Preparation method of magnesium solvent and magnesium oxide product

Abstract

The present invention provides a magnesium solvent and a preparation method of a magnesium oxide product. Among them, the magnesium solvent includes: hydrogen peroxide, and any one or more of chromium chloride, calcium chloride, calcium oxide, magnetite, ferric chloride, potassium chloride, sodium chloride, aluminum chloride, zinc oxide, zinc chloride, copper chloride or ethylenediaminetetraacetic acid. It can solve the problem of high cost in preparing high-purity magnesium oxide in the prior art and is applicable to the field of purification of magnesium-containing oxides.

Description

Technical Field

[0001] The present invention relates to the field of purification of magnesium oxide-containing substances, and more particularly, to a magnesium solvent and a method for preparing a magnesium oxide product. Background Art

[0002] At present, the demand for high-purity and high-density magnesite in metallurgy, electronics, chemical industry, etc. is increasing continuously. In recent years, due to the limitations of production costs and technical levels, domestic manufacturers often only mine rich ores, and the ore powder and low-grade ores generated during the mining process are often piled up as waste rocks, resulting in a great waste of resources and environmental pollution. With the increase in the mining volume, the special-grade magnesite has shown a gradually depleted trend. Therefore, improving the utilization rate of low-grade magnesite resources and enhancing the separation grade and yield of high-purity magnesium oxide have become the main issues at present.

[0003] During the smelting process of magnesite, in order to improve the purity of magnesium oxide, impurity removal procedures are usually required to remove impurities that affect the quality of magnesium oxide. The main impurities are silica, iron oxide, calcium oxide, and unoxidized raw material impurities. At present, the purification of magnesite in China is mainly by flotation. Flotation purification of magnesite has disadvantages such as complex process flow and high investment; chemical beneficiation methods are also used, but this method has disadvantages such as complex process, difficult control of process parameters, and high costs; there is also the method of light calcination physical purification. This method has a simple process flow and only requires putting the crushed magnesite into a reverberatory furnace, suspension furnace or multi-layer furnace and fully roasting at 600-800°C. The reverberatory kiln has low investment, quick results, and relatively low activity of magnesium oxide, about 100-180s; the suspension furnace and multi-layer furnace have high investment, quick results, and the activity of the products can reach 30-60s (citric acid method). However, affected by the light calcination process, the magnesium oxide content produced is between 96-97.2%, and it can only provide medium-grade raw materials for products below high-purity grade 97. The low purity of light calcined magnesium oxide cannot be used to prepare high-value-added products. The activity of light calcined magnesium oxide is relatively low, and the sintering performance of the products is poor, increasing the raw material cost and fuel cost of production. Therefore, improving the purity and activity of light calcined magnesium oxide has become an important issue in the current field of inorganic chemical industry. Summary of the Invention

[0004] The main object of the present invention is to provide a magnesium solvent and a method for preparing a magnesium oxide product to solve the problem of high cost in preparing high-purity magnesium oxide in the prior art.

[0005] To achieve the above object, according to the first aspect of the present invention, a magnesium solvent is provided, which comprises: hydrogen peroxide, and any one or more of metal oxides, metal chlorides or ethylenediaminetetraacetic acid.

[0006] Furthermore, the mass ratio of hydrogen peroxide in the magnesium solvent is 5% - 25%, preferably 9% - 20%.

[0007] Further, the metal oxide includes any one or more of iron tetroxide, calcium oxide, and zinc oxide; the metal chloride includes any one or more of chromium chloride, calcium chloride, ferric trichloride, potassium chloride, sodium chloride, aluminum chloride, zinc chloride, or copper chloride.

[0008] To achieve the above object, according to the second aspect of the present invention, a method for preparing a magnesium oxide product is provided, and the preparation method includes: a) using the above-mentioned magnesium solvent to dissolve the magnesium oxide raw material to obtain a first magnesium-containing solution; b) adding an oxidizing agent and a flocculant to the first magnesium-containing solution to obtain a second magnesium-containing solution; c) adding a precipitation reagent to the second magnesium-containing solution to obtain a magnesium-containing precipitate; d) calcining the magnesium-containing precipitate to obtain a magnesium oxide product.

[0009] Further, a) includes: adding the magnesium oxide raw material to water, stirring until evenly mixed, adding the magnesium solvent, and continuously stirring for 1 to 2 hours.

[0010] Further, the magnesium oxide raw material includes industrial magnesium oxide, and the purity of the industrial magnesium oxide is 80% to 90%; preferably, the purity of the magnesium oxide product is ≥99%, and more preferably the purity is ≥99.5%.

