Method for recovering magnesium metal in calcium carbide furnace purification ash

Abstract

The invention discloses a method for recovering magnesium metal in calcium carbide furnace purified ash. The method comprises the following steps: 1, calcining the calcium carbide furnace purified ash; 2, crushing the calcium carbide furnace purified ash after calcination; 3, generating magnesium hydroxide and calcium hydroxide; step 4, carrying out carbonization reaction on magnesium hydroxide and calcium hydroxide; 5, filtering after the reaction is completed, adding sodium hydroxide into filtrate for treatment, and then filtering; 6, calcining the solids obtained in the step 4 and the step 5; 7, calcium oxide and aluminum oxide in the solid obtained in the step 4 are separated for standby application; 8, the materials are added into a blast furnace according to the proportion for magnesium-aluminum alloy smelting; and ninthly, the magnesium-aluminum alloy ingot is obtained after pouring and cooling. The magnesium metal in the calcium carbide furnace purification ash can be conveniently recycled, and meanwhile the magnesium metal is low in hardness, prone to oxidation and not prone to storage and transportation, so that aluminum oxide in the calcium carbide furnace purification ash is recycled, and part of calcium oxide is added to adjust the performance of the obtained magnesium-aluminum alloy.

Description

Technical Field

[0001] The present invention belongs to the field of magnesium recovery from carbide furnace purification ash, and specifically relates to a method for recovering magnesium metal from carbide furnace purification ash. Background Art

[0002] Carbide furnace purification ash refers to the solid waste dust collected after treating high-temperature furnace gas through a purification device during the production of calcium carbide. These dusts mainly contain a large amount of toxic substances such as alkalis and cyanides, which will have harmful effects on human health if treated outdoors. Currently, the main way to recycle carbide furnace purification ash is as a filler for the production of some building materials. However, although carbide furnace purification ash contains a large amount of calcium oxide, it also contains rich magnesium oxide and a certain amount of aluminum oxide. Directly using it as landfill or as a filler for the production of some building materials is a waste of resources. Summary of the Invention

[0003] The present invention provides a method for recovering magnesium metal from carbide furnace purification ash to solve the defects in the prior art.

[0004] The present invention is realized through the following technical solutions:

[0005] A method for recovering magnesium metal from carbide furnace purification ash includes the following steps:

[0006] Step 1: Recover carbide furnace purification ash and calcine it;

[0007] Step 2: Crush the calcined carbide furnace purification ash;

[0008] Step 3: Add water 10 - 15 times the mass of the crushed carbide furnace purification ash and heat it to generate a mixed solution of magnesium hydroxide and calcium hydroxide;

[0009] Step 4: Feed the mixed solution of magnesium hydroxide and calcium hydroxide obtained in Step 3 into a closed container and then introduce carbon dioxide gas for reaction;

[0010] Step 5: Filter after the reaction is completed, add sodium hydroxide solution to the filtrate for reaction, and filter again after the reaction is completed;

[0011] Step 6: Calcine and crush the solids obtained in Step 4 and Step 5 again respectively;

[0012] Step 7: Separate calcium oxide and aluminum oxide from the powder of the solid after calcination in Step 4 for standby;

[0013] Step 8: Conduct component detection on the magnesium oxide obtained after calcining the solid in Step 5, the calcium oxide and aluminum oxide separated in Step 7, and then add them to the blast furnace for smelting of magnesium-aluminum alloy according to the ratio;

[0014] Step 9: After pouring and cooling, a magnesium-aluminum alloy ingot is obtained.

[0015] For a method for recovering magnesium metal from carbide furnace purification ash as described above, in Step 1, the calcination temperature is 1200 - 1400 °C and the calcination time is 20 - 30 min.

[0016] For a method for recovering magnesium metal from carbide furnace purification ash as described above, in Step 2, after crushing, it is sieved through a 200-mesh sieve and reserved for use.

[0017] For a method for recovering magnesium metal from carbide furnace purification ash as described above, in Step 3, the heating temperature is 90 - 100 °C and the reaction time is 2.5 - 3 h.

[0018] For a method for recovering magnesium metal from carbide furnace purification ash as described above, in Step 4, the reaction time is 30 - 50 min.

[0019] For a method for recovering magnesium metal from carbide furnace purification ash as described above, in Step 6, after crushing, it is sieved through a 400-mesh sieve and reserved for use.

