Desiliconization collecting agent in magnesite and preparation and use method thereof

Abstract

The invention aims to provide a desilicication collecting agent in magnesite as well as a preparation method and a use method of the desilicication collecting agent in the magnesite, aiming at the defects of the conventional magnesite flotation collecting agent. The desilicication collecting agent in the magnesite is a product obtained by performing hydroxyl activation on fatty acid, then performing amidation reaction on the fatty acid and amino acid organic matters, and then performing acidification and crystallization; the main vibration peaks in the infrared spectrum of the material are N-H, O-H, C-H, and C = O. The preparation process is simple and easy to operate, the prepared collecting agent has a good flotation effect, and the desilicication rate of magnesite can be effectively increased.

Description

Technical Field

[0001] This invention belongs to the field of magnesite beneficiation, and particularly relates to a desilication collector for magnesite and its preparation and application methods. Background Technology

[0002] Magnesite, a key industrial mineral resource, is a natural magnesium carbonate mineral with the chemical formula MgCO3. It has extremely wide applications and occupies an indispensable position in many industrial sectors.

[0003] In the metallurgical industry, magnesite is a core raw material for producing refractory materials. This is because magnesite possesses excellent high-temperature resistance, enabling it to withstand chemical corrosion and mechanical wear in high-temperature environments, ensuring the stable operation of equipment such as furnaces, and playing a crucial role in the normal production of the metallurgical industry. In the building materials sector, magnesite can be made into magnesite cement. Magnesite cement has many advantages such as high strength, rapid setting, fire resistance, and corrosion resistance, and is widely used in the manufacture of building components, flooring, and decorative panels. In some building sites with strict fire protection requirements, such as large shopping malls and hotels, magnesite cement products provide better safety guarantees for buildings due to their excellent fire resistance. Magnesite also plays an important role in the chemical industry. Through processing, it can be used to produce chemical products such as magnesium sulfate and magnesium carbonate. Among them, magnesium sulfate is used as a fertilizer in agriculture, while magnesium carbonate has wide applications in pharmaceuticals, rubber, and plastics. In addition, magnesite is also showing its potential in the environmental protection field, and can be used to treat wastewater and exhaust gases. With the continuous development of industry, the demand for magnesite is also constantly increasing.

[0004] Flotation is an important method for improving the quality and reducing impurities of magnesite, and the performance of the desilication collector plays a decisive role in the desilication effect of magnesite flotation. Currently, dodecylamine is one of the commonly used desilication collectors in the magnesite flotation desilication process, but it has many drawbacks.

[0005] Dodecylamine exhibits poor selectivity, making it difficult to precisely adsorb onto the surface of siliceous minerals during flotation. This results in a large amount of magnesite floating alongside silica-bearing minerals, reducing the recovery rate of magnesite in the concentrate. In practical applications, this not only wastes resources but also increases the difficulty and cost of subsequent purification. Furthermore, the foam generated by dodecylamine is difficult to manage. In flotation operations, the stability and flowability of foam significantly impact flotation efficiency and subsequent separation operations. The foam formed by dodecylamine is often too stable and difficult to break, posing significant challenges to foam separation and management, prolonging the flotation process, and reducing production efficiency. Dodecylamine also has poor water solubility and degradability. Its poor water solubility leads to poor dispersion of dodecylamine in the pulp, hindering its collecting effect and impacting flotation efficiency. Its poor degradability makes it difficult to decompose in the environment, posing a potential threat to the ecological environment and contradicting current green and environmentally friendly development principles.

[0006] Most other existing publicly available magnesite desilication collectors are mixed collectors, but their main component is still dodecylamine, and they also contain laurylamine polyoxyethylene ether and pine oil, which have foaming effects, making the collector composition complex. This complexity not only increases the cost and difficulty of reagent preparation but also brings many inconveniences to practical operation, such as making it more difficult to control the amount of reagent added and the uniformity of mixing the reagent with the slurry. Therefore, developing a highly efficient, environmentally friendly, simple-composition, and easy-to-operate magnesite desilication collector is urgently needed. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of current flotation collectors for magnesite by providing a desilication collector for magnesite and its preparation and application methods. The preparation process of this invention is simple and easy to operate, and the prepared collector exhibits good flotation performance, effectively improving the desilication rate of magnesite.

