Pub Date : 1997-01-01DOI: 10.2473/SHIGENTOSOZAI.113.799
R. Matsuhashi
Sulfuric acid solution is the most common environment in various industrial processes and it is well known that the ion affect on the rate of corrosion of steels. In this paper, corrosion resistance of mild steels, low alloy steels, stainless steels and Ni-base alloys in such environment, are reviewed based on various studies. Types of stainless steels are developed for the environment and the evaluation of these steels is reported for both laboratory scale and field tests.
{"title":"Corrosion Resistance of Steels in Sulfuric Acid Solution.","authors":"R. Matsuhashi","doi":"10.2473/SHIGENTOSOZAI.113.799","DOIUrl":"https://doi.org/10.2473/SHIGENTOSOZAI.113.799","url":null,"abstract":"Sulfuric acid solution is the most common environment in various industrial processes and it is well known that the ion affect on the rate of corrosion of steels. In this paper, corrosion resistance of mild steels, low alloy steels, stainless steels and Ni-base alloys in such environment, are reviewed based on various studies. Types of stainless steels are developed for the environment and the evaluation of these steels is reported for both laboratory scale and field tests.","PeriodicalId":22754,"journal":{"name":"The Mining and Materials Processing Institute of Japan","volume":"39 1","pages":"799-804"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80612496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-01-01DOI: 10.2473/SHIGENTOSOZAI.113.571
Hideyo Osanai, I. Matsuoka
The depressing effect of raising pulp temperature on pyrite flotation have been investigated by using diethyl dithiophosphate (ethyl aerofloat, E. A. F.) as a collector. The mechanism of depression have been studied in terms of collector adsorption and changes in concentration of sulfate, hydroxide and iron ions in pulp during conditioning, and the surface products after conditioning identified by diffuse reflectance infrared fourier transform spectroscopy (DRIFTS) and X-ray photo-electron spectroscopy (XPS).The results obtained are as follows:The flotation recovery of pyrite at pH 6 was only slightly decreased by raising pulp temperature from25°C to °C in the presence of large amounts of collector, but it was significantly depressed in moderate collector addition of the order of 200-300 g/t.There was no difference between collector adsorption at 25 °C and that at 60°C in the collector addition less than 500 g/t. Accordingly, the depression of pyrite by raising pulp temperature can not be explained by the decrease of collector adsorption.From the changes of the concentration of sulfate, hydroxide and iron ions before and after conditioning at 25°C or 60°C, it was suggested that basic iron sulfate was precipitated on pyrite surface during conditioning at either pulp temperature, but the amount precipitated at 60 t was much larger than that at 25°C, because the oxidation reaction of pyrite surface took place at 60°.The existence of sulfate on the pyrite surface after conditioning at 60 t was detected by DRIFTS and XPS.From the above experimental results, it is concluded that pyrite depression by raising pulp temperature is mainly attributed to the formation of hydrophilic basic iron sulfate which offsets the hydrophobization effect with collector adsorption.
{"title":"Depressing Effect of Raising Pulp Temperature on Pyrite Flotation.","authors":"Hideyo Osanai, I. Matsuoka","doi":"10.2473/SHIGENTOSOZAI.113.571","DOIUrl":"https://doi.org/10.2473/SHIGENTOSOZAI.113.571","url":null,"abstract":"The depressing effect of raising pulp temperature on pyrite flotation have been investigated by using diethyl dithiophosphate (ethyl aerofloat, E. A. F.) as a collector. The mechanism of depression have been studied in terms of collector adsorption and changes in concentration of sulfate, hydroxide and iron ions in pulp during conditioning, and the surface products after conditioning identified by diffuse reflectance infrared fourier transform spectroscopy (DRIFTS) and X-ray photo-electron spectroscopy (XPS).The results obtained are as follows:The flotation recovery of pyrite at pH 6 was only slightly decreased by raising pulp temperature from25°C to °C in the presence of large amounts of collector, but it was significantly depressed in moderate collector addition of the order of 200-300 g/t.There was no difference between collector adsorption at 25 °C and that at 60°C in the collector addition less than 500 g/t. Accordingly, the depression of pyrite by raising pulp temperature can not be explained by the decrease of collector adsorption.From the changes of the concentration of sulfate, hydroxide and iron ions before and after conditioning at 25°C or 60°C, it was suggested that basic iron sulfate was precipitated on pyrite surface during conditioning at either pulp temperature, but the amount precipitated at 60 t was much larger than that at 25°C, because the oxidation reaction of pyrite surface took place at 60°.The existence of sulfate on the pyrite surface after conditioning at 60 t was detected by DRIFTS and XPS.From the above experimental results, it is concluded that pyrite depression by raising pulp temperature is mainly attributed to the formation of hydrophilic basic iron sulfate which offsets the hydrophobization effect with collector adsorption.","PeriodicalId":22754,"journal":{"name":"The Mining and Materials Processing Institute of Japan","volume":"114 1","pages":"571-575"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78967959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-01-01DOI: 10.2473/SHIGENTOSOZAI.113.940
