scholarly journals Coagulation-sedimentation Method Using Aluminum Sulfate and Calcium Hydroxide for Removal of Boric Acid from Wastewater. Improvement of Removal Rate of Boric Acid by Addition of Gypsum into Wastewater.

2002 ◽  
pp. 265-268 ◽  
Author(s):  
Satoshi KUDO ◽  
Masahiro SAKATA
Keyword(s):  
Boric Acid ◽  
Calcium Hydroxide ◽  
Aluminum Sulfate ◽  
Removal Rate ◽  
Sedimentation Method

Effects on Coagulation to Biogas-Slurry from Cattle Dung

2014 ◽  
Vol 955-959 ◽  
pp. 360-365
Author(s):  
Min Han ◽  
Cheng Hong Feng ◽  
Shun Li Wang ◽  
Ye Quan Fu ◽  
Li Qing An ◽  
...  
Keyword(s):  
Ferric Chloride ◽  
Aluminum Sulfate ◽  
Ph Value ◽  
Removal Rate ◽  
Ammonia Nitrogen ◽  
National Standard ◽  
Cattle Dung ◽  
Biogas Slurry ◽  
Coagulant Dosage ◽  
Degree Of Purification

To explore purification approach of anaerobic-digested-slurry from cattle dung, this study translated a technology in inorganic coagulation. Under the same condition, a coagulation experiment was carried out by three kinds inorganic coagulants such as polyaluminium chloride (PAC), aluminum sulfate and ferric chloride, respectively, then measured indicators of pH value, BOD5 value, CODcr value, ammonia nitrogen value, turbidity value. Results showed that there was a varying degree of purification effect, and the removal rate of the above indicators increased as the coagulant dosage increasing, the ferric chloride with the dosage of 960mg/L was the best one in purifying effect among the three coagulants. It is feasible that coagulation technology was used to pretreatment biogas slurry from cattle dung, and most of the indicators reached Chinese national standard basically (GB 18596-2001).

scholarly journals Preparation and Mechanism of a New Enhanced Flocculant Based on Bentonite for Drinking Water

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Feng-shan Zhou ◽  
Jie Li ◽  
Lin Zhou ◽  
Yang Liu
Keyword(s):  
Drinking Water ◽  
Ferrous Sulfate ◽  
Metal Ion ◽  
Aluminum Sulfate ◽  
Removal Rate ◽  
Metal Ion Removal ◽  
Drinking Water Standard ◽  
Aluminum Ions ◽  
Heavy Metal Ion Removal ◽  
Base Composite

Bentonite is characterized by the large specific surface, good adsorption, ion exchange ability, and nontoxicity. An enhanced bentonite base composite flocculant (BTA) can be prepared from treating the calcium base bentonite and compositing various functional additives. Bentonite was firstly treated by citric acid, then the talc and activated carbon turned to be acid part and simultaneously the part that was treated by sodium bicarbonate and calcium hydroxide turned to be alkaline part, and finally the acid bentonite part and alkaline bentonite part were mixed up with preground powder of polymeric chloride aluminium (PAC), cationic polyacrylamide (CPAM), ferrous sulfate, and aluminum sulfate, and after all of the processing flocculant BTA was obtained. The optimum preparation process of flocculant BTA has shown 29.5% acid bentonite part, 29.5% alkaline bentonite part, 15% PAC, 1% CPAM, 5% ferrous sulfate, and 20% aluminum sulfate. BTA was used to treat drinking water with high turbidity and metal ion in Karamay City, Xinjiang. The treated water was surely up to the drinking water standard of China in decolorization rate, deodorization rate, heavy metal ion removal rate, and so forth, and contents of residual aluminum ions and acrylamide monomer in drinking water were considerably decreased.

Experimental Investigation on Denting in PWR Steam Generators: Causes and Corrective Actions

1983 ◽  
Vol 105 (4) ◽  
pp. 755-762 ◽  
Author(s):  
F. Nordmann ◽  
G. Pinard-Legry ◽  
J. Daret ◽  
J. P. Brunet
Keyword(s):  
Carbon Steel ◽  
Boric Acid ◽  
Calcium Hydroxide ◽  
River Water ◽  
Ph Value ◽  
Steam Generators ◽  
Oxide Morphology ◽  
Specific Effects ◽  
On Line ◽  
Oxygen Addition

Denting studies have been undertaken in order to assess the influence of the most important parameters which could initiate corrosion of the carbon steel occurring in the tube-tube support plate crevices of some PWR steam generators. Tests have been carried out in model boilers where feedwater was polluted with sea or river water. Specific effects of chloride or sulfate and influence of oxygen content, magnetite addition and pH value were investigated. In magnetite prepacked crevices, denting is obtained within 1000 hrs for seawater pollution of 0.3 ppm chloride at the blowdown. In neutral chloride or in river water, denting is observed only with oxygen addition. Denting prevention is effective in the case of an on-line addition of phosphate, boric acid, or calcium hydroxide. For denting stopping, boric acid or calcium hydroxide is efficient even with a high seawater pollution. Soaks cannot stop denting if they are not followed by an on-line treatment (boric acid, calcium hydroxide). With quadrifoil holes, denting doesn’t occur. In very severe test conditions, 13 percent Cr steel can be corroded, but the corrosion rate is low and oxide morphology is different from that growing on carbon steel.

