Patent Grant
9199246
1. Technical Field
The present invention relates to a gold concentrate recovery system and a gold concentrate recovery method for recovering gold concentrates from gold ores containing gangue minerals or sulfide minerals.
2. Related Art
There are various concentration methods adopted for recovering concentrates from ores. For example, a gold ore concentration method currently employed crushes gold ores, and pulverizes the gold ores into particles having an appropriate particle size. The recovered concentrate particles are suspended in cyanide solution to leach gold. This method is called a cyanide process, by which process gold is separated from gangue minerals or sulfide minerals and concentrated. Another method currently employed initially separates gold concentrates from gangue minerals or sulfide minerals by gravity concentration and flotation, and then further separates and concentrates gold by using the cyanide process.
According to the cyanide process performed in these methods, entire gold contained in coarse ore particles is difficult to be dissolved. In this case, gold recovery is insufficiently achieved.
For overcoming this drawback, a technology of table gravity concentration (also called flowing film concentration) is proposed as a method for recovering high-grade gold concentrates. This method achieves direct refinement only by performing gravity concentration (for example, see Patent Literature 1). In addition, such a technology is proposed which automates control of a partition plate by combining the foregoing table gravity concentration and an image processing technology (for example, see Patent Literature 2).
In this case, low specific gravity ore particles having low specific gravity such as gangue minerals and sulfide minerals contained in the ore slurry supplied to the shaking table 102 go over the riffles 103 by the flow of the additive water supplied from the water supply launder 105 independently from the oscillation movement of the shaking table 102. Then, these low specific gravity ore particles fall toward a front side surface 102c of the shaking table 102 as indicated by arrows 150a, 150b, and 150c in
On the other hand, high specific gravity ore particles having high specific gravity shift in the extension direction of the riffles 103 in accordance with the oscillation movement of the shaking table 102, and flow out of the riffles 103 into a flat area 112 where the riffles 103 are not provided. Ore particles having large particle diameters are more likely to shift in the water flow direction of the additive water (width direction of the shaking table 102) by the flow of the additive water supplied from the water supply launder 105 or by others than ore particles having small particle diameters when the specific gravity of these large particle diameter and small particle diameter ore particles are the same. Accordingly, a stream 140a of high specific gravity, small particle diameter, and high gold grade ore particles, and a stream 140b of high specific gravity and large particle diameter ore particles are formed in the flat area 112. The stream 140a of high specific gravity, small particle diameter, and high gold grade ore particles is separated from the stream 140b of high specific gravity and large particle diameter ore particles by using a partition plate 107. The high specific gravity, small particle diameter, and high gold grade ore particles are recovered as concentrates into a concentrate recovery storage tank 110, while the high specific gravity and large particle diameter ore particles are recovered as tailings into a second tailing recovery storage tank 109. The part forming a stream of high gold grade ore particles is called a gold line.
The gold concentrates recovered by this method are directly smelted and casted, and produced into ingot products (called dore as well) having a purity of 90% or higher.
Patent Literature 1: U.S. Pat. No. 6,818,042
Patent Literature 2: JP 2012-139675 A
Depending on the characteristics of gold ores, it may occur that the pulverization of gold ores into an appropriate particle size produces both fine ore particles having high specific gravity (that is, having a large gold content) and having particle diameters of approximately 100 μm, and coarse ore particles having high specific gravity similarly to the specific gravity of the fine ore particles and having particle diameters approximately in the range from 200 μm to 500 μm. In this case, a part of the high specific gravity and large particle diameter gold ore particles shift in the water flow direction of the additive water by the flow of the additive water supplied from the water supply launder 105 or by others while flowing in the flat area 112, and form a stream different from the stream (first gold line) 140a of high specific gravity, small particle diameter, and high gold grade ore particles as illustrated in
There is still another problem arising from the foregoing method. When the stream (first gold line) 140a of the high specific gravity, small particle diameter, and high gold grade ore particles is not linear, errors produced in separating the stream (first gold line) 140a of the high specific gravity, small particle diameter, and high gold grade ore particles from the stream (tailings layer) 140b of the high specific gravity and large diameter ore particles increase by the partition plate 107, in which condition the operation is difficult to stabilize. More specifically, when the first gold line 140a has deviation or winding, ore particles which should be recovered as concentrates may be recovered as tailings. On the other hand, ore particles which should be recovered as tailings may be recovered as concentrates. Furthermore, the partition plate 107 needs to move in accordance with deviation or winding of the first gold line 140a while monitoring the first gold line 140a during operation.