Mikiya Tanaka
{"title":"Recycling. Extraction and Recovery Techniques. Solvent Extraction.","authors":"Mikiya Tanaka","doi":"10.2473/SHIGENTOSOZAI.113.940","DOIUrl":"https://doi.org/10.2473/SHIGENTOSOZAI.113.940","url":null,"abstract":"","PeriodicalId":22754,"journal":{"name":"The Mining and Materials Processing Institute of Japan","volume":"68 1","pages":"940-944"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79054912","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-01-01DOI: 10.2473/SHIGENTOSOZAI.113.67
S. Kimura, Shinobu Fujisaku, N. Tsuchiya, K. Nakatsuka
Soda lime glass beads were solidified by hydrothermal hot-pressing at 300°C for a period of 1 hour with NaOH, KOH, NaCl, KCl, Na2SO4, HCl solutions and deionized water, respectively. Shrinkage was monitored during experiment, and the solidified products were examined by SEM-EDX, XRD, FT-IR, TG and Shore hardness tester. The cross-section of the reacted glass bead showed three distinct layers of varying thickness that have undergone different degrees of alteration. The degree of alteration was higher approaching the surface of the glass beads. The surfaces of the glass beads were highly altered, deformed and cemented with each other. The final shrinkage increased in the order of acidic, neutral and alkali solution. The Shore hardness was found to increase with any increase in shrinkage for solutions containing same cation but was higher for Na+ solution than K+ solution. Thermogravimetric results indicated that the water contents in solidified products with K+ solutions were higher than the ones with Na+ solutions. This suggests that the drop in the hardness was caused by the presence of larger amount of water in solidified products with K+ than Na+.
{"title":"Effect of Electrolytes on Solidification of Glass Beads by Hydrothermal Hot-Pressing.","authors":"S. Kimura, Shinobu Fujisaku, N. Tsuchiya, K. Nakatsuka","doi":"10.2473/SHIGENTOSOZAI.113.67","DOIUrl":"https://doi.org/10.2473/SHIGENTOSOZAI.113.67","url":null,"abstract":"Soda lime glass beads were solidified by hydrothermal hot-pressing at 300°C for a period of 1 hour with NaOH, KOH, NaCl, KCl, Na2SO4, HCl solutions and deionized water, respectively. Shrinkage was monitored during experiment, and the solidified products were examined by SEM-EDX, XRD, FT-IR, TG and Shore hardness tester. The cross-section of the reacted glass bead showed three distinct layers of varying thickness that have undergone different degrees of alteration. The degree of alteration was higher approaching the surface of the glass beads. The surfaces of the glass beads were highly altered, deformed and cemented with each other. The final shrinkage increased in the order of acidic, neutral and alkali solution. The Shore hardness was found to increase with any increase in shrinkage for solutions containing same cation but was higher for Na+ solution than K+ solution. Thermogravimetric results indicated that the water contents in solidified products with K+ solutions were higher than the ones with Na+ solutions. This suggests that the drop in the hardness was caused by the presence of larger amount of water in solidified products with K+ than Na+.","PeriodicalId":22754,"journal":{"name":"The Mining and Materials Processing Institute of Japan","volume":"1244 1","pages":"67-71"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76814294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-01-01DOI: 10.2473/SHIGENTOSOZAI.113.945
Y. Umetsu
{"title":"Recycling. Extraction and Recovery Techniques. Electrolytic Processes.","authors":"Y. Umetsu","doi":"10.2473/SHIGENTOSOZAI.113.945","DOIUrl":"https://doi.org/10.2473/SHIGENTOSOZAI.113.945","url":null,"abstract":"","PeriodicalId":22754,"journal":{"name":"The Mining and Materials Processing Institute of Japan","volume":"26 5 1","pages":"945-947"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82703658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-01-01DOI: 10.2473/SHIGENTOSOZAI.113.825
Y. Obara, K. Imai, N. Nakamura, K. Sugawara
Knowledge of the rock stress is one of keys to design and construct rock structures. Thein-situstresses, therefore, have to be accurately measured. Since rock stress measurement is generally time consuming task, the new technique development is being expected to determine the complete stress state from a measurement in a single borehole. Thus, the stress relief method should be improved to meet its demand.Many stress relief methods to determine the complete state of stress have been proposed and developed. Among these methods, the CSIRO hollow inclusion stress cell has been most popular in the world, since it enables us to accurately measurein-situstresses. The eight-elements strain gauge, the hemispherical shaped strain cell and the conical shaped strain cell have been used in Japan. In these three methods, the conical-ended borehole technique with sixteen-elements conical shaped strain cell has an advantage to reduce the time, effort and cost for a series of rock stress measurements, combining