Cbc Composite Basic Research, Was Prepared Using Industrial Waste Residue

At present, the annual output of industrial waste residues has reached 1.2 billion tons and the total accumulation is more than 7 billion tons, covering 6.5 hundred million square meter filed, with comprehensive utilization rate 52%. Large accumulation of solid waste is not only taking up land, polluting environment, but also causing wastage of available resources. Thus, solid waste is the major issue that must be made to resolve in our socio-economic development process. Practice shows that, some waste disposal methods such as traditional landfill, storage and incineration have not been suitable for the growing shortage of resources and environmental pollution times and we must follow renewable resources and recycling technologies routes.After about 20 years of development and accumulation, the solid waste resource cause in our country has made certain progress, with growing waste utilization rate and rapid changing technological methods. The target that the rate of comprehensive utilization of industrial waste residue had achieved 50% in "10th Five-Year Plan" through both the representation technology developing to the high-tech direction of waste composite materials, microcrystalline glass, light materials, silicon and aluminum ferroalloy and the large scale waste use of technology such as cement base materials, wall materials, road works, pit backfill. But on the whole, the bottlenecks of technology has not been breakthrough and the facts that small scale, low level of technology, inefficient universal has not been fundamentally changed. Therefore, we must develop the core technology of waste resources recovery that possess recycling efficient, adaptable and good economic returns.According to the inspiration that cement base material is provided with good capacity for accepting the solid waste, favorable operation, low cost and the choiceness performance of ceramics , a low-temperature ceramics cement should be produced with industrial waste residues through changing its mineral structure and reorganization firstly , and a new kind of CBC composite material could be prepared according to the the principles of waste resource composite materials through derived from cement.CBC is abbreviation for Chemically Bonded Ceramics, first proposed by Professor D. Roy, referring to a kind of ceramics material not need to be sintered by high-temperature but to concreted through chemical method, mainly including MDF, DSP, AAS three high-performance cement materials. Academician Zhongwei Wu further elaborated the development prospects of these types of materials, and initiated the PC, RPC, HPC. On the basis of the development, scholars of Qinghua University and South China University of Technology had a keen interest in Geopolymer cement material produced with kaolin invented by J. Davidovits, and conducted with some research and reports, but rarely see related research data.In the non-silicate cement system, taking comprehensive physical, chemical, thermal methods to make the original silicate structures of industrial waste residues such as fly ash, phosphorus slag, tailings unbind and activate to become cement materials, this cement was provided with traditional cement operational performance , consolidating under the conditions of water medium to form a ceramic body structure (CBC) mainly in the structure of long silicon and aluminum chain , not need to sinter at high temperature and no extremeness rigor technics conditions . It is easy to produce vary performances of the CBC composite materials derived from cement with particles, fibers, foams, polymers. This method of industrial waste residues resource recovery has not been reported by others , so it is in original innovative features .Compared with traditional materials: the matrix of CBC composite materials produced by industrial waste residues is chemical bond ceramics, so its main performance is superior to concrete based cement. It could be generated in concrete production processes and utilized industrial waste residues at a large scale . CBC composite material is produced and developed in close to normal temperature atmosphere, avoiding the high temperature sintering and waste emissions in traditional cement and ceramics production. The main raw materials are bulk of industrial waste residues, low-cost, rich sources with significant environmental benefits. Therefore, the systematic study of formation mechanisms, performance and related factors of CBC composite materials produced by industrial waste residues, not only have higher theoretical and academic value, but also be good for virtuous circle of our ecological environment, sustainable use of resources development strategy .In this research, the activation mechanisms of industrial waste residues was explored, the nature of waste residues was analyzed and the study method was identified. Research shows that different kinds of activation methods must be required according to the nature of industrial waste residues , and mainly sum up physical, chemical and heat treatment.1) The primary role of physical activation is to increase of the particle surface ,make conglutinate particles scattered , produce new surface, form surface errors and accelerate the elution of reactive SiO₂, Al₂O₃ , which is good for making the external ion penetrated, and provided a prerequisite for active play.2) The primary role of Chemical activation is to make the high degree of convergence silicate network depolymerization generate CSH, CAH, AFt, AFm through the addition of various alkaline catalyst , the hydration substance different from nature of waste residue even in the same inspired conditions. The offspring of fly ash stimulated by alkali and alkali earth metal solution is amorphous aluminum silicate gel and CSH weaving silicate network structure. The hydration substance of slags which was stimulated by sodium hydroxide and water glass were needle shaped C-S-H gels and hydrate calcium aluminum gels. Needle shaped C-S-H gels are generated by condensation polymerization between silicic acid anions which was generated by condensation polymerization of water glass and Ca²⁺, Al³⁺ generated by slag depolymerization . Hydrate calcium aluminum gels are generated by re-gather of monomers which resulted from slag depolymerization. The hydration substance of metakaolin were C-S-H gels, C₄AH₁₃, C₃AH₆) and C₂ASH₆ activated with lime.3) Heat activation need to be adopted to coal gangue, tailings, and red mud because they contained clay minerals. The theory basis is that clay mineral is Stratiform structure aluminium silicate mineral, under the calcine conditions, the link and allocation of stability silicon oxygen tetrahedron structure and aluminium oxide octahedron structure will occur larger change. The existing broken