The present invention has been developed to solve the aforementioned problems. It is an object of the present invention to provide a gold concentrate recovery system and a gold concentrate recovery method capable of recovering gold concentrates from gold ores with high efficiency and stability.
A gold concentrate recovery system recovering gold concentrates according to the present invention is a gold concentrate recovery system recovering gold concentrates from gold ores including: a shaking table including a plurality of riffles on an upper surface of the shaking table, and oscillating in the extension direction of the riffles, wherein the riffles include a plurality of first riffles disposed on the upper surface of the shaking table, and at least a second riffle disposed on the upper surface of the shaking table in a flat area where the first riffles are not provided, the first riffles concentrate ore particles based on specific gravity of the ore particles, and generate a gold line in the flat area, the ore particles being particles of gold ores supplied together with additive water, and the second riffle is disposed on the downstream side of flow of the additive water and on the downstream side of a stream of the gold line with respect to a position where the gold line starts appearing in the flat area, and returns, again to the gold line, gold ore particles shifted toward the downstream side of the flow of the additive water in the flat area by the flow of the additive water and separated from the gold line.
In a gold concentrate recovery method according to the present invention a plurality of first riffles on an upper surface of a shaking table oscillated in the extension direction of the first riffles concentrate ore particles based on specific gravity of the ore particles, and generate a gold line in a flat area on the upper surface of the shaking table, the ore particles being particles of gold ores supplied to the upper surface of the shaking table together with additive water, and the flat area being an area where the first riffles are not provided, and at least a second riffle provided on the flat area, and disposed on the downstream side of flow of the additive water and on the downstream side of a stream of the gold line with respect to a position where the gold line starts appearing in the flat area returns, again to the gold line, gold ore particles shifted toward the downstream side of the flow of the additive water in the flat area by the flow of the additive water and separated from the gold line.
According to the present invention, the first riffles are disposed on the upper surface of the shaking table of the table gravity concentrator to concentrate ore particles based on specific gravity of the ore particles. The ore particles are particles of gold ores supplied together with additive water. Moreover, at least the one second riffle is disposed on the upper surface of the shaking table in the flat area, which is an area where the first riffles are not disposed and an area where the gold line is generated, on the downstream side of the flow of the additive water and on the downstream side of the stream of the gold line with respect to the position where the gold line starts appearing in the flat area. According to the present invention, therefore, the second riffle returns, again to the gold line, gold ore particles shifted toward the downstream side of the flow of the additive water in the flat area by the flow of the additive water and separated from the gold line. Accordingly, the table gravity concentrator recovers not only high specific gravity and small particle diameter gold ore particles, but also high specific gravity and large particle diameter gold ore particles not as tailings as recovered in the conventional method, but as concentrates. Thus, efficient recovery of gold ore particles is achievable.
Moreover, according to the present invention, at least the one second riffle is positioned on the downstream side of the flow of the additive water and on the downstream side of the stream of the first gold line with respect to the position where the gold line starts appearing in the flat area. In this case, the gold line becomes more linear and deviation and winding of the gold line are reduced. Accordingly, this structure decreases, more than the conventional method, the possibility that ore particles which should be recovered as concentrates are recovered as tailings, and the possibility that ore particles which should be recovered as tailings are recovered as concentrates. This advantage can reduce errors produced in separating the stream (first gold line) of high specific gravity, small particle diameter, and high gold grade ore particles from the stream (tailing layer) of high specific gravity and large particle diameter ore particles, and allow efficient and stable recovery of gold ore particles. Furthermore, according to the present invention, the higher linearity of the stream of the gold line reduces or eliminates to none the labor of shifting the partition plate in accordance with deviation and winding of the gold line while monitoring the gold line during operation. Accordingly, efficient and stable recovery of gold ore particles is achievable.
A gold concentrate recovery system and a gold concentrate recovery method according to the present invention are hereinafter described in detail with reference to the drawings. The present invention is not limited to the examples described herein, but may be modified in arbitrary manners without departing from the scope of the present invention.
As illustrated in
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As illustrated in
The ore supply launder 4 and the water supply launder 5 may be formed integrally with each other and constitute a launder unit. The ore supply launder 4 and the water supply launder 5 are not limited to be attached to the dam 6. Alternatively, the ore supply launder 4 and the water supply launder 5 may be attached to the shaking table 2, or other constituent elements of the table gravity concentrator 1.
