CA1046668A - Process for treating slurry turbid water - Google Patents
Process for treating slurry turbid waterInfo
- Publication number
- CA1046668A CA1046668A CA200,153A CA200153A CA1046668A CA 1046668 A CA1046668 A CA 1046668A CA 200153 A CA200153 A CA 200153A CA 1046668 A CA1046668 A CA 1046668A
- Authority
- CA
- Canada
- Prior art keywords
- slurry
- floc
- turbid water
- coagulant aid
- water
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Abstract
ABSTRACT OF THE DISCLOSURE
A process for treating slurry turbid water is disclosed for separating same into dense slurry of fine solid particles and one aqueous medium contained therein. This process includes the steps of adding given amounts of a coagulant aid and a separation-accelerating material to said slurry turbid water for mixing: agitating the mixture thus prepared for improving the contact between said coagulant aid separation-accelerating material and solid particles constituting said slurry turbid water thereby forming floc collecting said floc together with said separation-accelerating material in a specific position to leave a purified or clean aqueous medium, and separating said floc including said separation-accelerating material from said purified or clean aqueous medium.
A process for treating slurry turbid water is disclosed for separating same into dense slurry of fine solid particles and one aqueous medium contained therein. This process includes the steps of adding given amounts of a coagulant aid and a separation-accelerating material to said slurry turbid water for mixing: agitating the mixture thus prepared for improving the contact between said coagulant aid separation-accelerating material and solid particles constituting said slurry turbid water thereby forming floc collecting said floc together with said separation-accelerating material in a specific position to leave a purified or clean aqueous medium, and separating said floc including said separation-accelerating material from said purified or clean aqueous medium.
Description
~04~6~3 ___________________________ Field of the Invention This invention relates to a process for treating-slurry turbid water consisting of suspended solid particles and an aqueous medium, and more particularly to a process for separating dense slurry of suspended solid particles from said aqueous medium. This invention is further associated with a process for purifying slurry turbid water which is formed in the upper layer of slurry when said slurry is stored in a large pond, a reservoir or other suitable containers, and discharging said purified or clean aqueous medium out of a system, while recovering dense slurry of suspended solid particles.
Description of the Prior Art Recently, an efficient method for transporting powdered materials or solid particles such as of iron ore has been in demand arising from industries, particularly from a field of ore transportation where transporting iron ore from a mine to an iron works situated overseas or at a far distance. One of the solutions suggested for this problem is a so-called slurry transportation method. Resorting to pipe lines, iron ore in a slurry form is transported to a destination such as a slurry storing pond or reservoir for different purposes, such as;
subsequent loading of iron ore on a carrier, or subsequent processing in an iron works on land.
However, there is a problem encountered in this solu-tion, particularly when rapid or efficient treatment of slurry j~ of iron ore is desired, is the separation of suspended solid in an aqueous medium, i.e., water or sea water. In detail, when such slurry iron ore is fed into a reservoir or a container, . ~ , ~' ~0~1~;66~3 1 there should have been formed a layer of supernatant liquid and precipitated dense iron ore, both layers being distinctly se-parated. Unfortunately, however, this type of suspended solid is not likely to be settled at the bottom of a reservoir in such a suitable manner. Naturally, large sized solid particles in the slurry may be rapidly settled at the bottom of a reservoir.
However, in the upper layer formation of slurry floc containing fine solid particles occurs. Settling velocity of this type of slurry turbid water formed as an upper layer of slurry stored in a reservoir is very slow, before it becomes eventually settled at the bottom of the reservoir or container. To make the matters worse, when such a turbid water is discharged as waste on land or at sea, a serious problem of pollution is encountered throughout the modern world. Such slurry turbid water contains harmful metallic elements therein.
Accordingly, an efficient treatment must be found to cope with slurry turbid water in the upper layer of slurry stored in a re~ervoir, container or ore-carrier's hold must be obtained and separation of dense slurry from the aqueous medium must be obtained in an efficient manner, before sailing of the carrier, or for immediate subsequent processing required for an iron works on land.
Until now, no attempts have met with success in solv-ing this type of problem using only natural settling takes a long time, before clear supernatant water is obtained or before distinct separation of dense slurry occurs from an aqueous medium, i.e., water or sea water.
SUMMARY OF THE INVENTION
________________________ It is accordingly a principal object of the present invention to provide a process for efficiently treating slurry 1~4~
1 turbid water formed in the upper layer of slurry stored in a reservoir on land, including other suitable containers, thereby separating suspended solid from the aqueous medium contained thereinr i.e., water in an efficient manner.
It is another object of the invention to provide a process for treating slurry turbid water formed in the upper layer of slurry for recovery of suspended solid from such slurry turbid water.
It is a still further object of the invention to pro-vide a process for efficiently treating the slurry turbid waterof the type described for recovery of coagulant aid and separa-tion-accelerating material, (co-precipitation material) together with the aforesaid recovery of suspended solid.
It is a yet further object of the invention to provide a process for efficiently treating the slurry turbid water of the type described, in a continuous treating method.
According to the first aspect of the present invention, there is provided a process for treating slurry turbid water formed in the upper layer of slurry stored in reservoirs on land, other suitable containers or carrier's hold, wherein given amounts of a coagulant aid and co-precipitation materials are added to said slurry turbid water for mixing, the mixture thus prepared is then agitated for improving the contact between said co-agulant aid/co-precipitation material and suspended solid con-stituting said slurry turbid water to t~ereby obtain floc of solid particles, said floc is collected in a specific position in said turbid water to leave a purified or aqueous medium, and then said floc are separated from said purified or clean aqueous medium.
According to the second aspect of the invention, there is provided a process for treating slurry turbid water formed in ' - . : . - . . - - . . , 1~4~6~3 1 the upper layer of slurry stored in a reservoir on land, other suitable container or carrier's hold, wherein given amounts of . a coagulant aid and a co-precipitation material are added to said slurry turbid water for treating, it is then agitated for improving the contact between said coagulant aid/co-precipitation material and suspended solid constituting said slurry turbid water to thereby obtain floc of solid particles, said treated slurry turbid water is then separated into an upper layer of supernatant liquid layer and a lower layer of floc according to settling, said floc is then rinsed with water to obtain separate clean co-precipitation material and/or coagulant aid and fine solid particles, said fine solid particles are then dehydrated to obtain solid cakes, and said clean co-precipitation material and/or coagulant aid are again added to treat the :new slurry turbid water, whereby the slurry turbid water may be treated continuously.
According to the third aspect of the present invention i9 to provide a process for treating slurry turbid water formed in the upper layer of slurry stored in a reservoir on land, other suitable container or carrier's hold, wherein a given amount of coagulant aid is added to said slurry turbid water, then compressed air is injected into said slurry turbid water to thereby disperse solid particles settled in the lower part of said reservoir back in said upper slurry turbid water and , mixing and agitating said coagulant aid and said settled solid particles together in said slurry turbid water, whereby said slurry turbid water may be rapidly in the lower part of said reservoir, while discharging a supernatant water from said reservoir.
According to the fourth aspect of the present invention, there is provided a process for treating slurry turbid water - 4 - ~:
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104~6f~8 1 formed in the upper layer of slurry stored in a reservoir on land, other suitable container or carrier's hold, wherein given amounts of a coagulant aid and ferromagnetic powder are added to the slurry turbid water and was agitated. As the result of the agitating thus formed floc, said floc is then separated by utilizing a magnetic force from said slurry turbid water, leaving a clear aqueous medium.
Meant by the term, "separation-accelerating material"
as used herein may be a co-precipitation material which acceler-ates the velocity of suspended solid in slurry turbid water by utilizing gravity of material, or may be solid particles of a relatively larger si~e which is part of said slurry turbid water and apt to be readily settled in the lower part of a reservoir on land, other suitable container or carrier's hold or may be ferromagnetic particles which aid in separation of suspended solid in said slurry turbid water by utilizing a magnetic force, i.e. t by attracting the aforesaid to electromagnet plates.
BRIEF DESCRIPTION OF THE DRAWINGS
------_----_--_______________________ Fig. 1 is a flow sheet of one embodiment of the process for treating slurry turbid water according to the present inven-tion;
Fig. 2a is a cross-sectional view of an agitating device as used in the process according to the present invention;
E~g. 2b is a cross-sectional view of Fig. 2a;
Fig. 3a is a cross-sectional view of a settling treat-ment device;
Fig. 3b is a cross-sectional view taken along the line A-A of Fig. 3a;
' 30 Fig. 4 is a plan view of ore slurry carrier embodying the present invention;
.
1 Fig. 5A and B are vertical and horizontal cross sectional views illustrating the usage of coagulant aid;
Fig. 6 is a flow chart illustrating one embodiment of the process according to the present invention;
Fig. 7 is a plan view of an outline of an ore carrier, to which the process of the present invention may be applied;
Fig. 8 is a cross-sectional view of a device for use in rinsing and separating a co-precipitation material used in the process of the present invention;
Fig. 9 is a plot showing the relationship between the residual turbidity of water which has been treated according to the process of the present invention and agitating time due to compressed air injected into slurry turbid water;
Fig. 10 is a fragmentary, perspective view of a com-pressed air injection pipe and a coagulant aid injection pipe used in the process according to the present invention;
Fig. 11 is an enlarged view showing a compressed air injection pipe and a coagulant aid injection pipe as shown in Fig. 10;
Fig. 12 is a perspective view of an arrangement, wherein partition walls are provided around an injection pipe;
Fig. 13 is an outline showing mixing plates placed above a compressed air injection pipe;
Fig. 14 is a flow sheet of one embodiment of the process according to the present invention;
Fig. 15 is a side elevation illustrating a magnetic separating tub;
Fig. 16 is a flow sheet of another embodiment of the process according to the present invention; and Fig. 17 is a plan view of an outline of an ore carrier, to which the process according to the present invention is applied.
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DESCRIPTION OF THE PREFERRED EMBODIMENTS
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For simplicity, the process according to the present invention will be described particularly by referring to an ore slurry carrier rather than a large size pond or a reservoir used on land. However, such an example should by no means be con-strued as being limitative in its nature.
In general, the process will be described by using underlined headings corresponding to the aspects of the present invention.
The First Aspect of the Invention A feature (i) of the first aspect of the process according to the present invention is that given amounts of coagulant aid and a co-precipitation material are added, for treating, to the slurry turbid water formed in the upper layer of slurry contained in a hold of an ore carrier, the mixture thu8 prepared is then agitated and allowed to stand for a while, whereby the aforesaid slurry turbid water i8 separated into clean supernatant water and settled solid particles or granules. Mean-while, the aforesaid slurry turbid water in general consists ofvery fine particles and moreover the specific gravity of the particles is relatively small, such that even if the slurry turbid water is allowed to settle for a long period of time in a hold, only a small part of particles is apt to be settled, leaving a greater part thereof in suspension or in a floating condition. Accordingly, inorganic coagulant aid such as sulfuric band or PAC or high-polymer coagulant aids such as denatured polyacryl amid are added to the slurry turbid water in a hold ; ~ -~ of a carrier to thereby intensionally cause the formation of ,, 30 floc, for mixing slurry turbid water by a coagulant aid ,, .
