Research Status and Development Direction of Mineral Materials Science in China

Libing Liao

1 Introduction to Materials Science and Engineering

1.1 Basic Concepts

Material (Material): a substance used by human beings to make objects, devices, components, machines, and other products used in life and production.

Materials are substances, but not all substances can be called materials, such as fuels, chemical raw materials, industrial chemicals, food and drugs, are generally not considered materials.

Materials are a sign of the level of scientific and technological development and the degree of modernization of a country.

Materials science, energy science, and information science are the three pillars of modern science and technology.

New materials, information and biotechnology are the main symbols of the new technological revolution. Material Science (Material Science) is based on crystallography, solid state physics, thermodynamics and dynamics, metallurgy and chemical engineering and other disciplines, the intrinsic laws of materials and applications of science. Materials Engineering (Material Engineering or Technology) is based on the performance required in the application of materials, the application of known laws and theories, from the composition, structure, properties, etc. until the specific application of engineering design and implementation of science.

Material Science and Technology (Material Science and Technology) is a discipline that studies and applies the relationship between the composition, organization, structure, and preparation processes of materials and their properties and uses.

1.2 Classification of materials

(1) According to the composition, microstructure and properties of the materials are divided into: inorganic nonmetallic materials (Inorganic Nonmetallic Materials), organic polymer materials (Organic Polymers), metal materials (Metals and Alloys. Metallic Materials) and Composites.

(2) according to the nature and use of materials: ① engineering (structural) materials (Structural Materials). By its structural characteristics and determine the strength of the material, hardness and other mechanical properties to meet the structural needs of engineering and technology, mainly used in engineering and technology of a class of materials. Including metal materials, ceramic materials, polymer materials, composite materials. ② functional materials (Functional Materials). With special electric, magnetic, optical, acoustic, thermal, force, chemical and biological functions of the new materials; information technology, biotechnology, energy technology and other high-tech fields and important basic materials for national defense construction; at the same time, the transformation of certain traditional industries, such as agriculture, chemical industry, building materials and so on play an important role. In the field of global new materials, functional materials account for about 85%. Special functional materials for the development of high technology plays an important role in promoting and supporting, is the new century biology, energy, environmental protection, space and other key materials in the field of high technology, has become the focus of the development of new materials in various countries, is the development of high technology in various countries in the strategic competition hotspot. Functional materials according to the use of performance is divided into microelectronic materials, optoelectronic materials, sensor materials, information materials, biomedical materials, eco-environmental materials, energy materials, machine sensitive (intelligent) materials.

(3) Nanomaterials (Nano-Materials): is about atomic clusters, nanoparticles, nanofilms, carbon nanotubes and nanosolid materials in general. Clusters: particles that contain a few to hundreds of atoms or have a scale of less than 1 nm, an aggregate of atoms between atoms and solids. Nanoparticles: larger than atomic clusters and smaller than usual particles, generally 1 to 100 nm in size. nanofilms: thin films containing nanoparticles and atomic clusters, thin films with nano-sized thickness, nanoscale second-phase particle deposition coatings, nanoparticle composite coatings, or multilayer films. It has quasi-3D structure and features with unusual properties. Nanosolids: solids with new atomic structure or microstructural properties obtained by the arrangement of atoms in nuclei with defects such as grain boundaries, phase boundaries, or dislocations at the nanoscale level. Nanocrystalline materials (with a high density of defective cores, more than 50% of the atoms are located in the defective cores), nanostructured materials (consisting of many defective core regions separated by elastic distorted crystalline regions), nanocomposites (O-O composites: different kinds of nanoparticles are composited; O-2 composites: nanoparticles are dispersed into 2D thin-film materials; O-3 composites: nanoparticles are dispersed into 3D solids). Basic properties of nanoparticles: discontinuity of electronic energy levels (quasi-continuous energy level discretization), quantum size effect, small size effect, surface effect, macroscopic quantum tunneling effect. The special properties of nanoparticles lead to a range of special properties of nanomaterials.

