One problem with this approach is the gas formation due to the anaerobic activity. Thickening agents for surfactant systems evonik personal care. The high rate thickeners became popular in the mid 1980s and are relatively newcomers to the sedimentation line of equipment. It has a flocculent mix chamber, inclined settling plates and automatic sludge level control system.
Our clarifier range includes pinnedbed clarifiers and sludgebed clarifiers. Pyrometallurgy towards clean metallurgical processing 2012. High rate thickeners are designed to provide roughly 12 times the throughput of conventional machines of similar size. Ultra rakeless thickeners ult feature a deep mud bed and a steep floor slope to assist in compressing the mud without the use of rakes. The distinguish feature of these equipment was that the feed was injected into the sediment bed.
The altaflo is a rakeless thickener that uses rapid dewatering in the hindered settling zone to achieve a very high settling rate. Thickeners are used to concentrate solids, while clarifiers are used to purify liquids. However, the control approaches developed for conventional thickeners are often found to be insufficient for paste thickeners in industrial. The altaflo typically operates at twice the settling rate of a high rate thickener. It stays constant at different speeds of the viscometer.
High rate thickeners hiflo phoenix process equipment. The construction of steadystate profiles in both cases is completed in sections 5. They differ from conventional thickeners in feed well design, size and control. Shear rate the velocity gradient or the rate of change of velocity at which one layer passes over an adjacent layer is the shear rate. The smaller equipment size substantially reduces capital, installation costs, and plant space when compared with a.
Equipment questionnaire global leader in highrate thickeners. Data analysis is completely manual and hence time consuming. Mclanahans thickener range spans economical ultra rakeless thickeners to high rate, high density and paste thickeners. Our process engineers tailor the right product selection for your application. Phosphoric acid plant design begins with desired production rate in tons of p2o5, and. Andritz launches new dilution system for thickeners.
The following is a short cut to designing your own thickener. Inhouse testing confirms process outcomes and appropriate duty using the underflow yield stress as a measure of viscosity for the defining output of each type of thickener. Feed densities up to 55 % discharging underflow at 70 % solution could be halved no other thickener can compare. High rate or conventional thickeners, which are typically limited to about 20 or 30 pascal yield stress. Several iterations of area may be required to achieve a practical thickener size and pumping rate. Effect of thickener concentration on ks values and color fastness rates of cyan ink jet printed fabrics. The new and improved andritz interstage mixing and dilution system for ccd circuits helps to reduce the footprint and consequently cut capex while maintaining low operating costs. Equipment questionnaire magra process engineering pty. The lamella gravity settler thickener lgst design is a high rate gravity settler combined with a circular, picketfence sludge thickener scraper. With the different flow rate configurations available, each system can be adjusted flexibly to the individual customers needs. Readers may only download, print and save electronic copies of whole works. As the compression zone gets deeper, the underflow density for a given flux rate increases, as a result of two factors.
Paste thickeners are uniquely different than conventional and high rate thickeners. Tailings management sustainable and complete dewatering. Hlr hydraulic loading rate mh q sludge flow sent to the thickening unit m3h a horizontal thickener surface. My topic is about calculations for sizing a high rate thickener. The settling rate of any pulp is easily determined by simple laboratory tests such as outlined below. The dilution system does not interfere with the thickener settling process and can also accommodate slurries with low ph values. Our thickener range includes high rate thickeners, high density thickeners, paste thickeners and conventional thickeners and offers designs up to 100m in diameter, catering for a variety of applications in various industries.
The gas formed will cause the flotation of the solids in the thickener. Hence, for a given sluny rate, selection of a high plint of the thickener. The difference between a clarifier and a thickener is subtle as they will visually look the same. Conventional thickeners, high compression thickeners and clarifiers. Andritz thickening and clarification solutions are designed to achieve the highest production rates without compromising efficiency. International journal for applied science personal care. The concentrations of soda ash and urea in the pretreatment were 40 and 100 gl respectively. Testing is required for the selection of correct thickener or clarifier size and configuration for each customers application. Knowing how to size a thickener and determine the capacity required to handle a predetermined tonnage of a certain pulp, by overflowing a clear solution and obtaining the desired pulp density of thickener discharge, depends upon the settling rate of that particular pulp. The phenomenological theory of continuous thickening of flocculated suspensions in an ideal cylindrical thickener is provides a method for thickener design. The settler section utilizes the same countercurrent flow principle and the inclined plate design used in packaged lamella gravity settlers.