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~o~ s and rapid settling an~ hence the rapid separation of suspended solid. However, the results are that even though the floc is formed, the floc is apt to remain in the floating condition and even if only a part thereof is attempted to be settled, a long period of time is required. This is particularly true in the ~-case of powdered ore slurry which has been subjected to floata-tion, because the fine suspension particles themselves have floating agents adhered thereto. This is also true, in case the specific gravity of liquid which is to be added to powdered ore to give a slurry condition is relatively high as that of sea water. For this reason, according to the present invention, a co-precipitation material having a relatively large grain size and higher specific gravity, as compared with suspended solid in turbid water is added thereto for the purpose of enhancing the settling of the suspended solid floating in the slurry, thereby achieving rapid and positive separation or purification o~
slurry turbid water. This greatly contributes not only to saving in time of carrier's lay days but also to prevention of pollution, and thus the industrial value of such an attempt is highly eva-luated. Included by the aforesaid co-precipitation materials are powdered ore, sand or the like, and those should be greater in specific gravity than that of the suspended solid. It is imper-ative that the mixture of slurry turbid water coagulant aid and co-precipitation material be thoroughly mixed and agitated to the aforesaid end. In this respect, such agitation may resort to a direct agitation within a carrier, such as by introducing compressed air into the aforesaid mixture which dwells in the ~, upper layer of the slurry for effecting so called bubbling or mechanical agitation, or otherwise such slurry turbid water may be transferred to an agitating device placed on board for agita-tion. With the treatment on board, it is required to provide a ~-.
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1 settling and separating device for sedimentation and separation of the mixture agitated. For this purpose, a conventional type settling tub, cyclone, centrifugal separator, a screw feeder and the like may be employed.
A further feature (ii) of the first aspect of the present invention is that powdered bodies of the same composition as those of the suspended solid are used as co-precipitation materials. This is particularly advantageous, because if different kinds of co-precipitation materials are used, those may exert adverse effect on the properties of slurry, and hence the co-precipitation material is employed. This then dictates the provision of a removing device for co-precipitation material contained therein. Furthermore, settled particles usually contain useful components, such that the feed back of the sedimental coagulated bodies to a land side is not recommendable from economical viewpoint, while discharging of such particles into sea is not recommendable from the viewpoint of pollution.
The use of the solid particles of the same composition as that of the suspended solid may avoid such complicated problems.
A still further feature (iii~ of the first aspect of the present invention is that, after the slurry turbid water has been formed in the upper layer of slurry contained in a carrier's hold, part of powdered bodies of the type described are con-tinuously fed to an agitating apparatus on board for mixing and agitation, and the mixture thus prepared is then fed to a settling device for separation into a clear supernatant water and precipitated particles, after which the aforesaid supernatant water is discharged out of the carrier, while the floc i~ fed back to the hold of a carrier for recovery. In other words, the slurry turbid water is not designed as to be treated directly _ 9 _ .
~04~668 1 within a carrier's hold but fed to an agitating device provided on board, wherein the slurry turbid water, coagulant aid and co-precipitation material are thoroughly mixed, and then fed to a settling device on board for separation into a clean super-natant water and floc. This further provides additional advantage of the feasibility of a continuous treatment of the slurry turbid water. In other words, the continuous feeding of the slurry turbid water from a carrier's hold to the aforesaid devices on board may provide good compatibility with the con-tinuous feed back of the separated floc into the hold. Thesupernatant thus obtained may ~e discharged into the sea, because such has been completely purified at this time. The floc re-covered from the slurry turbid water usually amount to about 10 to 20% of the whole slurry to be transported. In this meaning, the treatment according to the present invention may also provide con9iderable economical advantage. Alternatively, the floc thus obtained may be again used as co-precipitation material for the ; subsequent treatment.
A yet further feature (iv) of the first aspect of the present invention is that the slurry turbid water is fed to an agitating device which includes barrier plates and is provided in the route of pipings.
A further feature (v) of the first aspect of the invention is the use of a feed pipe which contains a coagulant aid of a solid form which is intended to be dissolved into slurry turbid water which is being fed through piping.
Now, description will be given in more detail on the first aspect of the process according to the present invention with reference to Figs. 1 to 5.
Fig. 1 shows a flow sheet of the process embodying the first aspect of the present invention. The slurry 1 which has .1 ' .
10466~3 1 been loaded in the hold 2 of a carrier is separated into slurry turbid water 3 dwelling in the upper part of the slurry and precipitated solid particles 4 in the lower portion of the hold.
The slurry turbid water 3 floating in the upper part of the slurry is then fed by way of a feed pipe 7 to an agitating device 8 provided in the piping route.
On the other hand, part of precipitated solid particles 4 is fed as co-precipitation material by means of a slurry pump 6 by way of the feed pipe 7 to the agitating device 8. On the other hand, a coagulant aid 9 adjusted to a suitable concentration by dissolving same into water is fed in a given amount to the mixture of slurry turbid water and co-precipitation material, i.e., solid particles by means of a chemical pump 10. Thus, the slurry turbid water 3, co-precipitation material 4 and coagulant aid are agitated by being passed through the agitating device 8 and then to the subsequent step of a settling device 11. The mixture is settled in the settling device 11, thereby allowing the clean supernatant water 12 to overflow the settling device 11 for continuous discharge. On the other hand, the floc 13 ~ are fed to a carrier hold 2.
The maximum efficacy of the addition of the co-preci~
pitation material 4 and coagulant aid 9 requires the provision of optimum concentrations of such particles and aid. Accordingly, the feed rate of such materials to be fed by means of pumps P
5, P2 6, P3 10 should be controlled. The experiments reveal that the range of the optimum concentrations of the aforesaid particles and aid should not necessarily be controlled strictly, such that a wide range of the concentrations will not impair the objects of the present invention.
Table 1 illustrates the results of the treatment of the slurry turbid water according to the first aspect of the invention, in which conslderable decrease in residual suspended solid degree results in the case of the combined used of co-precipitation ma-terial.
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c~ E~o-a ~ 8 1 Fig. 2 shows one example of the agitating device pro-vided in the route of piping for mixing and agitating the slurry turbid water coagulant aid and co-precipitation material but serving as a feed piping as well, in the longitudinal and trans-verse cross sectional views. In this example, a plurality of sets of agitating propellers 17 are mounted on a shaft 16 within the slurry turbid water feed pipe 7, while the deflecting directions of the respective propellers are reversed between each of the two aforesaid sets of propellers, thereby creating whirl flows having opposite directions, when the slurry turbid water passes through the pipe, for providing a strong agitating effect.
Fig. 3 is longitudinal and transverse cross sectional views (A-A) of one example of the settling device for use in the process of the present invention. There are provided a plurality of partition plates 21 within the settling device ll for extending the distance of treated slurry suspension through the aforesaid device.
While the slurry turbid water passes through the device 11 in directions shown by arrows, treated floc contained therein will be settled, thereby leaving a clean supernatant liquid which in turn is discharged through a discharge port provided in the device. The floc are collected in a discharge passage 23 by means of a screw feeder 22 provided in the lower portlon of the device 11. Connected to the discharge passage 23 is a floc feeding pump 24, whexeby the floc are returned to the hold of a carrier.
Fig. 4 shows a plan view of an outline of an ore carrier equipped with various devices suitable for practicing the pFocess of the present invention. Shown at 31 is a slurry . . . . .
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10~66~3 1 turbid water feed pipe, at 2 a hold of a carrier, at 5 a slurry suspension feeding device from the hold, at 6 a co-precipitation solid particles feeding devicej at 35 an agitated water feeding pipe, at 32 a coagulant aid reservoir, at 10 a coagulant aid feed pump, at 11 a settling device, at 33 a supernatant water discharge pipe, at 24 a discharge device for discharging floc which have been separated within the settling device and at 34 a discharge pipe for use in the aforesaid device 24.
In practice, there are provided a plurality of holds in an ore carrier, but two of them are shown in Fig. 4 for simplicity of description.
The slurry which has been loaded in a hold 2 of a carrier by way of a slurry feed pipe 31 is .settled in the hold, thereby leaving slurry turbid water in the upper layer thereof. The slurry suspension is then fed by means of slurry turbid water feed device 5 by way of a slurry turbid water feed pipe 7 to the agitating device 8. On the other hand, the solid particles which have been settled in the hold are fed, as co-precipitation material, by means of the solid particle feeding device 6 by way of the slurry turbid water feed pipe 7 to the agitating device 8.
A given rate of coagulant aid is fed by means of coagulant aid feed pump 10 from the coagulant aid reservoir 32 to the slurry turbid water in a position downstream of the agitating device 8.
The slurry turbid water, coagulant aid and co-sedimental solid particles are thoroughly mixed and agitated in the agitating device 8 and then fed to the setting device 11. The slurry turbid water is then separated into clean supernatant liquid and treated floc while the supernatant liquid is discharged out of a carrier ~ and, on the other hand, the floc is fed back by means of the floc 30 discharge device 24 by way of a discharge pipe 34 to the hold 2 .1 .
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~04666~3 1 of a carrier. Thus, both the treatment of the slurry and the feed-back of floc may be accomplished at the same time in a continuous but efficient manner.
~ owever, those two operations should not necessarily be carried out in the same carrier, but a separate carrier for exclusive use of treating slurry turbid water may be provided in combination with the aforesaid carrier.
Fig. 5 illustrates an example where solid coagulant aid is used in the process of the present invention. Fig. 5A
0 shows one usage of the coagulant aid formed to a given shape.
There is provided an opening 41 in part of the feed pipe 7, with a container 42 of a mesh form housed therein. A coagulant aid 43 formed to a desired shape is placed in the container 42. With such an arrangement, the slurry turbid water flowing through the pipe keeps contacting a high polymer coagulant aid which in turn is dissolved into the slurry turbid water.
Fig. 5B shows one usage of the coagulant aid 43 formed to a cylindrical form, which is inserted in part of the feed pipe 7. However, a retaining portion 44 is provided for the pipe for ao retaining the coagulant aid therein in combination with a pro-jecting portion 45. For charging the coagulant aid therein, the retaining portion may be split into two parts, one of which may be removable.
The use of the solid coagulant aid further improves the efficiency of addition of coagulant aid to slurry turbid water, thus affording improved overall efficiency of the process accord-ing to the present invention.
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The_Second Aspect of the Invention The second aspect of the process for treating slurry ~
. .
' ~L04~i668 1 turbid water formed in the layer of slurry will be described with reference to Figs. 6 to 8.
