阅读说明：本技术 一种综合利用菱镁矿的方法 (Method for comprehensive utilization of magnesite ) 是由 吴玉胜 李来时 刘宁 刘金亮 于 2020-05-14 设计创作，主要内容包括：本发明涉及一种综合利用菱镁矿的方法,步骤一、将菱镁矿磨细至通过100目筛；步骤二、将硫酸铵固体加热分解,制备硫酸氢铵溶液；步骤三、将步骤一获得的细矿加入步骤二获得的硫酸氢铵溶液中混合制成矿浆；步骤四、将矿浆加热反应,反应结束后加入草酸,反应均匀后进行第一次固液分离,获得粗液和浸出渣；步骤五、向获得的粗液中依次通入空气和步骤二产生的部分氨气后进行第二次固液分离,获得纯净的含镁离子溶液和含铝铁的固体渣；步骤六、将步骤五得到的含镁离子溶液同时通入步骤二产生的氨气和步骤四产生的二氧化碳气体,反应结束后进行第三次固液分离,获得碱式碳酸镁和硫酸铵溶液。本发明实现了菱镁矿生态化综合处理的目的。(The invention relates to a method for comprehensively utilizing magnesite, which comprises the following steps of grinding magnesite until the magnesite passes through a 100-mesh sieve; step two, heating and decomposing the ammonium sulfate solid to prepare an ammonium bisulfate solution; step three, adding the fine ore obtained in the step one into the ammonium bisulfate solution obtained in the step two, and mixing to prepare ore pulp; step four, heating the ore pulp for reaction, adding oxalic acid after the reaction is finished, and carrying out first solid-liquid separation after the reaction is uniform to obtain a crude liquid and leaching residues; step five, sequentially introducing air and part of ammonia gas generated in the step two into the obtained crude liquid, and then carrying out secondary solid-liquid separation to obtain pure magnesium ion-containing solution and solid slag containing ferro-aluminum; and step six, introducing the magnesium ion-containing solution obtained in the step five into ammonia gas generated in the step two and carbon dioxide gas generated in the step four at the same time, and performing solid-liquid separation for the third time after the reaction is finished to obtain basic magnesium carbonate and ammonium sulfate solution. The invention realizes the purpose of ecological comprehensive treatment of magnesite.)

1. A method for comprehensively utilizing magnesite is characterized by comprising the following steps: the method comprises the following steps:

firstly, grinding magnesite until the magnesite passes through a 100-mesh sieve to prepare fine ore;

heating and decomposing the ammonium sulfate solid to generate ammonium bisulfate and ammonia gas, and dissolving the ammonium bisulfate in water to prepare an ammonium bisulfate solution;

step three, adding the fine ore obtained in the step one into the ammonium bisulfate solution obtained in the step two, and mixing to prepare ore pulp;

step four, heating the ore pulp under the stirring condition to react to generate carbon dioxide gas, adding oxalic acid into the solution after the reaction is finished, stirring until the reaction is uniform, and then carrying out first solid-liquid separation to obtain crude liquid and leaching residues;

step five, sequentially introducing air and part of ammonia gas generated in the step two into the obtained crude liquid, and then carrying out secondary solid-liquid separation to obtain pure magnesium ion-containing solution and solid slag containing ferro-aluminum;

and step six, introducing the magnesium ion-containing solution obtained in the step five into ammonia gas generated in the step two and carbon dioxide gas generated in the step four under the condition of stirring for reaction, and performing solid-liquid separation for the third time after the reaction is finished to obtain basic magnesium carbonate and ammonium sulfate solution.

2. The method for comprehensively utilizing magnesite according to claim 1, wherein the method comprises the following steps: and in the third step, the liquid-solid ratio of the ammonium bisulfate solution in the ore pulp to the magnesite fine ore is 2.5-6.0, and the molar ratio of the ammonium bisulfate to the magnesium in the magnesite is 2-4.

3. The method for comprehensively utilizing magnesite according to claim 1, wherein the method comprises the following steps: stirring the ore pulp in the fourth step at a speed of 80-200 r/min, reacting for 30-240 min, and reacting at a temperature of 60-150 ℃; adding oxalic acid into the solution, and continuously stirring for 30-120 min until the reaction is uniform.

4. The method for comprehensively utilizing magnesite according to claim 1, wherein the method comprises the following steps: and D, stopping introducing the ammonia gas when the time for introducing the ammonia gas in the step five is after stopping introducing the air and the pH value of the solution is 5.0-7.0.

5. The method for comprehensively utilizing magnesite according to claim 1, wherein the method comprises the following steps: and fifthly, introducing air into the solution in a pipeline introducing mode, wherein an outlet of the pipeline faces the bottom of the solution, the vertical distance between the upper side of the outlet of the air pipeline, which is positioned at the bottom end of the liquid, and the bottom end of the liquid is 50-200 mm, the introducing speed of the air is 20-100 ml/min, and the introducing time of the air is 10-120 min.

