A recovery system and method for fine-grained bauxite

Abstract

The present invention discloses a recovery system and method for fine-grained bauxite, which includes subjecting a bauxite tailings pulp with a concentration of 8-13% to primary concentration and desliming through a hydrocyclone to obtain a hydrocyclone overflow and a sand-containing pulp with a concentration of 25-42%; pumping the sand-containing pulp into a thickener for secondary concentration and desliming to obtain a thickener overflow and a thickener underflow of the dehydrated sand-containing pulp; pumping the dehydrated sand-containing pulp into a stirring tank for stirring and scrubbing to obtain a sand-containing pulp with a stable concentration of 25-28%; the sand-containing pulp with a stable concentration enters a suspension vibration ore separator for separation to separate out bauxite concentrate with an Al2O3 content of 50-70%, a SiO2 content of 5.5-11%, and a mass ratio of Al2O3 / SiO2 greater than 4 and high-silica tailings. The present invention uses an economical ore dressing method to recover bauxite concentrate from bauxite tailings pulp, which can not only effectively reduce the content of harmful component SiO2 in the ore, but also make the alumina-silica ratio in the concentrate meet the technological requirements for alumina purification.

Description

Technical Field

[0001] The present invention relates to the field of ore dressing, and particularly to a recovery system and method for fine-grained bauxite. Background Art

[0002] In the bauxite ore dressing process, the ore is often separated from clay by water washing. The separated bauxite ore enters the alumina production process after being crushed to the qualified size, while the separated slime is sent to the sludge storage tank (tailings pond) for storage after concentration. Alumina enterprises are facing the dilemma of having no land to stack red mud and no reservoir to discharge slime. According to statistics, 1.0 - 2.5 tons of slime need to be discharged for every 1 ton of alumina produced. According to the annual output of alumina in China, the annual production of slime in China reaches more than 200 million tons. And the Al 2 0 3 content is relatively high, with a grade of 35 - 40%. The Al 2 0 3 / Si0 2 mass is 1.3 - 1.5, which has a high recovery value. However, the slime has extremely fine particle size, -0.019mm accounts for 74.26%, and the proportion of clay particles and colloidal particles is very high, which can be approximately regarded as a colloid. Therefore, the difficulty of ore dressing and recovery is extremely great. China is a region short of bauxite resources. How to utilize the tailings and slime resources, effectively reduce the tailings discharge, and facilitate the sustainable development of the bauxite industry is a technical problem that needs to be solved urgently in this field. Summary of the Invention

[0003] The purpose of the present invention is to provide a recovery system and method for fine-grained bauxite, so as to realize its efficient utilization in the bauxite tailings slurry, which is a waste in the alumina production process.

[0004] To achieve the above purpose, on the one hand, the present invention provides a recovery method for fine-grained bauxite, including the following steps:

[0005] (1) Concentrating and de-sludging the bauxite tailings slurry with a concentration of 8 - 13% through a hydrocyclone to obtain the overflow of the hydrocyclone and the underflow of the hydrocyclone with a concentration of 25 - 42%. The underflow of the hydrocyclone is a sand-containing slurry, and the overflow of the hydrocyclone is slime smaller than -10μm;

[0006] (2) Pumping the sand-containing slurry in step (1) into a thickener for secondary concentration and de-sludging to obtain the overflow of the thickener and the underflow of the thickener. The underflow of the thickener is the dehydrated sand-containing slurry, and the overflow of the thickener is slime smaller than -10μm;

[0007] (3) Pumping the dehydrated sand-containing slurry in step (2) into a mixing tank for stirring and scrubbing to obtain a sand-containing slurry with a stable concentration. The concentration of the sand-containing slurry with a stable concentration is 25 - 28%;

[0008] (4) The sand-containing pulp with stable concentration in step (3) enters the suspension vibration ore separator for separation, and the bauxite concentrate and high-silica tail mud are separated. The content of Al 2 0 3 in the bauxite concentrate is 50-70%, and the content of Si0 2 is 5.5-11%. The mass ratio of Al 2 0 3 / Si0 2 is greater than 4.

[0009] Preferably, in step (1), the particle size of the solid particles in the bauxite tailing pulp is less than 2 mm, and the content of Al 2 0 3 in the bauxite tailing pulp is 30-45%, and the content of Si0 2 is 23-40%.

[0010] Preferably, the overflow of the hydrocyclone in step (1), the overflow of the thickener in step (2), and the high-silica tail mud in step (4) all enter the thickening tank.