the compact overcoring, the diameter of which equals to that of the pilot borehole.In the present study, the conical shaped strain cell has been modified and refined to improve the accuracy in rock stress measurement, increasing the number of strain measured on the conical bottom surface of the borehole with a cross typed strain gauge. This paper, firstly, shows how the stress tensor can be determined from the strains on a conical bottom surface of a single borehole. Then the accuracy of the proposed method was compared with that of existing method to confirm that the proposed method gives us more accurate results. Secondly, based on an in-siturock stress measurement, this paper indicates that the proposed method can be more effectively used forin-siturock stress measurements than the existing one. Also, process simulation of the strains and stresses on the conical bottom surface during the stress relieving gave well consistent results with measured data, which indicates that the proposed method is quite reliable forin-siturock stress measurements.
{"title":"Improvement of the Conical-ended Borehole Technique for Rock Stress Measurement with a High Accuracy.","authors":"Y. Obara, K. Imai, N. Nakamura, K. Sugawara","doi":"10.2473/SHIGENTOSOZAI.113.825","DOIUrl":"https://doi.org/10.2473/SHIGENTOSOZAI.113.825","url":null,"abstract":"Knowledge of the rock stress is one of keys to design and construct rock structures. Thein-situstresses, therefore, have to be accurately measured. Since rock stress measurement is generally time consuming task, the new technique development is being expected to determine the complete stress state from a measurement in a single borehole. Thus, the stress relief method should be improved to meet its demand.Many stress relief methods to determine the complete state of stress have been proposed and developed. Among these methods, the CSIRO hollow inclusion stress cell has been most popular in the world, since it enables us to accurately measurein-situstresses. The eight-elements strain gauge, the hemispherical shaped strain cell and the conical shaped strain cell have been used in Japan. In these three methods, the conical-ended borehole technique with sixteen-elements conical shaped strain cell has an advantage to reduce the time, effort and cost for a series of rock stress measurements, combining the compact overcoring, the diameter of which equals to that of the pilot borehole.In the present study, the conical shaped strain cell has been modified and refined to improve the accuracy in rock stress measurement, increasing the number of strain measured on the conical bottom surface of the borehole with a cross typed strain gauge. This paper, firstly, shows how the stress tensor can be determined from the strains on a conical bottom surface of a single borehole. Then the accuracy of the proposed method was compared with that of existing method to confirm that the proposed method gives us more accurate results. Secondly, based on an in-siturock stress measurement, this paper indicates that the proposed method can be more effectively used forin-siturock stress measurements than the existing one. Also, process simulation of the strains and stresses on the conical bottom surface during the stress relieving gave well consistent results with measured data, which indicates that the proposed method is quite reliable forin-siturock stress measurements.","PeriodicalId":22754,"journal":{"name":"The Mining and Materials Processing Institute of Japan","volume":"127 1","pages":"825-831"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77200752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-01-01DOI: 10.2473/SHIGENTOSOZAI.113.211
Kinue Tsunematsu, H. Tateyama, K. Kimura, O. Ishibashi
The effect of the structural properties of kaolin minerals on the intercalation process of urea was investigated using kaolinite and two kinds of halloysite. The results are summarized as follow.(1) The urea intercalated gradually and regularly into the interlayer site of kaolinite with plate morphology, but intercalated immediately and irregularly into that of halloysite with tubular and spherical morphologies.(2) The decomposition temperature of the urea intercalated into kaolin minerals were lower than that of pure urea. The difference between the decomposition of the urea intercalated and that of pure urea was examined by IR spectrum analysis. The asymmetric and symmetric ν(NH2) stretching frequencies at 3, 504cm-1 and 3, 389cm-1 correspond to NH2 groups interacting with the oxygens located on the basal tetrahedral layer. Intercalation of urea within the kaolin minerals structure increased the ν(CN) stretching frequency from 1, 468cm-1 for the urea to 1, 477cm-1 for intercalated molecules. These results indicate that the hydrogen bonding of urea molecules intercalated into the interlayer site of kaolin minerals are weak as compared with the hydrogen bonding of pure urea molecules.(3) The ν(CN) stretching frequency of two kinds of halloysite showed broader pattern compared with that of kaolinite, but the ν(NH2) bending frequency of halloysites shifted to higher frequency than that of kaolinite. These results show that the hydrogen bonding of urea intercalated into the interlayer site of halloysite is different from the that of kaolinite.