Fig. 6 is a flow chart illustrating the process of the present invention, while Fig. 7 is a plan view of an outline of an ore carrier. In those figures, the slurry 101 of solid particles is transferred by way of a slurry feed pipe 133 from land into the hold of a carrier. The slurry thus loaded is then subjected to natural settling and separated into the slurry turbid water 103 forming the upper layer of the slurry loaded and the settled solid particles forming the lower layer. Then, the slurry turbid water 103 thus formed is then fed by way of a feed pipe 105 to a blending tub 106 provided on the deck of a carrier, continuously. This blending tub 106 may be of a con-ventional type or one provided with an agitating device. On the other hand, a coagulant aid 107 is prepared in a container close to the aforesaid blending tub, the concentration thereof being adjusted to a desired concentration by adding water thereto, and thus the coagulant aid is continuously fed by means of a chemical pump 108 to the blending tub 106. Furthermore, there is provided a container whish contains a co-pxecipitation material 112, in the vicinity of the blending tub 106. A given flow rate of the co-precipitation material is continuously fed to the blending tub 106. The slurry turbid water, to which has been added a coagulant aid and a co-precipitation material, is then fed by means of a slurry pump 110 from the blending tub 106 by way of a feed pipe 109 to an agitating device 111 (a static mixer) pro-vided in the route of a piping for thorough mixing and agitation.
The agitating device 111 contains mixing plates or rotary blades within a pipe, serving the dual purposes of feeding and agitation of slurry turbid water and the like. The slurry turbid water, .
10~ti6C~3 1 after mixing, is then fed to a settling and separating tub 114 and allowed to stand for a while. Meanwhile, the slurry turbid ~ater, coagulant aid and co-precipitation material have been thoroughly mixed such that the formation of the floc of suspended solid has been enhanced. As a result, the suspended solid in the settling tub 114 may be separated, due to co-precipitation effect of co-precipitation material, into clean supernatant liquid 115 forming the upper layer and the sedimental coagulated bodies 116 forming the lower layer thereof. In passing, the aforesaid settling tub 114 may be of a conventional type or cyclone, centrifugal separator or screw feeder. The supernatant water 115 forming the upper layer is then discharged from the settling tub 114 into sea. The floc 116 now consisting of suspended solid, co-precipitation material and coagulant aid are fed by means of a slurry pump 118 by way of a slurry feed pipe 119 to a co-precipitation and separating device 113. A
rinsing device 120 serves to rinse with water to remove the suspended solid and coagulant aid which have been adhered to the co-precipitation material, from the aforesaid co-precipitation material, thereby recovering the co-precipitation material for repeated use. In this respect, the rinsing device utilizes '! means such as rotational agitation, high pressure water injection or supersonic wave and the like. For rinsing co-precipitation material, the water content of floc should be maintained more than 15%. However, water may be added in the rinsing device 120 separately, or part of the supernatant water may be added to the floc, when same is fed from the settling and separating tub 114. The co-precipitation material separating device 113 serves to separate the rinsed co-precipitation material 112 from the fine solid particles 117. In other words, a classifier, endless screen separator, centrifugal separator are used for dehydrating ; ' , '''' ~.
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1 and separating fine solid particles 117. Alternatively, a rin-sing device 120 may be combined with the separator 113 to provide a single unit for convenience of using same as a continuous treating device provided on the deck of a carrier. Fig. 8 shows one example of the rinsing device as described herein. In this device, the floc 116 which is being fed continuously by way of the slurry feed pipe 119 from the aforesaid settling and separating tub 114 is supplied to the rinsing and separating device 113, while the rinsing and separating device 113 is pro-vided with a rotatable agitating blade 128, on which is mounteda motor 127 in the upper portions thereof, said rotatable blade 128 being inserted in said floc, whereby the rotation of the motor 127 causes the rotation of the agitating blade 128 for agitation of the floc. During this agitation, the co-precipitation material is rinsed. Furthermore, there is provided an air in~ecting pipe 130 provided in the lower portion of the device 113 for injecting high pressure air 129 into the floc for acceler-ating the agitation. The fine solid particles 117 which contains coagulant aid, and has been separated from co-precipitaton material, is introduced to the lower portion of the device 113 and discharged by way of discharge pipe 131, continuously and then fed to the dehydrating device 122. In addition, the device is equipped with a screw feeder 132 connected to motor 127' for transferring the co-precipitation material 112 upwardly for discharging same out of the device 113.
In this manner, the co-precipitation material 112 is rinsed and thus separated from the floc 116 and then charged as a new co-precipitation material into the blending tub 106. The repeated use of such a cycle of an operation permits the con-tinuous circulation of the aforesaid materials. Included by the .
' . .
1 co-precipitation materials which are employable in the process of the present invention are ceramics such as Sic, Wc, A12O3 and the like or high polymer resins such as fluoro-resin, alkyd resin or metals such as sus powder, Ta powder and the like~ Those co-precipitation materials permit their continuing use for a long period of time, affording re-producing capability, as well as high abrasion resistance and corrosion resistance. Furthermore, those co-precipitation materials may be used in small amounts for treating a considerably large mass of slurry turbid water and particularly adapted for use within a carrier.
On the other hand, the fine solid particles 117, ~rom which the co-precipitation material has been removed, is fed to the dehydrated 122 by means of a pump 118 and then separated into a separator water 123 containing a coagulant aid and a 801id dehydrated cake 124.
Although part of the coagulant aid i8 contained in the dehydrated cake 124, a ma~ority of the coagulant aid is extracted into the separated water 123 at the time of dehydration. The 5eparated dehydrated cake 124 is recovered and fed back to the hold 102. The separated water 123 containing coagulant aid is then fed to the blending tub 106 for the subsequent repeated use, as in the case with the aforesaid co-precipitation material.
Thus, the co-precipitation material and coagulant aid may be repeatedly added to the slurry turbid water which is con-tinuously fed from a hold to a blending tub on the deck of a carrier, while the slurry turbid water may be recovered as solid particles.
, Meanwhile, the coagulant aid 107 is dissolved in water for use, as has been described earlier, but this may be provided in the solid form for placing same into a slurry feed pipe 105 which leads to the blending tub 106 on the deck.
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1 The mird Aspect of the Invention The third aspect of the process according to the present invention will be described with reference to Figs. 9 to 13.
Fig. 9 shows a plot illustrating the relationship between the residual suspended solid degree and agitating time after slurry turbid water of 50 ltr containing suspended solid of about 500 ppm has been subjected to air agitation in a laboratory. In this case, the feed rate of air was 0.2 ltr/min.
amount of the coagulant aid added was 10 ppm and the concentration of the co-precipitation material was 10%. The desired agitation resulted for a duration as short as 4 minutes, while the excess-ively long duration of agitation presents a danger of causing re-dispersion. In practical application, an air injection pipe i8 moved through slurry turbid water at a desired speed and hence for a desired duration of agitation. The mixing and agitation of the coagulant aid, co-precipitation material and suspended solid cause floc to adhere to the co-precipitation material and, as a result, they will be rapidly precipitated, while the clean supernatant liquid, i.e., aqueous medium may be discharged by means of a pump, ejector or the like out of the carrier.
Figs. lO to 13 refer to the apparatus for practicing the process of the present invention.
Referring to Fig. 10, shown at 201 is a hold of an ore carrier. The slurry, for instance, of iron ore may be rapidly separated into suspended solid particles 202 and slurry turbid water 203, after being loaded in the hold of a carrier. After loading, an air injection pipe 204 is placed on top of the layer of the precipitation solid particles, or alternatively the air injection pipe 204 may be placed before loading of slurry in the hold of a carrier. The air injection pipe 204 is connected by 10466~8 1 way of a flexible air feed pipe 205 to a compressed air source (not shown). In addition, the air injection pipe 204 may move along the longitudinal direction of the hold 201 by means of an automatic travelling device 208 along the guide rails 207 mounted on the inner walls of the hold 201. This travelling device may be a wheeled platform provided with rollers adapted to roll on the guide rails 207 by means of a suitable drive means. The aforesaid air injection pipe 204 and the coagulant aid injection pipe 211 are mounted on the wheeled platform.
The air injection pipe 204 as shown in Fig. 11 is pro-vided with a plurality of injecting holes 209, while part of the injection holes 209 are open in a direction against that of the solid particles which are being settled, such that part of the settled solid particles will be blown upwardly due to the air stream being injected.
Integrally provided for the air injection pipe 204 are a plurality of coagulant aid feed pipes 211 having a plurality of injection holes 210, through which the coagulant aid is injected. The coagulant aid injection pipes may be moved to-gether with the air injection pipe 204. The coagulant aid isfed from a coagulant aid reservoir (not shown) by way of a feed pipe 206 by means of a constant flow rate feed pump (not shown) and added through the coagulant aid injection holes 10 to the slurry turbid water. The coagulant aid of only 10 ppm is sufficient for the slurry suspension to which same is to be added, while the feed rate of the coagulant aid is adjusted commensurate to the moving speed of the air injection pipe. The air injected through the air injection pipe 204 ascends in the form of bubbles through the slurry turbid water, whereby the co-precipitation material blown from the bottom and slurry turbid !
1046~8 1 water and coagulant aid are mixed and agitated and as a result the slurry turbid water adheres to co-precipitation material to form floc of a relatively large size, which in turn is settled rapidly.
As shown in Fig. 12, for enhancing the agitating effect, there is provided partition walls 213 having a plurality of holes, around the air injection pipe 204, whereby the slurry turbid water confined by the aforesaid partition walls may be efficiently agitated, as the air injection pipe 204 and coagulant aid in-jection pipe 211 move.
Fig. 13 shows another example where there are provided a plurality of barrier plates 214 in the passage of air bubbles but above the air injection pipe 204 in a manner that the air bubbles ascend along staggered paths, in an attempt to enhance the agitating effect. In passing, the barrier plates~214 are affixed to a supporting bar 215 extending vertically from the air injection pipe 204 in a staggered relation.
Rapid settling of floc results in the area which is 8ubjected to the aforesaid agitation, and then clean supernatant water is discharged by means of a water pump P out of a carrier from the surface of the supernatant water.
As is apparent from the foregoing description, the third aspect of the process according to the present invention permits rapid and efficient treatment of slurry turbid water dwelling in the upper portion of slurry contained in the hold of a carrier, without having rècourse to other specific equip-ments provided on board.
The Fourth Aspect of the Invention The fourth aspect of the process according to the present invention will be described with reference to Figs. 14 to ~7.
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Fig. 14 shows a flow sheet of one embodiment of the present invention. Slurry turbid water 301 is fed by means of a pump 302 to blending tub 302, continuously. The blending tub 303 may be of a conventional type or may be one having an agita-ting means such as impellers. Close to the blending tub 303, there is provided a coagulant aid 304 whose concentration has been adjusted to a desired value by adding water thereto. The coagulant aid 304 is fed by means of a pump 304 at a constant feed rate in the aforesaid blending tub 303, commensurate to lO the feed rate of slurry turbid water. The coagulant aid which has been described earlier may be used in this case, as well.
On the other hand, there is provided ferromagnetic particles 306 in a position close to the blending tub 303, whereby it may be fed at a con9tant rate by means of a hopper or feeder and the like to the biending tub 303. The ferromagnetic particles which may be used in the process according to the present invention are Fe, Co, Ni, FeO, Fe~O4 and the like. Naturally, those should not neces~arily be used in 100%, i.e., there may be used magnetic ore and the like which contains a plenty of FeO and Fe3O4 and 20 provides high corrosion resistance and lower cost.