[0011] Further, the mass ratio of the magnesium solvent to the magnesium oxide raw material is 0.5 to 2:1.

[0012] Further, the oxidizing agent includes one or more of sodium hypochlorite, potassium permanganate, ozone, hydrogen peroxide, sodium carbonate, sodium bicarbonate, sodium borohydride, sodium thiosulfate, sodium perchlorate, sodium chloride, hydrazine hydrate, thiourea, or urea.

[0013] Further, the flocculant includes one or more of polyaluminum chloride, polyaluminum sulfate, polyferric chloride, polyferric sulfate, starch, chitosan, cellulose, or polyacrylamide.

[0014] Further, the precipitation reagent includes one or more of sodium hydroxide, ammonia water, or potassium hydroxide.

[0015] Further, the conditions for calcining the magnesium-containing precipitate are 900 to 1200 °C for 1 to 3 hours.

[0016] Applying the technical solution of the present invention, using the above-mentioned magnesium solvent can dissolve the magnesium oxide raw material, thus facilitating the subsequent purification steps. The development of this magnesium solvent greatly simplifies the process of purifying magnesium oxide and reduces the reaction cost. Detailed Embodiments

[0017] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the embodiments.

[0018] As mentioned in the background art, in the prior art, existing technologies such as flotation method, chemical beneficiation method or light calcination physical purification method all have problems of being difficult to obtain high-purity magnesium oxide or having high preparation costs and complex processes. Therefore, in this application, the inventors tried to explore a magnesium solvent, which can dissolve magnesium oxide raw materials, so as to carry out subsequent purification and preparation. Thus, a series of protection schemes of this application are proposed.

[0019] In a first typical embodiment of this application, a magnesium solvent is provided, which includes hydrogen peroxide, and any one or more of metal oxides, metal chlorides or ethylenediaminetetraacetic acid (EDTA).

[0020] In this magnesium solvent, hydrogen peroxide acts as a water-based oxidant to play a synergistic effect, stimulating the Lewis acid reaction to improve the dissolution ability. Metal chlorides act as the main body of Lewis acid to react with magnesium-based compounds in a composite dissolution reaction. Metal oxides are used to control the intensity of the chemical reaction and induce the orderly progress of the chemical reaction. EDTA is used to regulate the reaction process, control the reaction temperature and balance the acidity of the dissolution process system. In the above magnesium solvent, magnesium oxide can be dissolved by using hydrogen peroxide and metal chlorides alone.

[0021] Components such as calcium chloride in the above magnesium solvent have low costs and good effects, but the purity of magnesium can be improved by means such as selective ion exchange resin, extraction, recrystallization or high-temperature melting crystallization in the later stage. Even if the above means are not adopted, the actual purity of magnesium oxide has reached the high-purity level.

[0022] In a preferred embodiment, the mass ratio of hydrogen peroxide in the magnesium solvent is 5% - 25%, preferably 9% - 20%, including but not limited to 9%, 10%, 12%, 14%, 16%, 18% or 20%.

[0023] In a preferred embodiment, the metal oxides include any one or more of iron tetroxide, calcium oxide, zinc oxide; the metal chlorides include any one or more of chromium chloride, calcium chloride, ferric chloride, potassium chloride, sodium chloride, aluminum chloride, zinc chloride or copper chloride.

[0024] In the above magnesium solvent, the proportion of hydrogen peroxide is preferably 5% - 25%. Within this range, the magnesium solvent can be stored stably and has good fluidity. In actual use, it is convenient to add and control the addition amount of the magnesium solvent. Hydrogen peroxide mainly plays a synergistic effect. Its presence can effectively improve the reaction process, enhance the reaction activity, and is environmentally friendly, suitable for large-scale industrial production.

[0025] In the second typical embodiment of the present application, a method for preparing a magnesium oxide product is provided. The preparation method includes: a) using the above-mentioned magnesium solvent to dissolve the magnesium oxide raw material to obtain a first magnesium-containing solution; b) adding an oxidizing agent and a flocculant to the first magnesium-containing solution to obtain a second magnesium-containing solution; c) adding a precipitation reagent to the second magnesium-containing solution to obtain a magnesium-containing precipitate; d) calcining the magnesium-containing precipitate to obtain a magnesium oxide product.

