Claims:Claims:
1. A Settleometer (100)to measure settling rate and analyse settling profile during sedimentation or dewatering of an ore suspension, comprising:
a measuring cylinder (104) for suspending the ore suspension;
atleast a pair of vertical supporting racks (112a, 112b) positioned diagonal oppositely close to the circumference of the measuring cylinder (104) and each of the vertical supporting racks comprising a guide rail (116a, 116b); and
each pair of the guide rails (116a, 116b) being deployed with a transmitter (T) and the opposite being deployed with a receiver (R), the transmitter (T) and the receiver (R) being movable over the guide rail (116a, 116b) in sync, the receiver (R) being configured to intercept light emitted from the transmitter through the ore suspension and post intercepting predetermined light the transmitter and the receiver moves to next position to again transmit and intercept light.

2. The Settleometer (100) as claimed in claim 1, wherein the measuring cylinder (104) being deployed with a plunger (108), the plunger (108) being configured to move to and fro within the cylinder to mix the ore suspension.

3. The Settleometer (100) as claimed in claim 1, wherein the transmitter (T) and the receiver (R) being coupled to a control unit (120), the control unit(120) being configured to analyse the data intercepted at various points on the guide rails.

4. The Settleometer as claimed in claim 3, wherein a display unit (124) being coupled to the control unit (120) to display various analysis executed.

5. The Settleometer (100) as claimed in claim 1, wherein the measuring cylinder (104) is transparent and calibrated.

6. The Settleometer (100) as claimed in claim 1, wherein the transmitter (T) and the receiver (R) are photo-electric sensor.

7. The Settleometer (100) as claimed in claim 1, wherein the plunger (108) being fixed above the measuring cylinder (104) by means of a plunger support (128).

8. The Settleometer (100) as claimed in claim 1, wherein the plunger (108) being pneumatic plunger.

9. The Settleometer (100) as claimed in claims 1 and 8, wherein the measuring cylinder (104), the vertical supporting racks (112a, 112b) and the plunger support (128) being fixed over a platform (132).
, Description:A SETTLEOMETER TO MEASURE SETTLING RATE AND ANALYSE SETTLING PROFILE DURING SEDIMENTATION OR DEWATERING
Technical Field:
[001] The present invention relates to anequipment to measure settling rate and analyse settling profile during sedimentation or dewatering test with arrangement for proper mixing of slurry with reagent.

Background:
[002] In the process of beneficiation of ores, the oresundergo many process such as crushing, screening, gravity separation and jigging. In this process, huge quantity of slimes gets generated which is very finer in size below 150 microns to 10 microns.

[003] These slimes in the form of slurry reports to thickener where solid liquid separation takes place. In this process, the solid sediments in a very slow process and subsequently water is recovered from the overflow which is recycled back to beneficiation plant for washing of ore. To enhance the process of dewatering different reagents are applied to the slurry reporting thickener. These reagents act as a flocculating reagent by binding the fine particles which causes formation of flocs and rapid settling of the same.

[004] The efficiency of this dewatering process in any beneficiation plant is one of the most critical process. Every thickener has designed rise rate; the rate at which the slurry rises in the thickener. So, to have clear water as overflow the settling rate of the solids should be always greater than the rise rate. Although the solids have the tendency to settle by virtue of gravity the higher concentration of solids in the slurry leads to hindered settling and subsequently delays the settling rate. In order to achieve the desired settling rate external agents such as flocculant or coagulant are mixed in the slurry which aids the settling process. Selection of appropriate reagent and its optimum dosages is very critical and important aspects.

[005] At present the selection of reagent is done through lab scale settling or dewatering studies. This test is done using a measuring cylinder in which a known volume of slime or slurry is taken. Calculated amount of reagent is added in the cylinder via help of syringes and then the slurry and reagent is mixed manually with the help of plunger. Plungers are rod of measured height equal to the cylinder having a flat circular plate welded at the bottom. The flat surface has perforations or opening for movement of slurry when the plungers moved down in the cylinder. After mixing of slurry with reagents for particular time the solids start settling in the cylinder and the mud level (interface between clear water and the dense slurry zone) is clearly visible. The mud level position is tabulated with respect to time and finally the slope of the graph mud level index vs time gives the settling rate.

[006] At present, there are several methods of conducting lab scale settling studies. Most of the methods are manual and needs high degree of precision to ensure correct findings.

