Critical materials selection for 700℃clean and high-efficiency coal-fired boiler

One of the pathways for achieving the goal of increasing the efficiency of coal-fired power plants and reducing the emission of pollutants and CO_2 is by improving the steam temperature and pressure.But the increase of steam parameters depend on the development of new high-temperature metal materials.This paper presented the constructive suggestions on critical materials selection for China's new generation of 700℃clean and high-efficiency coal-fired boiler by summarizing the research and development situation of critical materials for coal-fired boilers operating at 700℃/35 MPa of the Europe,Japan and USA.

Coal and coal byproducts:A large and developable unconventional resource for critical materials—Rare earth elements

Rare earth elements（REEs） are critical materials and provide significant values to national security,energy production, environmental protection and economic growth. The supply of REEs in U.S. solely relies on import as domestic production of REEs was ceased because of the environmental concerns during mining and lack of competitiveness. Nonetheless, unconventional REEs-containing resources,including produced water. acid mine drainage, and coal and coal byproducts（C＆CBs） contain significant amounts of REEs. However, the concentrations of REEs in these resources are several orders of magnitude lower than that of REEs ores. Thus, extraction of REEs from these materials is challenging. Here we report REEs extraction with environmentally friendly method that successfully concentrated REEs from312 ppm in fly ash to 99.4% in the final product. Especially, the five critically important REEs（Dy, Eu, Nd.Tb. and Y） account for up to ～63% of the total weight of all REEs in the final 99.4%-purity product. Coal fly ash is one of the major solid coal utilization byproducts, representing great potential resources for REEs extraction. Extraction of REEs from these unconventional resources could be the way to secure domestic supply of these critical materials.

Influence of the gassing materials on the dielectric properties of air

Influence of the gassing materials, such as PA6, PMMA, and POM on the dielectric properties of air are investigated. In this work, the fundamental electron collision cross section data were carefully selected and validated. Then the species compositions of the air–organic vapor mixtures were calculated based on the Gibbs free energy minimization. Finally, the Townsend ionization coefficient, the Townsend electron attachment coefficient and the critical reduced electric field strength were derived from the calculated electron energy distribution function by solving the Boltzmann transport equation. The calculation results indicated that H;O with large attachment cross sections has a great impact on the critical reduced electric field strength of the air–organic vapor mixtures. On the other hand, the vaporization of gassing materials can help to increase the dielectric properties of air circuit breakers to some degree.

Exploring the potential for improving material utilization efficiency to secure lithium supply for China's battery supply chain

Lithium-ion battery(LIB)is the key technology for climate change mitigation.The sustainability of LIB supply chain has caused widespread concern since the material utilization efficiency of LIB supply chain has not been well investigated.This study aims to fill this research gap by conducting a dynamic material flow analysis of lithium in China from 2015 to 2021.Results indicate that within the temporal boundary,lithium flow and in-use stock grew significantly in China due to the rapid development of the EV market,with lithium flow in domestic production of basic chemicals increasing by 614%to 100 kt,end-use consumption increasing by 160%to 35 kt,and in-use stock increasing by 62%to 195 kt.China has been a net importer of lithium,of which cumulative imports and exports were 343 kt and 169 kt,respectively.In addition,103 kt of lithium was converted to inventories or was lost during the processing from 2015 to 2021.By optimizing inventory and processing,developing substitutes for lithium for non-battery applications,and improving lithium recycling,China's net import dependency of lithium could be reduced from 27%-86%to 0%-16%.Our study demonstrates that it is urgent to improve material utilization efficiency so that the lithium resource supply can be secured.

Promotion and implementation of Polish mining investments in foreign markets on the example of Latin America

Foreign investments are essential in deepening economic relations between the EU and Latin America.As Latin America is fortunate enough to have deposits of metals that have become particularly desirable due to the green industrial revolution,it remains one of the dominant directions of exploration and investment in the mining sector.To intensify cooperation within the mining industries based on their complementarity,common goals,and shared values,the EU-Latin America Mineral Development Network Platform was established for all entities relevant to the mining sector,not only authorities but also businesses(including SMEs)and scientific and research units.To create a common European understanding of best practices in the processing and mining of raw materials in terms of social,environmental,and economic performance,voluntary EU principles for sustainable raw materials have been developed.Moreover,many EU countries working on updating or implementing(Poland)mineral policies,and more and more EU and Polish mining companies have been reporting non-financial aspects and impacts on local development,also in foreign countries.At the end of 2022,the European Commission proposed a Critical Raw Materials Act:securing the new gas&oil at the heart of our economy initiative to enhance the diversification and supply of critical raw materials to Europe.So far,the largest Polish foreign investment is a copper mine in Sierra Gorda in Chile,owned by KGHM Polska Mied´z SA together with the Japanese Sumitomo Group(from February 2022,Australian mining group South32).Even according to KGHM CEO,Marcin Chludzi´nski,the Sierra Gorda mine had needed restructuring and now is a demanding but very satisfying project.KGHM reported that the revised EBITDA for 2021 was the highest and achieved PLN 10.3 billion(ca EUR 2.3 billion)year on year(+56%)and for the first time,Sierra Gorda began to pay off its liabilities towards the owners.Moreover,the mine received an award in the category of large producers awarded by the State Mining Association in Chile(SONAMI).In addition to mining activities in the field of exploration and exploitation of deposits,Poland is developing cooperation in technology(mining machinery)and education.To ensure sustainable extraction of raw materials additional skills are required,in particular in the area of management and social sciences.The aim of the paper is to analyze and identify factors and best practices enhancing international cooperation and the environmental sustainability of minerals in line with the 2030 Agenda for Sustainable Development on the example of Polish investments in Chile.The analyzed case studies in a broader context,including the EU and Polish mineral policy,allow for the development of certain recommendations and tools for the promotion of foreign investments in the mining industry.

Controlling the gelation temperature of biomimetic polyisocyanides

Thermosensitive polymers show an entropy-driven transition from a well-solvated to a poorly solvated polymer chain, resulting in a more compact globular conformation. The transition at the lower critical solution temperature（LCST） is often sharp, which allows for a wide range of smart material applications.At the LCST, oligo（ethylene glycol）-substituted polyisocyanides（PICs） form soft hydrogels, composed of polymer bundles similar to biological gels, such as actin, fibrin and intermediate filaments. Here, we show that the LCST of PICs strongly depends linearly on the length of the ethylene glycol（EG） tails; every EG group increases the LCSTand thus the gelation temperature by nearly 30 ℃. Using a copolymerisation approach, we demonstrate that we can precisely tailor the gelation temperature between 10 ℃ and 60 ℃and, consequently, tune the mechanical properties of the PIC gels.