Wash middling coal composite conditioning agent and ore grinding dissociation re-flotation method using same

Abstract

The invention discloses a composite conditioning agent for middling coal. The composite conditioning agent comprises inorganic acid and metal fluoride. The composite tempering agent can synergistically enable washing middling coal to be fully dissociated, intergrowth bodies of useful minerals and gangue minerals which are closely symbiotic in the washing middling coal are destroyed and separated into single mineral particles (mineral monomers), the subsequent flotation ash content and coal selectivity are facilitated, and clean coal with ground ash content can be obtained with a high recovery rate. The invention further discloses a middling coal ore grinding dissociation and flotation method adopting the composite tempering agent. According to the method, the composite hardening and tempering agent is adopted for carrying out ore grinding dissociation treatment on the middling coal, then flotation treatment is carried out, high-selectivity separation of ash in the middling coal and coal is achieved, the ash content in clean coal can be reduced, and the recovery rate of the clean coal is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of coal flotation, and in particular relates to a composite conditioning agent for washed coal and a grinding, dissociation and re-flotation method having the same. Background Art

[0002] In recent years, almost all washed middling coal (including some coal slime) from China's main coking coal preparation plants has been directly sold or used as fuel for power plants. In particular, some small and medium-sized coal preparation plants in coal-rich areas have been abandoned in large quantities due to the immaturity of their production technology, which has increased environmental pressure in mining areas and caused great waste of scarce coal. At the same time, air pollution caused by the combustion of high-ash coal has brought many environmental and social problems, which has attracted great attention from the country. Therefore, further processing of washed middling coal to obtain low-ash clean coal and seeking efficient and reasonable separation processes are of far-reaching significance for the rational utilization of my country's coal resources and environmental protection.

[0003] Reselection of washed middling coal is an important way to increase the yield of clean coal. Therefore, it is of great practical significance to develop and study efficient sorting methods to promote the full recovery and value-added utilization of washed middling coal. With conventional flotation methods, due to the insufficient dissociation depth of washed middling coal, there are still a large number of coal gangue conjoined bodies in the dissociated materials, which has a negative impact on the flotation process, resulting in the ash content and yield of clean coal failing to meet the expected targets.

[0004] To achieve separation and enrichment of washed coal, it is necessary to separate the minerals in the washed coal as much as possible and realize the dissociation of mineral monomers. The washed coal is fully dissociated, and the closely coexisting useful minerals and gangue minerals in the ore are destroyed to separate them into single mineral particles (mineral monomers). Then, the washed coal is deeply floated, deashed and improved through multiple scavenging, roughing and concentrating flotation processes, achieving efficient and accurate separation of target minerals and ash in coal, and obtaining low-ash, high-quality clean coal products. Summary of the invention

[0005] The present invention aims to solve one of the technical problems in the related art at least to a certain extent. To this end, the main purpose of the present invention is to provide a composite conditioning agent for washed medium coal, aiming to enhance the dissociation effect of washed medium coal.

[0006] The present invention also provides a method for grinding, dissociating and refloating washed middling coal using the composite conditioning agent, aiming to fully dissociate the washed middling coal, reduce the ash content of the clean coal, and improve the clean coal recovery rate.

[0007] The objective of the present invention is achieved through the following technical solutions:

[0008] A composite conditioning agent for washed medium coal comprises an inorganic acid and a metal fluoride.

[0009] In some specific embodiments, the inorganic acid is one or more of sulfuric acid, hydrochloric acid, and boric acid.

[0010] In some specific embodiments, the metal fluoride is one or more of sodium fluoride, potassium fluoride, and lithium fluoride.

[0011] In some specific embodiments, the mass ratio of the inorganic acid to the metal fluoride is 100:1-1000.

[0012] Furthermore, the mass ratio of the inorganic acid to the metal fluoride is 100:5-100.

