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Godkänd; 2015; 20150226 (andbra)

With its well-instrumented pipe loops of various sizes, the GIW Hydraulic Laboratory has, over the years, developed a large corpus of slurry-transport data. Numerous technical papers have been produced, and also a textbook, now in its third edition. A paper from 1982, together with the first and second editions of the text, presented methods of calculating stratification ratios for pipeline flows of heterogeneous slurries. This stratification ratio (R), which is needed in calculating pressure drops for particulate pipeline flows, is the fraction of total solids that contributes to mechanical friction by rubbing against the bottom of the pipe. The remaining solids are carried by the fluid phase. A combination of experimental work and analysis published in the last few years has shown the importance of the fluid force developed near the pipe wall. The influence of this force is now applied to the stratification ratio. The basic parameter is seen to be the ratio of the near-wall lift force on a particle to its submerged weight. This ratio depends primarily on a dimensionless quantity denoted Θ, and is also influenced by the lift coefficient of the particle, which, in turn, introduces a minor dependence on a particle Reynolds number Re*. It was noted that the quantity Θ is itself composed of a Froude Number for the flow (which can be related to the deposition limit) and the diameter ratio d/D. An analysis of experimental data has given a new expression for R in terms of Θ and Re*. Godkänd; 2008; 20081223 (ysko)

The term complex here refers to the intermediate area between homogeneously and heterogeneously flowing slurries. Typical examples are residual products ("tailings") from the mining industry with average particle sizes of 20 to 100 microns. The performance derating are of special interest when centrifugal slurry pumps are applied to these slurries at high solids concentrations. The Hydraulic Institute's slurry (ANSI/HI 2005) and viscous Newtonian liquid (ANSI/HI 2004) standards are briefly covered with focus on applicable viscosities for non-Newtonian slurry behaviour. Various experimental results are discussed and found to give maximum deratings in head and efficiency of about 10 and 15 %, respectively, provided stable head curves can be maintained. Magnified shock losses, circulatory flows and blockage of slurry and possibly vapour tendencies in the pump entrance region may be considered as mechanisms behind unstable head curves together with the flow behaviour of the slurry. Godkänd; 2008; 20081228 (keni)

The rheological and depositional character of tailings from two base metal concentrators are presented based on results obtained in connection with pilot-scale thickening tests and feasibility considerations. Thickening to a volumetric solids concentration of over 45% ( 70% by mass) close to the disposal area results in a non-segregating slurry that can be deposited at average slopes of 3-4%.Operating literature data from installations are briefly described and some macroscopic depositional mechanisms and design features are discussed. Godkänd; 2008; 20081229 (ysko)

The feasibility of pumping tertiary crushed raw ore together with mine water with centrifugal slurry pumps in series is briefly demonstrated in a comparison with truck transport to the processing plant. Pumping can also be effective if considered early in the mine planning because of less waste rock handling. Furthermore, in large-scale open-pit mining, only a 0.5 m-diameter pipeline is required for up to 20 Mtonnes per year. Tertiary crushing with an autogeneous type of crusher giving a comparatively wide particle size distribution may gain some effectiveness in the pumping, however the system integration potential can mainly be related to possible energy savings and increased throughput in grinding operations as outlined by Lindqvist (2008). Godkänd; 2008; 20080328 (ysko)

An elevated location of a paste thickener on a ridge close to the disposal area is considered at a Swedish iron ore mine. About 0.7 Mtonnes of thickened tailings are planned to be layered as paste in the vicinity of the thickener over several years with pipeline lengths of up to 900 m after about 20 years. In order to clarify the pipeline pumping characteristics of the tailings product for volumetric solids concentration from 40 to 50%, experiments in loop systems with pipeline inner diameters from 0.063 to 0.152 m have been carried out with various types of pumps. The results and comparisons carried out here showed that the performance of centrifugal pumps cannot simply be related to the rheology, but factors related to pump design and build-up tendencies of material within the pump and other particle properties may be of equal importance. During the first years of operation only one thickener underflow pump is required. The reliability and performance for various pump configurations are planned to be investigated systematically in order to meet the most effective longterm solution for paste thickener operation, pipeline distribution and placement in the disposal area as the discharge point advances over the life of the project. Godkänd; 2007; 20080111 (ysko)

