A triconstituent self-assembly strategy was employed, where resorcinol and formaldehyde were used as carbon source, tetraethyl orthosilicate was used as silica source, and triblock copolymer Pluronic F127 was used as structure directing agent. The effects of hydrochloric acid (HCl) concentration on the composite yield and the textural properties of carbons were investigated. The composite yield was seen to increase until a HCl concentration of 0.66 M. The effect of carbon source (resorcinol-formaldehyde (RF)) to Pluronic F127 ratio (RF/F127) was also investigated. The pore sizes slightly varied around 6 nm at low RF/F127 ratios, while the RF/127 = 2 ratio gave a 8.1-nm pore size and 711-m2/g surface area. The resultant carbons are promising for use in areas such as fuel cells, where diffusion limitations affect the performance.

Effect of hydrochloric acid on grain size analysis of the Quaternary red clay rich in tiny ferromanganese nodules, Jiangxi province, southern China

There are many tiny ferromanganese nodules that cannot be found and eliminated easily in Quaternary red clay in southern China. The existence of these tiny ferromanganese nodules may influence grain size analysis results. Therefore, this paper focuses on the effects of the ferromanganese nodules on the grain size analysis and the effects of hydrochloric acid (HCl) on removing these nodules. The experimental results showed that the nodules clearly influenced the results of grain size analysis. The tiny ferromanganese nodules increased the coarse fraction and show a low peak in the coarse fraction of >100 μm on the frequency curves. The addition of HCl in the pretreatment process of grain size analysis can eliminate the effects of these tiny nodules effectively. Additionally, the HCl reacts with clay minerals and causes a reduction of the <4 μm fraction.

Effect of inorganic acid on the phase transformation of alumina

This paper focused on the effect of hydrochloric acid and nitric acid on phase transformation of gamma to alpha alumina. The microstructure, phase composition of specimens and crystallite sizes of α-Al2O3 are investigated by X-ray diffraction, SEM, Scherrer formula and external standard method. The results showed that the phase transitions of alumina was affected by the kinds and concentrations of inorganic acid. Hydrochloric acid was more advantageous to promote the transformation of γ-alumina to α-alumina than nitric acid above 900 °C. In addition, the α-fraction of specimens obtained by Al2O3-HCl gels increased from 71.0% to 87.1% after calcination at 1000 °C when acid concentration increased from 0.1*10-4 mol/L to 0.1mol/L. On the contrary, the α-fraction of specimens obtained by Al2O3-HNO3 gels decreased from 79.4% to 73.9%. And at 1100 °C up to nearly 100% of α-alumina in the specimens was obtained. Moreover, both hydrochloric acid and nitric acid were beneficial to the growth of the crystallite sizes of prepared α-Al2O3. Meanwhile the effect of hydrochloric acid on the phase transitions of alumina was further promoted by employing a two-step heat-treatment method. XRD and SEM confirmed that the first-step heat-treatment played an important role in the course of the calcination processes for low-temperature of α-alumina formation.