6. The method for comprehensively utilizing magnesite according to claim 1, wherein the method comprises the following steps: and D, dissolving the solid slag containing the aluminum and the iron obtained in the step five in sufficient sodium hydroxide solution with the concentration of 15-40% at the temperature of 80-140 ℃ for 10-60 min, separating to obtain iron hydroxide and sodium aluminate solution, and calcining the iron hydroxide at the temperature of 600-100 ℃ to obtain the ferric oxide with the purity of 94.0-97.0%.

7. The method for comprehensively utilizing magnesite according to claim 1, wherein the method comprises the following steps: and introducing ammonia gas and carbon dioxide gas in the sixth step at the same time, wherein the pH value of the solution after reaction is 7.5-9.0.

8. The method for comprehensive utilization of magnesite according to claim 7, wherein: and after the step six is finished, continuously stirring for 60-360 min after ammonia gas and carbon dioxide gas are introduced.

9. The method for comprehensively utilizing magnesite according to claim 1, wherein the method comprises the following steps: washing the leaching residue obtained in the fourth step with 3 times of hot distilled water with the mass temperature of more than or equal to 80 ℃ for 3-5 times, drying, and drying the leaching residue, wood dust 10-30%, MgO 10-20%, MgCl 15-30% according to the mass percentage of 20-30%₂5-10% of water, 1-2% of liquid organic silicon, 0.5-2% of polyvinyl acetate and 1-3% of plasticizer are mixed uniformly and then cured at room temperature for 3 days to obtain the magnesite product, wherein the performance indexes of the magnesite product are as follows: a density of 1300-1500 kg/m²The compressive strength is 5-9 MPa in 7 days, the softening coefficient is 0.53-0.59, and the heat conductivity is 0.2-0.27.

10. A method for comprehensive utilization of magnesite according to claim 1, 7 or 8, characterized in that: magnesium ion solution that contains of step six is located liquid container (6), ammonia and carbon dioxide gas let in into liquid container through two kinds of pipelines, two kinds of pipelines include standpipe (1) and coil pipe (3), coil pipe (3) are located the bottom of liquid container (6), the lower extreme of standpipe (1) is located the central authorities of coil pipe (3), the lower extreme of standpipe (1) is inclosed, the lateral wall that standpipe (1) is located coil pipe (3) central authorities department evenly arranges and is equipped with standpipe venthole (4), the interior week pipe wall of coil pipe (3) evenly arranges and is equipped with coil pipe venthole (5), coil pipe (3) intercommunication has coil pipe intake pipe (2), the inlet end of coil pipe intake pipe (2) is used for letting in the ammonia, the inlet end of standpipe (1) is used for letting in the carbon dioxide.

Technical Field

The invention belongs to the technical field of mineral processing, and relates to a comprehensive utilization method of magnesite resources, in particular to a method for comprehensively utilizing magnesite.

Background

By the end of 2019, the worldwide proven storage of magnesite is about 140 hundred million tons, and countries with large storage mainly comprise China, Korea, Russia, New Zealand and Czech, and the storage accounts for about 80% of the world's total storage, wherein the storage of China accounts for 25% of the world's total storage. The magnesite reserves in Liaoning province are about 30 hundred million tons, which account for 85% of the whole country and 20% of the world. The Liaoning magnesite ore deposit is mostly layer-controlled crystal magnesite ore deposit, the Mohs hardness is 4, and the density is 3.1%. Although magnesite reserves in China are abundant, mine management is backward, ores are unreasonably mined, excessive mined and exported in a large quantity, the reserves of high-grade magnesite are rapidly reduced, a large quantity of tailings are generated in the mining process, the phenomenon of 'mining rich and abandoning poor' is serious due to long-term raw material type product development, and a large quantity of low-grade ores with the magnesium oxide content of less than 45 percent accounting for 30-40 percent of mined ores are abandoned, so that great pressure is brought to the environment, and extreme waste of magnesium resources is caused. Therefore, how to efficiently and comprehensively utilize magnesite resources, especially waste resources, has become a major problem to be solved urgently in the magnesite industry.

At present, the research methods for comprehensively utilizing the low-grade magnesite mainly comprise a mineral separation technology, an acid leaching method, an ammonium leaching method, a carbonization method and the like, wherein the mineral separation technology is already applied in industry, but the problem that tailings need to be treated still exists in the mineral separation process, and the purpose of 'dry eating and complete squeezing' of the tailings is not fundamentally realized. The prior technologies such as acid leaching method, ammonium leaching method, carbonization method and the like have various problems, and have not been reported in relevant industrial implementation.

Disclosure of Invention

Object of the Invention

Aiming at the defects of the existing magnesite, particularly low-grade magnesite in the utilization technology, the invention provides a method for comprehensively utilizing magnesite, and the purpose of ecologically producing basic magnesium carbonate from magnesite is realized.

