Analysis and Prospect of Waste Heat Utilization from Blast Furnace Slag Flushing

Estimating the residual heat of blast furnace slag flushing in China,classifying and introducing the current proposed methods of slag flushing waste heat utilization,and listing existing cases.In order to better save energy and water in the slag flushing process of blast furnaces,an ideal comprehensive cascade utilization system scheme for annual recovery of waste heat is proposed.Based on the measured waste heat data of a steel plant,design calculations are carried out to further analyze the economic feasibility of the new scheme and provide reference for its promotion and application.

Formation cause,composition analysis and comprehensive utilization of rare earth solid wastes

Based on practical situation of rare earth industrial chain,production process and rare earth materials that could produce solid wastes on batch were discussed.Formation cause,formation volume,composition analysis and comprehensive utilization of the solid wastes of rare earth hydrometallurgy slag,electrolysis slag,Fe-based rare earth permanent magnetic materials,Co-based rare earth permanent magnetic materials,rare earth hydrogen storage materials,rare earth polishing powders and rare earth catalysts were ...

Technology of comprehensive disposal and utilization of municipal solid waste (MSW)

The project for treating MSW of 200 tons each day was built in Yibin, Sichuan Province of China. The disposal processes are: separation and selection of usable resources; compost and fermentation of “heavy” organic waste (kitchen, garden composting rubbish); incineration of “light” waste (plastic, paper, wood and bamboo etc.) and landfill of inorganic waste. The thermal energy generated in the process can be used as 1/3 of the whole energy for drying fertilizers. In the process, there is no wastewater drainage, and air emissions can be effectively controlled by a series of measures. The sanitary and environmental indicators of disposal site meet the national standards. This project has worked well for two years. It not only disposes of and reduces the MSW, but also retrieves the resource effectively. The organic fertilizer has been applied in the ten thousand acres of fields, with productivity increase by more than 10%.

Advances in Research on Comprehensive Utilization of Tea Waste

China is a big producer and consumer of tea. A huge amount of tea waste is produced in China every year, resulting in environmental pollution and enormous natural resources waste. From the perspective of utilization way, this pa- per summarized the research progresses in tea waste as a raw material for ex- tracting active ingredients and preparing absorbent, activated carbon, bio-organic fer- tilizer, animal feed and nutrients for edible fungi cultivation. In addition, the develop- ment trend of comprehensive utilization of tea waste was prospected. It is found that the comprehensive utilization of tea waste using a variety of techniques can im- prove the utilization efficiency of tea waste and reduce production costs. Finally, a simple and practical comprehensive utilization program was proposed to provide a reference for practical application.

Analysis of Comprehensive Utilization of Coconut Waste

This paper describes and analyzes the coconut cultivation in China,and the current comprehensive utilization of waste resources generated during cultivation and processing of coconut.The wastes generated in the process of cultivation include old coconut tree trunk,roots,withered coconut leaves,coconut flower and fallen cracking coconut,mainly used for biogas extraction,direct combustion and power generation,brewing,pharmacy,and processing of building materials;the wastes generated during processing include coconut water,coconut coat,coconut shell and coconut meal,mainly used for processing beverages,pharmaceutical products,activated carbon,medium and feed.This paper analyzes and explores some problems in the process of comprehensive utilization of coconut waste in China,such as insufficient understanding,inadequate development and lack of research efforts,and finally puts forth the corresponding development countermeasures.

Review of the fabrication and application of porous materials from silicon-rich industrial solid waste

Porous materials have promise as sound insulation, heat barrier, vibration attenuation, and catalysts. Most industrial solid wastes, such as tailings, coal gangue, and fly ash are rich in silicon. Additionally, a high silicon content waste is a potential raw material for the syn- thesis of silicon-based, multi-porous materials such as zeolites, mesoporous silica, glass-ceramics, and geopolymer foams. Representative sil- icon-rich industrial solid wastes (SRISWs) are the focus of this mini review of the processing and application of porous silicon materials with respect to the physical and chemical properties of the SRISW. The transformation methods of preparing porous materials from SRISWs are summarized, and their research status in micro-, meso-, and macro-scale porous materials are described. Possible problems in the application of SRISWs and in the preparation of functional porous materials are analyzed, and their development prospects are discussed. This review should provide a typical reference for the recycling and use of industrial solid wastes to develop sustainable “green materials.”