As illustrated in
As illustrated in
As illustrated in
The first riffles 3a are constituted by upstream riffles 3a1, midstream riffles 3a2, and downstream riffles 3a3. The upstream riffles 3a1, midstream riffles 3a2, and downstream riffles 3a3 are disposed in this order on the upper surface 2a of the shaking table 2 from the rear side surface 2d side toward the front side surface 2c side of the shaking table 2. Each unit of the upstream riffles 3a1, midstream riffles 3a2, and downstream riffles 3a3 is constituted by a plurality of riffles.
The upstream riffles 3a1 are so provided as to gradually increase in length from the rear side surface 2d toward the front side surface 2c of the shaking table 2. For example, the upstream riffles 3a1 are so provided that a line L1 connecting the left side surface 2f side tips of the upstream riffles 3a1 is inclined at an angle of 37.4 degrees toward the rear side surface 2d with respect to the length direction of the shaking table 2, that is, inclined at an angle of 52.6 degrees toward the right side surface 2e with respect to the width direction of the shaking table 2. In other words, the upstream riffles 3a1 are so provided that an angle of 123.1 degrees is formed by the extension direction of the midstream riffles 3a2 and the line L1 connecting the tips of the upstream riffles 3a1.
The midstream riffles 3a2 are longer than the upstream riffles 3a1 in the extension direction. Similarly to the upstream riffles 3a1, the midstream riffles 3a2 are so provided as to gradually increase in length from the rear side surface 2d toward the front side surface 2c of the shaking table 2. For example, similarly to the upstream riffles 3a1, the midstream riffles 3a2 are so provided that a line L2 connecting the left side surface 2f side tips of the midstream riffles 3a2 is inclined at an angle of 37.4 degrees toward the rear side surface 2d with respect to the length direction of the shaking table 2, that is, inclined at an angle of 52.6 degrees toward the right side surface 2e with respect to the width direction of the shaking table 2. In other words, the midstream riffles 3a2 are so provided that an angle of 123.1 degrees is formed by the extension direction of the downstream riffles 3a3 and the line L2 connecting the tips of the midstream riffles 3a2. Accordingly, the line L2 connecting the tips of the midstream riffles 3a2 is so defined as to become parallel with the line L1 connecting the tips of the upstream riffles 3a1.
The downstream riffles 3a3 extend from the upper surface 2a toward the left side surface 2f of the shaking table 2.
The foregoing angles of the line L1 connecting the tips of the upstream riffles 3a1 and L2 connecting the tips of the midstream riffles 3a2 are presented by way of example only and not limited to these. These angles of the likes L1 and L2 may be arbitrarily varied as necessary. Moreover, the angles of the line L1 connecting the tips of the upstream riffles 3a1 and L2 connecting the tips of the midstream riffles 3a2 are not required to be the same. These angles of the lines L1 and L2 may be set different from each other.
A flat area 12 is provided at the left rear corner of the upper surface 2a of the shaking table 2. The flat area 12 is an area where the first riffles 3a are not formed. The flat area 12 has a substantially triangular shape in the plan view. As illustrated in
As illustrated in
For example, each of the second riffles 3b is constituted by a long member having a width of 0.3 inch, a length of 1 inch in the thickness direction between the upper surface 2a and the lower surface 2b of the shaking table 2, and a length of 9 inches in the extension direction. The second riffles 3b are disposed on the flat area 12 of the shaking table 2 on the front side surface 2c side of the shaking table 2 and on the left side surface 2f side of the shaking table 2 with respect to the of the riffle on the uppermost row of the midstream riffles 3a2 in the first riffles 3a, from which position of the tip of the uppermost riffle 3a2 the first gold line 40a is generated. The five second riffles 3b are provided on the flat area 12 of the shaking table 2 while inclined at 19.5 degrees toward the rear side surface 2d side of the shaking table 2 with respect to the length direction (front side surface 2c) of the shaking table 2, in other words, inclined at 90 degrees with respect to the right side surface 2e (left side surface 2f) of the shaking table 2.
The second riffles 3b are disposed such that a line L3 connecting the left side surface 2f side tips of the second riffles 3b is inclined at an angle of 10.1 degrees toward the rear side surface 2d with respect to the length direction of the shaking table 2, that is, inclined at an angle of 79.9 degrees toward the right side surface 2e with respect to the width direction of the shaking table 2. In other words, the second riffles 3b are disposed such that an angle of 27.3 degrees is formed by the line L2 connecting the tips of the midstream riffles 3a2 and the line L3 connecting the tips of the second riffles 3b.