(4) Porous Materials: have high specific surface area, high adsorption, ion exchange properties. They are widely used in the fields of adsorption, separation, catalysis, nanotechnology, molecular recognition, petrochemicals, fine chemicals and molecular electronic devices. According to the classification scheme of the International Union of Pure and Applied Chemistry (IUPAC), porous materials are classified according to the pore size into: microporous materials (d < 2nm), mesoporous materials (2nm < d < 50nm), macroporous materials (d > 50nm).

(5) four elements of materials research: properties and performance (Property and Performance), composition (Composi-tion), structure (Structure) and synthesis and processing (Process)

2 Introduction to Mineral Materials Science

2.1 Basic Concepts

Mineral Material (Mineral Material): natural minerals or rocks as the main raw materials, by not purifying metals and chemical materials for the purpose of processing, transformation of materials obtained or can be directly applied to its physical and chemical properties of minerals or rocks. Mineral materials science (Mineral Material Science): is the study of mineral materials, composition, structure, properties, performance, processing and preparation process and the relationship between each other and the engineering application of mineral materials and technology of a comprehensive fringe disciplines.

2.2 Research content of mineral material science

Basic theoretical research: the nature of mineral materials and its mineral composition, amorphous composition, chemical composition, trace elements and other material components of the relationship between the nature of mineral materials and the mineral crystal structure, crystal chemistry, polymorphism, crystallinity, order, etc., as well as the relationship between the rock structure, structure and so on. Crystalline boundaries, surface, particle size, etc.; the nature of the mineral material and its use of raw materials, ore types, raw material origin, etc.; the nature of the mineral material and its processing and transformation of the temperature, pressure, atmosphere, mineralizing agent, binder, emulsifier, coupling agent, etc., the relationship between the processing conditions; and so on.

Production technology and application research: production process route of mineral materials, processes, equipment, the best formula and other engineering technology issues, as well as the application of mineral materials, applicable conditions and preservation methods.

2.3 Classification of Mineral Materials

Divided according to the composition, structure and properties of mineral materials (monoclinic, diclinic ......);

Divided according to the use of mineral materials (ceramics, glass, refractories ...... );

Divided by the state of mineral materials (monocrystalline, polycrystalline, amorphous, composite, dispersed);

Divided according to the characteristics of the processing process: natural mineral materials, deep-processed mineral materials, composite and synthetic mineral materials;

Comprehensive classifications: molten slurry-type materials (fused injection of crystals, vitreous enamel fibers, etc.), sintered materials (refractory, ceramics, etc.), thermal insulation materials

Suggested classification scheme (according to the nature and use of the material): structural mineral materials (stone, structural ceramics, mineral-reinforced polymer composites, etc.), functional mineral materials (environmental mineral materials, nano-mineral materials, biomedical mineral materials, special functional mineral materials, etc.).

2.4 The significance of the study of mineral materials

Nonmetallic minerals in the national economy has a very important role in almost all areas of the national economy, with the continuous development of science and technology, non-metallic minerals are still expanding the field of application. In economically developed countries, the total output value of non-metallic minerals is greater than the total output value of metal minerals, so some scholars to non-metallic minerals output value is greater than the output value of metal minerals as a measure of a country whether to reach the mark of industrialized countries, and predicted that the 21st century will enter the "Neolithic era". The development and application of non-metallic minerals lies not only in the mastery of non-metallic mineral resources, but also in the mastery of non-metallic mineral development and application of advanced technology. China's non-metallic mineral resources are very rich, there are 87 kinds of proven reserves, the origin of more than 6000 places. However, due to China's non-metallic mineral development and application of backward technology, most of the non-metallic minerals are rough products, so the total output value is very low.

It is of great significance to carry out and strengthen the research of mineral material science to improve the utilization of non-metallic mineral resources in China, to improve the quality of life of the people, and to promote the economic and social development.