The New Understanding of Potash Development Scale and the Comprehensive Utilization of Resources in Chaerhan Salt lake

This paper briefly introduces resources characteristics and development advantages for Charhan salt lake;and elaborated the technology progress to increase potassium mining scale systematically,the impact of the

Recent Advances in the Synthesis of Zeolites from Solid Wastes

With the rapid development of industrialization,it is inevitable to produce solid wastes in the fields of energy petrochemical industry.However,the storage and utilization of these solid wastes have become a considerable challenge.Due to the main element composition of these solid wastes including silicon and aluminum,it has attracted extensive attention for synthesizing zeolites.This review summarized the properties of major solid wastes including coal fly ash,coal gangue,spent fluid catalytic cracking(FCC)catalyst,lithium slag,bauxite residue,and waste glass.Then,the preparation of LTA,FAU,ZSM-5,SSZ-13,Beta,and MOR zeolites from these solid wastes were introduced.Finally,the current challenges and perspectives were discussed.

Solid State Reaction Yielding a Mineral Utilizing Silica Obtained from an Agricultural Waste

Wollastonite, a mineral of wide industrial applications was synthesised from rice husk ash silica and limestone. A number of raw batches consisting of these starting materials, in 1:1 molar ratio, were heat treated to produce it through solid state reaction from 900℃ to 1300℃. The conducted reaction was monitored by XRD step by step. Amount of Wollastonite formed at every temperature was also studied to some extent. Analyses of the obtained data indicated that the target mineral formation was quite effective and almost proportional to a rise in temperature up to 1200℃. The results from both, XRD and chemical analysis were found in fair agreement with one another

Thermodynamic data calculation for iron phases in sulfoaluminate cementitious materials prepared using solid wastes

The preparation of sulfoaluminate cementitious materials(SCM)is a promising way to massively utilize solid wastes.Iron phases are significant in SCM system but the thermodynamic data of some key minerals,such as6 CaO·Al2 O3·2 Fe2 O3(C6 AF2)and 6 CaO·2 Al2 O3·Fe2 O3(C6 A2 F),are missing,which greatly hinders the SCM optimization in a theoretical way.This work,for the first time,calculated the standard formation enthalpy,Gibbs free energy of formation,entropy and molar heat capacity for C6 AF2 and C6 A2 F and lowered the errors to the least with the reference of C4 AF data in the literature.By building the function diagram of Gibbs free energy changes with temperature for the basic iron phase formation reactions with the obtained thermodynamic data,it is proved that the formation likeliness of C6 AF2 is higher than that of C6 A2 F,as is accordant to the literatures and verifies the correctness of obtained data.This work provides a good theoretical foundation to optimize SCM mineral system and to study relevant mechanism deeply.

New Advanced Technology on Waste Resourcelization of the Black Pulping Liquor

Combining the characteristics of the black pulping liquor that contains a lot of lignin and other biomass resources, the technology of comprehensive waste utilization is employed. The reconstructive preparation of modified urea-formaldehyde glue by adding black pulping liquor and the application in extruding the medium density fibre board using this modified urea-formaldehyde glue is researched. Results show that when applying the preparation technology that alkaline reaction and then weak acid reaction, the appropriate preparation process is as follows： the adding urea process is divided into three stages （proportion 2 ： 1 ： 1） ; the pH value is 8.0, and the reaction time is 40 min in the addition reaction stage; the pH value will be naturally reduced to 3.5 -5.0, and the reaction time is 45 min in the aggregation reaction stage; the pH value is 8.0 in the urea complement stage. And the optimal condition of the reconstructive preparation the modified ureaformaldehyde glue is adding the condensed black pulping liquor after hydroxymethylation in the beginning of polycondensation reaction by 5% proportion. The application in extruding medium density fibre board with this modified urea-fosmaldehyde glue is proved feasible.

