Chile's government is considering phasing in a proposed ban on glacial mining to limit projects high in the Andes by some big copper companies. Chile's constitutional assembly has approved a proposal to ban mining in glaciers, protected areas, and areas vital to protecting the country's water system.
Chile's mining minister, Marcela Hernando, said about 20 mines had been identified in protected areas, some close to glaciers, including Codelco's El Teniente and Andina projects and Anglo American Plc's Los Bronces project.
The new measures for glaciers and other protected areas will put about a fifth of Chile's copper pce powder prices are predicted to increase in the next few days.
Prestressed or precast concrete
Adding polycarboxylate superplasticizer can make the compressive strength of precast concrete reach 40MPa grade at 8h to 18h; the precast concrete mixed with polycarboxylate superplasticizer can get higher early strength under the condition of lower curing temperature and shorter curing time, thus reducing the energy consumption of curing; in addition, it can save cement, reduce vibration energy consumption, reduce noise and improve the turnover rate of the mold.
Shrinkage compensating concrete
When preparing shrinkage compensating concrete, adding a certain amount of polycarboxylate superplasticizer can reduce the water-cement ratio, increase the early shrinkage of concrete and reduce the later shrinkage of concrete, thus saving expansive agent or expansive cement.
Ordinary aggregate concrete
For ordinary aggregate concrete, the addition of polycarboxylate superplasticizer can reduce the pumping pressure and pipe pressure by about 30%; for lightweight aggregate concrete, the addition of polycarboxylate superplasticizer can reduce the pumping pressure and pipe pressure by more than 10%; in addition, the addition of polycarboxylate superplasticizer can reduce the increase of pumping resistance with the increase of pumping speed.
Steel-fiber reinforced concrete
For steel fiber reinforced concrete, the addition of polycarboxylate superplasticizer can reduce the workability loss caused by the addition of steel fiber; of course, compared with the concrete without steel fiber, the amount of polycarboxylate superplasticizer mixed with steel fiber reinforced concrete should be appropriately increased.
Super high strength concrete
Polycarboxylate superplasticizer has good water-reducing dispersion and strengthening effect, so it can be used to prepare ultra-high strength concrete. The study found that the concrete mixed with polycarboxylate superplasticizer (20%), which accounts for 1% to 3% of the weight of the cementitious material, can make the 100-day-old strength as high as 150MPa.
High-alumina cement concrete
In order to ensure the performance of high-alumina cement concrete, the general water-cement ratio is not higher than 0.40 and the cement content is not lower than 400kg/m3, otherwise the strength of concrete, especially in the later stage, will decrease. The reason is that metastable calcium aluminate hydrate is transformed into steady tricalcium aluminate hydrate. If polycarboxylate superplasticizer is added to high alumina cement concrete, the fluidized concrete with good workability can be obtained under the condition of low water-cement ratio, and the later strength of concrete is not affected. That is to say, the 2d compressive strength of high alumina cement superplastic concrete mixed with polycarboxylate superplasticizer is lower than that of standard concrete, while the compressive strength of 180d age is basically the same as that of base concrete, because polycarboxylate superplasticizer has no obvious effect on the hydration rate of high alumina cement.
High-performance concrete with high content of active admixtures such as fly ash, slag, and silica fume
When preparing high-strength concrete with a large amount of fly ash instead of ordinary cement, adding polycarboxylate superplasticizer can improve workability, reduce mixing water consumption by about 20%, and further improve strength. The addition of polycarboxylate superplasticizer into concrete can increase the amount of cement-based substitute materials such as fly ash or slag and reduce the amount of cement without affecting the strength of concrete. therefore, it has outstanding environmental and economic benefits. Similarly, when silica fume is added to cement slurry or concrete, the amount of water needed to achieve the same workability increases with the increase of silica fume content. For this reason, under the condition of a certain amount of silica fume, polycarboxylate superplasticizer can be added to reduce the water consumption of mixing, and polycarboxylate superplasticizer can also be added to increase the amount of silica fume under the condition of a certain amount of water consumption.
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The agreement reached by EU member states last month to reduce natural gas consumption officially came into effect on the 9th. According to the EU, the move is intended to prepare for possible disruptions in Russian gas supplies.
Under the agreement reached on July 26, EU member states agreed to reduce natural gas demand by 15 per cent from the average consumption over the past five years between August 1, 2022 and March 31, 2023, in accordance with their chosen measures.
Data from the European Commission show that to achieve the above goals, EU member states need to save a total of 45 billion cubic meters of natural gas, while Germany, a "big gas user", should save about 10 billion cubic meters.
If member states do not save enough natural gas and there is a shortage of gas supply, the EU will take compulsory measures to reduce natural gas demand. According to the German news agency, the threshold for the EU to launch the coercive measure is high, requiring at least 15 of the 27 member states to agree and representing at least 65% of the EU population.
The European Commission will review the agreement before May 2023 in the light of the overall situation of natural gas supplies in the EU to consider whether the agreement should be extended.
Luoyang Tongrun Nano Technology is a trusted chemical manufacturer and supplier providing high-quality chemicals and Nanomaterials. If you are looking for the pce powder, please feel free to contact us and send an inquiry.
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