The foregoing width, the length, the angle, the number and other conditions of the second riffles 3b are presented by way of example only and not limited to these. These may be arbitrarily varied as necessary. Moreover, the first gold line 40a is not limited to be generated from the tip of the riffle on the uppermost row of the midstream riffles 3a2 of the first riffles 3a, but may be generated from a riffle on a row shifted by several rows from the uppermost row. In this case, the second riffles 3b are disposed on the flat area 12 of the shaking table 2 on the front side surface 2c side of the shaking table 2 and on the left side surface 2f side of the shaking table 2 with respect to the tip of the corresponding riffle on the row shifted by several rows from the uppermost row. More specifically, an intersection P of the line L3 connecting the tips of the second riffles 3b and the line L2 connecting the tips of the midstream riffles 3a2 of the first riffles 3a is located on the front side surface 2c side of the shaking table 2 with respect to the tip of the corresponding riffle on the row shifted by several rows from the uppermost row.
The riffles 3 thus constructed are formed on the upper surface 2a of the shaking table 2 in the manner as follows, for example. Long members made of rubber or resin and constructed in correspondence with the foregoing first riffles 3a and the second riffles 3b are affixed to a body sheet formed by a rubber sheet or a resin sheet slightly larger than the shaking table 2. Then, the body sheet to which the first riffles 3a and the second riffles 3b are attached is placed on the upper surface 2a of the wooden shaking table 2 and attached to the upper surface 2a by staples or the like to form the riffles 3 on the upper surface 2a of the shaking table 2. For example, the body sheet and the long members, that is, the riffles 3, are made of linoleum.
The table gravity concentrator 1 thus constructed recovers gold concentrates from gold ores containing gangue minerals or sulfide minerals in the manner as follows.
Initially, as illustrated in
As a result, among the ore slurry supplied to the upper surface 2a of the shaking table 2, low specific gravity ore particles having low specific gravity such as gangue minerals and sulfide minerals receive resistance of water flow of the additive water flowing in the width direction of the shaking table 2, and flows in the water flow direction of the additive water (width direction of the shaking table 2) while going over the first riffles 3a independently from the oscillation movement of the shaking table 2. Then, the low specific gravity ore particles fall from the front side surface 2c of the shaking table 2, and are recovered as tailings into the first tailing recovery storage tank 8 provided on the front side surface 2c side of the shaking table 2 together with the additive water.
On the other hand, high specific gravity ore particles having high specific gravity shift in the extension direction along the first riffles 3a in accordance with the oscillation movement of the shaking table 2. Then, the high specific gravity ore particles flow into the flat area 12 from the tip of the riffle on the uppermost row of the midstream riffles 3a2 of the first riffles 3a, for example.
In this case, the high specific gravity and large particle diameter ore particles flowing in the flat area 12 are more likely to shift in the water flow direction of the additive water by the flow of the additive water from the water supply launder 5 than the high specific gravity and small particle diameter ore particles when the specific gravity of the large diameter particles and the small diameter particles are the same. Accordingly, the stream (first gold line) 40a of high specific gravity, small particle diameter, and high gold grade ore particles, and a stream (tailing layer) 40b of high specific gravity and large particle diameter ore particles are formed in the flat area 12. Furthermore, a part of the high specific gravity and large particle diameter gold ore particles shift in the water flow direction of the additive water during flow in the flat area 12 by the flow of the additive water from the water supply launder 5 or by others, and form a stream (second gold line) other than the first gold line 40a. However, according to the table gravity concentrator 1 provided with the second riffles 3b on the flat area 12, the high specific gravity and large particle diameter gold ore particles receiving the resistance of the water flow of the additive water and shifting in the water flow direction of the additive water on the flat area 12 are returned to the first gold line 40a by the second riffles 3b. Accordingly, the amount of gold ore particles constituted by the high specific gravity and large particle diameter gold ore particles and flowing along the second gold line is reduced to a smaller amount than the corresponding amount in the conventional method, or is reduced to none.
Then, the table gravity concentrator 1 separates the first gold line 40a from the tailing layer 40b using the partition plate 7 provided on the left side surface 2f of the shaking table 2 in such a condition as to freely shift along the left side surface 2f, for example. Subsequently, the table gravity concentrator 1 recovers the first gold line 40a together with the additive water into the concentrate recovery storage tank 10 provided on the left side surface 2f side of the shaking table 2. Furthermore, the table gravity concentrator 1 recovers the tailing layer 40b together with the additive water into the second tailing recovery storage tank 9 provided on the left side surface 2f side of the shaking table 2.