[0020] For a method for recovering magnesium metal from carbide furnace purification ash as described above, the specific operation for separating calcium oxide and aluminum oxide in Step 7 is as follows: Add the solid powder obtained by calcining and crushing the solid in Step 4 to a sodium hydroxide solution with a pH of 12 - 14 and a mass 6 - 8 times that of the solid powder. Then, select sodium dodecyl sulfonate as the collector and recover aluminum oxide by positive flotation. The remaining is calcium oxide.

[0021] For a method for recovering magnesium metal from carbide furnace purification ash as described above, in Step 8, inductively coupled plasma atomic emission spectrometry is used to detect the components of magnesium oxide obtained after calcining the solid in Step 5, calcium oxide and aluminum oxide separated in Step 7.

[0022] For a method for recovering magnesium metal from carbide furnace purification ash as described above, Step 8 is formulated according to the following weight parts: 50 - 80 parts of recovered magnesium oxide, 10 - 15 parts of recovered aluminum oxide, and 1 - 2 parts of recovered calcium oxide. After mixing according to the above ratio, first put 50 - 60 weight parts of carbon into the blast furnace, then add the mixture weighed according to the above ratio to the blast furnace, and remove oxygen elements under the temperature of 900 - 1100 °C and the vacuum condition of 50 - 200 Pa. Regularly detect the oxygen element concentration in the melt until the oxygen element content is lower than 100 ppm, and then fish out the slag.

[0023] For a method for recovering magnesium metal from carbide furnace purification ash as described above, the magnesium-aluminum alloy ingot obtained in Step 9 is cooled by water cooling.

[0024] The advantages of the present invention are as follows: The present invention can conveniently recover magnesium metal from the purified ash of the calcium carbide furnace. Since magnesium metal itself has a low hardness, is easy to oxidize, and is not easy to store and transport, the aluminum oxide in the purified ash of the calcium carbide furnace is recycled and part of calcium oxide is added to adjust the performance of the obtained magnesium-aluminum alloy. Moreover, the remaining high-purity calcium oxide can be recycled as lime, thus realizing the full utilization of resources. Specific Embodiments

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some, rather than all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0026] Example 1

[0027] Step 1: Recover the purified ash of the calcium carbide furnace and calcine it at a temperature of 1200 °C for 30 min;

[0028] Step 2: After pulverizing the calcined purified ash of the calcium carbide furnace, sieve it through a 200-mesh sieve for standby;

[0029] Step 3: Add water 10 times the mass of the pulverized purified ash of the calcium carbide furnace and react at a temperature of 100 °C for 2.8 h to generate a mixed solution of magnesium hydroxide and calcium hydroxide;

[0030] Step 4: Feed the mixed solution of magnesium hydroxide and calcium hydroxide obtained in Step 3 into a closed container and then introduce carbon dioxide gas to react for 35 min;

[0031] Step 5: After the reaction is completed, filter. Add sufficient sodium hydroxide solution to the filtrate for reaction, and filter again after the reaction is completed;

[0032] Step 6: Calcine the solids obtained in Step 4 and Step 5 again respectively, pulverize them, and sieve them through a 400-mesh sieve for standby;

[0033] Step 7: Add the solid powder obtained by calcining and pulverizing the solid in Step 4 into a sodium hydroxide solution with a pH of 13.7 and a mass 7 times that of it. Then select sodium dodecyl sulfonate as a collector and recover aluminum oxide by positive flotation. The remaining main component is calcium oxide;

[0034] Step Eight: Conduct component detection on the magnesium oxide obtained by calcining the solid in Step Five, the calcium oxide separated in Step Seven, and the aluminum oxide to ensure that the purity of all three is above 95%. If the purity does not meet the standard, further purification can be carried out to ensure the performance of the obtained magnesium-aluminum alloy; The proportioning is carried out according to the following weight parts: 50 parts of recycled magnesium oxide, 10 parts of recycled aluminum oxide, and 1 part of recycled calcium oxide. After mixing according to the above proportion, first put 50 weight parts of carbon into the blast furnace, and then add the mixture weighed according to the above proportion into the blast furnace. Remove the oxygen element under the temperature of 900 °C and the vacuum condition of 50 Pa. Regularly detect the oxygen element concentration in the melt until the oxygen element content is lower than 100 ppm, and then fish out the slag;

[0035] Step Nine: After casting and shaping, use water cooling to cool down to obtain a magnesium-aluminum alloy ingot.