Static Modulus of Ettringite in Different Environment

2017 ◽  
Vol 726 ◽  
pp. 576-580
Author(s):  
Peng Chen ◽  
Zu Quan Jin ◽  
Jun Feng Fan
Keyword(s):  
Sodium Chloride ◽  
Calcium Carbonate ◽  
Magnesium Sulfate ◽  
Calcium Hydroxide ◽  
Chemical Reaction ◽  
Aluminum Sulfate ◽  
Chloride Ions ◽  
Experimental Result ◽  
Magnesium Ion ◽  
Static Modulus

The pure ettringite, (Ca6Al2(OH)12(SO4)3· 32H2O), was synthesized by chemical reaction with saturation calcium hydroxide and aluminum sulfate. The ettringite in different environments including various concentration of sodium chloride, 5% magnesium sulfate and carbonation for 3 days were synthesized. And then these ettringtie specimens were prepared under different pre-loads. The static modulus and phase composites were tested. The experimental result shown that the influence of chloride ions concentration on the static modulus of ettringite could be ignored. And the magnesium ion reduced the generation of ettringite, and promoted the formation of gypsum. The static modulus of ettringite increased with carbonation time due to the formation of calcium carbonate.

Study of the Hydration Process of Synthetic Preparation of Ettringite by Direct Addition of Aluminum Sulfate and Calcium Hydroxide

2018 ◽  
Vol 276 ◽  
pp. 60-65
Author(s):  
Marcela Fridrichová ◽  
Dominik Gazdič ◽  
Jana Mokrá ◽  
Karel Dvořák
Keyword(s):  
Calcium Hydroxide ◽  
Aluminum Sulfate ◽  
Xrd Analysis ◽  
Standard Laboratory ◽  
X Ray Diffraction ◽  
X Ray ◽  
Saturated Water ◽  
Direct Addition ◽  
Different Temperatures ◽  
The Stability

The stability of ettringite as high-watery mineral is highly dependent on the ambient temperature. Under standard laboratory conditions, onset of decomposition of this phase occurs at temperature of 80°C already and the theoretical temperature of the complete decomposition of ettringite is 180°C. Ettringite decomposition can occur at significantly different temperatures under humidity conditions other than the laboratory ones. Within the work verification of the possibility of synthetic preparation of ettringite by direct addition of aluminum sulfate, Al2(SO4)3·18H2O, and calcium hydroxide, Ca (OH)2, as an alternative method to the yeelimite hydration procedure was carried out. The stability of the resulting systems was examined in two different environments, namely in a laboratory environment and the environment of saturated water vapour. The phase composition of the samples was determined by X-ray diffraction (XRD) analysis, thermal analysis and scanning electron microscopy (SEM).

Optimization of Operating Conditions on Ceramic Printing Wastewater Treatment with Coagulation and Sedimentation Method

2013 ◽  
Vol 664 ◽  
pp. 383-389
Author(s):  
Yong Li Zhang ◽  
Xu Biao Yu ◽  
Chao Hai Wei ◽  
Ling Ling Shang ◽  
Ce Shi
Keyword(s):  
Wastewater Treatment ◽  
Ph Value ◽  
Removal Rate ◽  
Mixing Time ◽  
Operating Conditions ◽  
Intensity Increase ◽  
Sedimentation Method ◽  
Water Ph ◽  
Time Extension ◽  
Stirring Intensity

The ceramic printing wastewater was treated with coagulation sedimentation method by adopted AlCl3 polymerization (PAC) as a coagulant. In order to optimize the wastewater treatment of operating conditions, with absorbance, turbidity and conductivity for testing index, the PAC dosing quantity, stirring time, stirring intensity and influx water pH value on the influence of the wastewater treatment. The results show that the wastewater absorbance and turbidity with PAC dosing quantity increase, mixing time extension and stirring intensity increase present reduced trend, with the water pH increases present first decreases trend of increase; Proper operating conditions of wastewater treatment: PAC dosing quantity 90 mg/L, mixing time 15 min, mixing strength medium speed and influx water pH value is about seven. On this condition, ceramic printing wastewater treatment of effluent decolorization rate reached 86.9%, turbidity removal rate reached 92.5%, conductivity is 2.05 x 103 s/cm.