The slurry turbid water, to which have been added coagulant aid and ferromagnetic particles at a given ratio is then fed to an agitating device 307 for thorough mixing. The agitating device 307 used may be one having impellers or a blend-ing tub having means whereby to introduce a high pressure gas therein, or otherwise agitating means (for instance, a static mixer) provided in the route of a piping which means also serves to feed the slurry turbid water. The suspended solid in slurry turbid water after agitation, will be coagulated by the coagulant 30 aid to form floc having a high specific gravity. Then, the slurry . ' .
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,. ~ . , . :
.~. . . . . .
~0~6Çif~8 1 turbid water is fed to the subsequent step, i.e., a magnetic separation tub 308.
Fig. 15 is a cross-sectional view of the magnetic se-paration tub 308. As shown, the separation tub 308 is divided by partition plates 321A and 321B into three compartments, i.e., X, Y and Z tubs. In addition, X and Y tubs are divided into two parts, respectively, by the partition plates 320A and 320B.
The partition plates 320A and 320B may be energized by causing an electric current to flow therethrough by way of a lead wire 322', thereby generating magnetic force. Shown at 322 is a switch for the aforesaid partition plates 320A and 320B. The slurry turbid water 301 after mixing is fed by way of 319 to the X tub in the magnetic separation tub 308. Since the solid particles are coagulated by the coagulant aid to give floc having a high specific gravity, they will soon be sedimented in the bottom of the tub. However, in case that the suspended solid consists of fine particles or is a heavy liquid, it takes a long period of time until the whole floc is settled completely.
For this reason, an electric current is caused to flow through a switch 222 to the partition plate 320A, i.e., the electromagnet, as shown in Fig. 15, thereby generating a magnetic force. Then, the ferromagnetic particles in the floc is rapidly attracted by the magnetic force to the partition plate 320A. When the amount of the floc attracted to the partition plate 320A is saturated, then the switch is thrown to the side leading to the partition plate 320B. The floc which has grown up to a considerably large size and contains suspended solid particles, ferromagnetic par-ticles and coagulant aid therein will be rapidly settled by their own gravity, when released from the magnetic force. The switch 322 is then thrown to the side leading to the partition . . ; . .
- - . . . .. . . , -104~;6~;i8 1 plate 322A, whereby the new floc fed from the feed pipe 319 wi11 be attracted thereto. Thus, such a cycle is repeated to effect the continuous treatment.
The slurry turbid water is almost purified in the X
tub and then fed to the Y tub. The partition plate 320B generates a magnetic force cyclically, such that the floc which has not been completely settled in the X tub may be positively attracted thereto and then settled. The clean liquid in the Y tub, i.e., clean water 309 is then fed from the partition plate 321B to 0 the Z tub, after which the clean water 309 will be discharged through a discharge pipe 330. On the other hand, the floc which has been settled in the lower portions of X and Y tubs, i.e., settled solid particles 310 are discharged by way of a slurry discharging pipe 331. The magnetic separation tub 308 is only indicated herein for description purpose and thus should not be construed as being limitative in its nature.
Fig~ 16 shows a flow sheet of the ferromagnetic particles contained in the settled particles 310 and the coaguiant aid.
More particularly, the settled solid particles 310 which have been separated in the magnetic separation tub 308 is fed to a rinsing device 312. In case the ferromagnetic particles are magnetized to a high level, it is preferable that the ferro-magnetic particles be passed through a demagnetizing device, before feeding to the rinsing device 312, thereby reducing then coagulating force caused due to the residual magnetic force among particles. The rinsing device 312 is intended to rinse and remove, with a small amount of water, the solid particles and coagulated particles whicX adhere to ferromagnetic solid particles. --~Thus, the rinsing device 312 may be of a known type which is pro-vided with bubbling means such as using the rotational agitation, , 104~
1 high pressure gas in~ection or means such as using a high pressure injection or supersonic wave and the like. The precipitated solid particles 310 which have been rinsed is then separated by means of a magnetic separation device 314 into ferromagnetic particles 306 and coagulant aid plus fine solid particles 313.
The magnetic separating device 314 as used herein is of a drum type or belt type, whereby ferromagnetic particles may be select-ively recovered from the precipitated solid particles. The ferromagnetic particles 306 which have been recovered are de-0 magnetized by means of demagnetizer as required, and then addedto the blending tub 303 again for repeated use.
On the other hand, the fine solid particles 313 is fed to a dehydrator 315 of a known type such as a filtrating device, filter press, vacuum dehydrator and the like. Thus, the fine solid particles 313 is separated into separated water 317 con-taining coagulant aid and a dehydrated cake 316 of a solid form.
The dehydrated cake is recovered for repeated use, not to mention the case where the recovered cake contains useful materials.
Furthermore, the separated water 307 containing coagulant aid is then added as coagulant aid by means of a pump to the new slurry turbid water for repeated use like ferromagnetic particles 306. This eliminates or minimizes the use of the ferromagnetic particles and coagulant aid which are to be fed to the blending tub 303. Those tubs and devices may be provided on board.
Fig. 17 shows a plan view of an outline of an ore carrier, to which is applied the process according to the present invention.
The procedures as used in this case is almost similar to those used in the previous case. The slurry is loaded in a hold 325 by way of a feed pipe 324. The slurry turbid water is ~.
, ` - 26 - ~
. ~.
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1 fed by means of a pump 326 by way of a feed pipe 327 to a blending tub 303 provided on board. The ferromagnetic particles 304 and coagulant aid 306 are prepared in the same manner as in the previous case. The slurry turbid water, to which have been added the aforesaid ferromagnetic particles 304 and coagulant aid 306, is then fed to an agitating device 307 provided in the route of piping. The slurry turbid water which has completed mixing and agitation is then fed to the magnetic separation tub 308, where it is separated into a clean water, and precipitated mixture consisting of fine solid particles and ferromagnetic particles and coagulant aid, and then the clean water 309 is discharged out of a carrier. The aforesaid precipitated solid particles are separated into fine solid particles and ferromagnetic particles by means of a rinsing device 312 and magnetic separation device 314, after which the ferromagnetic particles are again added to the blending tub 303 for repeated use.
On the other hand, the fine solid particles are fed to the dehydrator 315, where it is separated into separated water, containing coagulant aid and solid dehydrated cake con-sisting of fine solid particles, after which the separated watercontaining coagulant aid is added to the blending tub for re-peated use. Like the previous case, the ferromagnetic particles may be demagnetized in the same manner as in the previous case, while the dehydrated cake is recovered in the hold 325 of a carrier. Thus, the slurry turbid water may be treated contin-uously by means of devices provided on the carrier itself, or by the use of a hold of a carrier.
While the description has been given in the case where the process according to the present invention is applied to a slurry carrier, the process of the invention may apparently be ' .
- ~ 04f~
1 applied to the slurry stored in a reservoir, pond or other containers on land.
It will be understood that the above description is merely illustrative of the preferred embodiments of the invention.
Additional modifications and improvements utilizing the discoveries of the present invention can be readily anticipitated by those skilled in the art from the present disclosure, and such modifi-cations and improvements may be fairly be presumed to be within the scope and purview of the invention as defined by the claims that follow.
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Description of the Prior Art Recently, an efficient method for transporting powdered materials or solid particles such as of iron ore has been in demand arising from industries, particularly from a field of ore transportation where transporting iron ore from a mine to an iron works situated overseas or at a far distance. One of the solutions suggested for this problem is a so-called slurry transportation method. Resorting to pipe lines, iron ore in a slurry form is transported to a destination such as a slurry storing pond or reservoir for different purposes, such as;
subsequent loading of iron ore on a carrier, or subsequent processing in an iron works on land.
However, there is a problem encountered in this solu-tion, particularly when rapid or efficient treatment of slurry j~ of iron ore is desired, is the separation of suspended solid in an aqueous medium, i.e., water or sea water. In detail, when such slurry iron ore is fed into a reservoir or a container, . ~ , ~' ~0~1~;66~3 1 there should have been formed a layer of supernatant liquid and precipitated dense iron ore, both layers being distinctly se-parated. Unfortunately, however, this type of suspended solid is not likely to be settled at the bottom of a reservoir in such a suitable manner. Naturally, large sized solid particles in the slurry may be rapidly settled at the bottom of a reservoir.
However, in the upper layer formation of slurry floc containing fine solid particles occurs. Settling velocity of this type of slurry turbid water formed as an upper layer of slurry stored in a reservoir is very slow, before it becomes eventually settled at the bottom of the reservoir or container. To make the matters worse, when such a turbid water is discharged as waste on land or at sea, a serious problem of pollution is encountered throughout the modern world. Such slurry turbid water contains harmful metallic elements therein.
Accordingly, an efficient treatment must be found to cope with slurry turbid water in the upper layer of slurry stored in a re~ervoir, container or ore-carrier's hold must be obtained and separation of dense slurry from the aqueous medium must be obtained in an efficient manner, before sailing of the carrier, or for immediate subsequent processing required for an iron works on land.
Until now, no attempts have met with success in solv-ing this type of problem using only natural settling takes a long time, before clear supernatant water is obtained or before distinct separation of dense slurry occurs from an aqueous medium, i.e., water or sea water.
SUMMARY OF THE INVENTION
________________________ It is accordingly a principal object of the present invention to provide a process for efficiently treating slurry 1~4~
1 turbid water formed in the upper layer of slurry stored in a reservoir on land, including other suitable containers, thereby separating suspended solid from the aqueous medium contained thereinr i.e., water in an efficient manner.
It is another object of the invention to provide a process for treating slurry turbid water formed in the upper layer of slurry for recovery of suspended solid from such slurry turbid water.
It is a still further object of the invention to pro-vide a process for efficiently treating the slurry turbid waterof the type described for recovery of coagulant aid and separa-tion-accelerating material, (co-precipitation material) together with the aforesaid recovery of suspended solid.
It is a yet further object of the invention to provide a process for efficiently treating the slurry turbid water of the type described, in a continuous treating method.
According to the first aspect of the present invention, there is provided a process for treating slurry turbid water formed in the upper layer of slurry stored in reservoirs on land, other suitable containers or carrier's hold, wherein given amounts of a coagulant aid and co-precipitation materials are added to said slurry turbid water for mixing, the mixture thus prepared is then agitated for improving the contact between said co-agulant aid/co-precipitation material and suspended solid con-stituting said slurry turbid water to t~ereby obtain floc of solid particles, said floc is collected in a specific position in said turbid water to leave a purified or aqueous medium, and then said floc are separated from said purified or clean aqueous medium.
According to the second aspect of the invention, there is provided a process for treating slurry turbid water formed in ' - . : . - . . - - . . , 1~4~6~3 1 the upper layer of slurry stored in a reservoir on land, other suitable container or carrier's hold, wherein given amounts of . a coagulant aid and a co-precipitation material are added to said slurry turbid water for treating, it is then agitated for improving the contact between said coagulant aid/co-precipitation material and suspended solid constituting said slurry turbid water to thereby obtain floc of solid particles, said treated slurry turbid water is then separated into an upper layer of supernatant liquid layer and a lower layer of floc according to settling, said floc is then rinsed with water to obtain separate clean co-precipitation material and/or coagulant aid and fine solid particles, said fine solid particles are then dehydrated to obtain solid cakes, and said clean co-precipitation material and/or coagulant aid are again added to treat the :new slurry turbid water, whereby the slurry turbid water may be treated continuously.