bond and action spot to form metakaolin. The configuration of metakaolin atomic is irregular, presenting thermodynamic metastable state and possessing higher eruption reactive, and it could reacted with Ca(OH)₂convertted from cement and generate new glue substances such as hydration calcium aluminum, hydration calcium silicate,.CBC cement material is the basic of composite materials and its preparation is the focus study in this paper. According to the different natures of waste, three systems CBC cement materials including fly ash, phosphorus slag and tailings were studied systemically.1) In the system of fly ash CBC cement, lime, sodium hydroxide, gypsum, sodium sulfate, sodium carbonate, flue ash have all shown some inspired effects. The stimulate effect was better when two or more mixed than single. Especially it would get a significant mutual stacking effect when lime and sodium hydroxide were mixed at a certainly proportion. On this basis, the way that addition to the potassium aluminium sulphate, ferric chloride, sodium silicate, amphetamine-tanks latex, stearic acid calciutm which plays a role of improving intensity, plugging pore and suppressing float frost. In certain inspired system circumstances, the conditions of ratio of water and glue, conservation, storage, and changings of raw material would affect the performances of CBC cement.2) In the system of phosphorus residue CBC cement, Na₂O-SiO₂ inspired system was more suitable. In this system, module of water glass, the amount of excitated agent, ratio of water and glue, surface active agent and conservation conditions could directly affect the performance of cement .3) In the system of tailings CBC cement, tailings need to be calcine firstly, , the heat treatment conditions of tailings, the modules and the dosage of water glass both were important factors in the excitated system of Na₂O-SiO₂. Better effects could be produce if mixed with slag or fly ash in tailings, and this CBC cement was more suitable concreted in vapor pressure.4) XRD shows that, mechanical milling could only change externalities of fly ash particles but not change its mineral structure. The main mineral characteristics of fly ash has no significant changes when the CBC cement of Na₂O-CaO- fly ash was maintained in 0. 5MPa steam pressure for eight hours, and there were two neonatal hydration products include calcium silicic acid and calcium aluminosilicate , and there were not hydrate silicate calcium, calcium hydroxide and Aft gels which generated from Portland cement, also hydrate sodium silicate , hydrate sodium aluminium and other Na⁺ salt were not detected by diffraction peak . All above facts indicated that the hydrate substance were unformed aluminosilicate. The hydrate substance of phosphorus residue CBC cemenIn were hydrate calcium silicate and calcium carbonate and the main basic attributes of phosphorus slag had not changed, In this system, hydrate calcium silicate was generated by Ca (OH)₂ released from phosphorus residue reacted with water glass and reorganization and condensation polymerization of unformed hydrate silicate separated from phosphorus residue . The hydrate substance of tailings CBC cement were mainly long chain aluminum silicates formed from the active SiO₂, Al₂O₃ generated in the process of sintered reacted with alkaline excitated agent , Si-O-Si and Si-O-Al silicate structure generated after through hydration, recomposition, ion exchange, condensation polymerization. Therefore, it shown good physical mechanics and resistant corrosive performance.5) SEM reveals that the concreted body structure of three CBC cement is compact, there is no clear interface between aggregate and cement, which is one of the reasons why they are provided with good mechanics performance and low water absorption rate. On the basis of CBC cement, the preparation mechanism of particle enhanced and polymers modified CBC composite materials have been studied basically.6) The main factors affecting the performance of CBC composite materials were the performance of CBC cement, aggregate species, ratio of gels and aggregate, ratio of water and cement, molding conditions and conservation processes in the particles strengthen system. Studies show that, in the systems of phosphorus slag, tailings and fly ash CBC cement, it was available to equivalent substitute 25-30% of the phosphorus slag, slag, copper slag, quartz sand, glass and other mineral for active powder such as fly ash. The casting tailings, phosphorus slag, quartz sand, slag could be used as aggregate. The interface situation of basal body and aggregate could be improved by adding water reducing agent and surface active agent and lead to improve the performance of composite materials through reducing water consumption. Either pressed or cast shaped craft was practicable, but normally, press shaped craft could produce better performance. CBC composite materials were suitable for conservation in the hot and damp condition, the higher the temperature was, the shorter time required. It could produce high-intensity composite materials with compressive strength of more than 100MPa under the condition of reasonable technological parameters.7) The effects of polymers differ from the systems of CBC composite materials enhanced with particle. The modifying effect of amphetamine-tanks latex to the system of phosphorus residue CBC composite materials was obvious, it could condense the time of concretion , significantly improve the bending intensity and reduce the rate of water absorption. A new CBC-PM composite materials whose continuous phase was CBC and scattered phase was polymer could be formed modified with thermoplastic waste plastic in the condition of steam pressure conservation. In this composite materials, these parameters such as ratio of glue and aggregate, ratio of glue and polymer, configuration of plastic, quantity of mud and conservation craft directly affect the performance of composite materials. The CBC-PM composite materials was provided with the performances of ceramics and macromolecular for example corrosion resistance, enduring heat hot and high impact, and could be used as wood.8)Techno-economic analysis shows that , CBC composite materials was provided with excellent physical mechanics performance and stability, enduring sink and freezing, corrosion resistance, withstand high temperatures and enduring heat hot, which could be used widely to replace concrete, ceramics, stone, macromolecular polymers, and metal materials. The manufacture process of CBC composite materials was simple and almost no secondary waste emissions, which is consistent with the national industries policy of energy and environmental protection and fit for the resources recovery of so many industrial waste residues. The expected social, economic and environmental benefits will be significant.