[0008] One of the technical solutions of the present invention is a desilication collector for magnesite, which is a product obtained by hydroxyl activation of fatty acids followed by amidation reaction with amino acid organics and then acidification and crystallization.

[0009] The main vibrational peaks in the infrared spectrum of this product are: NH, OH, CH, and C=O.

[0010] The second technical solution of the present invention is a method for preparing the desilication collector in the above-mentioned magnesite, specifically including the following steps:

[0011] Step (1) Carboxyl activation reaction: Mix fatty acids and activators with anhydrous ethanol solvent and stir until completely dissolved; heat up, add condensing agent to the reaction solution, and keep the temperature to react after the addition is complete to generate an activation intermediate;

[0012] The fatty acid is one or both of dodecanoic acid and tetradecanoic acid; the activator is one or more of N-hydroxysuccinimide (NHS), N-hydroxythiosuccinimide (sulfo-NHS), and N-hydroxyphthalimide (NHPI).

[0013] The condensing agent is one or more of N,N-dicyclohexylcarbodiimide (DCC), N,N-diisopropylcarbodiimide (DIC), and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC·HCl);

[0014] Step (2) amidation reaction: Cool the reaction solution to room temperature, add amino acid organic matter, adjust the pH of the reaction solution, and then stir the reaction.

[0015] The amino acid-based organic compound is taurine or methyl 2-aminoethanesulfonate;

[0016] Step (3) Product purification: After the reaction is completed, the reaction solution is filtered to remove the precipitate, and the filtrate is distilled under reduced pressure to recover ethanol, resulting in a pale yellow oily substance. Deionized water is added to the oily substance, and the solution is heated and stirred to dissolve. The pH is then adjusted with an acid solution to precipitate white crystals. The solution is then allowed to stand and cool to room temperature, and the crystals are collected by filtration to obtain the collector.

[0017] Furthermore, in the above-mentioned method for preparing a desilication collector in magnesite, in step (1), the molar ratio of fatty acid to activator is 0.5-1.5:1-2.0.

[0018] Furthermore, in the above-mentioned method for preparing a desilication collector in magnesite, in step (1), the reaction temperature is 25-42℃ and the reaction time is 2-6h.

[0019] Furthermore, in the above-mentioned method for preparing a desilication collector in magnesite, in step (1), the molar ratio of condensing agent to fatty acid is 0.55-1.65:1.

[0020] Furthermore, in the above-mentioned method for preparing a desilication collector in magnesite, in step (2), the molar ratio of amino acid organic matter to fatty acid is 0.55-1.6:1.

[0021] Furthermore, in the above-mentioned method for preparing a desilication collector in magnesite, in step (2), the pH is adjusted to 7-8 and the stirring reaction time is 4-6h.

[0022] Furthermore, in the above-mentioned method for preparing a desilication collector in magnesite, in step (3), the pH is adjusted to 3-4.

[0023] The third technical solution of the present invention is a method for using a desilication collector in magnesite, wherein a desilication collector is added to the magnesite slurry, and the ratio of the amount of desilication collector added to the slurry is 150-200 g / t, and conventional magnesite flotation operation is carried out.

[0024] Furthermore, the above-mentioned method for using a desilication collector in magnesite involves flotation conditions of: pulp concentration of 28-32%, pH of 7.8-8.2, temperature of 27-29℃, rotation speed of 1600-1900 r / min, and separation 3-4 times.

[0025] Compared with the prior art, the advantages of the present invention are:

[0026] The preparation process of this invention is simple and easy to operate, saves energy and costs, and has the advantages of good selectivity, good degradability, and stable foam performance. It has a wide range of applications and the desiliconization rate reaches 90%-95%. Detailed Implementation

[0027] The present invention will be further described below with reference to specific embodiments and comparative examples.

[0028] The magnesite used in this invention was obtained from a magnesite mine in Haicheng; the composition of the magnesite is: MgO: 41.43%, SiO2: 3.65%; CaO: 0.76%; Fe2O3: 41.43%. 3： 0.33%.