[0013] As the same inventive concept, the present invention also provides a method for grinding and separating washed coal, which uses the aforementioned composite conditioning agent to grind and separate the washed coal.

[0014] In some specific embodiments, the grinding and dissociation is specifically as follows: a formulated amount of water is added to the washed coal to obtain a slurry, which is then poured into a ball mill, and a composite conditioning agent is added to perform grinding and dissociation treatment.

[0015] In the present invention, the existing means can be used for slurry treatment, and the requirements of the slurry after slurrying can be adjusted as needed. For example, the solid content of the coal gasification slime in the slurry is 80g / L to 350g / L, preferably 100g / L to 200g / L;

[0016] In some specific embodiments, the slurrying time is 2 min to 120 min, preferably 5-15 min;

[0017] In some specific embodiments, the amount of the composite conditioning agent is 100 g / t to 500 g / t, preferably 200 g / t to 400 g / t;

[0018] In some specific embodiments, the grinding dissociation time is 10 min to 30 min, preferably 15 min to 20 min.

[0019] In the present invention, the slurry obtained by grinding and dissociation treatment can be directly subjected to flotation;

[0020] As the same inventive concept, the present invention also provides a flotation separation method for washed coal, which adopts the grinding and separation method to grind and separate the washed coal, and then performs flotation treatment.

[0021] In some specific embodiments, the specific steps of the flotation treatment are: pouring the ore pulp after grinding and dissociation into a flotation tank, adding a flotation agent, and performing flotation treatment.

[0022] In some specific embodiments, the flotation reagent comprises a collector;

[0023] Furthermore, the collector can be a coal flotation collector known in the industry. For example, in the present invention, the collector is at least one of white oil, shale oil and wash oil; the amount of the collector can be adjusted as needed, for example, its amount is 3000-6000g / t; further, it can be 4000-5000g / t (referring to the amount of collector per ton of washed dry coal is 4000-5000g).

[0024] In some specific embodiments, a frother is added to the flotation reagent. Further, the frother can be a foaming component known in the industry for coal flotation, for example, the frother is 2-octanol. The amount of the frother can be adjusted as needed, for example, the amount of the frother is 500-3000 g / t, preferably 1-2 kg / t (referring to 1-2 kg of frother per ton of dry coal washed).

[0025] In some specific embodiments, an inhibitor is added to the flotation agent; the inhibitor is, for example, sodium hexametaphosphate; the amount of the inhibitor can be adjusted as needed, for example, the amount of the inhibitor is less than or equal to 3000 g / t, and can further be 0.1-1 kg / t (referring to the amount of the inhibitor per ton of dry coal gasification slime is 0.1-1 kg).

[0026] In some specific implementations, the flotation treatment process is specifically as follows: the number of roughing selections is 1 time, the number of scavenging selections is 1 to 2 times, and the number of cleaning selections is 1 to 3 times.

[0027] Compared with the prior art, the present invention has at least the following advantages:

[0028] 1) The present invention has found that the use of a composite conditioning agent including an inorganic acid and a metal fluoride can synergistically dissociate the washed coal fully, destroy the closely coexisting useful minerals and gangue minerals therein, and separate them into particles of a single mineral (mineral monomers), which is beneficial to the subsequent flotation of ash and coal selectivity, and is beneficial to obtaining clean coal with low ash content at a high recovery rate.

[0029] 2) The grinding and separation method provided by the present invention adopts the composite conditioning agent to carry out grinding and separation treatment on the washed coal, which can effectively improve the efficient and highly selective separation of ash and coal, is beneficial to improving the efficiency of clean coal, and is beneficial to reducing the ash content therein.

[0030] 3) The flotation treatment method provided by the present invention, benefiting from the grinding and dissociation treatment process, can achieve highly selective separation of ash and coal in washed coal based on existing flotation means, which is beneficial to reducing the ash content in clean coal and improving the recovery rate of clean coal. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the specific embodiments of the present invention, the drawings required for use in the specific embodiments or the description of the prior art will be briefly introduced below.