{"title":"Effect of Structure and Morphology of Kaolin Minerals on the Intercalation of Urea.","authors":"Kinue Tsunematsu, H. Tateyama, K. Kimura, O. Ishibashi","doi":"10.2473/SHIGENTOSOZAI.113.211","DOIUrl":"https://doi.org/10.2473/SHIGENTOSOZAI.113.211","url":null,"abstract":"The effect of the structural properties of kaolin minerals on the intercalation process of urea was investigated using kaolinite and two kinds of halloysite. The results are summarized as follow.(1) The urea intercalated gradually and regularly into the interlayer site of kaolinite with plate morphology, but intercalated immediately and irregularly into that of halloysite with tubular and spherical morphologies.(2) The decomposition temperature of the urea intercalated into kaolin minerals were lower than that of pure urea. The difference between the decomposition of the urea intercalated and that of pure urea was examined by IR spectrum analysis. The asymmetric and symmetric ν(NH2) stretching frequencies at 3, 504cm-1 and 3, 389cm-1 correspond to NH2 groups interacting with the oxygens located on the basal tetrahedral layer. Intercalation of urea within the kaolin minerals structure increased the ν(CN) stretching frequency from 1, 468cm-1 for the urea to 1, 477cm-1 for intercalated molecules. These results indicate that the hydrogen bonding of urea molecules intercalated into the interlayer site of kaolin minerals are weak as compared with the hydrogen bonding of pure urea molecules.(3) The ν(CN) stretching frequency of two kinds of halloysite showed broader pattern compared with that of kaolinite, but the ν(NH2) bending frequency of halloysites shifted to higher frequency than that of kaolinite. These results show that the hydrogen bonding of urea intercalated into the interlayer site of halloysite is different from the that of kaolinite.","PeriodicalId":22754,"journal":{"name":"The Mining and Materials Processing Institute of Japan","volume":"11 1","pages":"211-215"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91070792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-01-01DOI: 10.2473/SHIGENTOSOZAI.113.929
Y. Okano
{"title":"Recycling. Physical Separation Techniques. Evaluation of Separation Performance.","authors":"Y. Okano","doi":"10.2473/SHIGENTOSOZAI.113.929","DOIUrl":"https://doi.org/10.2473/SHIGENTOSOZAI.113.929","url":null,"abstract":"","PeriodicalId":22754,"journal":{"name":"The Mining and Materials Processing Institute of Japan","volume":"55 1","pages":"929-931"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88652662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-01-01DOI: 10.2473/SHIGENTOSOZAI.113.53
H. Kitahara, O. Ogawa
As a basic study of the oxidizing roasting in a Dwight-Lloyd sinterig machine in the ISP, lead-zinc concentrate, zinc concentrate, recycled sinter fines, and pulverized sinter fines were roasted in air, and behavior of sulfur-containing compounds was investigated.The results can be summarized as follows.1. The charge to the sintering machine is discharged before it is brought, as a whole, to equilibrium with the gas phase in the machine.2. The roasting reactions are complicated owing to competitive formation and/or decomposition of oxides, sulfates, and basic sulfates.3. Most sulfur remains in the sinter as basic sulfates of lead and zinc.4. Desulfurization of recycled sinter fines and pulverized sinter fines by roasting in air is slow at temperatures below 1, 200°C which prevail in the sintering machine.