By this method, the table gravity concentrator 1 recovers gold concentrates from gold ores containing gangue minerals or sulfide minerals.
According to the table gravity concentrator 1, therefore, the first riffles 3a are disposed on the upper surface 2a of the shaking table 2 to concentrate ore particles based on specific gravity of the ore particles. The ore particles are constituted by gold ores and supplied together with additive water. Moreover, the second riffles 3b are disposed on the upper surface 2a of the shaking table 2 in the flat area 12, which is an area where the first riffles 3a are not disposed and an area where the first gold line 40a is generated, on the downstream side of flow of the additive water and on the downstream side of the stream of the first gold line 40a with respect to the position where the first gold line 40a starts appearing in the flat area 12. Accordingly, the second riffles 3b of the table gravity concentrator 1 return, again to the first gold line 40a, the gold ore particles shifted toward the downstream side of the flow of the additive water in the flat area 12 by the flow of the additive water and separated from the first gold line 40a. In this case, the table gravity concentrator 1 recovers not only high specific gravity and small particle diameter gold ore particles, but also high specific gravity and large particle diameter gold ore particles not as tailings as recovered in the conventional method, but as concentrates. Thus, efficient recovery of gold ore particles is achievable.
Moreover, according to the table gravity concentrator 1, the second riffles 3b are positioned on the downstream side of the flow of the additive water and on the downstream side of the stream of the first gold line 40a with respect to the position where the first gold line 40a starts appearing in the flat area 12. In this case, the first gold line 40a flows along the second riffles 3b, wherefore the first gold line 40a becomes more linear and deviation and winding of the first gold line 40a are reduced. Accordingly, the table gravity concentrator 1 decreases, more than the conventional method, the possibility that ore particles which should be recovered as concentrates are recovered as tailings, and the possibility that ore particles which should be recovered as tailings are recovered as concentrates. This advantage can reduce errors produced in separating the stream (first gold line) 40a of high specific gravity, small particle diameter, and high gold grade ore particles from the stream (tailing layer) 40b of high specific gravity and large particle diameter ore particles, and allow efficient and stable recovery of gold ore particles. Furthermore, according to the table gravity concentrator 1, the first gold line 40a flows along the second riffles 3b and becomes more linear as discussed above. This advantage can reduce the labor of shifting the partition plate 7 in accordance with deviation and winding of the first gold line 40a while monitoring the first gold line 40a during operation, or eliminate this labor to none, when the partition plate 7 is positioned on an extension line of the line L3 connecting the tips of the second riffles 3b, for example. Accordingly, efficient and stable recovery of gold ore particles is achievable.
The number of the second riffles 3b provided on the flat area 12 is not limited to five. The number of the second riffles 3b to be provided on the flat area 12 may be different numbers as long as the second riffles 3b can return high specific gravity and large particle diameter gold ore particles separated from the first gold line 40a again to the first gold line 40a. For example, as illustrated in
As illustrated in
The second riffles 3b are not limited to have a uniform length, but may have different lengths for each as illustrated in
As illustrated in
As illustrated in
A part or all of the second riffles 3b may be made higher than the first riffles 3a so as to eliminate the possibility that high specific gravity and large particle diameter gold ore particles separated from the first gold line 40a go over the second riffles 3b. According to this structure, going over the second riffles 3b becomes more difficult for high specific gravity and large particle diameter gold ore particles separated from the first gold line 40a. Accordingly, recovery of a larger amount of gold ore particles is achievable.
The second riffles 3b are only required to return high specific gravity and large particle diameter gold ore particles separated from the first gold line 40a again to the first gold line 40a. Thus, the second riffles 3b to be provided on the flat area 12 may be only one riffle. In other words, it is only required that at least the one second riffle 3b is provided on the flat area 12.
The material of the riffles 3 is not limited to linoleum, but may be rubber material, resin material, metal material, or other known materials. The riffles 3 are not limited to be produced by the method discussed herein which attaches the body sheet provided with long members to the upper surface 2a of the shaking table 2 to form the riffles 3 on the upper surface 2a of the shaking table 2. Alternatively, the riffles 3 may be directly attached to the upper surface 2a of the shaking table 2 to be formed thereon. In addition, the shaking table 2 is not limited to a wooden component, but may be a component made of metal or resin.
A width of a gold line produced at the time of recovery of gold concentrates from gold ores, and an overall recovery rate were measured by using a table gravity concentrator including second riffles which are disposed on a flat area of an upper surface of a shaking table. Note that the present invention is not limited to examples described below.