3 China's mineral material science research status

3.1 Research on deep processing of non-metallic mineral raw materials

Research is mainly toward ultrafine crushing, fine grading, purification and modification and multi-species direction. As a result of progress in the development of crushing technology, ultra-fine crushing and grading equipment, our country has been able to carry out a variety of particle size crushing and grading, individual minerals crushing and grading level has reached the international advanced level. Purification research has also made great progress, mainly in: for new types of minerals purification of new processes emerge in large quantities, the traditional non-metallic mineral purification process has been improved, micro-fine particle purification and high purity processing technology and equipment has been a significant development.

In short, in the theory, methods, equipment, mineral processing, mineral processing chemicals have achieved promising results in the application of research. China now has a basic mature processing of high-purity graphite, quartz, diatomite, kaolin, bentonite, rutile and other technologies.

3.2 Mineral pore or interlayer domains of ions, molecular exchange, insertion-related research

has become a hot spot in the study of mineral materials. The research object is mainly zeolite and other minerals with pore structure, rock and montmorillonite-based various clay minerals and graphite and other minerals with layer structure. The research includes: pore or interlayer ion exchange technology and its application; clay minerals interlayer "column support", insertion technology and its application. The aim is to utilize the exchangeability of substances in the pore or interlayer domains of these minerals and the swellable nature of the interlayer domains, or to modify these properties so that they have new and excellent characteristics that can be utilized. For example, by modifying clay minerals, zeolites or expanded graphite with the ability to adsorb different hazardous components, adsorbents can be prepared that can be used for a variety of environmental treatments. The research and application areas in this regard are very wide, in addition to the application in sewage treatment, modified pore structure and laminated structure of mineral rocks are also widely used as catalyst carriers, fertilizer synergists, water repellents, swelling agents, anti-settling agents, gelling agents, bonding agents, plasticizers, thickening agents, suspending agents, decolorants, conductive materials, fast-ionic conductor materials, dyeing agents, desiccant, filtration agents, and so on.

3.3 Mineral surface modification technology and its application research

That is, the use of physical and chemical methods of mineral surface treatment, change its surface properties, such as the surface atomic structure and functional groups, surface hydrophobicity, electrical properties, chemical adsorption and reaction properties, etc., to achieve the purpose of improving or enhancing the performance of the application of minerals. Mainly for the minerals as fillers added to a variety of organic polymers, so that the minerals and polymers have good compatibility, but also to improve the dispersion of mineral fillers in the polymer. The research mainly includes: the selection of surface modifiers, the effect of different surface modifiers on different minerals, the surface modification process, the effect of surface modification and so on.

Surface modifiers are divided into organic and inorganic categories: ① organic surface modifiers: coupling agents (silane, titanate, zirconium and complexes, etc.), advanced fatty acids and their salts, polyolefin oligomers, unsaturated organic acids, organic amines; ② inorganic surface modifiers: titanium oxide, sodium oxide, iron oxide, zirconium oxide, alumina, silicon oxide and other metal oxides.

Currently the most widely used surface modifiers are coupling agents, including silane coupling agent and titanate coupling agent is the most widely used. Silane coupling agent on the surface of the active hydroxyl mineral effect is better, on boron, iron, carbon oxides, the effect of the second, the surface does not contain hydroxyl carbonate, alkali metal oxides are almost ineffective.

Titanate coupling agent on the minerals applicable to a wide range of surface active hydroxyl quartz as well as the surface of neutral or alkaline calcium carbonate, titanium dioxide, feldspar, hornblende, and most of the non-metallic minerals have a good coupling effect.

3.4 Research on new building materials with non-metallic minerals as raw materials

Non-metallic minerals as raw materials for building materials is the most traditional research field of mineral materials. With the development of science and technology, the level of research in this field has also been improved, new technologies continue to emerge, is still an important field of mineral materials research.

The research content is mainly focused on three aspects: the application of traditional raw materials and minerals of new technology research, the discovery of new raw materials and minerals instead of traditional raw materials and minerals, new building materials development research.

The application field is extremely wide, involving a variety of coatings, refractories, cement, glass, ceramic products and so on.