[0029] The sources of the chemical reagents used in the examples and comparative examples:

[0030] Table 1. Detailed List of Pharmaceuticals

[0031]

[0032] The preparation method of the desilication collector in magnesite in the examples specifically includes the following steps:

[0033] Step (1) Carboxyl activation reaction: Mix fatty acids and activators with anhydrous ethanol solvent and stir until completely dissolved; heat up, add condensing agent to the reaction solution, and keep the temperature to react after the addition is complete to generate an activation intermediate;

[0034] The molar ratio of fatty acids to activator is 0.5-1.5:1-2.0; the activation reaction temperature is 25-42℃; and the holding time is 2-6h.

[0035] The molar ratio of the condensing agent to the fatty acid is 0.55-1.65:1;

[0036] The fatty acid is one or both of dodecanoic acid and tetradecanoic acid;

[0037] The activator is one or more of N-hydroxysuccinimide (NHS), N-hydroxythiosuccinimide (sulfo-NHS), and N-hydroxyphthalimide (NHPI);

[0038] The condensing agent is one or more of N,N-dicyclohexylcarbodiimide (DCC), N,N-diisopropylcarbodiimide (DIC), and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC·HCl);

[0039] Step (2) amidation reaction: Cool the reaction solution to room temperature, add amino acid organic matter, adjust the pH of the reaction solution, and then stir the reaction.

[0040] The amino acid-based organic compound is taurine or methyl 2-aminoethanesulfonate;

[0041] The molar ratio of the amino acid-based organic compounds to the fatty acids is 0.55-1.6:1;

[0042] Adjust the pH to 7-8 and stir for 4-6 hours;

[0043] Step (3) Product purification: The reaction solution is filtered to remove the precipitate, and the filtrate is distilled under reduced pressure to recover ethanol, resulting in a pale yellow oily substance; deionized water is added to the oily substance, and the mixture is heated and stirred to dissolve it. The pH is adjusted with an acid solution to precipitate white crystals; the solution is allowed to stand and cool to room temperature, and the crystals are collected by filtration to obtain the collector.

[0044] Adjust the pH to 3-4.

[0045] The following example describes the method of using a desilication collector in magnesite. A desilication collector is added to the magnesite slurry at a ratio of 150-200 g / t. Conventional magnesite flotation is then performed under the following conditions: slurry concentration 28-32%, pH 7.8-8.2, temperature 27-29°C, rotation speed 1600-1900 r / min, and 3-4 flotation cycles.

[0046] Example 1

[0047] A desilication collector for magnesite, comprising the following steps:

[0048] (1) Carboxyl activation reaction: In a 500mL three-necked flask equipped with a stirrer, thermometer and reflux condenser, add 1mol dodecanoic acid and 1.1mol NHS, then add 200mL anhydrous ethanol and stir until completely dissolved; heat to 40℃, slowly add 1.1mol DCC ethanol solution, and keep the reaction at the temperature for 2.5h after the addition is complete to generate an activation intermediate;

[0049] (2) Amide reaction: Cool the three-necked flask to room temperature, slowly add 1.05 mol of taurine in ethanol solution, adjust the pH to 7.5 with 0.1 mol / L NaOH solution, and stir the reaction for 5 h;

[0050] (3) Product purification: The reaction solution was filtered to remove the precipitate, and the filtrate was distilled under reduced pressure (temperature 60℃, vacuum degree -0.09MPa) to recover ethanol, yielding a pale yellow oily substance; 100mL of deionized water was added to the oily substance, the temperature was raised to 60℃ and stirred to dissolve, the pH was adjusted to 3.5 with 0.1mol / L HCl solution, and white crystals precipitated; the crystals were collected by filtration after standing and cooling to room temperature, washed three times with a small amount of ice water, and finally dried in a vacuum drying oven at 80℃ to obtain a collector suitable for desilication of magnesite. The analysis of the infrared spectrum of the desilication collector prepared in this example is shown in Table 2.

[0051] The method of using the desilication collector in magnesite in this embodiment involves adding the desilication collector to the magnesite slurry. The ratio of the amount of desilication collector added to the slurry is 160 g / t. Magnesite flotation is then carried out under the following conditions: slurry concentration 30%, pH=8.0, temperature 28℃, and rotation speed 1700 r / min. The flotation is performed four times to obtain desilicationized magnesite.

