UTILIZATIONOF SOLID WASTE FROM STEEL MELTING SHOP. A House of Engineering Excellence

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1 UTILIZATIONOF SOLID WASTE FROM STEEL MELTING SHOP 1

2 UTILIZATION OF SOLID WASTE FROM STEEL MELTING SHOP Presentation by Shri Bikas Pandey, MECON Limited, Ranchi At MECON Community Hall MIST 2016, 30 th January,

3 CONTENTS Introduction Types of solid wastes Steel Production vs. Waste generation scenario Waste management-a key issue for steel plant Waste minimisation Waste utilisation Zero Waste steel making & sustainable technology R & D Efforts for solid waste management Suggestions & conclusion 3

4 INRODUCTION India is 3 rd Largest Steel Producer in the World as per production status of year 2015 and our steel market is having strong potential for growth and soon India will be 2 nd Largest steel Producer in the World. In steel industries, the production of steel is associate with generation of substantial amount of various types of wastes. Looking the growth potential and opportunities of steel sector, it is high time to focus with special attention for waste minimization and utilisation for steel industries. In the above prospective and due to focus on various concerns of market, business, environment etc. all type waste management needs special attention particularly our vision, attitude and commitment on this issue 4

5 INTRODUCTION Solid waste or any waste is not a waste unless it is dumped and/or remains unutilized. Waste from one industry can be a raw material for another industry/source of other valuable products Particularly solid wastes generation are unavoidable in steel plants but its possibility for use as value added by-products or saleable products is the key to successful waste management This will be strong step for making our vision successful for producing Clean & Green Steel with Zero Defect & Zero Effect 5

6 TYPES OF SOLID WASTES Solid waste generated from steel melting shop can be broadly categorised as: Process waste Slag Dust GCP Sludge Scrap Refractories Caster Scale Muck & debris etc. Non-process waste Card-board Rubber Electric wire Glass etc. 6

7 TYPICAL SOLID WASTES FROM INDIAN INTEGRATED STEEL PLANT THROUGH BF-BOF-CCP ROUTE 7

8 TYPICAL SOLID WASTES FROM INDIAN INTEGRATED STEEL PLANT THROUGH COREX-BOF-CCP-ROLLING MILL ROUTE Secondary steelmaking slag 3% Secondary steelmaking slag 2% Corex sludge 9% Corex dry slag 18% HM pretreatment dust 0% BOF slag 64% HM pretreatment slag 4% BOF dust/sludge 3% 8

9 TYPICAL SOLID WASTES FROM INDIAN STEEL PLANT THROUGH GAS BASED DR-EAF-CCP-ROLLING MILL ROUTE LF slag 4% EAF dust 4% Total spent refractories 1% Iron ore fines 4% ETP sludge 8% Mill scale 2% EAF slag 77% 9

10 STEEL PLANT INPUT & OUTPUT FLOW SHEET 2.8 tons raw materials 2.5 tons water 5 tons air Proce ess 8.5 tons moist dust laden gases 0.5 ton effluent water 0.4 to 0.8 ton solid waste 1.0 ton steel 10

11 STEEL PRODUCTION VS WASTE GENERATION In the first five decades of post independence era, till the year 2000 about 90 million tons of solid waste was estimated to accumulate. An estimation was there for another addition of about 180 million tons of solid waste till Till the year solid waste in the vicinity of integrated iron and steel plants in India estimated be about 270 million tons. Estimated projected capacity, production of crude steel and solid waste generation rate in Indian steel plants by is depicted as follows. 11

12 STEEL PRODUCTION VS WASTE GENERATION M T Capacity Production Solid waste generation As per our Draft of National Steel Policy 2025, India is aiming for producing 300mt of steel by 2025 and the solid wastes generation are likely to increase enormously in future. 12

13 WASTE MANAGEMENT Waste management practice involve collection, transport, processing, re cycling or disposal of waste materials, in properly defined ways with adequate efforts to reduce their effect on human health or local aesthetics or amenity. These practices shall be aimed for friendliness with the natural world and the environment and to recover resources from them. The waste hierarchy refers to the "4 Rs" reduce, reuse, recycle and restore which classify waste management strategies according to their desirability in terms of waste minimization. The aim of the waste hierarchy is to extract the maximum practical benefits from products and to generate the minimum amount of waste with aim of Zero waste. 13

14 WASTE MANAGEMENT The waste hierarchy as shown remains applicable for the most of waste minimization strategies 14

15 BASIC PRINCIPLE OF WASTE MANAGEMENT The principle of waste management basically involves : Minimisation of waste generation Utilisation of waste generation & recycling. The waste generated from steel plant needs to be taken care properly right from the beginning for its successful management. In steel industry for management of solid wastes followings are significant Solid waste generation is controlled by efficient and optimum use of raw materials. Solid wastes should be disposed carefully through a proper disposal systems. New technologies should be adopted for eco-friendly solid waste disposal. Transportation of solid waste from generation point to disposal point should be in a controlled and proper way. Displaying and identifying the area for solid waste disposal. 15

