Study on Preparation of Calcium Sulfate Whisker with Leaching Tailings of Nickel Ore

2011 ◽  
Vol 287-290 ◽  
pp. 2084-2087 ◽  
Author(s):  
Li Wang ◽  
Chun Yan Zhuang ◽  
De Qin Meng
Keyword(s):  
Sulfuric Acid ◽  
Calcium Sulfate ◽  
Preparation Method ◽  
Orthogonal Experiment ◽  
Raw Material ◽  
High Grade ◽  
Reaction Conditions ◽  
Acid Reaction ◽  
Calcium Sulfate Whiskers ◽  
Calcium Sulfate Whisker

Taking leaching tailings of the nickel ore as raw material, calcium sulfate whiskers were prepared. The effects of Mg/Ca mole ratio, concentration of sulfuric acid, reaction temperature and precipitating time on the recovery of calcium were studied in this paper. The preparation method and reaction conditions of fibrous calcium sulfate whisker have been optimized by an orthogonal experiment, in order to obtain a high grade whisker product which could meet industrial requirements on whiteness and size.

scholarly journals Efficient activation of persulfate by calcium sulfate whisker supported nanoscale zero-valent iron for methyl orange removal

RSC Advances ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 452-461
Author(s):  
Yi Han ◽  
Xian Zhou ◽  
Li Lei ◽  
Huiqun Sun ◽  
Zhiyuan Niu ◽  
...  
Keyword(s):  
Composite Material ◽  
Methyl Orange ◽  
Calcium Sulfate ◽  
Zero Valent Iron ◽  
Nanoscale Zero Valent Iron ◽  
Calcium Sulfate Whiskers ◽  
Calcium Sulfate Whisker

In order to improve the utilization of nanoscale zero-valent iron (nZVI) in activating persulfate (PS), a composite material of nZVI/CSW with nZVI supported on calcium sulfate whiskers (CSWs) was synthesized in this study.

Fractionation of broom (Cytisus striatus) biomass components via mild sulfite pretreatment and enzymatic hydrolysis

BioResources ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 118-140
Author(s):  
Tânia P. Gomes ◽  
Vera L. D. Costa ◽  
Álvaro F. C. Vaz ◽  
Rogério M. S. Simões
Keyword(s):  
Sulfuric Acid ◽  
Enzymatic Hydrolysis ◽  
High Performance ◽  
Raw Material ◽  
Maximum Temperature ◽  
Solid Residue ◽  
Reaction Conditions ◽  
Positive Role ◽  
Biomass Components ◽  
Pretreatment Conditions

The potential of broom biomass to produce oligo- and monosaccharides was investigated using mild sulfite pretreatment conditions followed by enzymatic hydrolysis. Both treatments were analyzed via response surface methodology using an experimental central composite rotatable design 24 + star, which explored the following variables: sulfuric acid charge (0% to 3%), sodium sulfite charge (0% to 4%, maximum temperature (150 °C to 190 °C), and time at maximum temperature (0 min to 30 min). Oligo- and monosaccharides in the pretreatment hydrolysates were determined using high performance liquid chromatography. The amount of total extracted xylose, mannose, and galactose ranged from 3.5% to 15.8% of the initial biomass, while the model estimated optimal reaction conditions enabled the extraction of practically all hemicellulose in the raw material. However, the mildest pretreatment reaction conditions, with low temperature and low sulfuric acid charges, provided a hydrolysate where a major part of the extracted polysaccharides remained in oligomer form, enabling their separation by filtration. The cellulose-rich solid residue was submitted to enzymatic hydrolysis using a Novozymes® enzymatic cocktail. The enzymatic hydrolysis was successful, but some polysaccharides remained in the solid residue, mainly composed of lignin. An enzymatic yield of 60% was attained with no added sulfite in the pretreatment at 190 °C, despite the confirmed positive role of sulfur content in the solid residues.

Study on the Preparation of Calcium Sulfate Whisker by Hydrothermal Method

2012 ◽  
Vol 602-604 ◽  
pp. 1369-1372 ◽  
Author(s):  
Kang Bi Luo ◽  
Hu Ping Li ◽  
Yan Xia Tan
Keyword(s):  
Hydrothermal Method ◽  
Calcium Chloride ◽  
Sodium Sulfate ◽  
Calcium Sulfate ◽  
Sulfate Solution ◽  
Solution Concentration ◽  
Raw Material ◽  
Molar Ratio ◽  
Feed Mode ◽  
Calcium Sulfate Whiskers

This article took the sodium sulfate and calcium chloride as the raw material and prepared calcium sulfate whiskers by hydrothermal method. The experimental results show that the calcium sulfate precursors are prepared by the reverse feed mode in which the sodium sulfate solution drop into the calcium chloride solution under the solution concentration 0.6 mol/L and the molar ratio of Na2SO4 to CaCl2 at 1:1.8. The precursors were placed in pH=6.12 hydrothermal environments and treated in the autoclave at 140 °C for 4 h to obtain the calcium sulfate whiskers having for the ratio of length to diameter at 97.5 and the better morphology.