[0026] Using the above-mentioned magnesium solvent to dissolve the magnesium oxide raw material can replace the use of acidic reagents to dissolve magnesium oxide in the prior art. Reagents such as hydrogen peroxide in the magnesium solvent are all neutral reagents, which are safe to use. The decomposition of hydrogen peroxide only produces water and oxygen, which is more environmentally friendly. It can also reduce the amount of alkali required to adjust the pH in the subsequent precipitation step.

[0027] In a preferred embodiment, a) includes: adding the magnesium oxide raw material to water, stirring until evenly mixed, then adding the magnesium solvent, and continuously stirring for 1-2 h.

[0028] In the above preparation method, first use the magnesium solvent to dissolve the magnesium oxide raw material to obtain a first magnesium-containing solution. During the dissolution process, first mix the magnesium oxide raw material with water evenly, and then add the magnesium solvent, which can make the magnesium oxide raw material and the magnesium solvent mix evenly, preventing some magnesium oxide raw materials from being difficult to contact with the magnesium solvent due to problems such as caking of the magnesium oxide raw material, thereby increasing the dissolution efficiency, prolonging the dissolution time, and reducing the reaction yield. After adding the magnesium solvent, a turbid liquid is formed, and the magnesium oxide raw material can dissolve spontaneously. Continuously stir the turbid liquid, the solution temperature can rise spontaneously, a large amount of gas is generated, and after continuously stirring the reaction, the solution becomes stable and drops to room temperature, that is, the reaction ends, and a first magnesium-containing solution is obtained. At this time, the magnesium oxide raw material is dissolved in the first magnesium-containing solution.

[0029] Adding an oxidizing agent and a flocculant to the first magnesium-containing solution can decolorize and flocculate precipitate the first magnesium-containing solution, remove impurities such as insoluble impurities in the first magnesium-containing solution, and obtain a second magnesium-containing solution. The magnesium purity of the second magnesium-containing solution at this time is relatively high. Adding a precipitation reagent to the second magnesium-containing solution reacts with magnesium ions to form magnesium hydroxide precipitate, thereby leaving soluble impurities in the solution and further purifying magnesium. Calcining the magnesium-containing precipitate, that is, magnesium hydroxide, can dehydrate and decompose magnesium hydroxide to obtain a magnesium oxide product. Through the above reaction, magnesium oxide is purified, and the obtained magnesium oxide product is a high-purity magnesium oxide product.

[0030] In a preferred embodiment, the magnesium oxide raw material includes industrial magnesium oxide, and the purity of the industrial magnesium oxide is 80%-90%; preferably, the purity of the magnesium oxide product ≥99%, more preferably the purity ≥99.5%.

[0031] In a preferred embodiment, the mass ratio of the magnesium solvent to the magnesium oxide raw material is 0.5 to 2:1.

[0032] To ensure the reaction efficiency, the mass ratio of the magnesium solvent to the magnesium oxide raw material can be flexibly adjusted during actual use according to factors such as the purity of the magnesium oxide raw material and the mass ratio of hydrogen peroxide in the magnesium solvent.

[0033] In a preferred embodiment, the oxidizing agent includes but is not limited to one or more of sodium hypochlorite, potassium permanganate, ozone, hydrogen peroxide, sodium carbonate, sodium bicarbonate, sodium borohydride, sodium thiosulfate, sodium perchlorate, sodium chloride, hydrazine hydrate, thiourea, or urea.

[0034] The above-mentioned oxidizing agent can oxidize impurities such as pigments in the raw material to achieve the effects of decolorization and impurity removal.

[0035] In a preferred embodiment, the flocculant includes but is not limited to one or more of polyaluminum chloride, polyaluminum sulfate, polyferric chloride, polyferric sulfate, starch, chitosan, cellulose, or polyacrylamide.

[0036] The above-mentioned flocculants are all existing commercially available products, which can adsorb impurities such as colloidal particles in the solution, further reduce the impurities in the solution, and improve the purity of magnesium.

[0037] In a preferred embodiment, the precipitation reagent includes but is not limited to one or more of sodium hydroxide, ammonia water, or potassium hydroxide.

[0038] After filtering the second magnesium-containing solution to remove solid impurities, a strong base reagent such as sodium hydroxide, ammonia water, or potassium hydroxide is added to the solution. The magnesium ions in the solution combine with hydroxide ions to produce a magnesium-containing precipitate (i.e., magnesium hydroxide). At this time, the impurities in the magnesium-containing precipitate are less and the purity is higher.