The Hydraulic Institute has just completed the task of developing a new ANSI/HI standard on Rotodynamic (Centrifugal) Slurry Pumps covering nomenclature, definitions, applications, and operation. The standard provides examples of all the different types of pumps available and has an extensive section on definitions. Slurries and their effect on performance and wear are covered. A slurry service class is established which then is used to limit velocities and head produced per pump to give acceptable wear. A special section deals with mechanical seals and a new method for determining flange loads is presented and guidelines are given for commissioning, start-up etc.The head limits and the performance derating are of special interest when centrifugal slurry pumps are applied to thickened tailings and paste-like slurries. For Newtonian liquids, the Hydraulic Institute's Viscosity Correction Method (ANSI/HI 2004) provides a procedure widely used for viscous effects on the performance. For the homogeneous flow of viscous slurries, the new slurry standard refers to an applicable viscosity to use with the method and to "consult the pump manufacturer for guidance regarding non-Newtonian slurry pump performance."Experimental performance results are presented here and applied to the viscosity correction method for a simulated tailings product slurry characterized by a fully sheared yield stress of about 100 Pa, evaluated from pipeline data. The pump was a GIW-LCC type three-vane all metal unit with a 0.3m-diameter impeller having an open shroud with a simple auger-like inducer. Results are also given for an underground hydraulic fill product characterized by a Newtonian kinematic viscosity which is 1300 times that for water. The different results obtained here point out the strong influence the rheological behavior has on the choice of pump size and the power requirement. Godkänd; 2007; 20080111 (ysko)

Recent experiments and analyses have provided greater understanding of friction losses for the size distribution of the particles forming the slurry. Wilson & Sellgren (2001), Wilson et al. (2006) and Sellgren & Wilson (2006) have proposed a multi-component model consisting of carrier fluid and pseudo-homogeneous, heterogeneous and fully-stratified solids. The technique presented here was found to estimate friction losses well when compared to reported experimental results with pipelines with diameters mainly from 0.2 to 0.5m for various mixtures of fine sand to coarse gravel and products from mineral processing and phosphate mining. Godkänd; 2007; 20080110 (ysko)

Godkänd; 2006; 20070122 (ysko)

Pumping a simulated sediment slurry at a low water content has been investigated at the GIW Hydraulic Testing Laboratory in a 3 inch (0.075 m) diameter loop with a centrifugal pump with an auger-like inducer. The results and earlier reported data from the Laboratory indicate that viscous sediments characterized by yield stresses in the range of about 2 to 4 psf (100 to 200 Pa) can be pumped effectively with centrifugal pumps. With yield stresses of up to 4 psf (200 Pa), the pressure requirement to overcome pipe friction for pipeline diameters of 4 and 16 inch (0.1 and 0.4 m), may be 0.35 and 0.09 psi per ft ( 8 and 2 kPa per m) of pipeline, respectively. Several pumps in series are therefore required also for moderate transportation distances. The results indicate that centrifugal pumps can be a cost-effective alternative for handling and transportation of sediments at a low water content. Godkänd; 2005; 20070525 (ysko)

There is a wide variety of industrial pastes or non-settling slurries pumped in mining, dredging and reclamation projects as products, refuse and tails. The types and/or names of some of the common ones are alumina red mud, phosphate clays, tar sands mature fine tails, tar sands (CT) consolidated clays and fly ash. The pipeline performance or friction of these varies dramatically with the type, its concentration and the particulars of the actual slurry making it difficult to select pumping equipment and to design associated pipelines. The GIW Hydraulic Laboratory in Grovetown Georgia has tested a number of these slurries over the last 30 years for various mining customers. Where available in the public domain and/or where permission has been obtained, the results of those tests are presented in this paper in a form usable for pipeline and pump system designers and users. Godkänd; 2005; 20061230 (ysko)

Godkänd; 2005; 20070525 (ysko)

Slurry pumps are used for the transportation of solids in coal, copper, iron ore, phosphate and in other mining operations. They are also used on dredges cleaning waterways, in environmental cleanup and in reclaiming land throughout the world. Slurries by their very nature are very abrasive requiring the impeller, casing and suction liner wet end component parts be replaced at regular intervals. It is not uncommon, for example, for six liners, three impellers and two casings to be consumed in one year. It is estimated that about $500 million in slurry pump wear parts are consumed every year. Numerical models now exist to predict component wear for a given set of operating conditions with a given design. The use of these models is however available to a select few and no general relations exist for the user. The writers in this paper model a selection of pump designs producing general relationships for the different pump casing, impeller and liner components for different duties. They then take these and show which offer the lowest cost of ownership for different services. Godkänd; 2005; 20061105 (ysko)

Godkänd; 2004; 20070122 (ysko)

The balance of the costs for capital, energy, maintenance and boundarylayer polymer injection is described in a model for life cycle cost assessmentsof pumping sewage sludges at a solids content (TS) in the range of15 to 35 %. A design tool for sludge pumping with solid contents of up to8 % is also described. Tests with centrifugal pumps for TS-values of up to10 % are presented. Kostnadsbalansen mellan kapital, energi, underhåll och glidfilminjicering av polymerer beskrivs i en livscykelbaserad modellansats för torrslamspumpning. Vidare beskrivs ett dimensioneringsverktyg för slampumpning vid torrsubstanshalter (TS) upp till 8 %. Tester med centrifugalpumpar för TS-halter upp mot 10 % presenteras. Godkänd; 2003; 20100414 (andbra)

Godkänd; 2003; 20090128 (andbra)