In Example 1, a width of a first gold line produced at the time of recovery of gold concentrates from gold ores, and an overall recovery rate were measured under the following experimental conditions by using a table gravity concentrator which includes five second riffles having the same length and disposed at uniform intervals on the flat area of the upper surface of the shaking table as illustrated in
<Experimental Conditions>
table gravity concentrator used: manufactured by Diester Industrie
oscillation of table gravity concentrator: 150 times/minute
In Example 1, the width of the first gold line was 20 mm, and the overall recovery rate was 60%.
According to Example 1, the width of the first gold line decreased to a width of approximately ⅔ of the width of the first gold line (30 mm) in Comparison Example 1 described below. It is assumed that the decrease in width came from a change of the stream of the high specific gravity and large particle diameter gold ore particles. More specifically, the obstruction of the second riffles switched the stream of the high specific gravity and large particle diameter gold ore particles to the first gold line from a second gold line where the gold ore particles are difficult to recover in the conventional method, and therefore increased the overlap between the stream of the first gold line and the stream of the second gold line. Furthermore, the structure in Example 1 recovered 20% of gold ore particles from large particle diameter ore particles which are difficult to recover in the conventional method. Accordingly, the structure in Example 1 improved the overall recovery rate, and recovered a larger amount of gold concentrates from gold ores in comparison with Comparison Example 1 whose overall recovery rate was 50% as will be described below.
In Example 2, a width of a first gold line and an overall recovery rate were measured under the foregoing experimental conditions similarly to Example 1, except that the used table gravity concentrator includes seven second riffles having the same length and disposed at uniform intervals on the flat area of the upper surface of the shaking table as illustrated in
In Example 2, the width of the first gold line was 30 mm, and the overall recovery rate was 63%.
More specifically, in Example 2, the width of the first gold line was equivalent to the corresponding width in Comparison Example 1 described below. However, the width of the first gold line increased while the degree of overlap between the first gold line and a second gold line remains the same. It is assumed from this result that the accuracy of recovery by using a partition plate increased. Moreover, the overall recovery rate in Example 2 increased from the overall recovery rate of 60% in Example 1. Accordingly, with increase in the number of the second riffles from that number in Example 1, the structure in Example 2 improved the overall recovery rate, and recovered a larger amount of gold concentrates from gold ores in comparison with Example 1.
In Example 3, a width of a first gold line and an overall recovery rate were measured under the foregoing experimental conditions similarly to Example 1, except that the used table gravity concentrator includes a plurality of second riffles having disposed at uniform intervals on the flat area of the upper surface of the shaking table throughout the range from midstream riffles of first riffles to the left side surface of the shaking table as illustrated in
In Example 3, the width of the first gold line was 30 mm, and the overall recovery rate was 82%. In addition, while the width of the first gold line remains 30 mm in Example 3, it was visually recognized that the linearity of the stream direction of the first gold line improved.
More specifically, in Example 3, the width of the first gold line was equivalent to the corresponding width in Comparison Example 1 described below similarly to Example 2. However, the width of the first gold line increased while the degree of overlap between the first gold line and a second gold line remains the same. It is assumed from this result that the accuracy of recovery by using the partition plate increased. Furthermore, with increase in the number of the second riffles from that number in Example 1 and Example 2, the structure in Example 3 improved the overall recovery rate, and recovered a larger amount of gold concentrations from gold ores in comparison with the overall recovery rate of 60% in Example 1, and the overall recovery rate of 63% in Example 2. It is assumed that this result came not only from the increase in the number of the second riffles from that number in Example 1 and Example 2, but also from the improvement of the linearity of the stream direction of the first gold line in comparison with Examples 1 and 2, achieved while the width of the first gold line and the degree of overlap between the first gold line and the second gold line remain the same as the corresponding width and overlap in Example 2. This improvement of the linearity is assumed to have further increased the accuracy of recovery by using the partition plate from the corresponding accuracy in Examples 1 and 2.
In Comparison Example 1, a width of a first gold line and an overall recovery rate were measured under the foregoing experimental conditions similarly to Example 1, except that the used table gravity concentrator was a conventional table gravity concentrator.
In Comparison Example 1, the overall recovery rate was an insufficient rate of 50%, resulting from the use of the conventional table gravity concentrator. It is assumed that this result came from a low degree of overlap between the first gold line stream and a second gold line stream, exhibited while the width of the first gold line was 30 mm similarly to Examples 2 and 3.
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| Number | Date | Country |
|---|---|---|
| 2012-139675 | Jul 2012 | JP |
