Thickner and clarifiers

This presentation involves a brief introduction and application of thickner and clarifier

1. Mehran University Of Engineering & Technology PARTICULATE TECHNOLOGY ASSIGNED BY: DR. ZEENAT MUHAMMAD ALI PRESENTED BY: SARWAN AHMED URSANI (18CH101) Dated: 20/07/2020

2. THICKENRES AND CLARIFIERS

3. WHAT WILL WE DISCUSS? INTRODUCTION TO THICKENERS WORKING OF THICKENRES TYPES OF THICKENERS APPLICATIONS OF THICKENERS INTRODUCTION TO CLARIFIERS WORKING OF CLARIFIERS APPLICATIONS OF CLARIFIERS

4. THICKENER Introduced in 1905, in mining industry. The purpose of the thickener is to separate the solid liquid by sedimentation and raise the density of mixture of solid and liquid In simple words, we can say that the thickener is machine that separates liquid form solids, due to which the density of our substance to be thickened increases. The driving force for the separation is gravitational, where the differences in phase densities drive the separation of the solids and liquid.

5. WORKING OF THICKENER Pipe feed is transferred to velocity feed box, to removes excess energy from slurry. Flocculant are added in the feed pipe for rapid agglomeration. Solid particles formed settle to the bottom of the Thickener. The dense Thickener solids are removed via a slurry pump through the underflow pipe. Clean water rises to the top of the Thickener and overflows. Collected clean water is sent to lake for reuse.

6. TYPES OF THICKENERS The thickeners are two types of thickeners, classified on the basis of location of rake deriving mechanism. Centrally driven thickener Peripherally driven thickener

7. Centrally Driven Thickener The centrally driven thickeners are further classified into two types a. Column Type Thickeners A kind of thickener where a central steel or concrete column takes vertically the reaction to the weight of the mechanism and horizontally the torque load. b. Bridge Type Thickeners In the bridge type a structure spans across the tank and is subjected vertically to the weight of the mechanism plus any solids that accumulate within the arms truss and horizontally to the twin forces imposed by the density of the raked underflow.

8. Peripherally Driven Thickener These thickeners incorporate a central column that serves as a axle to a rotating raking arm that spans radially towards the periphery of the tank. The outer end of the arm has a carriage with motorized wheels that are guided by a circumferential track and move the entire arm structure in a circular trajectory to convey the settled solids towards the center. The bridge is not subjected to any operational loads and serves merely as a walkway for accessing the column and its pivot point from the outside. These thickeners have no lifting devices therefore they cannot be used for storage.

9. Application Of Thickeners Thickeners can be supplied for a variety of applications from mineral processing to water treatment. Some applications where we have been involved in include: Tailings thickening for Platinum, Base Metals & Minerals Dewatering of Final Flotation Concentrates Treatment of Coal Slimes Gold Tailings Applications Phosphate Rock Treatment Counter Current Decantation (C.C.D) Clarification of Pregnant Liquor Solutions (P.L.S.) Water Treatment Applications Liquor Applications in the Pulp & Paper Industry Chemical Processing Neutralization of Acid Mine Water

10. CLARIFIERS The purpose of the Clarifier is to separate the solid from liquid by sedimentation and clarify the water. In simple words, we can say that the classifier is machine that separates liquid form solids, due to which the water is cleaned for reuse. Actually it is a method of dewatering of dilute pulp, to remove impurities from water.

11. WORKING OF CLARIFIERS The water with impurities is introduced into the clarifier at controlled velocity. The water is allowed some detention time in the clarifier tank, the solid material is suspended at the bottom. Tube settlers are added at the both sides of the tank, that help solids particles to settle at the bottom The oil, fats or grease are removed from the top of tank by a rotating skimmer The formed sludge is removed with the help of scrapper quickly. if left for an extended period of time, may become gluey and viscous, causing difficulties in its removal. The sludge is also called returned activated sludge

12. APPLICATIONS OF CLARIFIERS Potable water treatment Water consumed by humans, is treated with flocculation reagents and sent to clarifiers where it is clarified and then sent for further chemical treatment. Waste water treatment Sewage water is recycled these days to save the water, we use clarifiers as primary treatment to sewage water to remove floating and settable solids through sedimentation. Mining In mining applications, clarification through clarifiers is applied to both the product and tailings streams to recover water. This water is recycled in the process.

13. CONCLUSION Fundamentally, thickeners and clarifiers (which look visually like thickeners) are both used to settle solids which results in the separation of liquids and solids. The difference however is that thickeners are used to concentrate solids, while clarifiers are used to purify liquids.

14. THE FLOOR IS OPEN FOR QUESTIONS Thankyou!