According to the third aspect of the present invention i9 to provide a process for treating slurry turbid water formed in the upper layer of slurry stored in a reservoir on land, other suitable container or carrier's hold, wherein a given amount of coagulant aid is added to said slurry turbid water, then compressed air is injected into said slurry turbid water to thereby disperse solid particles settled in the lower part of said reservoir back in said upper slurry turbid water and , mixing and agitating said coagulant aid and said settled solid particles together in said slurry turbid water, whereby said slurry turbid water may be rapidly in the lower part of said reservoir, while discharging a supernatant water from said reservoir.
According to the fourth aspect of the present invention, there is provided a process for treating slurry turbid water - 4 - ~:
- . : :.
104~6f~8 1 formed in the upper layer of slurry stored in a reservoir on land, other suitable container or carrier's hold, wherein given amounts of a coagulant aid and ferromagnetic powder are added to the slurry turbid water and was agitated. As the result of the agitating thus formed floc, said floc is then separated by utilizing a magnetic force from said slurry turbid water, leaving a clear aqueous medium.
Meant by the term, "separation-accelerating material"
as used herein may be a co-precipitation material which acceler-ates the velocity of suspended solid in slurry turbid water by utilizing gravity of material, or may be solid particles of a relatively larger si~e which is part of said slurry turbid water and apt to be readily settled in the lower part of a reservoir on land, other suitable container or carrier's hold or may be ferromagnetic particles which aid in separation of suspended solid in said slurry turbid water by utilizing a magnetic force, i.e. t by attracting the aforesaid to electromagnet plates.
BRIEF DESCRIPTION OF THE DRAWINGS
------_----_--_______________________ Fig. 1 is a flow sheet of one embodiment of the process for treating slurry turbid water according to the present inven-tion;
Fig. 2a is a cross-sectional view of an agitating device as used in the process according to the present invention;
E~g. 2b is a cross-sectional view of Fig. 2a;
Fig. 3a is a cross-sectional view of a settling treat-ment device;
Fig. 3b is a cross-sectional view taken along the line A-A of Fig. 3a;
' 30 Fig. 4 is a plan view of ore slurry carrier embodying the present invention;
.
1 Fig. 5A and B are vertical and horizontal cross sectional views illustrating the usage of coagulant aid;
Fig. 6 is a flow chart illustrating one embodiment of the process according to the present invention;
Fig. 7 is a plan view of an outline of an ore carrier, to which the process of the present invention may be applied;
Fig. 8 is a cross-sectional view of a device for use in rinsing and separating a co-precipitation material used in the process of the present invention;
Fig. 9 is a plot showing the relationship between the residual turbidity of water which has been treated according to the process of the present invention and agitating time due to compressed air injected into slurry turbid water;
Fig. 10 is a fragmentary, perspective view of a com-pressed air injection pipe and a coagulant aid injection pipe used in the process according to the present invention;
Fig. 11 is an enlarged view showing a compressed air injection pipe and a coagulant aid injection pipe as shown in Fig. 10;
Fig. 12 is a perspective view of an arrangement, wherein partition walls are provided around an injection pipe;
Fig. 13 is an outline showing mixing plates placed above a compressed air injection pipe;
Fig. 14 is a flow sheet of one embodiment of the process according to the present invention;
Fig. 15 is a side elevation illustrating a magnetic separating tub;
Fig. 16 is a flow sheet of another embodiment of the process according to the present invention; and Fig. 17 is a plan view of an outline of an ore carrier, to which the process according to the present invention is applied.
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lo4~6~
DESCRIPTION OF THE PREFERRED EMBODIMENTS
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For simplicity, the process according to the present invention will be described particularly by referring to an ore slurry carrier rather than a large size pond or a reservoir used on land. However, such an example should by no means be con-strued as being limitative in its nature.
In general, the process will be described by using underlined headings corresponding to the aspects of the present invention.
The First Aspect of the Invention A feature (i) of the first aspect of the process according to the present invention is that given amounts of coagulant aid and a co-precipitation material are added, for treating, to the slurry turbid water formed in the upper layer of slurry contained in a hold of an ore carrier, the mixture thu8 prepared is then agitated and allowed to stand for a while, whereby the aforesaid slurry turbid water i8 separated into clean supernatant water and settled solid particles or granules. Mean-while, the aforesaid slurry turbid water in general consists ofvery fine particles and moreover the specific gravity of the particles is relatively small, such that even if the slurry turbid water is allowed to settle for a long period of time in a hold, only a small part of particles is apt to be settled, leaving a greater part thereof in suspension or in a floating condition. Accordingly, inorganic coagulant aid such as sulfuric band or PAC or high-polymer coagulant aids such as denatured polyacryl amid are added to the slurry turbid water in a hold ; ~ -~ of a carrier to thereby intensionally cause the formation of ,, 30 floc, for mixing slurry turbid water by a coagulant aid ,, .
~ .
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l. , ... ' ., , ,. .. ... , .... - .. - : ~
~o~ s and rapid settling an~ hence the rapid separation of suspended solid. However, the results are that even though the floc is formed, the floc is apt to remain in the floating condition and even if only a part thereof is attempted to be settled, a long period of time is required. This is particularly true in the ~-case of powdered ore slurry which has been subjected to floata-tion, because the fine suspension particles themselves have floating agents adhered thereto. This is also true, in case the specific gravity of liquid which is to be added to powdered ore to give a slurry condition is relatively high as that of sea water. For this reason, according to the present invention, a co-precipitation material having a relatively large grain size and higher specific gravity, as compared with suspended solid in turbid water is added thereto for the purpose of enhancing the settling of the suspended solid floating in the slurry, thereby achieving rapid and positive separation or purification o~
slurry turbid water. This greatly contributes not only to saving in time of carrier's lay days but also to prevention of pollution, and thus the industrial value of such an attempt is highly eva-luated. Included by the aforesaid co-precipitation materials are powdered ore, sand or the like, and those should be greater in specific gravity than that of the suspended solid. It is imper-ative that the mixture of slurry turbid water coagulant aid and co-precipitation material be thoroughly mixed and agitated to the aforesaid end. In this respect, such agitation may resort to a direct agitation within a carrier, such as by introducing compressed air into the aforesaid mixture which dwells in the ~, upper layer of the slurry for effecting so called bubbling or mechanical agitation, or otherwise such slurry turbid water may be transferred to an agitating device placed on board for agita-tion. With the treatment on board, it is required to provide a ~-.
~ ' .
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1 settling and separating device for sedimentation and separation of the mixture agitated. For this purpose, a conventional type settling tub, cyclone, centrifugal separator, a screw feeder and the like may be employed.
A further feature (ii) of the first aspect of the present invention is that powdered bodies of the same composition as those of the suspended solid are used as co-precipitation materials. This is particularly advantageous, because if different kinds of co-precipitation materials are used, those may exert adverse effect on the properties of slurry, and hence the co-precipitation material is employed. This then dictates the provision of a removing device for co-precipitation material contained therein. Furthermore, settled particles usually contain useful components, such that the feed back of the sedimental coagulated bodies to a land side is not recommendable from economical viewpoint, while discharging of such particles into sea is not recommendable from the viewpoint of pollution.
The use of the solid particles of the same composition as that of the suspended solid may avoid such complicated problems.
A still further feature (iii~ of the first aspect of the present invention is that, after the slurry turbid water has been formed in the upper layer of slurry contained in a carrier's hold, part of powdered bodies of the type described are con-tinuously fed to an agitating apparatus on board for mixing and agitation, and the mixture thus prepared is then fed to a settling device for separation into a clear supernatant water and precipitated particles, after which the aforesaid supernatant water is discharged out of the carrier, while the floc i~ fed back to the hold of a carrier for recovery. In other words, the slurry turbid water is not designed as to be treated directly _ 9 _ .
~04~668 1 within a carrier's hold but fed to an agitating device provided on board, wherein the slurry turbid water, coagulant aid and co-precipitation material are thoroughly mixed, and then fed to a settling device on board for separation into a clean super-natant water and floc. This further provides additional advantage of the feasibility of a continuous treatment of the slurry turbid water. In other words, the continuous feeding of the slurry turbid water from a carrier's hold to the aforesaid devices on board may provide good compatibility with the con-tinuous feed back of the separated floc into the hold. Thesupernatant thus obtained may ~e discharged into the sea, because such has been completely purified at this time. The floc re-covered from the slurry turbid water usually amount to about 10 to 20% of the whole slurry to be transported. In this meaning, the treatment according to the present invention may also provide con9iderable economical advantage. Alternatively, the floc thus obtained may be again used as co-precipitation material for the ; subsequent treatment.
A yet further feature (iv) of the first aspect of the present invention is that the slurry turbid water is fed to an agitating device which includes barrier plates and is provided in the route of pipings.
A further feature (v) of the first aspect of the invention is the use of a feed pipe which contains a coagulant aid of a solid form which is intended to be dissolved into slurry turbid water which is being fed through piping.
Now, description will be given in more detail on the first aspect of the process according to the present invention with reference to Figs. 1 to 5.
Fig. 1 shows a flow sheet of the process embodying the first aspect of the present invention. The slurry 1 which has .1 ' .
10466~3 1 been loaded in the hold 2 of a carrier is separated into slurry turbid water 3 dwelling in the upper part of the slurry and precipitated solid particles 4 in the lower portion of the hold.
The slurry turbid water 3 floating in the upper part of the slurry is then fed by way of a feed pipe 7 to an agitating device 8 provided in the piping route.
On the other hand, part of precipitated solid particles 4 is fed as co-precipitation material by means of a slurry pump 6 by way of the feed pipe 7 to the agitating device 8. On the other hand, a coagulant aid 9 adjusted to a suitable concentration by dissolving same into water is fed in a given amount to the mixture of slurry turbid water and co-precipitation material, i.e., solid particles by means of a chemical pump 10. Thus, the slurry turbid water 3, co-precipitation material 4 and coagulant aid are agitated by being passed through the agitating device 8 and then to the subsequent step of a settling device 11. The mixture is settled in the settling device 11, thereby allowing the clean supernatant water 12 to overflow the settling device 11 for continuous discharge. On the other hand, the floc 13 ~ are fed to a carrier hold 2.
The maximum efficacy of the addition of the co-preci~
pitation material 4 and coagulant aid 9 requires the provision of optimum concentrations of such particles and aid. Accordingly, the feed rate of such materials to be fed by means of pumps P
5, P2 6, P3 10 should be controlled. The experiments reveal that the range of the optimum concentrations of the aforesaid particles and aid should not necessarily be controlled strictly, such that a wide range of the concentrations will not impair the objects of the present invention.
Table 1 illustrates the results of the treatment of the slurry turbid water according to the first aspect of the invention, in which conslderable decrease in residual suspended solid degree results in the case of the combined used of co-precipitation ma-terial.