Cylinder/Jar Test:
[007] The batch cylinder and jar test is carried out using four/six identical jars containing same volume and concentration of feed (slurry). These are charged simultaneously with different reagent and doses. The jars are stirred simultaneously at predetermined speeds. The treated feed samples are mixed rapidly and then slowly after which they are allowed to settle. These three stages correspond respectively to the fundamental process of dispersing the flocculant onto the particle surface, gently sweeping the colloidal particles together to form large flocs, allowing them to settle. At the end of the settling period, test samples are drawn from the jars and turbidity of supernatant liquid is measured. A plot of turbidity against the flocculant dose gives an indication of optimum dose (i.e. the minimum dose required to attain the desired clarity).

Settling Test:
[008] Settling test is conventionally conducted according to the standard procedure, in 1000 ml of standard measuring cylinders. A suspension of high solids content is taken in the cylinder and mixed well by shaking. Require dosage of flocculant solution is added. The cylinder is inverted up and down for ten times and is allowed to keep undisturbed situation to form interface between flocs and supernatant. Settling curves showing fall in the interface heights vs settling time is plotted.

[009] With the above mentioned standard practices many works has been done to evaluate the suitable reagent for dewatering from arrays of reagents. Equipment like capillary suction time apparatus have been also used to measure both the dewatering efficiency of reagents.

[0010] According to the work done by G W Chen, W W Lin and D J Lee the dewaterability of sludge can be determined by two ways: the residue moisture amount in the sludge cake after dewatering process (the bound water), and the easiness of filtration of the sludge (the filterability). Also, various techniques had been proposed for measuring the bound water in the sludge (Lee and Lee 1995).

[0011] The Buchner filtration/dewaterability test is a common test.

[0012] The whole purpose of capillary suction time apparatus is to characterize sludge dewatering ease and rapidity. The time the filtrate requires to travel a fixed distance in the filter paper is referred to as the capillary suction time. A large capillary suction time implies poor filterability and vice-versa.

[0013] In the work done B P Singh and L Besra in ‘The effect of flocculants and surfactants on the filtration and dewatering of Iron ore fines’ the filtration and separation characteristic of iron ore fines has been investigated. This work included characterization, evaluation of suitable reagent to enhance settling and dewatering rate, determination of optimum dosage of flocculants.

[0014] A common setup used to measure the effect of dewaterability of slurry on addition of reagent and in general is shown in the figure attached below.

[0015] Also, there are many other techniques to measure the dewaterability, filterability and selection of suitable reagent for the mentioned purpose for any sludge.

[0016] However, in the past development had been to develop lab scale setup to measure the settling rate of solids during dewatering process. In the invention US patent no. 4194391 and US patent no 5431037 the inventor could produce setup which could measure the settling rate via observing settling time. In both the inventions sample of flocculated slurries were taken in a measuring cylinder and a turbidity sensor attached in the middle of the vessel measures the initial turbidity at the inception of settling process. The sensor then measures time taken in reduction of turbidity to the minimum set point. This time is considered as settling time and hence can be related to settling rate. But the inventions could not provide the settling profile. Also, both the setup was for plant scale applications and cannot be used for selection of suitable reagent study.

[0017] Thus, the whole process of dewatering or settling test is completely manual and needs higher degree of accuracy while performing the test. As any error while noting the mud level, mixing of reagent and slurry can lead to huge error and thus effecting the results or objective of the test.

Disclosure of the Invention

[0018] The present invention provides a Settleometer to measure settling rate and analyse settling profile during sedimentation or dewatering of an ore suspension, comprising a measuring cylinder for suspending the ore suspension, atleast a pair of vertical supporting racks positioned diagonal oppositely close to the circumference of the measuring cylinder and each of the vertical supporting racks comprises a guide rail. Each pair of the guide rails comprises a transmitter and the opposite comprises a receiver, the transmitter and the receiver are movable over the guide rail in sync, the receiver intercepts light emitted from the transmitter through the ore suspension and post intercepting predetermined light intensity, the transmitter and the receiver moves to next position to again transmit and receiver light.

[0019] In a preferred embodiment, the transmitter and the receiver is coupled to a control unit to analyse the data received at various points on the guide rails. The display unit is coupled to the control unit to display various analysis executed.

[0020] For a better understanding of the invention and to show how the same may be performed, a preferred embodiment thereof will now be described, by way of non-limiting example only, with reference to accompanying drawings.

Brief Description of Drawings
[0021] FIG. 1 is a front view of prior art Buchner filtration/dewaterability test.

[0022] FIG. 2 is an isometric view of a Settleometer in accordance with an embodiment of the invention.

[0023] FIG. 3a is a pictorial view of the Settleometer of FIG. 2.

[0024] FIG. 3b is a pictorial view of a display unit of the Settleometer.

Description of Preferred Embodiment
[0025] In accordance with an embodiment of the invention a Settleometer (100) has been shown in FIG. 2. The Settleometer (100) is configured to measure a settling rate and analyse settling profile during sedimentation or dewatering of an ore suspension using a reagent. The Settleometer (100) comprises a measuring cylinder (104) for suspending the ore suspension.