Field Utilization of Dried Water Hyacinth for Phosphorous Recovery from Source-Separated Human Urine

This research demonstrated the feasibility of converting source-separated human urine into a solid fertilizer by means of continuous absorption and solar thermal evaporation using dried water hyacinth as adsorbent. In a preliminary experiment, the dried petioles of water hyacinth (DWH) absorbed urine in a mean rate of 18.78 ml·g-1 within 7 d, retrieving about 3.46% urine dissolved solids (UDS). In an advanced experiment, the DWH’s capacity of urine absorption declined from an initial 2.73 L·kg-1·d-1 to 0.68 L·kg-1·d-1, with a requirement of material change in about 25 effective days and an average ratio of 25 (L) to 1 (kg). Phosphorus (P2O5) concentration in the adsorbent increased from 0.46% (material baseline) to 3.14% (end product), suggesting a satisfactory recovery of the element. In field application, the urine was discharged, not in wet weather, onto the DWH via a tube connected to a waterless urinal. There are several ways to use the UDS-DWH as P(K)-rich fertilizer, e.g., making soluble fertilizer for foliage spraying to encourage prolific flowering and fruiting. Apparently, utilization of water hyacinth waste to recover dissolved plant nutrient elements from source-separated urine will benefit the environment in a wide range of perspectives. The herein innovative use of water hyacinth is also expected to be useful in the recycling of certain dissolved hazardous materials.

Site Selection of Waste Slag Yard and Design of Protective Measures in Water Supply Project of Drawing from the Songhua River in Central Cities of Jilin

Water supply project of drawing from the Songhua River in central cities of Jilin is taken as research object.On the basis of analyzing project characteristics and natural conditions of the project area,site selection of waste slag yard of water diversion project and design of water and soil conservation measures are discussed.Rationality of site selection of waste slag yard and pertinence of prevention and control measures of water and soil loss in waste slag yard are analyzed,and comprehensive utilization of waste slag in large-scale production and construction projects is explored.

Analysis and Economic Evaluation of Hourly Operation Strategy Based on MSW Classification and LNG Multi-Generation System

In this study,a model of combined cooling,heating and power system with municipal solid waste(MSW)and liquefied natural gas(LNG)as energy sources was proposed and developed based on the energy demand of a large community,andMSW was classified and utilized.The systemoperated by determining power by heating load,and measures were taken to reduce operating costs by purchasing and selling LNG,natural gas(NG),cooling,heating,and power.Based on this system model,three operation strategies were proposed based on whether MSW was classified and the length of kitchen waste fermentation time,and each strategy was simulated hourly throughout the year.The results showed that the strategy of MSW classified and centralized fermentation of kitchen waste in summer(i.e.,strategy 3)required the least total amount of LNG for the whole year,which was 47701.77 t.In terms of total annual cost expenditure,strategy 3 had the best overall economy,with the lowest total annual expenditure of 2.7730×108 RMB at LNG and NG unit prices of 4 and 4.2 RMB/kg,respectively.The lower heating value of biogas produced by fermentation of kitchen waste from MSW being classified was higher than that of MSW before being classified,so the average annual thermal economy of the operating strategy of MSW being classified was better than that of MSW not being classified.Among the strategies in which MSW was classified and utilized,strategy 3 could better meet the load demand of users in the corresponding season,and thus this strategy had better thermal economy than the strategy of year-round fermentation of kitchen waste(i.e.,strategy 2).The hourly analysis data showed that the net electrical efficiency of the system varies in the same trend as the cooling,heating and power loads in all seasons,while the relationship between the energy utilization efficiency and load varied from season to season.This study can provide guidance for the practical application of MSW being classified in the system.