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c~ E~o-a ~ 8 1 Fig. 2 shows one example of the agitating device pro-vided in the route of piping for mixing and agitating the slurry turbid water coagulant aid and co-precipitation material but serving as a feed piping as well, in the longitudinal and trans-verse cross sectional views. In this example, a plurality of sets of agitating propellers 17 are mounted on a shaft 16 within the slurry turbid water feed pipe 7, while the deflecting directions of the respective propellers are reversed between each of the two aforesaid sets of propellers, thereby creating whirl flows having opposite directions, when the slurry turbid water passes through the pipe, for providing a strong agitating effect.
Fig. 3 is longitudinal and transverse cross sectional views (A-A) of one example of the settling device for use in the process of the present invention. There are provided a plurality of partition plates 21 within the settling device ll for extending the distance of treated slurry suspension through the aforesaid device.
While the slurry turbid water passes through the device 11 in directions shown by arrows, treated floc contained therein will be settled, thereby leaving a clean supernatant liquid which in turn is discharged through a discharge port provided in the device. The floc are collected in a discharge passage 23 by means of a screw feeder 22 provided in the lower portlon of the device 11. Connected to the discharge passage 23 is a floc feeding pump 24, whexeby the floc are returned to the hold of a carrier.
Fig. 4 shows a plan view of an outline of an ore carrier equipped with various devices suitable for practicing the pFocess of the present invention. Shown at 31 is a slurry . . . . .
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10~66~3 1 turbid water feed pipe, at 2 a hold of a carrier, at 5 a slurry suspension feeding device from the hold, at 6 a co-precipitation solid particles feeding devicej at 35 an agitated water feeding pipe, at 32 a coagulant aid reservoir, at 10 a coagulant aid feed pump, at 11 a settling device, at 33 a supernatant water discharge pipe, at 24 a discharge device for discharging floc which have been separated within the settling device and at 34 a discharge pipe for use in the aforesaid device 24.
In practice, there are provided a plurality of holds in an ore carrier, but two of them are shown in Fig. 4 for simplicity of description.
The slurry which has been loaded in a hold 2 of a carrier by way of a slurry feed pipe 31 is .settled in the hold, thereby leaving slurry turbid water in the upper layer thereof. The slurry suspension is then fed by means of slurry turbid water feed device 5 by way of a slurry turbid water feed pipe 7 to the agitating device 8. On the other hand, the solid particles which have been settled in the hold are fed, as co-precipitation material, by means of the solid particle feeding device 6 by way of the slurry turbid water feed pipe 7 to the agitating device 8.
A given rate of coagulant aid is fed by means of coagulant aid feed pump 10 from the coagulant aid reservoir 32 to the slurry turbid water in a position downstream of the agitating device 8.
The slurry turbid water, coagulant aid and co-sedimental solid particles are thoroughly mixed and agitated in the agitating device 8 and then fed to the setting device 11. The slurry turbid water is then separated into clean supernatant liquid and treated floc while the supernatant liquid is discharged out of a carrier ~ and, on the other hand, the floc is fed back by means of the floc 30 discharge device 24 by way of a discharge pipe 34 to the hold 2 .1 .
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~04666~3 1 of a carrier. Thus, both the treatment of the slurry and the feed-back of floc may be accomplished at the same time in a continuous but efficient manner.
~ owever, those two operations should not necessarily be carried out in the same carrier, but a separate carrier for exclusive use of treating slurry turbid water may be provided in combination with the aforesaid carrier.
Fig. 5 illustrates an example where solid coagulant aid is used in the process of the present invention. Fig. 5A
0 shows one usage of the coagulant aid formed to a given shape.
There is provided an opening 41 in part of the feed pipe 7, with a container 42 of a mesh form housed therein. A coagulant aid 43 formed to a desired shape is placed in the container 42. With such an arrangement, the slurry turbid water flowing through the pipe keeps contacting a high polymer coagulant aid which in turn is dissolved into the slurry turbid water.
Fig. 5B shows one usage of the coagulant aid 43 formed to a cylindrical form, which is inserted in part of the feed pipe 7. However, a retaining portion 44 is provided for the pipe for ao retaining the coagulant aid therein in combination with a pro-jecting portion 45. For charging the coagulant aid therein, the retaining portion may be split into two parts, one of which may be removable.
The use of the solid coagulant aid further improves the efficiency of addition of coagulant aid to slurry turbid water, thus affording improved overall efficiency of the process accord-ing to the present invention.
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The_Second Aspect of the Invention The second aspect of the process for treating slurry ~
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' ~L04~i668 1 turbid water formed in the layer of slurry will be described with reference to Figs. 6 to 8.
Fig. 6 is a flow chart illustrating the process of the present invention, while Fig. 7 is a plan view of an outline of an ore carrier. In those figures, the slurry 101 of solid particles is transferred by way of a slurry feed pipe 133 from land into the hold of a carrier. The slurry thus loaded is then subjected to natural settling and separated into the slurry turbid water 103 forming the upper layer of the slurry loaded and the settled solid particles forming the lower layer. Then, the slurry turbid water 103 thus formed is then fed by way of a feed pipe 105 to a blending tub 106 provided on the deck of a carrier, continuously. This blending tub 106 may be of a con-ventional type or one provided with an agitating device. On the other hand, a coagulant aid 107 is prepared in a container close to the aforesaid blending tub, the concentration thereof being adjusted to a desired concentration by adding water thereto, and thus the coagulant aid is continuously fed by means of a chemical pump 108 to the blending tub 106. Furthermore, there is provided a container whish contains a co-pxecipitation material 112, in the vicinity of the blending tub 106. A given flow rate of the co-precipitation material is continuously fed to the blending tub 106. The slurry turbid water, to which has been added a coagulant aid and a co-precipitation material, is then fed by means of a slurry pump 110 from the blending tub 106 by way of a feed pipe 109 to an agitating device 111 (a static mixer) pro-vided in the route of a piping for thorough mixing and agitation.
The agitating device 111 contains mixing plates or rotary blades within a pipe, serving the dual purposes of feeding and agitation of slurry turbid water and the like. The slurry turbid water, .
10~ti6C~3 1 after mixing, is then fed to a settling and separating tub 114 and allowed to stand for a while. Meanwhile, the slurry turbid ~ater, coagulant aid and co-precipitation material have been thoroughly mixed such that the formation of the floc of suspended solid has been enhanced. As a result, the suspended solid in the settling tub 114 may be separated, due to co-precipitation effect of co-precipitation material, into clean supernatant liquid 115 forming the upper layer and the sedimental coagulated bodies 116 forming the lower layer thereof. In passing, the aforesaid settling tub 114 may be of a conventional type or cyclone, centrifugal separator or screw feeder. The supernatant water 115 forming the upper layer is then discharged from the settling tub 114 into sea. The floc 116 now consisting of suspended solid, co-precipitation material and coagulant aid are fed by means of a slurry pump 118 by way of a slurry feed pipe 119 to a co-precipitation and separating device 113. A
rinsing device 120 serves to rinse with water to remove the suspended solid and coagulant aid which have been adhered to the co-precipitation material, from the aforesaid co-precipitation material, thereby recovering the co-precipitation material for repeated use. In this respect, the rinsing device utilizes '! means such as rotational agitation, high pressure water injection or supersonic wave and the like. For rinsing co-precipitation material, the water content of floc should be maintained more than 15%. However, water may be added in the rinsing device 120 separately, or part of the supernatant water may be added to the floc, when same is fed from the settling and separating tub 114. The co-precipitation material separating device 113 serves to separate the rinsed co-precipitation material 112 from the fine solid particles 117. In other words, a classifier, endless screen separator, centrifugal separator are used for dehydrating ; ' , '''' ~.
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~046~
1 and separating fine solid particles 117. Alternatively, a rin-sing device 120 may be combined with the separator 113 to provide a single unit for convenience of using same as a continuous treating device provided on the deck of a carrier. Fig. 8 shows one example of the rinsing device as described herein. In this device, the floc 116 which is being fed continuously by way of the slurry feed pipe 119 from the aforesaid settling and separating tub 114 is supplied to the rinsing and separating device 113, while the rinsing and separating device 113 is pro-vided with a rotatable agitating blade 128, on which is mounteda motor 127 in the upper portions thereof, said rotatable blade 128 being inserted in said floc, whereby the rotation of the motor 127 causes the rotation of the agitating blade 128 for agitation of the floc. During this agitation, the co-precipitation material is rinsed. Furthermore, there is provided an air in~ecting pipe 130 provided in the lower portion of the device 113 for injecting high pressure air 129 into the floc for acceler-ating the agitation. The fine solid particles 117 which contains coagulant aid, and has been separated from co-precipitaton material, is introduced to the lower portion of the device 113 and discharged by way of discharge pipe 131, continuously and then fed to the dehydrating device 122. In addition, the device is equipped with a screw feeder 132 connected to motor 127' for transferring the co-precipitation material 112 upwardly for discharging same out of the device 113.
In this manner, the co-precipitation material 112 is rinsed and thus separated from the floc 116 and then charged as a new co-precipitation material into the blending tub 106. The repeated use of such a cycle of an operation permits the con-tinuous circulation of the aforesaid materials. Included by the .
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1 co-precipitation materials which are employable in the process of the present invention are ceramics such as Sic, Wc, A12O3 and the like or high polymer resins such as fluoro-resin, alkyd resin or metals such as sus powder, Ta powder and the like~ Those co-precipitation materials permit their continuing use for a long period of time, affording re-producing capability, as well as high abrasion resistance and corrosion resistance. Furthermore, those co-precipitation materials may be used in small amounts for treating a considerably large mass of slurry turbid water and particularly adapted for use within a carrier.
On the other hand, the fine solid particles 117, ~rom which the co-precipitation material has been removed, is fed to the dehydrated 122 by means of a pump 118 and then separated into a separator water 123 containing a coagulant aid and a 801id dehydrated cake 124.
Although part of the coagulant aid i8 contained in the dehydrated cake 124, a ma~ority of the coagulant aid is extracted into the separated water 123 at the time of dehydration. The 5eparated dehydrated cake 124 is recovered and fed back to the hold 102. The separated water 123 containing coagulant aid is then fed to the blending tub 106 for the subsequent repeated use, as in the case with the aforesaid co-precipitation material.
Thus, the co-precipitation material and coagulant aid may be repeatedly added to the slurry turbid water which is con-tinuously fed from a hold to a blending tub on the deck of a carrier, while the slurry turbid water may be recovered as solid particles.
, Meanwhile, the coagulant aid 107 is dissolved in water for use, as has been described earlier, but this may be provided in the solid form for placing same into a slurry feed pipe 105 which leads to the blending tub 106 on the deck.
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1 The mird Aspect of the Invention The third aspect of the process according to the present invention will be described with reference to Figs. 9 to 13.
Fig. 9 shows a plot illustrating the relationship between the residual suspended solid degree and agitating time after slurry turbid water of 50 ltr containing suspended solid of about 500 ppm has been subjected to air agitation in a laboratory. In this case, the feed rate of air was 0.2 ltr/min.
amount of the coagulant aid added was 10 ppm and the concentration of the co-precipitation material was 10%. The desired agitation resulted for a duration as short as 4 minutes, while the excess-ively long duration of agitation presents a danger of causing re-dispersion. In practical application, an air injection pipe i8 moved through slurry turbid water at a desired speed and hence for a desired duration of agitation. The mixing and agitation of the coagulant aid, co-precipitation material and suspended solid cause floc to adhere to the co-precipitation material and, as a result, they will be rapidly precipitated, while the clean supernatant liquid, i.e., aqueous medium may be discharged by means of a pump, ejector or the like out of the carrier.