16 WASTE REDUCTION AND /OR ELIMINATION In general by reducing or eliminating wastes an industry can: Solve the waste disposal problems created by land bans Reduce waste disposal costs Reduce costs for energy, water and raw materials Reduce operating costs Protect workers, the public and the environment Reduce risk of spills, accidents and emergencies Reduce vulnerability to lawsuits and improve its public image Generate income from wastes that can be sold. 16

17 UTILISATION OF SOLID WASTE Utilisation of various process generated solid waste are from steel melting shop are highlighted as follows: SMS SLAG Slag Atomizing Plant (SAP) Precision Slag Ball (PS Ball) 17

18 UTILISATION OF SOLID WASTE SMS Slag can be used as Soil conditions : The soil can be corrected for its PH bay suitable adding liming agent including slag.the basicity of the SMS slag makes it a good liming material for acidic soil. Phosphorous in the slag acts as nutrient to the soil. Therefore, SMS Slag can be used as soil conditioner. Tiles manufacturing : SMS slags have been successfully used for flooring tiles. Other uses of SMS Slag which are been tried are : Abrasive blasting material Water treatment media Polymer concrete material Hume pipe, tetra-pod, concrete bricks, concrete pipes etc. Use of SMS slag briquettes in BOF steel making Replacement of natural sand in cement mortar etc. 18

19 UTILISATION OF SOLID WASTE Water treatment media Rail Ballast Concrete Pipes 19

20 TYPICAL SMS SLAG TILES 20

21 STEEL SLAG: ROAD & PAVEMENT MATERIAL 21

22 TYPICAL SMS SLAG BRICKS & PAVING BLOCKS 22

23 UTILISATION OF SOLID WASTES BOF Sludge Briquettes & micro-pellet as a replacement to sized Iron Ore In BOF Steel Making 23

24 STEEL SLAG TYPICAL FLY ASH BRICKS Innovative use of BOF slag fines in making Fly ash LD slag brick 24

25 SMS SHOP DUST UTILISATION OF SOLID WASTES Dust collected from dedusting FES system of the SMS shop contains high % of Fe>40% and it is usable for reuse in sinter making plant. BOF GCP SLUDGE 25

26 BOF SLUDGE & DUST Sludge has high Fe2O3 content : Can be used as alternative Raw material with iron corrective material in cement industries Sludge generated from BOF-GCP is rich is iron (>40% Fe) and it dominantly constitutes Fe2O3 and therefore it can be used for sinter making. The sludge generated from ETP plant is pumped to sludge dewatering plant having filter process after dewatering dry filter cake is produced. These dry filter cakes are transported to raw material stock yard for feeding the same to sinter plant for sinter making. LIME DOLOMITE PLANT DUST Due to high content of CaO & MgO, these dust can be used for sinter making. 26

27 UTILISATION OF SOLID WASTES SCRAP Scrap generated can be use as coolant material or re-melting in process of steel melting REFRACTORIES Waste refractories can be broadly used as follows: Reusable portion of salvaged refractories are recycled. Broken pieces are recycled/sold to outside parties. Preparation of mortar etc. SCALE FROM CONTINUOUS CASTER COOLING Scales are generated during cooling of continuous cast product by direct spray. The dewatered scale from scale pit may be transported to raw materials stock yard from where it shall be conveyed to mill scale bunker of sinter plant for manufacture of sinter. The wastes are being used and recycled in various way in different industries depending on several local governing factors and provisions etc. 27

28 EXTENT OF WASTE UTILISATION As per the overall existing practices of waste utilization in India, the extent of various solid waste used/recycled needs to be reviewed for developments in waste utilisation. The national average of specific generation of wastes and the extent to which wastes can be reused, recycled and disposed are shown in below: Shop Name of solid waste Specific generation, kg per ton of shop product Extent of reuse/recycle (%) Extent of disposal (%) Place of recycling/ reuse BOF Shop EAF Shop BOF dust + Sludge BOF slag STEEL MAKING PLANT Sinter plant Cement making, rail ballast, subsoil drains, asphalt aggregate, EAF dust Sinter plant EAF slag Cement making, rail ballast, subsoil drains, asphalt aggregate 28

29 EXTENT OF WASTE UTILISATION Continuous casting plant Caster Shop Caster scale Sinter plant, pellet plant, EAF Caster sludge Sinter plant These figures drives us to the increase our efforts for solid waste utilisation to reach the level of 100% utilisation. 29