3.5 Research on the comprehensive utilization of useful elements in non-metallic minerals

Generally speaking, the development and utilization of non-metallic minerals do not aim at extracting and utilizing a certain element in them, which is the biggest difference with metal minerals.

Because of the scarcity of resources and some non-metallic minerals, rocks have special composition, structure, comprehensive utilization of non-metallic minerals in the study of certain elements is increasingly important.

For example, due to the serious shortage of potassium resources in China, has become a major factor affecting the development of China's agriculture, and many non-metallic minerals and rocks are rich in potassium, so the development and utilization of non-metallic minerals and rocks in the potassium, caused by the attention of mineral materials researchers, potassium feldspar, potassium-containing shale, ilmenite and other potassium-rich minerals and rocks have been carried out one after another over the activation and preparation of potassium fertilizer into the minerals.

3.6 Synthetic mineral materials research

Synthetic mineral materials research includes two aspects: the use of a natural mineral synthesis of another mineral; chemical reagents to synthesize minerals.

The main new achievements: the production of activated silicon dioxide by reacting with phosphoric acid using Aubergine, the production of ultra-light calcium silicate using natural zeolite, the synthesis of zeolite using foliated paraffin, synthetic diamonds, synthetic soapstone, synthetic chalcopyrite-type solar cell materials, the synthesis of silicon nitride, sialon and so on using quartz, fly ash and so on as raw materials.

3.7 Research on Environmental Mineral Materials

Environmental mineral materials refers to natural mineral rocks as the main raw materials, in the preparation and use of the process can be compatible and coordinated with the environment or can be degraded by the environment after disposal or the environment has a certain purification and restoration function of the material.

The use of natural minerals to develop environmental mineral materials have unique conditions, because: mineral materials raw materials are natural minerals, and the environment has good compatibility; mineral materials production energy consumption, low cost; comprehensive utilization of mine tailings itself belongs to the study of environmental materials; a lot of mineral materials have a very good environmental restoration, environmental purification function.

So, vigorously carry out and strengthen the mineral environmental materials research in line with the characteristics of mineral materials, the establishment of environmental mineral materials discipline branch is the requirement of the times, is an important development direction of mineral materials.

Based on the characteristics of mineral materials and applications in the field of environmental protection, the main direction of development of environmental mineral materials is: ① environmental engineering mineral materials - that is, with environmental restoration (such as atmospheric and water pollution control, etc.), environmental purification (such as sterilization, disinfection, filtration, separation, etc.) and environmental substitution (such as substitution of environmental) Environmental engineering mineral materials - that is, with environmental repair (such as air and water pollution control, etc., environmental purification (such as sterilization, disinfection, filtration, separation, etc.) and environmental substitution function (such as substituting the environmental load of the material) of the mineral materials; ② environmentally compatible mineral materials - that is, with the environment has a very good compatibility and coordination of mineral materials (eg, ecological building materials).

Mineral materials used for environmental purposes began a long time ago, in recent years it is much attention, new technologies, new materials, new applications are endless.

Mineral materials in addition to the traditional sewage treatment, atmospheric adsorption, filtration, decolorization and other aspects of the application level continues to improve, in the ecological building materials (such as low-temperature fast-fired ceramics, with heat preservation, insulation, sound absorption, dimming and other functions of building materials, etc.), fungicides, disinfectants, mine tailings comprehensive utilization and other aspects of the new application of technology and products.

3.8 Nano mineral materials research

This is a new field of mineral materials research, related to many of the above research areas. For example, the deep processing of non-metallic minerals in the ultra-fine crushing, is developing in the direction of nanoscale, has prepared a number of nanoscale non-metallic mineral products; through the column support, the laminated structure of silicate minerals stripped to nanoscale particles used for rubber and plastic products enhancement, etc. has become a laminated structure of the mineral modification of the application of the new direction; the synthesis of microporous, mesoporous mineral materials, filling (self-assembly) will be more and more people's attention, and so on.

3.9 Biomedical mineral materials research

Including biomedical materials and mineral medicine.