Effect of Different Kinds of CaSO4 Whisker on the Bending Strength and Hygroscopicity of Gypsum Board

2014 ◽  
Vol 638-640 ◽  
pp. 1322-1325 ◽  
Author(s):  
Chang Chen ◽  
Yu Bin Wang ◽  
Hua Wang ◽  
Qian Qian Deng ◽  
Lei Du ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Calcium Sulfate ◽  
Bending Strength ◽  
Gypsum Board ◽  
Specific Strength ◽  
Different Types ◽  
Calcination Method ◽  
Calcium Sulfate Whiskers ◽  
Calcium Sulfate Whisker ◽  
Properties Of Composites

Different kinds of hemihydrate calcium sulfate whiskers were fabricated by calcination method under the condition of 115-600 °C. And the density, moisture rate and mechanical properties of composites of gypsum and whisker were studied. The specific strength of composites was investigated. The results show that gypsum boards with whisker calcined at 115 °C and 300 °C have the maximum and minimum densities, which are about 1658 kg/m3 and 1604 kg/m3, respectively. Hydration ability of anhydrous calcium sulfate whisker is the strongest. The values of specific strength of gypsum board reinforced by different types of whiskers suggested that the porosity of the composites changed with the different kinds of whiskers, which agreed well with the moisture rate and mechanical properties.

scholarly journals Effects of Calcium Sulfate Whiskers on the Mechanical Properties and Light Transmittance of PE Greenhouse Films

2022 ◽  
Vol 2160 (1) ◽  
pp. 012004
Author(s):  
Runmeng Qiao ◽  
Zhengping Zhong ◽  
Qiao Liu ◽  
Jialei Liu ◽  
Wenqing He
Keyword(s):  
Mechanical Properties ◽  
Calcium Sulfate ◽  
Light Transmittance ◽  
Major Goal ◽  
Tear Strength ◽  
Calcium Sulfate Whiskers ◽  
New Formula ◽  
High Orientation ◽  
Calcium Sulfate Whisker ◽  
Orientation Structure

Abstract Calcium sulfate whisker (CSW) is a kind of fiber crystal material with high orientation structure. The major goal of this research is to study the changes of mechanical properties and light transmittance of PE greenhouse film with different proportions of CSW. The experimental results show that the mechanical properties and light transmittance of PE/CSW films are enhanced compared with the pure PE. For PE/2%CSW, it shows a 18.6% increase in tear strength, a 3.1% increase in luminous transmittance and 17.7% increase in haze. The PE/5%CSW demonstrates a 12.8% higher in tensile strength, a 20.5% higher in tear strength, a 23.9% lower in luminous transmittance and a 53.0% higher in haze. This article gives a new formula to strengthen the mechanical properties of PE greenhouse films and finds the direction for the research and development of astigmatic covering film.

Synthesis of Amino Propionic Acid Modified Polypropylene-Graft-Styrene Fiber

2014 ◽  
Vol 1033-1034 ◽  
pp. 420-423
Author(s):  
Yao Ran Sun ◽  
Shu De Duan ◽  
Rui Xia Guo ◽  
Rui Sheng Hu ◽  
Hai Li Yun
Keyword(s):  
Aqueous Solution ◽  
Propionic Acid ◽  
Ir Spectrum ◽  
Orthogonal Experiment ◽  
Experimental Results ◽  
Raw Material ◽  
Carboxyl Groups ◽  
Propanoic Acid ◽  
Reaction Conditions ◽  
Amino Propionic Acid

The amino propanoic acid chelating fiber (APACF) was prepared by immobilizing tetraethylenepentamine (TEPA) and propionic acid on polypropylene-graft-styrene (PP-g-ST). The synthetic conditions of amino PP-g-ST fiber and APACF were optimized by the way of L16(45) orthogonal experiment, and the optimizing reaction conditions were obtained. APACF was characterized by FTIR, and the changes of IR spectrum verified the introduction of carboxyl groups to the raw material. The experimental results revealed that the APACF can be used to remove and enrich copper from aqueous solution.