[0036] Example 2

[0037] Step One: Calcinate the recovered carbide furnace purification ash at a temperature of 1400 °C for 20 min;

[0038] Step Two: Crush the calcined carbide furnace purification ash and sieve it through a 200-mesh sieve for standby;

[0039] Step Three: Add 15 times the mass of water to the crushed carbide furnace purification ash and react at a temperature of 100 °C for 2.5 h to generate a mixed solution of magnesium hydroxide and calcium hydroxide;

[0040] Step Four: Feed the mixed solution of magnesium hydroxide and calcium hydroxide obtained in Step Three into a closed container and then introduce carbon dioxide gas to react for 45 min;

[0041] Step Five: After the reaction is completed, filter, add sufficient sodium hydroxide solution to the filtrate for reaction, and filter after the reaction is completed;

[0042] Step Six: Calcinate the solids obtained in Step Four and Step Five again respectively, crush them, and sieve them through a 400-mesh sieve for standby;

[0043] Step Seven: Add the solid powder obtained by calcining and crushing the solid in Step Four into a sodium hydroxide solution with a pH of 12.5 and a mass 8 times that of it. Then select sodium dodecyl sulfonate as the collector and recover aluminum oxide by positive flotation. The main remaining component is calcium oxide;

[0044] Step 8: Conduct component detection on the magnesium oxide obtained by calcining the solid in Step 5, the calcium oxide separated in Step 7, and the aluminum oxide to ensure that the purity of all three is above 95%. If the purity does not meet the standard, further purification can be carried out to ensure the performance of the obtained magnesium-aluminum alloy; the proportioning is carried out according to the following weight parts: 80 parts of recycled magnesium oxide, 15 parts of recycled aluminum oxide, and 2 parts of recycled calcium oxide. After mixing according to the above proportion, first put 60 weight parts of carbon into the blast furnace, and then add the mixture weighed according to the above proportion into the blast furnace. Under the conditions of a temperature of 1100°C and a vacuum of 200 Pa, remove the oxygen element, and regularly detect the oxygen element concentration in the melt until the oxygen element content is lower than 100 ppm, and then fish out the slag;

[0045] Step 9: After casting and shaping, use water cooling to cool down to obtain a magnesium-aluminum alloy ingot.

[0046] Example 3

[0047] Step 1: Calcinate the recovered carbide furnace purification ash at a temperature of 1300°C for 25 minutes;

[0048] Step 2: Crush the calcined carbide furnace purification ash and sieve it through a 200-mesh sieve for standby;

[0049] Step 3: Add the crushed carbide furnace purification ash to 13 times its mass of water and react at a temperature of 96°C for 2.8 hours to generate a mixed solution of magnesium hydroxide and calcium hydroxide;

[0050] Step 4: Feed the mixed solution of magnesium hydroxide and calcium hydroxide obtained in Step 3 into a closed container and then introduce carbon dioxide gas to react for 40 minutes;

[0051] Step 5: After the reaction is completed, filter, add sufficient sodium hydroxide solution to the filtrate for reaction, and filter after the reaction is completed;

[0052] Step 6: Calcinate the solids obtained in Step 4 and Step 5 again, crush them, and sieve them through a 400-mesh sieve for standby;

[0053] Step 7: Add the solid powder obtained by calcining and crushing the solid in Step 4 into a sodium hydroxide solution with a pH of 13.5 that is 7 times its mass, and then select sodium dodecyl sulfonate as the collector to recover aluminum oxide by positive flotation. The remaining main component is calcium oxide;

[0054] Step 8: Conduct component detection on the magnesium oxide obtained by calcining the solid in Step 5, the calcium oxide and aluminum oxide separated in Step 7, and ensure that the purity of the three is above 95%. If the purity does not meet the standard, further purification can be carried out to ensure the performance of the obtained magnesium-aluminum alloy; The ratio is as follows by weight: 70 parts of recycled magnesium oxide, 13 parts of recycled aluminum oxide, and 1.7 parts of recycled calcium oxide. After mixing according to the above ratio, first put 56 parts by weight of carbon into the blast furnace, and then add the mixture weighed according to the above ratio into the blast furnace. Remove the oxygen element under the temperature of 1000 °C and the vacuum condition of 140 Pa, and regularly detect the oxygen element concentration in the melt until the oxygen element content is lower than 100 ppm, and then fish out the slag;

[0055] Step 9: After casting and shaping, cool it down by water cooling to obtain a magnesium-aluminum alloy ingot.