Figs. lO to 13 refer to the apparatus for practicing the process of the present invention.
Referring to Fig. 10, shown at 201 is a hold of an ore carrier. The slurry, for instance, of iron ore may be rapidly separated into suspended solid particles 202 and slurry turbid water 203, after being loaded in the hold of a carrier. After loading, an air injection pipe 204 is placed on top of the layer of the precipitation solid particles, or alternatively the air injection pipe 204 may be placed before loading of slurry in the hold of a carrier. The air injection pipe 204 is connected by 10466~8 1 way of a flexible air feed pipe 205 to a compressed air source (not shown). In addition, the air injection pipe 204 may move along the longitudinal direction of the hold 201 by means of an automatic travelling device 208 along the guide rails 207 mounted on the inner walls of the hold 201. This travelling device may be a wheeled platform provided with rollers adapted to roll on the guide rails 207 by means of a suitable drive means. The aforesaid air injection pipe 204 and the coagulant aid injection pipe 211 are mounted on the wheeled platform.
The air injection pipe 204 as shown in Fig. 11 is pro-vided with a plurality of injecting holes 209, while part of the injection holes 209 are open in a direction against that of the solid particles which are being settled, such that part of the settled solid particles will be blown upwardly due to the air stream being injected.
Integrally provided for the air injection pipe 204 are a plurality of coagulant aid feed pipes 211 having a plurality of injection holes 210, through which the coagulant aid is injected. The coagulant aid injection pipes may be moved to-gether with the air injection pipe 204. The coagulant aid isfed from a coagulant aid reservoir (not shown) by way of a feed pipe 206 by means of a constant flow rate feed pump (not shown) and added through the coagulant aid injection holes 10 to the slurry turbid water. The coagulant aid of only 10 ppm is sufficient for the slurry suspension to which same is to be added, while the feed rate of the coagulant aid is adjusted commensurate to the moving speed of the air injection pipe. The air injected through the air injection pipe 204 ascends in the form of bubbles through the slurry turbid water, whereby the co-precipitation material blown from the bottom and slurry turbid !
1046~8 1 water and coagulant aid are mixed and agitated and as a result the slurry turbid water adheres to co-precipitation material to form floc of a relatively large size, which in turn is settled rapidly.
As shown in Fig. 12, for enhancing the agitating effect, there is provided partition walls 213 having a plurality of holes, around the air injection pipe 204, whereby the slurry turbid water confined by the aforesaid partition walls may be efficiently agitated, as the air injection pipe 204 and coagulant aid in-jection pipe 211 move.
Fig. 13 shows another example where there are provided a plurality of barrier plates 214 in the passage of air bubbles but above the air injection pipe 204 in a manner that the air bubbles ascend along staggered paths, in an attempt to enhance the agitating effect. In passing, the barrier plates~214 are affixed to a supporting bar 215 extending vertically from the air injection pipe 204 in a staggered relation.
Rapid settling of floc results in the area which is 8ubjected to the aforesaid agitation, and then clean supernatant water is discharged by means of a water pump P out of a carrier from the surface of the supernatant water.
As is apparent from the foregoing description, the third aspect of the process according to the present invention permits rapid and efficient treatment of slurry turbid water dwelling in the upper portion of slurry contained in the hold of a carrier, without having rècourse to other specific equip-ments provided on board.
The Fourth Aspect of the Invention The fourth aspect of the process according to the present invention will be described with reference to Figs. 14 to ~7.
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Fig. 14 shows a flow sheet of one embodiment of the present invention. Slurry turbid water 301 is fed by means of a pump 302 to blending tub 302, continuously. The blending tub 303 may be of a conventional type or may be one having an agita-ting means such as impellers. Close to the blending tub 303, there is provided a coagulant aid 304 whose concentration has been adjusted to a desired value by adding water thereto. The coagulant aid 304 is fed by means of a pump 304 at a constant feed rate in the aforesaid blending tub 303, commensurate to lO the feed rate of slurry turbid water. The coagulant aid which has been described earlier may be used in this case, as well.
On the other hand, there is provided ferromagnetic particles 306 in a position close to the blending tub 303, whereby it may be fed at a con9tant rate by means of a hopper or feeder and the like to the biending tub 303. The ferromagnetic particles which may be used in the process according to the present invention are Fe, Co, Ni, FeO, Fe~O4 and the like. Naturally, those should not neces~arily be used in 100%, i.e., there may be used magnetic ore and the like which contains a plenty of FeO and Fe3O4 and 20 provides high corrosion resistance and lower cost.
The slurry turbid water, to which have been added coagulant aid and ferromagnetic particles at a given ratio is then fed to an agitating device 307 for thorough mixing. The agitating device 307 used may be one having impellers or a blend-ing tub having means whereby to introduce a high pressure gas therein, or otherwise agitating means (for instance, a static mixer) provided in the route of a piping which means also serves to feed the slurry turbid water. The suspended solid in slurry turbid water after agitation, will be coagulated by the coagulant 30 aid to form floc having a high specific gravity. Then, the slurry . ' .
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~0~6Çif~8 1 turbid water is fed to the subsequent step, i.e., a magnetic separation tub 308.
Fig. 15 is a cross-sectional view of the magnetic se-paration tub 308. As shown, the separation tub 308 is divided by partition plates 321A and 321B into three compartments, i.e., X, Y and Z tubs. In addition, X and Y tubs are divided into two parts, respectively, by the partition plates 320A and 320B.
The partition plates 320A and 320B may be energized by causing an electric current to flow therethrough by way of a lead wire 322', thereby generating magnetic force. Shown at 322 is a switch for the aforesaid partition plates 320A and 320B. The slurry turbid water 301 after mixing is fed by way of 319 to the X tub in the magnetic separation tub 308. Since the solid particles are coagulated by the coagulant aid to give floc having a high specific gravity, they will soon be sedimented in the bottom of the tub. However, in case that the suspended solid consists of fine particles or is a heavy liquid, it takes a long period of time until the whole floc is settled completely.
For this reason, an electric current is caused to flow through a switch 222 to the partition plate 320A, i.e., the electromagnet, as shown in Fig. 15, thereby generating a magnetic force. Then, the ferromagnetic particles in the floc is rapidly attracted by the magnetic force to the partition plate 320A. When the amount of the floc attracted to the partition plate 320A is saturated, then the switch is thrown to the side leading to the partition plate 320B. The floc which has grown up to a considerably large size and contains suspended solid particles, ferromagnetic par-ticles and coagulant aid therein will be rapidly settled by their own gravity, when released from the magnetic force. The switch 322 is then thrown to the side leading to the partition . . ; . .
- - . . . .. . . , -104~;6~;i8 1 plate 322A, whereby the new floc fed from the feed pipe 319 wi11 be attracted thereto. Thus, such a cycle is repeated to effect the continuous treatment.
The slurry turbid water is almost purified in the X
tub and then fed to the Y tub. The partition plate 320B generates a magnetic force cyclically, such that the floc which has not been completely settled in the X tub may be positively attracted thereto and then settled. The clean liquid in the Y tub, i.e., clean water 309 is then fed from the partition plate 321B to 0 the Z tub, after which the clean water 309 will be discharged through a discharge pipe 330. On the other hand, the floc which has been settled in the lower portions of X and Y tubs, i.e., settled solid particles 310 are discharged by way of a slurry discharging pipe 331. The magnetic separation tub 308 is only indicated herein for description purpose and thus should not be construed as being limitative in its nature.
Fig~ 16 shows a flow sheet of the ferromagnetic particles contained in the settled particles 310 and the coaguiant aid.
More particularly, the settled solid particles 310 which have been separated in the magnetic separation tub 308 is fed to a rinsing device 312. In case the ferromagnetic particles are magnetized to a high level, it is preferable that the ferro-magnetic particles be passed through a demagnetizing device, before feeding to the rinsing device 312, thereby reducing then coagulating force caused due to the residual magnetic force among particles. The rinsing device 312 is intended to rinse and remove, with a small amount of water, the solid particles and coagulated particles whicX adhere to ferromagnetic solid particles. --~Thus, the rinsing device 312 may be of a known type which is pro-vided with bubbling means such as using the rotational agitation, , 104~
1 high pressure gas in~ection or means such as using a high pressure injection or supersonic wave and the like. The precipitated solid particles 310 which have been rinsed is then separated by means of a magnetic separation device 314 into ferromagnetic particles 306 and coagulant aid plus fine solid particles 313.
The magnetic separating device 314 as used herein is of a drum type or belt type, whereby ferromagnetic particles may be select-ively recovered from the precipitated solid particles. The ferromagnetic particles 306 which have been recovered are de-0 magnetized by means of demagnetizer as required, and then addedto the blending tub 303 again for repeated use.
On the other hand, the fine solid particles 313 is fed to a dehydrator 315 of a known type such as a filtrating device, filter press, vacuum dehydrator and the like. Thus, the fine solid particles 313 is separated into separated water 317 con-taining coagulant aid and a dehydrated cake 316 of a solid form.
The dehydrated cake is recovered for repeated use, not to mention the case where the recovered cake contains useful materials.
Furthermore, the separated water 307 containing coagulant aid is then added as coagulant aid by means of a pump to the new slurry turbid water for repeated use like ferromagnetic particles 306. This eliminates or minimizes the use of the ferromagnetic particles and coagulant aid which are to be fed to the blending tub 303. Those tubs and devices may be provided on board.
Fig. 17 shows a plan view of an outline of an ore carrier, to which is applied the process according to the present invention.
The procedures as used in this case is almost similar to those used in the previous case. The slurry is loaded in a hold 325 by way of a feed pipe 324. The slurry turbid water is ~.
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1 fed by means of a pump 326 by way of a feed pipe 327 to a blending tub 303 provided on board. The ferromagnetic particles 304 and coagulant aid 306 are prepared in the same manner as in the previous case. The slurry turbid water, to which have been added the aforesaid ferromagnetic particles 304 and coagulant aid 306, is then fed to an agitating device 307 provided in the route of piping. The slurry turbid water which has completed mixing and agitation is then fed to the magnetic separation tub 308, where it is separated into a clean water, and precipitated mixture consisting of fine solid particles and ferromagnetic particles and coagulant aid, and then the clean water 309 is discharged out of a carrier. The aforesaid precipitated solid particles are separated into fine solid particles and ferromagnetic particles by means of a rinsing device 312 and magnetic separation device 314, after which the ferromagnetic particles are again added to the blending tub 303 for repeated use.
On the other hand, the fine solid particles are fed to the dehydrator 315, where it is separated into separated water, containing coagulant aid and solid dehydrated cake con-sisting of fine solid particles, after which the separated watercontaining coagulant aid is added to the blending tub for re-peated use. Like the previous case, the ferromagnetic particles may be demagnetized in the same manner as in the previous case, while the dehydrated cake is recovered in the hold 325 of a carrier. Thus, the slurry turbid water may be treated contin-uously by means of devices provided on the carrier itself, or by the use of a hold of a carrier.