Biomedical materials: materials that are used to interface with biological systems to diagnose, treat or replace tissues or organs in biological organisms or to enhance their functions. Also known as biomaterials.

Mineral medicine: a variety of medicinal herbs prepared from natural minerals as raw materials or one of the raw materials.

3.10 Special Mineral Functional Materials Research

For example, the discovery of photonic crystals with an opal-type structure, ordered square quartz used in the preparation of nonlinear optical crystals or as a template for the preparation of photonic crystals, modified montmorillonite used in the preparation of composite electrodes with high stability, repeatability and catalytic properties, fibrous seafoam as a reinforcing material for the preparation of friction materials.

3.11 Other applications of mineral materials research

Mineral materials research also includes gemstone processing and improvement, basic theoretical research on mineral materials and many other aspects, it is difficult to briefly summarize. Gemstone processing and improvement has developed into a specialized field, not to focus on.

4 important development direction of mineral materials

4.1 important non-metallic minerals in different physical fields and chemical environments in a variety of effects

Metallic minerals is mainly to apply it to a particular element, while non-metallic minerals is mainly the application of its physical and chemical properties and process characteristics. Process characteristics and mainly depends on the chemical composition of non-metallic minerals, structure, structure and its optical, electrical, thermal, magnetic, acoustic and dissolution, adsorption, catalytic, diffusion and other physical and chemical properties.

Therefore, the development and application of non-metallic minerals is based on the composition, structure and various physical and chemical properties of non-metallic minerals. Carry out non-metallic minerals field effect and application of basic research, will be able to obtain important non-metallic minerals complete physical and chemical performance parameters and find out these parameters and mineral composition, structure, the external environment of the relationship between the establishment of a non-metallic mineral database, is conducive to the development of mineral material design research. Improvement of the existing mineral processing technology, improve the existing material preparation process with these minerals as raw materials, to open up these non-metallic minerals new ways of application and new areas of application, to carry out research on the design of mineral materials are of great significance.

Research content: under the action of electric field, magnetic field, light wave, acoustic wave and so on, or in a variety of chemical environments, the non-metallic minerals of various parameters (i.e., non-metallic minerals, physical and chemical properties) to test; to explore the relationship between these parameters and the mineral composition, structure, and the relationship with the external conditions.

The purpose is to obtain comprehensive physicochemical parameters of important non-metallic minerals, and to lay the foundation for their effective application or to develop new fields of their application.

4.2 Surface and Interfacial Studies of Nonmetallic Minerals

The surface of a mineral is the interface between the mineral and the vacuum or the gas, and there are many active chemical properties on the surface as well as physical properties that are different from those in the body.

Mineral material interfaces are surfaces that are in contact between phases in a mineral material. The interface plays an extremely important role in the properties of multiphase mineral materials, and even control. Surface and interface are both different and related. The surface of mineral raw materials is the basis of the interface of mineral materials, and has an important influence on the interface of mineral materials. Therefore, the study of mineral surface and interface cannot be separated. The surface and interface problems of mineral materials have not been given enough attention. With the development of mineral materials science and the depth of research, the surface, interface and its engineering research will become a frontier field of mineral materials science research. For example, the surface, interface and its engineering are indispensable for the ultrafine and ultrapure processing of minerals and the development of nano mineral materials. The research will utilize advanced analytical techniques such as high-resolution electron microscopy, diffraction liner electron microscopy, scanning tunneling electron microscopy, X-ray spectroscopy, electron energy loss spectroscopy, and synchrotron radiation continuous X-ray energy dispersive diffraction, etc., to study the surface of minerals and mineral materials, the composition of the interfacial layer phase and the compositional changes, the dislocation type and distribution, and the residual stress, etc., and reveal the surface and interfacial composition and structure details and their relationship with the surface and interface on a wide range of microscopic scales. We will study the surface and interface composition, structural details and their relationship with material properties; focus on the pore structure characteristics of shelf and layer minerals, interlayer structure characteristics, and various chemical and physical properties of the pore and interlayer domains; and study the surface characteristics of mineral powders of various shapes and grain sizes, as well as the relationship with the processing technology. Focus on the exploration of minerals, ultra-pure, ultra-fine process and its impact on the surface of mineral powders, interfacial properties; the use of mineral surfaces, interfacial research results, the use of existing surface and interfacial engineering means, research and development of a series of important non-metallic minerals mainly layered minerals, deep processing of new technology, developed a series of excellent performance of the new mineral materials.