30 SOLID WASTES MINIMISATION Shop Type of waste Waste minimization measures BOF shop BOF dust/bof sludge Avoidance of over blown metal, minimization of fines in flux-mix, avoidance of late addition of fluxes, elimination of zinc-coated scrap in the burden, use of optimum top blowing rate, pressure and time in conjunction with bottom blowing rate and time, use of low Si hot metal, use of low SiO2 lime. BOF slag Use of low SiO2, high reactivity and low LOI lime, use of low-silicon and low sulphur hot metal, if necessary, through hot metal pre-treatment, computerized charge balance or process control. 30

31 SOLID WASTES MINIMISATION Shop EAF shop Type of waste EAF dust Waste minimization measures Minimization of wastes at source through improvement in process, operation and maintenance such as, continuous charging (Consteel process, Contiarc process, Finger shaft furnace; it reportedly reduces the volume of dust discharged by as much as 40%).Lime addition as a part of the bucket charge contrary to addition by pneumatic injection. Adoption of foamy slag practice to the optimum extent. Minimization of carbon blowing by maintaining not so high carbon opening in the bath. Providing adjustable speed derives (ASD) bag house fan to reduce dust emission by 2 to 3% over the whole tap-to-tap cycle.provision of computerized process control. Use of UHP in all solid charge operation to reduce tap to tap time. Continuous Casting shop EAF slag Caster scale/ sludge Improved charge-mix preparation, cost-effective optimization of charge-mix, maintaining of minimum basicity by controlling low opening of S & P in the bath through optimized charge-mix, betterment of flux quality. Air mist cooling. 31

32 ZERO WASTE CONCEPT IN STEEL MAKING Globally, steel industry has made tremendous efforts in the past decade to drastically reduce its operating costs and to comply with environmental requirements. In the way of making steel making as a sustainable technology business it is must that Zero Waste philosophy shall be accepted. A zero waste approach should means 1. A structured approach to minimize waste generation, energy consumption, emissions 2. View wastes & emissions as potential raw materials to be conserved or reused rather than wasted. 3. Clearly identify appropriate manufacturing processes and ensures bottom line cost savings. 4. Implement the identified projects which o Reduce process wastes o Convert waste to economically beneficial material o Develop new processes that eliminates waste. 32

33 ZERO WASTE CONCEPT IN STEEL MAKING For example, the COREX iron making process eliminates the need for coke making and coke oven gas byproduct recovery plants. Economics for every plant is uniquely determined by its location, age, product mix, equipment, cost structure among other factors. It is neither reasonable nor economical to attempt to make every process within a steel plant into a zero waste process, since the thermodynamics and kinetics of some reactions mitigate against achieving absolute zero waste. How ever the R&D efforts, process improvements and technological innovations can provide the solutions for making the zero waste philosophy successful in steel industry. 33

34 ROLE OF R&D FOR WASTE MANAGEMENT SYSTEM In the developing market of Indian Steel Industry and present level of utilisation of solid wastes in steel industries, it is need and requirement of time for adequate support from R& D. Government agencies shall take initiates along with private players of steel sectors for R&D opportunities for making the solid waste management system more effective. R&D efforts with support of Government and other bodies including private steel players can play significant role for the activities like More cost effective management for BOF dust/sludge by adopting the technology of cold briquetting and recycling the briquettes directly in to BOF Use of SMS slag/dust in BF process for Iron Making More use of DRI fine injection in EAF/other furnaces Interaction with cement, road builders and similar agencies to increase the use of SMS slag In-house up gradation and developments of operating practices and technologies 34

35 SUGGESTIONS & RECOMMENDATIONS Task force waste management committee for dedicated working in coordination with R &D, Marketing other agencies Reporting of Waste Management Committee (WMC) to apex body of management Scheduled timely audit for waste control & utilisation against bench marks for review of progress. Attitude development to review waste products as opportunity for business for making profit. All individuals shall be made responsible for waste management. Strong commitment from top management and reward/intensive scheme for employees for encouragement in order to achieved zero philosophy in steel plant, i.e, steel plant products of zero defect, zero waste & with zero inventory. 35

36 CONCLUSION Steel industry developments is focusing on Clean, green & sustainable technologies for its growth and aiming at improving the quality of life for everyone now and generation to come. In order to achieve the above objective for steel industry, the waste management system has a vital role without which developments & growth of steel making and its sustenance will be difficult. In this regard, we must adopt the methods and suitable technologies for 100% recycling and use of waste from steel plants. The enormous supports from R & D efforts in this filed are required for making waste management system not only as a success but also as a profit making business. This concept will strengthen us to achieve success in steel industry for making CLEAN & GREEN STEEL with ZERO DEFECT & ZERO EFFECT for our sustenance and growth in highly competitive global steel market. 36

37 THANK YOU 37