[0052] Table 2. Analysis of Infrared Spectra of the Substances Prepared in Example 1

[0053]

[0054] Examples 2-6

[0055] Examples 2-6 describe a desilication collector for magnesite and its preparation method and application, which are similar to those in Example 1, except that the experimental conditions are different, as detailed in Table 3.

[0056] Comparative Example 1

[0057] Comparative Example 1 is similar to Example 6, except that the ratio of fatty acids to activator was changed and the activation reaction was not heated.

[0058] Comparative Example 2

[0059] Comparative Example 2 is similar to Example 5, except that no amino acid substances were added.

[0060] Comparative Example 3

[0061] Comparative Example 3 is similar to Example 1, except that the activation reaction was not heated and the pH was not adjusted.

[0062] Comparative Example 4

[0063] Comparative Example 4 is similar to Example 1, except that it was not vacuum dried and the amount of flotation reagent was changed.

[0064] The examples and comparative examples are shown in Table 3. A desilication collector for magnesite, its preparation method, application test conditions, and application results are presented.

[0065] Table 3. Experimental conditions and application results for the examples and comparative examples.

[0066]

[0067] Note: Dodecanoic acid is denoted as C12, tetradecanoic acid as C14, taurine as T1, and methyl 2-aminoethanesulfonate as T2.

Claims

1. A desilication collector for magnesite, characterized in that, It is a product obtained by activating fatty acids with hydroxyl groups, reacting them with amino acid-based organic compounds, and then acidifying and crystallizing. The main vibrational peaks in the infrared spectrum of this product are: NH, OH, CH, and C=O.

2. The method for preparing the desilication collector in magnesite according to claim 1, characterized in that, Specifically, the following steps are included: Step (1): Mix the fatty acid and activator with anhydrous ethanol solvent and stir until completely dissolved; Heat the mixture, add a condensing agent to the reaction solution, and keep the mixture at the temperature after the addition is complete to generate an activated intermediate. The fatty acid is one or both of dodecanoic acid and tetradecanoic acid; the activator is one or more of N-hydroxysuccinimide, N-hydroxythiosuccinimide, and N-hydroxyphthalimide; the condensing agent is one or more of N,N-dicyclohexylcarbodiimide, N,N-diisopropylcarbodiimide, and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride. Step (2): Cool the reaction solution to room temperature, add amino acid organic matter, adjust the pH of the reaction solution, and then stir the reaction. The amino acid-based organic compound is taurine or methyl 2-aminoethanesulfonate; Step (3): After the reaction is complete, filter the reaction solution to remove the precipitate, and distill the filtrate under reduced pressure to recover ethanol, and obtain a pale yellow oily substance; add deionized water to the oily substance, heat and stir to dissolve, then adjust the pH with acid solution to precipitate white crystals; then let the solution stand and cool to room temperature, filter and collect the crystals to obtain the collector.

3. The method for preparing the desilication collector in magnesite according to claim 2, characterized in that, In step (1), the molar ratio of fatty acid to activator is 0.5-1.5:1-2.0, and the molar ratio of condensing agent to fatty acid is 0.55-1.65:

1.

4. The method for preparing the desilication collector in magnesite according to claim 2, characterized in that, In step (1), the reaction temperature is 25-42℃ and the reaction time is 2-6h.

5. The method for preparing the desilication collector in magnesite according to claim 2, characterized in that, In step (2), the molar ratio of amino acid organics to fatty acids is 0.55-1.6:

1.

6. The method for preparing the desilication collector in magnesite according to claim 2, characterized in that, In step (2), the pH is adjusted to 7-8 and the reaction time is 4-6 hours.

7. The method for preparing the desilication collector in magnesite according to claim 2, characterized in that, In step (3), the pH is adjusted to 3-4.

8. The method of using the desilication collector in magnesite as described in claim 1, characterized in that, A desilication collector is added to the magnesite slurry at a ratio of 150-200 g / t, and conventional magnesite flotation is carried out.

9. The method of using the desilication collector in magnesite according to claim 8, characterized in that, The flotation conditions are: pulp concentration 28-32%, pH 7.8-8.2, temperature 27-29℃, and rotation speed 1600-1900 r / min.

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