The Application of Calcium Sulfate Whisker in Styrene-Acrylic Emulsions

2010 ◽  
Vol 152-153 ◽  
pp. 821-824
Author(s):  
Hong Bo Liu ◽  
Ji Hu Wang ◽  
Shao Guo Wen ◽  
Chen Yu
Keyword(s):  
Mechanical Properties ◽  
Calcium Sulfate ◽  
Physical And Mechanical Properties ◽  
Contact Angles ◽  
Coating Films ◽  
Pencil Hardness ◽  
Calcium Sulfate Whiskers ◽  
Titanium Dioxides ◽  
Calcium Sulfate Whisker ◽  
Dispersing Agents

The styrene-acrylic emulsions were prepared by copolymerization of styrene, acrylic acid and n-butyl acrylate; coatings were achieved by adding calcium sulfate whiskers and titanium dioxides at the presence of dispersing agents and rheological additives. The physical and mechanical properties as well as contact angles of coating films formed on tinplate were characterized in detail. The pencil hardness was slightly decreased; the contact angle was greatly decreased from 69.8o to 12oby adding the calcium sulfate to indicate the hydrophilic coating films may have self-cleaning properties.

Research on Affecting Factor of Preparation of Calcium Sulfate Whisker with FGD Gypsum

2014 ◽  
Vol 624 ◽  
pp. 82-85
Author(s):  
Ying Wang ◽  
Dan Jun Tan ◽  
Xiao Li ◽  
Fan Li ◽  
Peng Qi Wang ◽  
...  
Keyword(s):  
Reaction Time ◽  
Reaction Temperature ◽  
Calcium Sulfate ◽  
Ph Value ◽  
Synthesis Method ◽  
Raw Material ◽  
Optimum Conditions ◽  
Fgd Gypsum ◽  
Slurry Concentration ◽  
Calcium Sulfate Whisker

Using FGD gypsum as raw material, calcium sulfate whisker was prepared by hydrothermal synthesis method. Through testing the aspect ratio of calcium sulfate whisker, the effect of reaction temperature, reaction time, desulfurization gypsum slurry concentration and pH value on the growth of calcium sulfate whisker were deeply researched. The optimum conditions for the preparation were that the reaction temperature was 150 °C, reaction time was 270min, the slurry concentration was 10% and the slurry pH value was 6.

scholarly journals EXTRACTION OF RARE EARTH ELEMENTS FROM SOLID WASTE OF PRODUCTION OF PHOSPHORIC ACID FOLLOWED BY SORPTION ON CATION EXCHANGE RESINS

2017 ◽  
Vol 60 (10) ◽  
pp. 87 ◽  
Author(s):  
Aleksandr V. Artamonov ◽  
Daria N. Smirnova ◽  
Nicolay N. Smirnov ◽  
Aleksandr P. Ilyin
Keyword(s):  
Rare Earth ◽  
Sulfuric Acid ◽  
Phosphoric Acid ◽  
Rare Earth Elements ◽  
Cation Exchange ◽  
Calcium Sulfate ◽  
Cation Exchanger ◽  
Raw Material ◽  
Cation Exchange Resins ◽  
Exchange Resins

The basis of production of extraction phosphoric acid is two simultaneous processes: dissolving phosphate raw material in a mixture of sulfuric and phosphoric (formed in the process) acids and crystallization of calcium sulfate (phosphogypsum). Phosphogypsum is an inevitable large-tonnage and cumbersome waste at sulfuric acid processing of apatite, which is of interest not only as a source of building gypsum, but also as an alternative rare earth raw material does not have a natural activity and containing rare-earth elements as a cerium and yttrium groups. As a raw material for the production of rare earth elements, calcium sulfate of three types has been used: phosphogypsum from a sludge accumulator, calcium phosphate phospho-hemihydrate and calcium sulfate phosphate dihydrate from a carousel filter produced by extraction phosphoric acid at JSC "PhosAgro-Cherepovets". The extraction of rare-earth elements from phosphogypsum from a sludge accumulator by leaching (percolation) with inorganic acids with subsequent sorption on cation-exchange resins is considered. As an adsorbent for extracting REE from leach solutions, cationite "Purolite" S-150 is used. A static exchange capacitance of cation exchanger is found that is the capacity of the resin when equilibrium is reached with a solution of a certain volume and composition. The static capacity of cation exchanger for rare-earth elements is 1.57%, which indicates a good absorbing capacity. Desorption of rare-earth elements from the cation exchanger is carried out with a solution of ammonium nitrate. The optimal solution for leaching was found to be sulfuric acid with a concentration of 5% by weight. The degree of extraction of rare-earth elements from phosphogypsum with sulfuric acid is about 82%.Forcitation:Artamonov A.V., Smirnova D.N., Smirnov N.N., Ilyin A.P. Extraction of rare earth elements from solid waste of production of phosphoric acid followed by sorption on cation exchange resins. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 10. P. 87-93

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