The presence of high aspect ratio particles in some tailings. When viewed from the outside high rate thickeners look very much like conventional machines except that their tanks have a greater height to diameter ratio. High rate thickeners clarifiers enviroclear company, inc. Like the high rate thickener, the paste thickener uses high floccu lant dosage and optimised feed. The hydrophobic thickeners provide a shearthinningflowbehaviour,thatmeans the viscosity decreases with increasing shear rate. Why highrate thickeners are now preferred by the gold industry. Using add reply allows you to attach images or pdf files and.
High rate thickeners can be supplied with flatbottom, onground tanks or elevated tanks, which feature short suction lines that reduce the risk of plugging. High rate thickeners that are built as dedicated machines are available in sizes up to 40 meter diameter but retrofits of conventional thickeners are often larger in size. Eimco hicap thickener webpage high capacity thickeners. Sizing a high rate thickener thickening, filtering, ccd. Paste thickener design to achieve downstream requirements. Much higher handling rate, tnd lower capital cost are obvious advantages of high lents and the concems of operational cost, especially keep some engineers selecting conventional thickeners. Phoenix hiflo high rate thickeners clarify wash plant effluent water while thickening the slurry to 4045% solids, greatly reducing the underflow slurry rate to the slurry pond. This can easily be observed by measuring the viscosity with a rotational viscometer at different speeds. Apr 01, 2015 in high rate thickeners, the rate of change of bed is of high importance and as such the bed level needs to be controlled.
How to size a highrate thickener thickening, filtering. Fundamentally, thickeners and clarifiers are both used to settle solids which results in the separation of liquids and solids. As already discussed previously thickeners are a major component in a plant layout and occupy large spaces which may be saved by introducing high rate machines. The hydrophilic thickeners provide a newtonianflowbehaviour,whichmeans the viscosity is independent of the shear. As a result of its innovative design and associated hydraulic efficiency, the plant area for the hiflo highrate thickener is greatly reduced, even making indoor installations practical. The key advantages of a high rate thickener over a conventional thickener. This paper uses the terms high density thickener hdt and deep cone thickener dct. Use add reply to replyparticipate in a topicdiscussion most frequent. In general these are all designed to produce underflow rheologies above what can be achieved in high rate or conventional thickeners, which are typically limited to about 20 or 30 pascal yield stress. The requirements for thickeners are continuously increasing. How to size a highrate thickener thickening, filtering, ccd. High rate thickeners, that produce a settling slurry underflow, have been in use for decades. Mip thickener design the following is a short cut to designing your own thickener.
These machines are characterized by a reduction in unit area. To facilitate us in giving you a proposal we would like the. Nov 30, 2017 the thickening process is the primary method of producing high solids slurries to bring the two together to make rational improvements to thickener design and. Thickeners are utilized in various solidliquid separation processes in order to increase the density of a process stream. Studies on parameter estimation and model predictive control. In the bridgesupported design, suitable for thickeners up to 50 m in diameter, the drive is supported by the bridge, driving the rakes with a centre shaft columnsupported design drives are supported by a stationary. Enviroclear manufacturer of clarifiers, thickeners, horizontal belt vacuum filters, pronto pressure filters, linear screens, and replacement drives. Forty years after the first high capacity 363 ickeners, a better choice to make. Tailings management sustainable and complete dewatering solutions. A wide variety of high rate thickener options are available to you, such as classification, feature, and usage.
Our main product offeringis the high rate thickener hrt which has several special features that provide advantages over conventional thickeners. Highrate thickeners, or clarifiers, recover immediately reusable process water for mineral and aggregate producers, as well as environmental contractors. The geometry of the unit provides for a deep compaction bed, allowing the thickener to achieve relatively high. High rate thickeners have shown themselves to be more costeffective than conventional thickeners in recovering water and cyanide in gold mines, and other. Rise rate based on the fl ow rate cubic meters per hour entering the thickener including dilution water both solids loading and rise rate are expressed as unit rates tph or m3hr per square meter of thickener surface. We offer beam or trusstype bridges, depending on thickener diameter.
