Properties of Tungsten Mine Waste Geopolymeric Binder (original) (raw)
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Investigations of tungsten mine waste geopolymeric binder: Strength and microstructure
Construction and Building Materials, 2008
This paper reports some results of a research project related to the development of a new binder using mineral waste mud from the Portuguese mine. Some aspects related to the effect of aggregates in the microstructure and mechanical behaviour of tungsten mine waste geopolymeric binder are reported in the present study. Test results showed that the aggregate type influences strength development.
Investigations on Mix Design of Tungsten Mine Waste Geopolymeric Binder
Construction and Building Materials, 2008
Strength data show that the parameters, which lead to optimum strength for 7 days curing, remain the same for long curing ages. However, when calcium hydroxide percentages above 10% are used, strength decrease after 14th curing day is noticed. In order to explain this behaviour several hypotheses are discussed. The use of an activator with a sodium hydroxide concentration of 24 M leads to a compressive strength of almost 70 MPa. The strength performance is typical of a very reactive binder, being suggested that it is due to the calcium hydroxide and also to the nucleation centers provided by the iron oxide of the mine waste mud. Results allow foreseeing that even higher strength performance could be achieved if lower water/sodium molar ratios were used.
This paper reports results of a research project related to the development of geopolymeric binder using mineral waste mud from the Portuguese tungsten mine Panasqueira. Abrasion and acid resistance of two ordinary Portland cement (OPC) strength class concrete mixtures (C20/25 and C30/37) and several tungsten mine waste mud (TMWM) geopolymeric binder mixtures was evaluated. Acid resistance was performed by submitting samples to solutions of sulphuric acid, nitric acid and chloridric acid, results of weight loss are reported. Abrasion resistance was assessed by the mass loss of cubic specimens when submitted to 1000 rotations with the Los Angeles apparatus test machine. This study indicates that TMWM geopolymeric binders possess higher acid and abrasion resistance than OPC based concrete mixtures.
Alkali Activated Geopolymeric Binder Using Tungsten Mine Waste: Preliminary Investigation
ABSTRACT This paper reports preliminary results of a PhD research project related to the development of an alkaliactivated geopolymeric binder using mineral waste mud from the Portuguese tungsten mine Panasqueira which is still operating. Mineralogical analysis indicates that the waste mud is compose mainly of muscovite and quartz with a high content of iron and alkali metals. Results of the dehydroxylation process are presented by x-ray diffraction and infrared emission spectroscopy patterns of quenched waste powder and also from compressive strength of alkali-activated mortar specimens, showing a significant potential as a geopolymeric source precursor. Considerations about Portuguese industrial waste production are made showing a high level ratio of CO2 emissions mostly from cement industry, a nation-wide lack of fly ash and blast furnace slag to be used as cementitious by-products and huge amounts of quarrying and mining wastes and also the need to preserve it`s large and protected natural areas leading to the use of alumino-silicate minerals as the only reasonable alternative to the development of alkali-activated friendly environmental binders. Materials raw cost comparisons between Portland cement based concretes and alkali-activated geopolymeric based concretes are also made showing that Portland cement based ones are by far the most economic ones but not for very long due to the expected increase in Portland cement cost under the recent implementation of CO2 emissions trading scheme (ETS).
Construction and Building Materials, 2008
Tungsten mine waste mud (TMWM) was investigated for its potential use as repair material of ordinary portland cement (OPC) concrete. Bond strength between OPC concrete substrate and three repair materials was analysed. TMWM geopolymeric binder and two commercial repair products were used as repair materials. Bond strength behaviour was assessed from slant shear tests. A total of 128 slant shear specimens were made in order to evaluate bond strength at 1, 3, 7 and 28 days curing. Four kinds of concrete substrate surface treatment were used, as cast against metallic formwork, as cast against wood formwork, saw cut and acid etching. This study indicates that TMWM geopolymeric binders possess very high bond strength even at early ages and that behaviour is not affected by low surface treatment roughness. Commercial repair products on the other hand show very low bond strength and are very dependent on surface treatment roughness. Scanning electron micrographs reveal that TMWM geopolymeric binders chemically bond to the concrete substrate, while cost comparisons show this geopolymeric repair solution is by far the most cost efficient.
Alkali activated geopolymeric binder using tungesten mine waste: preliminary investigation
2005
This paper reports preliminary results of a PhD research project related to the development of an alkaliactivated geopolymeric binder using mineral waste mud from the Portuguese tungsten mine Panasqueira which is still operating. Mineralogical analysis indicates that the waste mud is compose mainly of muscovite and quartz with a high content of iron and alkali metals. Results of the dehydroxylation process are presented by x-ray diffraction and infrared emission spectroscopy patterns of quenched waste powder and also from compressive strength of alkali-activated mortar specimens, showing a significant potential as a geopolymeric source precursor. Considerations about Portuguese industrial waste production are made showing a high level ratio of CO 2 emissions mostly from cement industry, a nation-wide lack of fly ash and blast furnace slag to be used as cementitious by-products and huge amounts of quarrying and mining wastes and also the need to preserve it`s large and protected natural areas leading to the use of alumino-silicate minerals as the only reasonable alternative to the development of alkali-activated friendly environmental binders. Materials raw cost comparisons between Portland cement based concretes and alkali-activated geopolymeric based concretes are also made showing that Portland cement based ones are by far the most economic ones but not for very long due to the expected increase in Portland cement cost under the recent implementation of CO 2 emissions trading scheme (ETS).
Alkali-activated tungsten mine waste mud binder versus OPC concrete : acid and abrasion resistance.
Abstract. This paper reports results of a research project related to the development of geopolymeric binder using mineral waste mud from the Portuguese tungsten mine Panasqueira. Abrasion and acid resistance of two ordinary Portland cement (OPC) strength class concrete mixtures (C20/25 and C30/37) and several tungsten mine waste mud (TMWM) geopolymeric binder mixtures was evaluated. Acid resistance was performed by submitting samples to solutions of sulphuric acid, nitric acid and chloridric acid, results of weight loss are reported. Abrasion resistance was assessed by the mass loss of cubic specimens when submitted to 1000 rotations with the Los Angeles apparatus test machine. This study indicates that TMWM geopolymeric binders possess higher acid and abrasion resistance than OPC based concrete mixtures.