固体废物的工业窑炉协同处置进展

工业窑炉协同处置固体废物是降低碳排放的重要途径。将固体废物作为替代燃料或原料在现有高温窑炉中进行处置,不仅可以减少污染物排放,还可实现固体废物的减量化、无害化和资源化利用。本文介绍了水泥窑、电厂燃煤锅炉、钢铁冶炼窑炉、煤气化炉等工业窑炉协同处置固体废物技术的现状,分析了多氯代二苯并-对-二口恶英/多氯代二苯并呋喃(PCDD/Fs)和重金属两类典型污染物的排放特征,指出了该技术当前存在的问题,并对其发展方向进行了展望。

赤泥提铁研究进展

我国赤泥堆存量已超过10亿t,主要类型为拜耳法赤泥,该赤泥中含铁量高达30%以上,是经济价值较高的铁资源。目前回收赤泥中铁资源的方法主要是高温还原焙烧-磁选,还原剂以固态碳基还原剂和气基还原剂为主,需大量能耗和成本。我国是农业大国,主要农作物秸秆年产量在7亿t以上,这些生物质具有碳中性、反应活性高、灰分含量低、储量高、可再生等优点,而且热解温度远远低于固态碳质还原剂,其还原三价铁的温度仅为300~800℃,属于低温热解,采用生物质还原焙烧赤泥可大幅降低能耗和成本。本文重点对固态碳质还原剂、气基还原剂和生物质还原剂还原三价铁的参数进行对比,并详细阐述了生物质热解过程及还原赤泥中Fe_(2)O_(3)的机理,认为生物质还原焙烧-磁选技术可以实现赤泥和农业秸秆等固体废弃物的减量化和高值化利用,具有极高的经济价值和环境效益。最后对未来研究赤泥中铁资源回收提出以下建议:加强探究技术耦合实现赤泥产业化处置;回收利用生物质热解产气及热量;探究尾渣综合利用途径;增强对铁铝矿物的分离研究,以实现铁精矿的连续动态化生产。

煤电化基地大宗固废“三化”协同利用基础与技术

我国14个大型煤炭基地及89个大宗固体废弃物综合利用示范基地建设,标志着矿区大宗固废利用已被纳入全国战略发展布局。长期以来煤炭资源高强度的开发与利用,造成矿区浅埋煤层资源临近枯竭,煤电化基地大规模固废堆积及地表沉陷,已成为制约矿区绿色低碳、高质量发展的难题。大宗煤基固废协同利用与绿色充填是解放“三下一上”压煤,延长矿井服务年限,实现固废无害化、资源化、规模化“三化”利用的有效途径。基于产煤大省山西省、“华东能源粮仓”安徽两淮基地及宁东能源化工基地的煤基固废种类和产量,详细阐述了以煤矸石、粉煤灰、炉底渣、气化渣和脱硫石膏等为主要材料的煤基固废通过重金属吸附解吸和络合钝化技术实现无害化处置,列举煤基固废分类应用于低热值煤基固废发电、制备建筑材料如水泥、砖瓦等资源化利用途径,对比分析煤基固废采煤沉陷区复垦回填及井下充填规模化利用途径,突出煤基固废井下充填的优越性。基于煤电化基地深部煤炭资源,提出绿色充填开采理论与关键技术,包括深部煤矸石源头减量与采选充协同技术、充填材料高效制备与深部井下输送技术及煤基固废充填材料深部多场耦合机理,探究多源煤基固废从源头、过程到终端的深部充填开采全过程的技术原理与方法,以解决矿区深部井下充填的技术难题。根据宁东基地任家庄煤矿、山西省霍尔辛赫煤矿及淮北矿区地质条件和充填目的,分别提出超前钻孔注充低位充填方案、关键层非典型特征条件下多离层梯级注浆方案和煤基固废协同利用关键技术,综合矿山固废处置与利用、深部煤炭资源开发利用、地表沉陷控制、生态环境保护等优势,形成煤电化基地大宗固废协同利用与绿色开采模式,为煤炭开采高质量化和环境低损伤化提供参考。