[0011] On the other hand, a recovery system for fine-grained bauxite includes a hydrocyclone, a thickening tank, a thickener, a mixing tank, a suspension vibration ore separator, a concentrate tank, a first slurry pump, and a second slurry pump; the overflow of the hydrocyclone enters the thickening tank, the underflow of the hydrocyclone is pumped into the thickener by the first slurry pump, the overflow of the thickener enters the thickening tank, the underflow of the thickener is pumped into the mixing tank by the second slurry pump, the slurry in the mixing tank enters the suspension vibration ore separator, the high-silica tail mud of the suspension vibration ore separator enters the thickening tank, the concentrate slurry of the suspension vibration ore separator enters the concentrate tank, and the concentrate slurry in the concentrate tank is dehydrated to obtain the bauxite concentrate.

[0012] Preferably, the tail mud slurry in the thickening tank is thickened and then discharged into the sludge storage tank.

[0013] Preferably, the suspension vibration ore separator is a suspension vibration conical surface ore separator, and the rotational speed of the suspension vibration conical surface ore separator is 0.5-1.5 r / min, the vibration frequency is 60-150 times / min, and the processing capacity is 70-120 tons / day.

[0014] In summary, compared with the prior art, the beneficial effects of the present invention are as follows:

[0015] 1. Through the recovery method and system of the present invention, the enrichment and desilication of Al 2 O 3 are realized, and the content of Al 2 O 3 is greater than 50%, and the SiO 2Qualified concentrate with a content of less than 11% and a mass ratio of aluminum to silicon greater than 4; through the economic beneficiation method of the present invention, not only can the harmful component SiO in the mineral be effectively reduced 2 content, making the mass ratio of aluminum to silicon in the concentrate meet the technological requirements for alumina purification, and providing technological support for the re-election project of bauxite tailings.

[0016] 2. The present invention does not require additional dosing, is green and environmentally friendly; only the ore sand that has been concentrated and de-sludged once by a hydrocyclone, after being concentrated, de-sludged a second time and scrubbed in a thickener and a stirring tank, is applied to a suspension vibration separator and reaches a concentrate with a mass ratio of aluminum to silicon greater than 4 through one separation.

[0017] 3. During the beneficiation process of the present invention, by stirring and scrubbing in a stirring tank, the suspension vibration cone surface separator can better de-sludge and de-silicon, and can effectively reduce the SiO in the concentrate 2 content and mud content.

[0018] 4. The present invention not only has a relatively high yield of recovered concentrate, obtaining huge economic benefits; but also comprehensively utilizes tailings resources, effectively reducing the tailings discharge volume, and becoming the main way for continuous production of mines. Description of the Drawings

[0019] Figure 1 is the industrial flow chart of the present invention. Detailed Embodiments

[0020] The following description of at least one exemplary embodiment is merely illustrative and in no way limits the present invention or its application or use. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention. Technologies, methods, and equipment known to those of ordinary skill in the relevant fields may not be discussed in detail, but where appropriate, the said technologies, methods, and equipment should be regarded as part of the authorization specification. In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0021] Example 1

[0022] As Figure 1 shown, a method for recovering fine-grained bauxite includes the following steps:

[0023] (1) Concentrating and de-sludging the bauxite tailings slurry with a concentration of 8-13% through a hydrocyclone to obtain the overflow of the hydrocyclone and the underflow of the hydrocyclone with a concentration of 25-42%. The underflow of the hydrocyclone is a sand-containing slurry, and the overflow of the hydrocyclone is ore mud less than -10 μm. Among them, the particle size of the solid particles in the bauxite tailings slurry is less than 2 mm, and the Al in the bauxite tailings slurry2 0 3 has a content of 30 - 45%, and SiO 2 has a content of 23 - 40%.

[0024] (2) Pump the sand - containing pulp in step (1) into a thickener for secondary thickening and de - sludging to obtain thickener overflow and thickener underflow. The thickener underflow is the dehydrated sand - containing pulp, and the thickener overflow is the slime less than - 10μm.

[0025] (3) Pump the dehydrated sand - containing pulp in step (2) into a mixing tank for agitation and scrubbing to obtain a sand - containing pulp with a stable concentration. The concentration of the sand - containing pulp with a stable concentration is 25 - 28%.

[0026] (4) The sand - containing pulp with a stable concentration in step (3) enters a suspension vibration ore separator for separation to separate out bauxite concentrate and high - silicon tailing mud. In the bauxite concentrate, the content of Al 2 0 3 has a content of 50 - 70%, and SiO 2 has a content of 5.5 - 11%, and the mass ratio of Al 2 0 3 / SiO 2 is greater than 4.