[0056] Perform performance detection on the magnesium-aluminum alloys prepared in Examples 1-3, and the results are shown in Table 1.

[0057] Performance indicators Tensile strength (MPa) Compressive strength (MPa) Yield strength (MPa) Example 1 287 213 145 Example 2 289 217 143 Example 3 284 221 149

[0058] Table 1

[0059] As can be seen from the data in Table 1, the magnesium-aluminum alloys prepared in Examples 1-3 of the present invention have relatively good performance in the performance detection of tensile strength, compressive strength, and yield strength, so they can be used in fields where high performance requirements are not required, thus realizing the recycling of magnesium metal in the carbide furnace purification ash.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: They can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; And these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for recovering magnesium metal from calcium carbide furnace purification ash, characterized in that: The steps include: Step 1: Recover the purified ash from the calcium carbide furnace and calcine it; Step 2: crushing the calcined calcium carbide furnace purified ash; Step 3: Add 10-15 times the mass of water to the crushed calcium carbide furnace purified ash and heat it to generate a mixed solution of magnesium hydroxide and calcium hydroxide; Step 4: the mixed solution of magnesium hydroxide and calcium hydroxide obtained in step 3 is fed into a closed container and then carbon dioxide gas is introduced to react; Step 5: After the reaction is completed, filter, add sodium hydroxide solution to the filtrate for reaction, and filter after the reaction is completed; Step 6: calcining the solids obtained in step 4 and step 5 again and then crushing them; Step 7: Separate calcium oxide and aluminum oxide from the powder after the solid is calcined in step 4 for later use; Step 8: Detect the composition of the magnesium oxide obtained after the solid calcination in step 5 and the calcium oxide and aluminum oxide separated in step 7, and then add them into the blast furnace according to the ratio to smelt the magnesium-aluminum alloy; Step nine: After pouring and cooling, a magnesium-aluminum alloy ingot is obtained.

2. The method for recovering magnesium metal from calcium carbide furnace purified ash according to claim 1, characterized in that: In the step 1, the calcination temperature is 1200-1400° C. and the calcination time is 20-30 minutes.

3. The method for recovering magnesium metal from calcium carbide furnace purified ash according to claim 1, characterized in that: After being crushed in the step 2, the product is sieved through a 200-mesh sieve for later use.

4. The method for recovering magnesium metal from calcium carbide furnace purified ash according to claim 1, characterized in that: The heating temperature in step 3 is 90-100° C. and the reaction time is 2.5-3 h.

5. The method for recovering magnesium metal from calcium carbide furnace purified ash according to claim 1, characterized in that: The reaction time in step 4 is 30-50 min.

6. The method for recovering magnesium metal from calcium carbide furnace purified ash according to claim 1, characterized in that: After the pulverization in step 6, the product is sieved through a 400-mesh sieve for later use.

7. The method for recovering magnesium metal from calcium carbide furnace purified ash according to claim 1, characterized in that: The specific operation of separating calcium oxide and aluminum oxide in step seven is as follows: adding the solid powder obtained by calcining and crushing the solid in step four into a sodium hydroxide solution with a pH of 12-14 and a mass of 6-8 times that of the solid powder, and then selecting sodium dodecyl sulfate as a collector, recovering aluminum oxide by positive flotation, and the remainder is calcium oxide.

8. The method for recovering magnesium metal from calcium carbide furnace purified ash according to claim 1, characterized in that: In the step eight, inductively coupled plasma atomic emission spectrometry is used to detect the composition of the magnesium oxide obtained after the solid calcination in step five and the calcium oxide and aluminum oxide separated in step seven.

9. The method for recovering magnesium metal from calcium carbide furnace purified ash according to claim 1, characterized in that: The step eight is prepared according to the following weight proportions: 50-80 parts of magnesium oxide, 10-15 parts of aluminum oxide, and 1-2 parts of calcium oxide are recovered. After mixing according to the above proportions, 50-60 parts of carbon by weight are first put into the blast furnace, and then the mixture weighed according to the above proportion is added to the blast furnace, and oxygen is removed at a temperature of 900-1100°C and a vacuum condition of 50-200Pa. The oxygen concentration in the melt is regularly detected until the oxygen content is lower than 100ppm, and then the slag is salvaged.

10. The method for recovering magnesium metal from calcium carbide furnace purified ash according to claim 1, characterized in that: The magnesium-aluminum alloy ingot obtained in step nine is cooled by water cooling.