While the description has been given in the case where the process according to the present invention is applied to a slurry carrier, the process of the invention may apparently be ' .
- ~ 04f~
1 applied to the slurry stored in a reservoir, pond or other containers on land.
It will be understood that the above description is merely illustrative of the preferred embodiments of the invention.
Additional modifications and improvements utilizing the discoveries of the present invention can be readily anticipitated by those skilled in the art from the present disclosure, and such modifi-cations and improvements may be fairly be presumed to be within the scope and purview of the invention as defined by the claims that follow.
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Claims (27)
1. A process for treating slurry turbid water containing suspended solids which is formed in an upper layer of slurry above a lower settled layer stored in a reservoir, comprising the steps of:
adding a coagulant aid and at least one separation-accelerating material, chosen from the group consisting of (a) a co-precipitation material, (b) solid particles of a relatively larger size than the suspended solids which are part of the settled layer or (c) ferromagnetic particles, to the slurry turbid water;
agitating the mixture thus obtained to improve contact between the coagulant aid and the suspended solids in the water causing a floc containing the suspended solids to form;
allowing the floc to settle out of the solution to form a floc settlement and a relatively clear aqueous medium; and separating the settled floc from the water.
adding a coagulant aid and at least one separation-accelerating material, chosen from the group consisting of (a) a co-precipitation material, (b) solid particles of a relatively larger size than the suspended solids which are part of the settled layer or (c) ferromagnetic particles, to the slurry turbid water;
agitating the mixture thus obtained to improve contact between the coagulant aid and the suspended solids in the water causing a floc containing the suspended solids to form;
allowing the floc to settle out of the solution to form a floc settlement and a relatively clear aqueous medium; and separating the settled floc from the water.
2. A process for treating slurry turbid water which forms in the upper layer of slurry stored in a reservoir, comprising the steps of:
adding a coagulant aid and co-precipitation material to said slurry turbid water for mixing;
agitating the mixture thus obtained to improve the con-tact between said coagulant aid and co-precipitation material and the suspended solid in said slurry turbid water;
forming floc containing said suspended solid;
allowing said floc to settle by gravity, thereby leaving clear supernatant water; and separating said clear supernatant water from said floc which has been allowed to settle.
adding a coagulant aid and co-precipitation material to said slurry turbid water for mixing;
agitating the mixture thus obtained to improve the con-tact between said coagulant aid and co-precipitation material and the suspended solid in said slurry turbid water;
forming floc containing said suspended solid;
allowing said floc to settle by gravity, thereby leaving clear supernatant water; and separating said clear supernatant water from said floc which has been allowed to settle.
3. A process as defined in claim 2, wherein said co-precipitation material has a grain size larger than that of said suspended solid in said slurry turbid water and a specific gravity greater than that of said aqueous medium.
4. A process as defined in claim 2, wherein said co-precipitation material is substantially of the same composition as that of said suspended solid constituting said slurry turbid water.
5. A process as defined in claim 2, wherein part of the solid particles which have settled in the lower portion of said reservoir, is fed as a co-precipitation material to the new slurry turbid water for repeated use.
6. A process as defined in claim 3, wherein said clean supernatant water separated from said floc which has been allowed to settle is discharged and said floc is returned to said reservoir.
7. A process as defined in claim 2, wherein the mixture consisting of suspended solid, coagulant aid and co-precipitation material is continuously agitated within an agitating device incorporated in piping, said agitating device being equipped with mixing plates therein.
8. A process as defined an claim 2, wherein said coagulant aid of the solid form is placed in the flow of the slurry turbid water so as to allow said coagulant aid to be dissolved continuously in said flow of the slurry turbid water.
9. A process for treating slurry turbid water which is formed in the upper layer of slurry contained in a reservoir, comprising the steps of:
separating and taking out said slurry turbid water from the reservoir;
9. A process for treating slurry turbid water which is formed in the upper layer of slurry contained in a reservoir, comprising the steps of:
separating and taking out said slurry turbid water from the reservoir;
Claim 9 continued ...
adding a coagulant aid and co-precipitation material agent to said slurry turbid water for mixing;
agitating the mixture thus obtained;
allowing the mixture thus agitated to stand still for a while;
separating floc which has settled in the lower portion of slurry turbid water, from the clean supernatant water formed in the upper portion of said slurry; and rinsing said floc thus separated to recover the useful materials accompanying said floc therefrom.
adding a coagulant aid and co-precipitation material agent to said slurry turbid water for mixing;
agitating the mixture thus obtained;
allowing the mixture thus agitated to stand still for a while;
separating floc which has settled in the lower portion of slurry turbid water, from the clean supernatant water formed in the upper portion of said slurry; and rinsing said floc thus separated to recover the useful materials accompanying said floc therefrom.
10. A process as defined in claim 9, wherein said floc is rinsed and separated into rinsed co-precipitation material and fine solid particles, then dehydrating the fine solid particles to there-by obtain a cake, while the co-precipitation material thus rinsed is used for continuous circulation for the step of adding co-precipitation material to said slurry turbid water.
11. A process as defined in claim 9, wherein said floc is rinsed and separated into rinsed co-precipitation material and fine solid particles, the fine solid particles thus obtained are dehy-drated for separating same into water containing coagulant aid and a solid cake, recovering said solid cake therefrom, said water which contains a coagulant aid and a co-precipitation material subjected to rinsing being continuously fed for the step of adding coagulant aid and co-precipitation material to said slurry turbid water.
12. A process as defined in claim 9, wherein the clean supernatant water which has been formed in the step of allowing said floc to settle for a while, is used as aqueous liquid for the rinsing step of said floc.
13. A process as defined in claim 9, wherein compressed air is injected during the step of rinsing said floc.
14. A process for treating slurry turbid water formed in the upper layer of slurry stored in a reservoir, comprising the steps of:
adding coagulant aid to the slurry turbid water in said reservoir for mixing;
injecting compressed air in said slurry suspension in a manner to disperse solid particles which have settled in the lower portion of said reservoir, through said slurry turbid water;
agitating said slurry turbid water, coagulant aid and said fine solid particles which have settled to improve the contact thereamong, thereby forming floc containing fine solid particles which have been in said slurry turbid water;
settling said floc in the lower part of said reservoir;
and discharging the clean supernatant water out of said reservoir.
adding coagulant aid to the slurry turbid water in said reservoir for mixing;
injecting compressed air in said slurry suspension in a manner to disperse solid particles which have settled in the lower portion of said reservoir, through said slurry turbid water;
agitating said slurry turbid water, coagulant aid and said fine solid particles which have settled to improve the contact thereamong, thereby forming floc containing fine solid particles which have been in said slurry turbid water;
settling said floc in the lower part of said reservoir;
and discharging the clean supernatant water out of said reservoir.
15. A process as defined in claim 13, wherein addition of said coagulant aid into said slurry turbid water and injection of compressed air therein are carried out at several different positions.
16. A process as defined in claim 14, wherein the dispersion and mixing of the coagulant aid and solid particles due to air agitation are enhanced by means of agitation-supplementing means located close to the compressed air injection means.
17. A process as defined in claim 14, wherein air agitating means and agitation-supplementing means are moved through the slurry turbid water, whereby there is formed a space subjected to vigorous agitation and a space relatively free of any agitation and the clean supernatant liquid in the latter space is continuously discharged out of the reservoir.
18. A process as defined in claim 14, wherein the coagulant aid is added to the slurry turbid water by utilizing an injection of compressed air into said slurry turbid water.
19. A process as defined in claim 14, wherein solid particles settled in the lower part of the reservoir serve as a co-precipitation material.
20. A process for treating slurry suspension which is formed in the upper layer of slurry stored in a reservoir, comprising the steps of:
separating and taking out of said slurry turbid water from said slurry;
adding coagulant aid and ferromagnetic particles to said slurry turbid water for mixing;
agitating the mixture thus obtained to improve the contact between said coagulant aid said ferromagnetic particles and sus-pended solid in said slurry turbid water, thereby coagulating said suspended solid together with said ferromagnetic particles to form floc;
collecting said floc in a specific position in said slurry, suspension by means of a magnetic force; and separation said floc.
separating and taking out of said slurry turbid water from said slurry;
adding coagulant aid and ferromagnetic particles to said slurry turbid water for mixing;
agitating the mixture thus obtained to improve the contact between said coagulant aid said ferromagnetic particles and sus-pended solid in said slurry turbid water, thereby coagulating said suspended solid together with said ferromagnetic particles to form floc;
collecting said floc in a specific position in said slurry, suspension by means of a magnetic force; and separation said floc.
21. A process as defined in claim 20, wherein said floc which is formed, has a specific gravity greater than that of said aqueous medium, whereby the floc is separated by using gravity settling and magnetic attraction.
22. A process as claimed in claim 21, wherein the floc is placed in a separating tub which contains at least two electro-magnets and said electromagnets are alternately energized thereby continuously separating the floc and the clean supernatant water by gravity and magnetic attraction.
23. A process as defined in claim 14, wherein said slurry contains powdered iron ore.
24. A process as defined in claim 1, wherein said coagulant aid is inorganic coagulant aid or organic coagulant aid.
25. A process as defined in claim 1, wherein said co-precipitation material is selected among solid particles con-stituting said slurry, SiC, WC, A1203, metallic powder, tantalum powder, fluoro-resin and alkyd resin.
26. A process as defined in claim 1, wherein the aqueous medium of said slurry is sea water.
27. A process as defined in claim 20, wherein said ferro-magnetic particles are selected among Fe, Co, Ni, FeO, Fe2O3, and magnetite ore.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5534473A JPS5510313B2 (en) | 1973-05-18 | 1973-05-18 | |
| JP6931873A JPS5018353A (en) | 1973-06-20 | 1973-06-20 | |
| JP48072461A JPS5020563A (en) | 1973-06-27 | 1973-06-27 | |
| JP9280073A JPS5041286A (en) | 1973-08-17 | 1973-08-17 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1046668A true CA1046668A (en) | 1979-01-16 |
Family
ID=27463193
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA200,153A Expired CA1046668A (en) | 1973-05-18 | 1974-05-16 | Process for treating slurry turbid water |
Country Status (2)
| Country | Link |
|---|---|
| BR (1) | BR7404046D0 (en) |
| CA (1) | CA1046668A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7364664B2 (en) | 2001-07-25 | 2008-04-29 | Sharp Kabushiki Kaisha | Foreign matter removing mechanism, fluid flow processing equipment, and foreign matter removing method |
-
1974
- 1974-05-16 CA CA200,153A patent/CA1046668A/en not_active Expired
- 1974-05-17 BR BR404674A patent/BR7404046D0/en unknown
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7364664B2 (en) | 2001-07-25 | 2008-04-29 | Sharp Kabushiki Kaisha | Foreign matter removing mechanism, fluid flow processing equipment, and foreign matter removing method |
Also Published As
| Publication number | Publication date |
|---|---|
| AU6883674A (en) | 1975-11-13 |
| BR7404046D0 (en) | 1974-12-31 |
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