[0027] The overflow of the hydrocyclone in step (1), the overflow of the thickener in step (3), and the tailing mud in step (5) all enter the thickening pond.

[0028] A recovery system for fine - grained bauxite includes a hydrocyclone, a thickening pond, a thickener, a mixing tank, a suspension vibration ore separator, a concentrate pond, a first slurry pump, and a second slurry pump; the overflow of the hydrocyclone enters the thickening pond, the underflow of the hydrocyclone is pumped into the thickener by the first slurry pump, the overflow of the thickener enters the thickening pond, the underflow of the thickener is pumped into the mixing tank by the second slurry pump, the slurry in the mixing tank enters the suspension vibration cone - surface ore separator, the walking speed at the edge of the separation surface of the suspension vibration cone - surface ore separator is 6 - 18 m / min, the vibration frequency is 60 - 200 times / min, and the processing capacity is 70 - 120 tons / day; the high - silicon tailing mud in the suspension vibration cone - surface ore separator enters the thickening pond, the concentrate slurry in the suspension vibration ore separator enters the concentrate pond, and the concentrate slurry in the concentrate pond is dehydrated to obtain bauxite concentrate. The tailing slurry in the thickening pond is thickened and then discharged into the sludge discharge reservoir.

[0029] Example 2

[0030] The recovery system and method of fine - grained bauxite in this example takes a certain tailing pulp as an example. The particle size of the solid particles in the certain tailing pulp is less than 2mm, and the main chemical components are Al 2 O 3 , SiO 2 and Fe2 O 3 , which are 30.24%, 25.19% and 15.02% respectively, and the mass ratio of aluminum to silicon is 1.20.

[0031] The recovery method and system of fine bauxite concentrate in Example 1 were used to recover the concentrate. The industrial test system was installed on December 20, 2021, debugged on December 26, 2021, and the test started on December 27, 2021. The test lasted until March 12, 2022, for 70 days.

[0032] On December 27, 2021, the tailings concentration, cyclone underflow concentration, and agitator concentration in the test were measured. The measurement results are shown in Table 1.

[0033]

[0034] Table 1

[0035] As can be seen from Table 1, the tailings concentration is relatively stable, at 9.1 - 11%. Affected by the mixing in the thickener, the cyclone underflow concentration varies greatly, with a variation range of 25 - 36%, which has a certain impact on ore dressing. The agitator tank concentration is relatively stable at 25 - 26%. The walking speed and vibration frequency at the edge of the sorting surface of the suspension vibration separator are adjusted according to the operation of the ore dressing machine to achieve less mixing, high concentrate grade, and high yield; the daily processing capacity of the suspension vibration separator is 120 tons / day. The output and yield of the whole system are not only affected by the recovery effect of the suspension vibration separator, but also by the recovery effect of the cyclone. According to the system concentrate yield = cyclone yield * suspension vibration separator operation yield, the system Al 2 O 3 recovery rate = system yield * concentrate grade / original tailings grade, and the recovery rate is calculated.

[0036]

[0037] Table 2

[0038] The obtained concentrate is shown in Table 2. The content of Al 2 0 3 is 50.74%, the content of SiO2 is 5.51%, the mass ratio of aluminum to silicon is increased from 1.20 to 9.21, the yield is 11.18%, and the re - selection effect of tailings slime is very ideal.

[0039] Example 3

[0040] The recovery system and method of fine bauxite in this example takes a certain tailings slurry as an example. The particle size of solid particles in the tailings slurry is less than 2 mm, and the main chemical components are Al 2 O 3 , SiO 2 and Fe2 O 3 , which are 40.00%, 29.95% and 15.03% respectively, and the mass ratio of aluminum to silicon is 1.34.

[0041] On December 29, 2021, the tailings concentration, cyclone underflow concentration, and agitator concentration in the test were measured. The measurement results are shown in Table 3.

[0042]

[0043] As can be seen from Table 3, the tailings concentration is relatively stable, at 9.8 - 13%. The cyclone underflow concentration is affected by the mixing of the thickener and varies greatly, with a variation range of 26 - 37%, which has a certain impact on ore dressing. The agitator tank concentration is relatively stable at 26 - 27%. The walking speed and vibration frequency at the edge of the sorting surface of the suspension vibration separator are adjusted according to the operation of the ore dressing machine to achieve less mixing, high concentrate grade, and high yield; the daily processing capacity of the suspension vibration separator is 120 tons / day. The output and yield of the entire system are not only affected by the recovery effect of the suspension vibration separator but also by the recovery effect of the cyclone. According to the system concentrate yield = cyclone yield * suspension vibration separator operation yield, the system Al 2 O 3 recovery rate = system yield * concentrate grade / original tailings grade, and the recovery rate is calculated.