{"title":"A Basic Study of the Oxidizing Roasting in the Sintering Process of ISP.","authors":"H. Kitahara, O. Ogawa","doi":"10.2473/SHIGENTOSOZAI.113.53","DOIUrl":"https://doi.org/10.2473/SHIGENTOSOZAI.113.53","url":null,"abstract":"As a basic study of the oxidizing roasting in a Dwight-Lloyd sinterig machine in the ISP, lead-zinc concentrate, zinc concentrate, recycled sinter fines, and pulverized sinter fines were roasted in air, and behavior of sulfur-containing compounds was investigated.The results can be summarized as follows.1. The charge to the sintering machine is discharged before it is brought, as a whole, to equilibrium with the gas phase in the machine.2. The roasting reactions are complicated owing to competitive formation and/or decomposition of oxides, sulfates, and basic sulfates.3. Most sulfur remains in the sinter as basic sulfates of lead and zinc.4. Desulfurization of recycled sinter fines and pulverized sinter fines by roasting in air is slow at temperatures below 1, 200°C which prevail in the sintering machine.","PeriodicalId":22754,"journal":{"name":"The Mining and Materials Processing Institute of Japan","volume":"36 1","pages":"53-59"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87369562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-01-01DOI: 10.2473/SHIGENTOSOZAI.113.107
K. Shin, Fangquan Li, S. Okubo
Through an extensive hydraulic fracturing experiment in granitic rock with low frequencies of joints, the initiation, reopening and closing behaviors have been carefully examined. zn this 3 rd report, the features which have not been dealt with in the previous two reports are discussed; the fracture direction and two deflection points in a shut-in curve.A numerical analysis based on the weakest-link theory reveals that, with increase of the maximum compression stress SH, the mean and the variability of hydro-fracturing tensile strength T increases, while the variability of fracture direction decreases.In this study, the vertical crack with a circular periphery tends to extend passing through the packers. When sufficient rate of flow is supplied for reopening the crack, the crack tip is fully open. After closing the water valve, the pressure is continuously decreasing, and the first deflection point Pctc is observed at the cracktip closing. With further pressure decrease, the crack surface is closing gradually from the outer to inner part. When the part of crack extended passing through the packers is closed, the second deflection point Ps2 is observed. Considering the crack-closing process, Ps2 should be larger than (3Sh-SH)/2 while Pctc is equal to the minimum compression stress Sh.In this experiment, different values of Ps2 have been observed at two depths while the values of Pctc (=Sh) are almost the same. According to the crack closing mechanism described above, smaller Ps2 suggests larger SH. At a depth with smaller Ps2, the variability of crack direction is small and SH is large. This result suggests that the variability of crack direction and Ps2 possibly give useful information for stress estimation.
{"title":"Hydraulic fracturing experiment in granitic rock with scarce joints in China(3rd Report). Characteristics of Initiation, Reopening and Closing Behavior of Hydraulic Fractured Crack.","authors":"K. Shin, Fangquan Li, S. Okubo","doi":"10.2473/SHIGENTOSOZAI.113.107","DOIUrl":"https://doi.org/10.2473/SHIGENTOSOZAI.113.107","url":null,"abstract":"Through an extensive hydraulic fracturing experiment in granitic rock with low frequencies of joints, the initiation, reopening and closing behaviors have been carefully examined. zn this 3 rd report, the features which have not been dealt with in the previous two reports are discussed; the fracture direction and two deflection points in a shut-in curve.A numerical analysis based on the weakest-link theory reveals that, with increase of the maximum compression stress SH, the mean and the variability of hydro-fracturing tensile strength T increases, while the variability of fracture direction decreases.In this study, the vertical crack with a circular periphery tends to extend passing through the packers. When sufficient rate of flow is supplied for reopening the crack, the crack tip is fully open. After closing the water valve, the pressure is continuously decreasing, and the first deflection point Pctc is observed at the cracktip closing. With further pressure decrease, the crack surface is closing gradually from the outer to inner part. When the part of crack extended passing through the packers is closed, the second deflection point Ps2 is observed. Considering the crack-closing process, Ps2 should be larger than (3Sh-SH)/2 while Pctc is equal to the minimum compression stress Sh.In this experiment, different values of Ps2 have been observed at two depths while the values of Pctc (=Sh) are almost the same. According to the crack closing mechanism described above, smaller Ps2 suggests larger SH. At a depth with smaller Ps2, the variability of crack direction is small and SH is large. This result suggests that the variability of crack direction and Ps2 possibly give useful information for stress estimation.","PeriodicalId":22754,"journal":{"name":"The Mining and Materials Processing Institute of Japan","volume":"2013 1","pages":"107-114"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87984298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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