A thickener is simply a large tank in which particles usually flocs are allowed to. The key advantages of a high rate thickener over a conventional thickener are as follows. The top part of the high density thickener, however, is going to look much the same as its cousins the high rate thickener and the paste thickener. A thickener will give you a high density underflow while a clarifier will not. The reliability and performance of delkor thickeners means. Testwork and sizing for paste thickeners international. Hi rate thickeners type typical thickener dimensions they produce a wide variety of thickeners, size up to dia. May 03, 2019 high rainfall water scarcity capex limitations opex limitations paste thickener underflow high rate thickener underflow high density thickener underflow cyclone sand dam water recovery what we offer our focus is on finding innovative dewatering techniques that minimise the risks, make use of economies of scale and deliver a valued return on. Phoenix thickeners use sedimentation technology to maximize the water recovery rate, providing clarified overflow water that can be recycled and reused in the process. Feedwell is the heart of a thickener australian centre for. Here, creating the optimal feed solids to promote the maximum freesettling flux and mixing the flocculant andor coagulant at the right place and in the right shear environment remain critical to. Highrate thickeners have shown themselves to be more costeffective than conventional thickeners in recovering water and cyanide in gold mines, and other. Eimco and dorroliver thickeners are available in both bridgesupported and columnsupported designs.
A high sludge blanket will make the underflow solids concentration high due to high solids residence time. Thickener selection is based on feed characteristics and standard benchscale tests combined with experience. Critical to thickener performance are two parameters. Eimco ecat lorem ipsum dolor sit amet clarifierthickener. The images below are taken from the top view of the thickener model. The principle of paste thickeners is that the compression zone is much deeper than on either high rate hrt or high compression hct units. High rate thickener special feed well design high density thickeners deeper sidewall and more robust drive paste thickeners ultra high rate thickeners our units are available in a variety of sizes starting from 3ft diameter pilot scale to 300ft diameter. Magra highrate thickener presentation 2011 chemical. Improve clarifier and thickener design and operation. Aug 08, 2018 in the 1980s, machines known as high capacity or high rate thickeners were introduced by various manufacturers. Thickener rdt, with over 300 installations, consumes the lowest amount of expensive polymer while offering the highest capture rate of 98% and therefore, the lowest cost of re. Thickeners are beneficial in a variety of applications, including areas where water is in short supply or very expensive, recirculated water is not suitable for reuse in a plant, ponds are located on minable reserves, or ponds must be.
Pdf understanding the thickening process researchgate. In the 1970s and 1980s, machines known as high capacity or high rate thickeners were introduced in the mining industry. Testwork and sizing for paste thickeners international mining. The smaller equipment size substantially reduces capital, installation costs, and plant space when compared with a conventional. The geometry of the unit provides for a deep compaction bed, allowing the thickener to achieve relatively high densities. We can also offer conventional thickeners, high compression thickeners and clari ers. The key features for high capacity thickeners are the feedwell design and the feed slurry dilution method. Studies on parameter estimation and model predictive.
The thickener was applied at various concentrations 0, 4, 8, or 12 gl in the pretreatment bath to determine the effect of cationization on the optimal level of thickener. High rate thickeners high rate thickeners are designed specifically to maximise the flocculation efficiency of flocculants. Hydraulic loading rate and solids load are the main design parameters. Steadystate, control, and capacity calculations for.
The reliability and performance of delkor thickeners means that they are well represented throughout the world. It should be noted that these designs cover a wide range. Process control figure 3 is a fairly manual style of. Using add reply allows you to attach images or pdf files and provide a more complete input. We can also offer conventional thickeners, high compression thickeners and clarifiers. High capacity, high rate, and conventional thickeners clarifiers provided for liquid solid separation for mining, chemical processing and industrial applications. Solids loading based on dry tonnes of solid entering the feedwell 2. Unlike conventional thickeners, high rate thickeners must use flocculants. Oct 12, 2020 this new, patented system is designed for flow rates between 600 and 9,000 m 3 h.
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