[0044]

[0045] Table 4

[0046] The obtained concentrate is shown in Table 4. The content of Al 2 0 3 is 60.82%, the content of SiO2 is 5.88%, the mass ratio of aluminum to silicon is increased from 1.34 to 10.34, the yield is 11.61%, and the re - selection effect of the tailings slime is very ideal.

[0047] Example 4

[0048] The recovery system and method of fine - grained bauxite in this example take a certain tailings pulp as an example. The particle size of the solid particles in the tailings pulp is less than 2 mm, and the main chemical components are Al 2 O 3 , SiO 2 and Fe 2 O 3 , which are 44.98%, 23.46% and 14.79% respectively, and the mass ratio of aluminum to silicon is 1.92.

[0049] On January 20, 2022, the tailings concentration, cyclone underflow concentration, and agitator concentration in the test were measured. The measurement results are shown in Table 5.

[0050]

[0051] Table 5

[0052] As can be seen from Table 5, the tailings concentration is relatively stable, at 9.1 - 12%. The underflow concentration of the hydrocyclone is affected by the mixing of the thickener and varies greatly, with a variation range of 31 - 42%, which has a certain impact on ore dressing. The concentration of the agitation tank is relatively stable at 26 - 28%. The walking speed and vibration frequency at the edge of the sorting surface of the suspension vibration separator are adjusted according to the operation of the ore dressing machine to achieve less mixing, high concentrate grade, and high yield; the daily throughput of the suspension vibration separator is 120 tons / day. The output and yield of the entire system are affected not only by the recovery effect of the suspension vibration separator but also by the recovery effect of the hydrocyclone. According to the system concentrate yield = hydrocyclone yield * suspension vibration separator operation yield, system Al 2 O 3 recovery rate = system yield * concentrate grade / original tailings grade, and the recovery rate is calculated.

[0053]

[0054] Table 6

[0055] The obtained concentrate is shown in Table 6. The content of Al 2 0 3 is 69.98%, the content of SiO2 is 10.93%, the aluminum-silicon ratio is increased from 1.92 to 6.40, the yield is 11.33%, and the re-election effect of the tailings slime is very ideal.

[0056] Example 5

[0057] Taking a certain tailings slurry as an example, the recovery system and method for fine-grained bauxite in this example. The particle size of the solid particles in a certain tailings slurry is less than 2 mm, and the main chemical components are Al 2 O 3 , SiO 2 , and Fe 2 O 3 , which are 43.24%, 39.94%, and 14.79% respectively, and the aluminum-silicon mass ratio is 1.08.

[0058] On January 21, 2022, the tailings concentration, hydrocyclone underflow concentration, and agitator concentration in the experiment were measured. The measurement results are shown in Table 7.

[0059]

[0060] Table 7

[0061] As can be seen from Table 7, the tailings concentration is relatively stable, at 8.1 - 10.2%. The underflow concentration of the hydrocyclone is affected by the mixing in the thickener and varies greatly, with a range of 30 - 42%, which has a certain impact on mineral processing. The concentration in the agitation tank is relatively stable at 25 - 26%. The walking speed and vibration frequency at the edge of the sorting surface of the suspension vibration separator are adjusted according to the operation of the ore dressing machine to achieve less mixing, high concentrate grade, and high yield; the daily throughput of the suspension vibration separator is 120 tons / day. The output and yield of the entire system are affected not only by the recovery effect of the suspension vibration separator but also by the recovery effect of the hydrocyclone. According to the system concentrate yield = hydrocyclone yield * suspension vibration separator operation yield, system Al 2 O 3 recovery rate = system yield * concentrate grade / original tailings grade, and the recovery rate is calculated accordingly.

[0062]

[0063] Table 8

[0064] The obtained concentrate is shown in Table 8. The content of Al 2 0 3 is 65.24%, the content of SiO2 is 8.07%, the aluminum-silicon mass ratio is increased from 1.08 to 8.08, the yield is 11.77%, and the re-election effect of the tailings slime is very ideal.

[0065] Example 6

[0066] Taking a certain tailings slurry as an example, the recovery system and method for fine-grained bauxite in this example. The particle size of the solid particles in a certain tailings slurry is less than 2 mm, and the main chemical components are Al 2 O 3 , SiO 2 , and Fe 2 O 3 , which are 31.61%, 38.87%, and 11.66% respectively, and the aluminum-silicon mass ratio is 0.81.