Technical scheme

A method for comprehensively utilizing magnesite comprises the following steps:

firstly, grinding magnesite until the magnesite passes through a 100-mesh sieve to prepare fine ore;

heating and decomposing the ammonium sulfate solid to generate ammonium bisulfate and ammonia gas, and dissolving the ammonium bisulfate in water to prepare an ammonium bisulfate solution;

step three, adding the fine ore obtained in the step one into the ammonium bisulfate solution obtained in the step two, and mixing to prepare ore pulp;

step four, heating the ore pulp under the stirring condition to react to generate carbon dioxide gas, adding oxalic acid into the solution after the reaction is finished, stirring until the reaction is uniform, and then carrying out first solid-liquid separation to obtain crude liquid and leaching residues;

step five, sequentially introducing air and part of ammonia gas generated in the step two into the obtained crude liquid, and then carrying out secondary solid-liquid separation to obtain pure magnesium ion-containing solution and solid slag containing ferro-aluminum;

and step six, introducing the magnesium ion-containing solution obtained in the step five into ammonia gas generated in the step two and carbon dioxide gas generated in the step four under the condition of stirring for reaction, and performing solid-liquid separation for the third time after the reaction is finished to obtain basic magnesium carbonate and ammonium sulfate solution.

And in the third step, the liquid-solid ratio of the ammonium bisulfate solution in the ore pulp to the magnesite fine ore is 2.5-6.0, and the molar ratio of the ammonium bisulfate to the magnesium in the magnesite is 2-4.

Stirring the ore pulp in the fourth step at a speed of 80-200 r/min, reacting for 30-240 min, and reacting at a temperature of 60-150 ℃; adding oxalic acid into the solution, and continuously stirring for 30-120 min until the reaction is uniform.

And D, stopping introducing the ammonia gas when the time for introducing the ammonia gas in the step five is after stopping introducing the air and the pH value of the solution is 5.0-7.0.

And fifthly, introducing air into the solution in a pipeline introducing mode, wherein an outlet of the pipeline faces the bottom of the solution, the vertical distance between the upper side of the outlet of the air pipeline, which is positioned at the bottom end of the liquid, and the bottom end of the liquid is 50-200 mm, the introducing speed of the air is 20-100 ml/min, and the introducing time of the air is 10-120 min.

And D, dissolving the solid slag containing the aluminum and the iron obtained in the step five in sufficient sodium hydroxide solution with the concentration of 15-40% at the temperature of 80-140 ℃ for 10-60 min, separating to obtain iron hydroxide and sodium aluminate solution, and calcining the iron hydroxide at the temperature of 600-100 ℃ to obtain the ferric oxide with the purity of 94.0-97.0%.

And introducing ammonia gas and carbon dioxide gas in the sixth step at the same time, wherein the pH value of the solution after reaction is 7.5-9.0.

And after the step six is finished, continuously stirring for 60-360 min after ammonia gas and carbon dioxide gas are introduced.

Washing the leaching residue obtained in the fourth step with 3 times of hot distilled water with the mass temperature of more than or equal to 80 ℃ for 3-5 times, drying, and drying the leaching residue, wood dust 10-30%, MgO 10-20%, MgCl 15-30% according to the mass percentage of 20-30%₂5-10% of water, 1-2% of liquid organic silicon, 0.5-2% of polyvinyl acetate and 1-3% of plasticizer are mixed uniformly and then cured at room temperature for 3 days to obtain the magnesite product, wherein the performance indexes of the magnesite product are as follows: a density of 1300-1500 kg/m²The compressive strength is 5-9 MPa in 7 days, the softening coefficient is 0.53-0.59, and the heat conductivity is 0.2-0.27.

Magnesium ion solution that contains of step six is located liquid container, ammonia and carbon dioxide gas let in into liquid container through two kinds of pipelines in, two kinds of pipelines include standpipe and coil pipe, the coil pipe is located liquid container's bottom, the lower extreme of standpipe is located the central authorities of coil pipe, the lower extreme of standpipe is inclosed, the lateral wall that the standpipe is located coil pipe central authorities department evenly arranges and is equipped with the standpipe venthole, the interior pipe wall of coil pipe evenly arranges and is equipped with the coil pipe venthole, the coil pipe intercommunication has the coil pipe intake pipe, the inlet end of coil pipe intake pipe is used for letting in the ammonia, the inlet end of standpipe is used for letting in carbon dioxide.

Advantages and effects

The method follows the national principle of 'reduction, resource and harmlessness' of related solid resources, no waste gas, waste water and waste discharge is generated in the whole process, and the purpose of ecological comprehensive treatment of the magnesite is realized. The main materials in the process can be circulated, the process is simple, the conditions are mild, the energy consumption is low, and the industrial production and popularization are easy to realize.

Drawings

FIG. 1 is a schematic diagram of a process flow for comprehensive utilization of magnesite;

FIG. 2 is a schematic perspective view of a coiled tube and standpipe;

FIG. 3 is a schematic view of the location of the coil and standpipe within the liquid container.

Detailed Description

The technical solutions of the present invention will be described in further detail with reference to the accompanying drawings and specific implementations, and all the portions of the present invention that are not described in detail are the prior art. As shown in fig. 1, a schematic diagram of a process flow for comprehensive utilization of magnesite is shown.