[0026] The ore suspension could be of coal ore or iron ore.

[0027] The measuring cylinder (104) is transparent and calibrated. The measuring cylinder (104) is deployedwith a plunger (108) for moving to and fro within the cylinder to mix the ore suspension.

[0028] In an embodiment, the plunger (108) can be pneumatic in nature.

[0029] Atleast a pair of vertical supporting racks are positioned diagonal oppositely close to the circumference of the measuring cylinder (104). For clarity in understanding two supporting racks have been shown and named as a first supporting rack (112a) and a second supporting rack (112b). The first supporting rack (112a) and the second supporting rack (112b) is deployedwith a first guide rail (116a) and a second guide rail (116b) respectively. The first guide rail (116a) is deployed with a transmitter (T) and the second guide rail (116b) is deployed with a receiver (R).The transmitter (T) and the receiver (R) are movable to and fro vertically over the first guide rail (116a) and the second guide rail (116b) respectively in sync.

[0030] The receiver (R) is configured to intercept light emitted from the transmitter (T) through ore suspension in the measuring cylinder (104). At initial level, i.e. from top of the cylinder, when the ore suspension is added, at a same height level interception may not be possible at first instance. Once ore starts to settle the interception by the receiver (R) starts to grow. Post sensing predetermined amount of light intensity, the transmitter (T) and the receiver (R) moves in sync to next position vertically down on the guide rail.

[0031] The predetermined amount of acceptance may vary greater than 70%.

[0032] Now again the transmitter (T) will transmit the light and the receiver (R) will intercept. Again, if the interception is more than the predetermined level, the transmitter (T) and the receiver (R) would move down to the next level, else will wait till the predetermined amount of light is received. The next position is already set in the program.

[0033] The transmitter (T) and the receiver (R) are photoelectric in nature.

[0034] The functionality of transmitter (T) and the receiver (R) and their movement over the guide rail (116a, 116b) are being controlled via a control unit (120).The transmitter (T) and the receiver (R) are coupled with the control unit (120). The control unit (120) is being configured to receive and analyse the data related to light emission and capturing through the transmitter and the receiver along with their position on their respective guide rails. A display unit (124) is coupled to the control unit (120) to display various analysis executed by the control unit (120).

[0035] The Settleometer (100) can be pictorially seen with display unit (124) in FIGs. 3a and 3b. The process of emitting of light and receiving of the same follows as per the previous case and subsequent downward movement of transmitter (T) and receiver (R) continues. At the end of the settling process the graph or the settling profile is developed. Also, the settling rate is calculated by the slope of the profile.

[0036] Post the process the movement of the transmitter and the receiver reaches the bottom of the cylinder, both returns back to their initial level over the top of the cylinder.

[0037] During the operation, mixing of slurry is done with the help of the plunger (108). The reagent solution of known strength is prepared and transferred to the container used for storing the same. The required amount of reagent is added to the slurry which is already taken in the measuring cylinder (104).

[0038] The control unit (120) controls the particular time for which the mixing is required. Once the process is set ON, the plunger (108) moves up and down in the measuring cylinder (104) for the time set, this helps in mixing of reagent with the slurry. Once it is completely mixed the settling process starts. The mud level is clearly visible and drops down as the time progress.

[0039] The transmitter (T) emits light from one end of the first guide rail (116a) to the receiver (R) and light is not detected until the solid level comes down. Once the clear liquid is obtained the ray passes through the transparent suspension and is detected by the receiver (R). The particular time is noted along with the position of the transmitter (T) and the receiver (R). Both the receiver (R) and the transmitter (T) travels down on the guide rail (116a, 116b) to the next level together and the similar process continue till the end of the settling process. At the end of the process the settling profile as well as the settling rate is tabulated. The data gets stored in the device and can be accessed via any computer or laptop connected to the same and further displayed on the displayed unit (124).The setup also calculates the slope of the graph and this is termed as settling rate.

[0040] The complete data is stored in the device and can be accessed via any hard drive and the prints can be taken.

[0041] The plunger (108) is fixed above the measuring cylinder (104) by means of a plunger support (128). Also, the measuring cylinder (104), the vertical supporting racks (112a, 112b) and the plunger support (128) are being fixed over a platform (132).

[0042] The graph and the settling profile is helpful in the following:
• In selection of suitable reagent and the optimum dosages.
• Remove manpower requirement and experts for carrying out settling study.

[0043] The invention described herein is susceptible to variations, modifications and/or additions than those specifically described and it is to be understood that the inventions all such variations, modifications and/or additions which fall within the scope of the following claims.