4.3 new mineral materials design research

Materials design is the rapid formation and development of a branch of materials science in recent years, is a combination of materials science theory and modern computer technology is the product of the socio-economic development of the materials science research requirements, because the traditional "trial and error" method has been The traditional "trial and error" method has been unable to prepare new materials to meet the requirements of the times, only in the theoretical guidance of the "rational design", that is, according to the specific requirements of the material, the material formula, preparation process, material properties and behavioral mechanisms for prediction.

Mineral material design has not been explicitly proposed, but there have been some reports of work related to this. It can be expected that with the development of mineral material design, the level of mineral material development will be raised to a new level, and new mineral materials will continue to appear. This work should pay attention to attract materials chemistry, materials physics and computer specialists and scholars to participate in a wide range of experts and scholars.

4.4 Research on Environmental Mineral Materials

In recent years, although the rapid development of environmental mineral materials, fruitful results, but environmental mineral materials as a branch of the discipline has not yet been established, environmental mineral materials, environmental engineering mineral materials, environmentally compatible mineral materials, environmental degradation of mineral materials, environmental burdensomeness assessment, life-cycle assessment (LCA) and other concepts have not yet been widely accepted. widely accepted.

In the future, research on environmental mineral materials should be further strengthened, the research and application level of environmental mineral materials should be improved, the application fields of environmental mineral materials should be expanded, the related theories (eco-design, eco-processing, and eco-assessment) of environmental mineral materials should be developed, and the influence of environmental mineral materials should be enlarged in the academia and industry.

Therefore, the development of environmental mineral materials science is still a long way to go.

4.5 Research on the theory of efficient application of agricultural mineral resources and application process

China is a large country with large population and large agricultural country, facing the huge pressure of feeding a large population with a small amount of land. The way to solve the problem can only rely on scientific farming, improve yield and maintain ecological balance. Natural non-metallic minerals can play an important role in all these aspects. The application of non-metallic minerals in agriculture mainly includes: the production of fertilizers, including nitrogen, phosphorus, potassium fertilizers; micronutrient fertilizers; rare earth elements fertilizers, organic fertilizers, etc.; as feed ingredients or additives; as a pharmaceutical minerals and carrier minerals used in the production of pesticides or pesticides directly; used for soil improvement.

The above applications have been carried out, but the application of low level of technology, the scope of narrow, far from meeting the needs of agricultural development, but also far from giving full play to the application of non-metallic minerals in this regard potential. For example, China is a shortage of potash resources in the country, the insoluble potassium in the potassium-containing mineral rocks for development research, can solve the problem of shortage of potash resources in China. However, there is still no major breakthrough in this area of research, and the main problem is that we have not yet searched for process technology with high efficiency, low cost and small environmental burden.

Research includes: activation, extraction and comprehensive utilization of potassium mineral rocks; non-metallic minerals in trace elements, rare earth elements and other useful elements of the comprehensive utilization of research; non-metallic mineral rocks in soil and water improvement, ecological environment improvement in the application of research.

4.6 Research on Nano Mineral Materials

Because nanomaterials have unique composition, structure, properties and preparation methods, the research in this area will continue to be the frontier field of materials science. Compared with other nanomaterials, the depth and breadth of research on nanomineral materials need to be increased. Therefore, in addition to other nanomaterials faced by the *** problem, nanomineral materials should strengthen the following aspects of research: nanomineral materials preparation of new technologies, the development of new nanomineral materials, nanomineral materials related to theoretical research.

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