TECHNOLOGY FOR STONE WASTE UTILISATION By Dr. S. S. Rathore Head of Mining Engineering Department College of Technology and Engineering Maharana Pratap University of Agriculture and Technology Udaipur, India
TWO MAIN TYPES OF WASTE • Small shapeless blocks deriving by cutting and sawing of stone B) Muds produced by sawing and polishing operations on slabs Air dried filter-pressed mud
A) Small shapeless blocks deriving by cutting and sawing of stone Re-used in the building industry as inert matter, aggregate in concretes and, as a function of its mineralogical composition, as raw material for other industrial processes. Discards from calcareous rocks with a suitable calcite content can be used to produce binders, or as weak abrasive agents; Discards from silicate-rich rocks (granitoid rocks) to produce, after beneficiation process, quartz-feldsphatic sands for the ceramic industry. Or……….
B) Muds produced by sawing and polishing operations on slabs Obtained after sawing and polishing processes; it is made up by fine grain size material produced by the rock mixed with the tool cooling water. Suitable processes allow to extract the solid portion. Two possible destinations 2) Recovery of the waste for possible technological applications as a function of its features • Landfill disposal as non-dangerous special waste
Necessary if we consider that sawing operations carried out with frames or diamond disks may determine an increase in the waste of heavy metals Cr, Ni, Cu, Mn, Fe Co, Cu If leaching tests provide values higher than those admittable, it is necessary to separate the metal fraction from the wastes. It was found out that this kind of separation can give satisfactorily results as far as Co is considered ….details in the next presentation
Landfill disposal = cost transportation Purchase and management of filter press Overall evaluation: Rs. 1-2 per kg of mud As a function of factors such as the type of plan, distance from the landfill, regional market, etc.
Recovery of the waste, on the basis of their mineralogical and chemical features, for different and compatible uses MUDS deriving from sawing of: STONES, MARBLE, SLATES GRANITES Features of the waste: muds bearing at least 85% of calcium carbonate on dry matter. Features of the waste: filter pressed muds bearing more than 50 % of silicates Recovery activity: dehydration, drying, sieving, grinding, micronizing: Recovery activity: dehydration, drying, sieving, grinding, micronizing, compacting and deironization: a) Paper industry; b) Production of hydropaintings; c) Neutralization of acid wastes; d) Reagent for desulphuration of combustion smokes; a) Brick industry as material added to the mixture (not higher than 5% of dry matter); b) ceramic industry; Common to both: -) Cement industry; -) Road subfloor (recover subordinate to the fulfillment of leaching tests on the untreated waste according to a normalized method); -) Environmental restorations (recover subordinate to the fulfillment of leaching tests on the untreated waste according to a normalized method); -) As blanketing material for urban solid waste landfill disposal areas; (recovery subordinate to the fulfillment of leaching tests on the untreated waste according to a normalized method);
Treated or untreated wastes, if admitted for a reuse, can be destined for technological applications in: • Pedotechnical uses - building industry Lightweigth Expanded Aggregates Lightweight concretes
In both directions the research was addressed in order to verify if it was possible to give an innovative contribution to this aspect - building industry Lightweight concretes Lightweigth Expanded Aggregates Previous experiences on the use of these wastes for the production of LEAs Wastes deriving from sawing and polishing operations may contain expanding agents
In particular, those showing a silicatic composition (GRANITE s.l.) can definitely give Lightweight expanded aggregates (LEAs) once properly mixed with other industrial wastes bearing expanding agents Dry mud from granite-type rocks LEAs + = industrial wastes bearing expanding agents (i.e. abrasive SiC ) DOUBLE ADVANTAGE Reuse of two different wastes
PEDOTECHNICAL USES 1) USE OF SILICATE BEARING WASTES AS POTASSIC FERTILIZERS For soils characterized by a low content of nutritional elements 2) USE OF SILICATE BEARING WASTES AS ENVIRONMENTAL RECOMPOSITION To produce artificial proto-horizons as substrate for plants 3) USE OF CARBONATE BEARING WASTES AS AMENDANT OF ACID SOILS Scale models in confined environments on soils with acid reaction (pH<5.5)
Waste recovery from ornamental stone industry Muds Unshaped small blocks Recover of ferrous elements (eventually diamond) Lightweigth Expanded Aggregates Pedotechnical uses (Plant growth)
MoU between IS.I.M, Italy and M/s R.K. Marble & MPUAT, Udaipur India Objectives of MoU • To enhance scientific, technical and professional contacts and partnership between Italy and India • To achieve general transfer of know-how and advanced technologies from Italy to India through training and research activities • Promote jointly a technical and scientific research on diamond wire technologies – on variable speed diamond wire saw machine and single diamond wire block dressing machine
TWO SCIENTIFIC REEARCH PROJECTS COMPLETED Project “A” Study on and test to know the influence of the peripheral speed on wire life, saw output etc.in white dolomitic marble stone (Machine used: Make – Marini, Italy ) Project “B” To know the performance of the new Italian technology i.e. stationary single diamond wire block dressing machine
Comparison of life of diamond wire (consists of 2000 beads) with variable speed machine and fixed speed machine (Peripheral speed 27 m/s and Thrust 55-60 amp.)
Operating cost comparison (Power only) for dressing block (2.4 m x 1.67 m)
INTERANTIONAL INDUSTRY PROJECTUNDERTAKEN RECENTLY Title of Project UTILIZATION OF STONE POWDER OF PROCESSING PLANTS Name of Principal Investigators Dr. S.S. Rathore, Deptt. Of Mining Engineering, MPUAT, Udaipur, India and Eng. Paolo Marone, IS.I.M.,Napoli, Italy
RESEARCH TARGET • Use of powder in Agriculture by making experiments with pot culture • Use of powder in block and brick making • Use in road filling • Production of light agreegate
PROPOSED WORK PLAN • To procure the necessary granite powder from the field to set up the experiments in India and Italian University. The selection of the powder will be from following possible site: • - The powder from Indian granites after polishing/grinding phase. • - The powder of Indian gang saw plants processing of big blocks • - The powder from Indian granites after steel grit gang saw phase. • Determination of chemical and mineralogical properties of the granite powder • To send of powder of various types to Italian University for testing purposes as per directive Of Eng Paolo Marone, IS.I.M., Italy • Setting experiments as pot culture in the department of mining engineering with varying the percentage of granite and marble and dolomite powder in same type of soil. Observation periodically under the supervision of scientist and contractual research assistant of the agriculture field. • Making blocks with various granite powder ratio and to carry out the strength properties of blocks and possible uses.