余热余压空气梯级利用的双涡流管有机朗肯循环综合性能分析与优化

为充分利用工业生产中的余热余压空气能量,同时降低ORC系统冷凝热损失,该文提出一种双涡流管ORC系统(ORC coupled with double vortex tubes,DVT-ORC)。利用热源涡流管将放热后的余热余压空气分离成冷、热空气,冷空气用于工质冷却,热空气作为二级蒸发器的热源且换热后其余压用于驱动气动增压泵;利用工质涡流管将透平乏气分离成冷、热气流,热气流经气动增压泵升压再循环,冷气流进入空气冷却器冷却。以150℃、0.6 MPa的空气为初始热源,R245fa为工质,建立热力与经济的多目标优化模型,分析双涡流管冷流比和透平排气压力对系统综合性能的影响;采用遗传算法进行优化,确定系统最优工况。结果表明:当热源涡流管冷流比大于0.3时,DVT-ORC输出功大于基本ORC输出功,工质涡流管与空气冷却器的㶲损失之和较基本ORC系统冷凝器的㶲损失最大可减小1240.32 kW,单位电力生产成本较低,DVT-ORC系统热力性与经济性提升。系统最佳运行工况在透平排气压力为0.3007 MPa、工质涡流管冷流比为0.8738、热源涡流管冷流比为0.8942时,对应的净输出功为173.94 kW、热效率为13.57%、单位电力生产成本为0.415元/(kW·h)。

三种固废改性生土材料配方设计及力学性能研究

为改善生土材料的力学性能,本研究以铁尾矿、煤矸石、电石渣、油泥与水泥等材料作为掺和料对生土进行改性。基于单形格子法设计配方,对3种配方、180个改性生土试件进行抗压强度试验,研究不同因素对试件破坏形态、抗压强度和试验数据离散性的影响;利用频数分析法,研究了固废改性生土材料的最优配方;通过CT扫描,从细观层面分析受荷后材料内部的分形和孔隙。结果表明:改性生土试件抗压破坏形态基本相同,极限位移受掺料影响显著。以煤矸石与电石渣、铁尾矿与水泥、油泥与水泥作为掺和料均可大幅提高改性生土试件的力学性能,掺和料种类、掺量对改性生土试件强度及数据离散性影响显著。经过频数寻优,3种配方的理想强度掺和料配比分别为1)铁尾矿12.1%~19.5%(质量分数,下同)、水泥13.9%~19.1%、生土65.5%~69.9%;2)电石渣6.7%~14.1%、煤矸石8.9%~11.8%、生土76.7%~81.8%;3)油泥11.4%~14.4%、水泥17.4%~19.4%、生土67.1%~70.5%。材料内部的分形和孔隙特征稳定,表现出较小的波动性和良好的密实性。

粉煤灰矿化电厂烟气CO_(2)技术及关键科学问题

燃煤发电是我国能源安全的重要保障,但烟气中会排放大量CO_(2),同时,也会产生大量粉煤灰。利用粉煤灰矿化封存电厂烟气CO_(2),并将矿化产物进行综合利用,可达到大宗固废处置与CO_(2)长效封存的双重目的。目前,粉煤灰矿化电厂烟气CO_(2)技术仍存在矿化效率低、反应时间长、CO_(2)处理量小等不足,其对应的关键科学问题和技术瓶颈亟待解决。简要介绍了粉煤灰矿化烟气CO_(2)的基本原理,分析了不同反应条件对粉煤灰碱土金属离子浸出和CO_(2)矿化反应效率的影响机制,对比了CO_(2)直接矿化反应工艺、碱土金属预浸出工艺、CO_(2)预吸收工艺等3种流程的优缺点,提出了包含粉煤灰碱土金属离子高效浸出、CO_(2)矿化反应过程强化、粉煤灰矿化CO_(2)智能装备、矿化效果综合评价等方面的粉煤灰高效矿化烟气CO_(2)技术体系,总结了粉煤灰矿化CO_(2)产物的物理化学性质,提出了粉煤灰矿化CO_(2)产物高值化综合利用的构想。最后,凝练出了粉煤灰碱土金属离子快速浸出与CO_(2)高效矿化特性、粉煤灰矿化CO_(2)大型反应器中多相混合与反应规律、粉煤灰浆液矿化CO_(2)产物性质的调控机制等3个关键科学问题,指明了基础研究-关键技术与装备研发-工程应用全链条的攻关方向,为粉煤灰高效矿化烟气CO_(2)及产物综合利用提供了参考,对于双碳目标实现和固废综合利用具有重要意义。