[0039] In a preferred embodiment, the conditions for calcining the magnesium-containing precipitate are 900 to 1200 °C for 1 to 3 hours.

[0040] Using the above calcination conditions to calcine the magnesium-containing precipitate, magnesium hydroxide undergoes a dehydration decomposition reaction under the action of high temperature, generating magnesium oxide and water. The water volatilizes under the action of high temperature, and a high-purity magnesium oxide product can be obtained through high-temperature calcination.

[0041] The beneficial effects of the present application will be further explained in detail below with specific examples.

[0042] Example 1

[0043] Take 100 g of light magnesium oxide, determine its purity to be 85.2%, disperse it fully in one liter of water, add 20 g of chromium chloride, 20 g of zinc oxide, 20 g of calcium chloride, 20 g of aluminum chloride, and 20 g of hydrogen peroxide, stir well for 1 hour. After the reaction ends, filter the solution, take the filtrate, add 25 g of sodium hypochlorite and 25 g of polyaluminum chloride, stir well, filter again for the second time to obtain a clear and transparent solution. Add sodium hydroxide to obtain a white precipitate. After calcination at 1000 °C for 2 hours, 81 g of high-purity magnesium oxide is obtained, with a recovery rate of 95.1% and a purity of 99.9%.

[0044] Example 2

[0045] Take 100 g of light magnesium oxide, determine its purity to be 85.3%, disperse it fully in one liter of water, add 50 g of ferric chloride, 50 g of aluminum chloride, and 10 g of hydrogen peroxide, stir well for 1 hour. After the reaction ends, filter the solution, take the filtrate, add 5 g of potassium permanganate and 20 g of polyferric chloride, stir well, filter again for the second time to obtain a clear and transparent solution. Add ammonia water to obtain a white precipitate. After calcination at 1000 °C for 2 hours, 82 g of high-purity magnesium oxide is obtained, with a recovery rate of 96% and a purity of 99.9%.

[0046] Example 3

[0047] Take 100 g of light magnesium oxide, determine its purity to be 84.8%, disperse it fully in one liter of water, add 20 g of zinc chloride, 30 g of aluminum chloride, 30 g of ferric chloride, 10 g of hydrogen peroxide, and 5 g of EDTA, stir well for 1 hour. After the reaction ends, filter the solution, take the filtrate, add 5 g of potassium permanganate and 20 g of polyferric chloride, stir well, filter again for the second time to obtain a clear and transparent solution. Add ammonia water to obtain a white precipitate. After calcination at 1000 °C for 2 hours, 80 g of high-purity magnesium oxide is obtained, with a recovery rate of 94.2% and a purity of 99.9%.

[0048] Example 4

[0049] Take 100 g of light magnesium oxide, determine its purity to be 85.2%, disperse it fully in one liter of water, add 10 g of chromium chloride, 30 g of aluminum chloride, 30 g of ferric chloride, 10 g of hydrogen peroxide, and 5 g of EDTA, stir well for 1 hour. After the reaction ends, filter the solution, take the filtrate, add 5 g of hydrazine hydrate and 20 g of polyferric chloride, and 5 g of urea, stir well, filter again for the second time to obtain a clear and transparent solution. Add ammonia water to obtain a white precipitate. After calcination at 1000 °C for 2 hours, 81 g of high-purity magnesium oxide is obtained, with a recovery rate of 94.6% and a purity of 99.5%.

[0050] Example 5

[0051] Take 100 g of light magnesium oxide, determine its purity to be 85.1%, disperse it thoroughly in one liter of water, add 10 g of chromium chloride, 30 g of aluminum chloride, 20 g of calcium oxide, 10 g of zinc oxide, 10 g of hydrogen peroxide, and 5 g of EDTA, and stir well for 1 hour. After the reaction ends, filter the solution, take the filtrate, add 15 g of sodium hypochlorite, 10 g of polyferric chloride, and 10 g of urea, stir well, filter again for the second time to obtain a clear and transparent solution, add ammonia water to obtain a white precipitate, and calcine at 1000 °C for 2 hours to obtain 81 g of high-purity magnesium oxide, with a recovery rate of 94.8% and a purity of 99.6%.

[0052] Example 6

[0053] Take 100 g of light magnesium oxide, determine its purity to be 85.5%, disperse it thoroughly in one liter of water, add 10 g of potassium chloride, 30 g of aluminum chloride, 10 g of copper chloride, 20 g of magnetite, 10 g of hydrogen peroxide, and 5 g of EDTA, and stir well for 1 hour. After the reaction ends, filter the solution, take the filtrate, add 20 g of hydrogen peroxide and 20 g of sodium chloride, stir well, filter again for the second time to obtain a clear and transparent solution, add ammonia water to obtain a white precipitate, and calcine at 1000 °C for 2 hours to obtain 81.5 g of high-purity magnesium oxide, with a recovery rate of 95% and a purity of 99.7%.