[0067] On January 22, 2022, the tailings concentration, hydrocyclone underflow concentration, and agitator concentration in the experiment were measured. The measurement results are shown in Table 7.

[0068]

[0069] Table 9

[0070] As can be seen from Table 9, the tailings concentration is relatively stable, ranging from 7.9% to 11.4%. The underflow concentration of the hydrocyclone is greatly affected by the mixing in the thickener, with a large variation range of 28% - 40%, which has a certain impact on ore dressing. The concentration in the agitation tank is relatively stable at 26% - 28%. The walking speed and vibration frequency at the edge of the sorting surface of the suspension vibration separator are adjusted according to the operation of the ore dressing machine to achieve less mixing, high concentrate grade, and high yield; the daily processing capacity of the suspension vibration separator is 120 tons per day. The output and yield of the entire system are affected not only by the recovery effect of the suspension vibration separator but also by the recovery effect of the hydrocyclone. According to the system concentrate yield = hydrocyclone yield * suspension vibration separator operation yield, system Al 2 O 3 recovery rate = system yield * concentrate grade / original tailings grade, and the recovery rate is calculated.

[0071]

[0072] Table 10

[0073] The obtained concentrate is shown in Table 10. The content of Al 2 0 3 is 51.05%, the content of SiO2 is 11.00%, the aluminum-silicon mass ratio is increased from 0.81 to 4.64, the yield is 10.23%, and the re-election effect of the tailings slime is very ideal.

[0074] The concentrations described in the above embodiments are all mass percentage concentrations.

[0075] The above description enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for recovering fine-grained bauxite, characterized in that, it comprises the following steps: (1) Concentrating and de-sludging the bauxite tailing slurry with a concentration of 8-13% through a hydrocyclone for the first stage to obtain the overflow of the hydrocyclone and the underflow of the hydrocyclone with a concentration of 25-42%. The underflow of the hydrocyclone is a sand-containing slurry, and the overflow of the hydrocyclone is slime less than -10μm; (2) Pumping the sand-containing slurry in step (1) into a thickener for secondary concentration and de-sludging to obtain the overflow of the thickener and the underflow of the thickener. The underflow of the thickener is the dehydrated sand-containing slurry, and the overflow of the thickener is slime less than -10μm; (3) Pumping the dehydrated sand-containing slurry in step (2) into a stirring tank for stirring and scrubbing to obtain a sand-containing slurry with a stable concentration. The concentration of the sand-containing slurry with a stable concentration is 25-28%; (4) The sand-containing pulp with stable concentration in step (3) enters the suspension vibration ore separator for separation to obtain bauxite concentrate and high-silica tail mud. The content of Al 2 0 3 in the bauxite concentrate is 50-70%, the content of Si0 2 is 5.5-11%, and the mass ratio of Al 2 0 3 / Si0 2 is greater than 4; The recovery system for fine-grained bauxite of the recovery method includes a hydrocyclone, a thickening pond, a thickener, a stirring tank, a suspension vibration ore separator, a concentrate pond, a first slurry pump and a second slurry pump; the overflow of the hydrocyclone enters the thickening pond, the underflow of the hydrocyclone is pumped into the thickener through the first slurry pump, the overflow of the thickener enters the thickening pond, the underflow of the thickener is pumped into the stirring tank through the second slurry pump, the mortar in the stirring tank enters the suspension vibration ore separator, the high-silicon tailing slime of the suspension vibration ore separator enters the thickening pond, the concentrate slurry of the suspension vibration ore separator enters the concentrate pond, and the concentrate slurry in the concentrate pond is dehydrated to obtain bauxite concentrate; In step (1), the particle size of the solid particles in the bauxite tailings pulp is less than 2 mm, and the content of Al 2 0 3 in the bauxite tailings pulp is 30-45%, and the content of Si0 2 is 23-40%.

2. The method for recovering fine-grained bauxite according to claim 1, characterized in that, the overflow of the hydrocyclone in step (1), the overflow of the thickener in step (2), and the high-silicon tailing slime in step (4) all enter the thickening pond.

3. The method for recovering fine-grained bauxite according to claim 1, characterized in that, the tailing slurry in the thickening pond is discharged into a sludge storage pond after thickening.

4. The method for recovering fine-grained bauxite according to claim 1, characterized in that, the suspension vibration ore separator is a suspension vibration conical surface ore separator, the walking speed at the edge of the separation surface of the suspension vibration conical surface ore separator is 6-18 m / min, the vibration frequency is 60-200 times / min, and the processing capacity is 70-120 tons / day.

Images