[0032] Figure 1 The present invention provides a process flow chart of the grinding, separation and flotation method for washed medium coal. DETAILED DESCRIPTION

[0033] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The following embodiments are only illustrative and not restrictive, and the protection scope of the present invention cannot be limited thereto.

[0034] When a certain amount, concentration or other value or parameter is expressed in the form of a range, a preferred range, or a preferred upper and lower numerical limit, it should be understood that it is equivalent to specifically revealing any range by combining any pair of upper range limits or preferred numerical values ​​with any lower range limit or preferred numerical value, regardless of whether the range is specifically disclosed. Unless otherwise indicated, the numerical range values ​​listed herein include the endpoints of the range, and all integers and fractions within the range.

[0035] Unless otherwise indicated, all percentages, parts, ratios, etc. herein are by weight.

[0036] The materials, methods and examples herein are exemplary and should not be construed as limiting unless otherwise specified. The materials, methods, devices or reagents used herein, etc., unless otherwise specified, can be purchased through commercial channels or prepared by conventional preparation methods in the art.

[0037] Embodiment 1:

[0038] In the present invention, the product obtained in the coal washing process of the medium-washed coal test coal washing plant, for example, the medium-washed coal used in the following embodiment comes from a coal washing plant in Inner Mongolia, and its air-dried ash content is 44.53%, the volatile content is 2.55%, and the fixed carbon content is 45.69%. The implementation includes the following steps:

[0039] A method for surface modification of coal gasification slime, the specific process flow is as follows Figure 1 As shown, the composite conditioning agent is used to fully grind, dissociate and flotate the washed coal, including the following steps:

[0040] Step (1): Pulping

[0041] Weigh 300g of washed coal and slurry it with 2L of water for 10min to obtain slurry;

[0042] Step (2): Grinding and dissociation

[0043] The slurry obtained in step (1) is poured into a ball mill, and a conditioning agent is added and ground for 15 minutes to fully dissociate to obtain a slurry; wherein the ratio (by mass) of dilute sulfuric acid and sodium fluoride in the composite conditioning agent is 100:50, and the amount of the composite conditioning agent is 300 g / t.

[0044] Step (3): Flotation

[0045] The specific steps of flotation process are:

[0046] Pour the washed coal slurry obtained in step (2) into a 1.5L flotation tank, add an inhibitor, a collector and a frother, then turn on the aeration switch and the scraper roughing, scavenging and cleaning operations to obtain clean coal products and tailings;

[0047] The collector is wash oil, the dosage is 4.5kg / t, the frother is octanol, the dosage is 1.5kg / t, the inhibitor is sodium hexametaphosphate, the dosage is 0.5kg / t; during the flotation process, the pulping concentration is 200g / L, the roughing times are 1, and the sweeping and cleaning times are 2; the test results under the above experimental conditions are as follows:

[0048]

[0049] Embodiment 2:

[0050] Compared with Example 1, the only difference is that the inorganic acid components are: Group (I): hydrochloric acid; Group (II): boric acid. The test results are:

[0051]

[0052] Embodiment 3:

[0053] Compared with Example 1, the only difference is that the metal fluoride components are: Group (I): potassium fluoride; Group (II): lithium fluoride. The test results are:

[0054]

[0055] Embodiment 4:

[0056] Compared with Example 1, the only difference is that the dosage of inorganic acid and metal fluoride in the composite conditioning agent is: Group (I): 100g / t, 50g / t Group (II): 100g / t, 75g / t Group (III): 100g / t, 25g / t The test results are:

[0057]

[0058] Embodiment 5:

[0059] Compared with Example 1, the only difference is that the types of collectors are: Group (I): white oil; Group (II): shale oil. The test results are:

[0060]

[0061] Embodiment 6:

[0062] Compared with Example 1, the only difference is that the grinding and dissociation time is: Group (I): 10min; Group (II): 30min; the test results are:

[0063]

[0064] Embodiment 7:

[0065] Compared with Example 1, the only difference is that the amount of washing oil used is: Group (I): 3000g / t; Group (II): 6000g / t; the test results are:

[0066]

[0067] Embodiment 8:

[0068] Compared with Example 1, the only difference is that the dosage of the inhibitor is: Group (I): 0 g / t; Group (II): 3000 g / t. The test results are:

[0069]

[0070] Embodiment 9:

[0071] Compared with Example 1, the only difference is that the dosage of the foaming agent is: Group (I): 3000g / t; Group (II): 500g / t. The test results are:

[0072]

[0073] Embodiment 10:

[0074] Compared with Example 1, the only difference is that the washed coal is directly floated without grinding and dissociation. The test results are:

[0075]

[0076] Embodiment 11:

[0077] Compared with Example 1, the only difference is that no composite conditioning agent is added during the grinding and dissociation of the washed coal. The test results are:

[0078]

[0079] Embodiment 12:

[0080] Compared with Example 1, the only difference is that the composite conditioning agent added during the washing coal grinding and dissociation contains only dilute sulfuric acid. The test results are:

[0081]

[0082] Embodiment 13:

[0083] Compared with Example 1, the only difference is that the composite conditioning agent added during the washing coal grinding and dissociation contains only sodium fluoride. The test results are:

[0084]

[0085] In summary, it can be seen from Examples 1-13 that the degree of dissociation of washed coal can be improved by grinding and dissociation, which creates prerequisites for flotation and is conducive to obtaining low-ash and high-quality clean coal; it can be seen from Examples 12-13 that the combination of the various agents in the composite conditioning agent can achieve synergy, which can significantly improve grinding and dissociation, improve the selectivity of ash in subsequent flotation, and improve the quality of the concentrate.

[0086] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A composite conditioning agent for washing medium coal, characterized in that: Includes inorganic acids and metal fluorides.

2. The composite conditioning agent for washed coal according to claim 1, characterized in that: The inorganic acid is one or more of sulfuric acid, hydrochloric acid and boric acid.

3. The composite conditioning agent for washed coal according to claim 1, characterized in that: The metal fluoride is one or more of sodium fluoride, potassium fluoride and lithium fluoride.

4. The composite conditioning agent for washed coal according to claim 1, characterized in that: The mass ratio of the inorganic acid to the metal fluoride is 100:1-1000.

5. A method for grinding and dissociation of washed coal, characterized in that: The composite conditioning agent described in any one of claims 1 to 4 is used to grind and dissociate the washed coal.

6. The method for grinding and dissociating washed coal according to claim 5, characterized in that: The grinding and dissociation process specifically comprises the following steps: adding a formulated amount of water to the washed coal to obtain a slurry, then pouring the slurry into a ball mill, and adding a composite conditioning agent to perform grinding and dissociation treatment.

7. The method for grinding and dissociating washed coal according to claim 6, characterized in that: The solid content of the coal gasification slime in the slurry is 80g / L to 350g / L; the slurrying time is 2min to 120min; the dosage of the composite conditioning agent is 100g / t to 500g / t; and the grinding dissociation time is 10min to 30min.

8. A method for flotation separation of washed coal, characterized in that: The grinding and separation method described in any one of claims 5 to 7 is used to grind and separate the washed coal, followed by flotation treatment.

9. The method for flotation separation of washed coal according to claim 8, characterized in that: The specific steps of the flotation treatment are: pouring the ore pulp after grinding and dissociation into the flotation tank, adding flotation reagents, and performing flotation treatment.

10. The method for flotation separation of washed coal according to claim 9, characterized in that: The flotation treatment process is specifically as follows: the roughing selection is performed once, the scavenging selection is performed 1 to 2 times, and the cleaning selection is performed 1 to 3 times.

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