[0054] Example 7

[0055] Same as Example 2, the difference is that 6 g of hydrogen peroxide is used. After calcination, 77 g of high-purity magnesium oxide is obtained, with a recovery rate of 90.3% and a purity of 98.9%.

[0056] Example 8

[0057] Same as Example 2, the difference is that 32 g of hydrogen peroxide is used. After calcination, 79 g of high-purity magnesium oxide is obtained, with a recovery rate of 92.6% and a purity of 99.4%.

[0058] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects: By using the above-mentioned magnesium dissolving agent, the magnesium oxide raw material can be dissolved and play a role in the above preparation method. By using the above preparation method, the magnesium oxide raw material with relatively low purity can be prepared into a high-purity magnesium oxide product. Compared with the prior art, the process method is simple, the operation is easy, the raw materials are easy to obtain, the preparation cost and the equipment investment cost are low, the purification effect is good, and it is suitable for large-scale industrial production. It can overcome the problems of high cost, low efficiency, and large pollution in the production of high-purity magnesium oxide in the prior art.

[0059] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a magnesium oxide product, characterized in that, The preparation method includes: a) Using a magnesium solvent to dissolve the magnesium oxide raw material to obtain a first magnesium-containing solution; b) Adding an oxidizing agent and a flocculant to the first magnesium-containing solution to obtain a second magnesium-containing solution; c) Adding a precipitation reagent to the second magnesium-containing solution to obtain a magnesium-containing precipitate; d) Calcining the magnesium-containing precipitate to obtain the magnesium oxide product; The magnesium solvent includes hydrogen peroxide and metal chlorides.

2. The preparation method according to claim 1, wherein The mass ratio of hydrogen peroxide in the magnesium solvent is 5% - 25%.

3. The preparation method according to claim 2, wherein, The mass ratio of hydrogen peroxide in the magnesium solvent is 9% - 20%.

4. The preparation method according to claim 1, wherein The magnesium solvent further includes any one or more of metal oxides or ethylenediaminetetraacetic acid.

5. The preparation method according to claim 4, wherein, The metal oxides include any one or more of iron tetroxide, calcium oxide, and zinc oxide.

6. The preparation method according to claim 1, characterized in that, The metal chlorides include any one or more of chromium chloride, calcium chloride, ferric chloride, potassium chloride, sodium chloride, aluminum chloride, zinc chloride, or copper chloride.

7. The preparation method according to any one of claims 1-6, characterized in that, Step a) includes: adding the magnesium oxide raw material to water, stirring until evenly mixed, then adding the magnesium solvent, and continuously stirring for 1 - 2 h.

8. The preparation method according to any one of claims 1-6, characterized in that, The magnesium oxide raw material includes industrial magnesium oxide, and the purity of the industrial magnesium oxide is 80% - 90%.

9. The preparation method according to claim 8, characterized in that, The purity of the magnesium oxide product is ≥99%.

10. The preparation method according to claim 9, characterized in that, The purity of the magnesium oxide product is ≥99.5%.

11. The preparation method according to any one of claims 1-6, characterized in that, The mass ratio of the magnesium solvent to the magnesium oxide raw material is 0.5 - 2:

1.

12. The preparation method according to any one of claims 1-6, characterized in that, The oxidizing agent includes one or more of sodium hypochlorite, potassium permanganate, ozone, hydrogen peroxide, sodium carbonate, sodium bicarbonate, sodium borohydride, sodium thiosulfate, sodium perchlorate, sodium chloride, hydrazine hydrate, thiourea, or urea.

13. The preparation method according to any one of claims 1-6, characterized in that, The flocculant includes one or more of polyaluminum chloride, polyaluminum sulfate, polyferric chloride, polyferric sulfate, starch, chitosan, cellulose, or polyacrylamide.

14. The preparation method according to any one of claims 1-6, characterized in that, The precipitation reagent includes one or more of sodium hydroxide, ammonia water, or potassium hydroxide.

15. The preparation method according to any one of claims 1-6, characterized in that, The conditions for calcining the magnesium-containing precipitate are 900 - 1200 °C for 1 - 3 hours.