Chemical Neutralization to Control Denting in Nuclear Steam Generators

1983 ◽  
Vol 105 (4) ◽  
pp. 763-770 ◽  
Author(s):  
T. A. Beineke ◽  
J. F. Hall ◽  
K. E. Marugg ◽  
D. B. Scott ◽  
R. M. Orsulak ◽  
...  
Keyword(s):  
Boric Acid ◽  
Calcium Hydroxide ◽  
Calcium Concentration ◽  
Chloride Concentration ◽  
Line Treatment ◽  
Steam Generators ◽  
Adverse Side Effects ◽  
On Line ◽  
Full Power ◽  
Power Operation

Laboratory testing at Combustion Engineering has indicated promise in controlling simulated steam generator tube denting through chemical neutralization. Testing was limited to on-line treatment, and two neutralizers have been evaluated: (i) calcium hydroxide, and (ii) boric acid. On-line treatment with calcium hydroxide successfully halted active denting whenever the bulk calcium concentration (in ppm) equaled or exceeded the bulk chloride concentration (in ppm). Calcium hydroxide also was effective as an alternative to ammonia as a pH controlling agent in two tests conducted without ingress of chloride. On-line treatment with boric acid consisted of a four-day soak at simulated low (approximately 30 percent) power with 50 ppm B followed by one month full-power operation with 10 ppm B. This treatment also halted denting. Nondestructive and destructive examination of test boilers gave no indication of adverse side effects associated with either neutralizer.

Removal of Soluble Phosphates From Water

1975 ◽  
Vol 10 (1) ◽  
pp. 193-213
Author(s):  
Chia-Su Wan ◽  
Maurice Adelman
Keyword(s):  
Calcium Hydroxide ◽  
Ferric Chloride ◽  
Chemical Treatment ◽  
Aluminum Sulfate ◽  
Molar Ratio ◽  
Sand Column ◽  
Residual Phosphorus ◽  
Ph Range ◽  
Phosphate Solutions

Abstract Chemical treatment using ferric chloride or aluminum sulfate in combination with calcium hydroxide has been studied for the purpose of removing phosphorus from ortho-phosphate, ortho-and pyro-phosphate and ortho- pyro- and tripoly-phosphate solutions in the pH range 7.5 to 9.5. The data showed that pyro- and tripoly-phosphate could be more easily removed than ortho-phosphate in the experimental pH range. The data also showed that the combination of ferric chloride and calcium hydroxide had better settling ability than the combination of aluminum sulfate and calcium hydroxide. With a molar ratio of 1:1 between iron or aluminum and phosphorus as ortho-phosphate and 150 mg/1 of calcium hydroxide, a supernatant of about 1 mg/1 P was obtained from a phosphorus solution of 10 mg/1 P as ortho-phosphate, 4 mg/1 P as pyro-phosphate and 6 mg/1 P as tripoly-phosphate near pH 9. After filtration through a sand column, the residual phosphorus was reduced to about 0.6 mg/1 P. The residual phosphorus could be further reduced to less than 0.2 mg/l P during the first eight hours and about 0.3 mg/1 P even after 24 hours by using a mixed column of sand and soil to replace the sand column.

Removal of Toxic Oxyanion from Aqueous Solution Using Calcium Alumino-Zincate

2014 ◽  
Vol 617 ◽  
pp. 40-45 ◽  
Author(s):  
Hiroyuki Sango ◽  
Masaya Hirano
Keyword(s):  
Aqueous Solution ◽  
South Asia ◽  
Calcium Hydroxide ◽  
Removal Rate ◽  
Polluted Area ◽  
The Other ◽  
Well Water ◽  
Arsenic Pollution ◽  
Removal Process ◽  
Chromate Ions

Various problems related to pollution of soil and groundwater caused by toxic oxyanion have been actualized in recent years. In particular, the enlargement of the polluted area by diffusion of chromate ions has been a worry in Japan, and arsenic pollution of well water is also a serious problem in South Asia nations. Removal process of chromate and arsenic in aqueous solution using 14CaO·5Al2O3·6ZnO, which is an easy-to-use method technically, has been investigated in our laboratory. The results obtained are summarized as follows: 1) Oxyanion of chromium and arsenic such as CrO42-, AsO33- and AsO43- ions are able to be removed from aqueous solution by addition of 14CaO·5Al2O3·6ZnO, however, the removal rate of those arsenic ions are much lower than that of CrO42-. 2) Removal of CrO42- from aqueous solution is caused by the immobilization to 3CaO·Al2O3·CaCrO4·12H2O, on the other hand, both AsO33- and AsO43- mainly occurred by the adsorption to unhydrated 14CaO·5Al2O3·6ZnO. 3) Simultaneous use of 14CaO·5Al2O3·6ZnO and calcium hydroxide is an effective method in the removal of CrO42-, AsO33- and AsO43- from aqueous solution.

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