Method for preparing nano calcium carbonate through resource utilization of blast furnace slag

Abstract

The invention belongs to the technical field of blast furnace slag resource utilization, and discloses a method for preparing nano calcium carbonate by blast furnace slag resource utilization, which comprises the following steps: carrying out chemical extraction treatment on blast furnace slag to obtain an extraction solution rich in calcium ions; wherein the blast furnace slag is blast furnace slag generated during pig iron smelting; introducing carbon dioxide into the leach liquor rich in calcium ions for reaction, and performing screening, washing and drying treatment after the reaction to obtain nano calcium carbonate; wherein the carbon dioxide is carbon dioxide gas captured by organic amine in the blast furnace gas purification process; wherein the carbon dioxide is carbon dioxide gas captured by organic amine in the blast furnace gas purification process; according to the method, the factory blast furnace slag is fully utilized, the prepared nano calcium carbonate has the advantages of high purity, high particle size concentration ratio and high product added value, and the method is high in process operability, easy to industrialize and low in cost.

Description

Technical Field

[0001] The invention belongs to the technical field of blast furnace slag resource utilization, relates to a method for preparing nano calcium carbonate, and particularly relates to a method for preparing nano calcium carbonate by utilizing blast furnace slag resources. Background Art

[0002] Blast furnace slag is a by-product discharged from the blast furnace when smelting pig iron. Specifically, the raw materials added to the blast furnace when smelting pig iron, in addition to iron ore and fuel coke, also need to add a considerable amount of limestone and dolomite as flux. When the furnace temperature reaches a predetermined temperature, the flux reacts with the iron ore at high temperature to produce pig iron and blast furnace slag. Among them, blast furnace slag is generally a fusible substance composed of gangue, ash, flux and other impurities that cannot enter the pig iron.

[0003] At present, the resource utilization of blast furnace slag is mostly stuck in the stage of low technical content and low product added value; among them, most of them are used as additives and auxiliary materials for building materials, and a small part of titanium-containing slag is used to manufacture photosensitive materials; with the development of technology, blast furnace slag is also used to develop high value-added products, such as: Chinese patent application "A method for resource utilization of coal furnace slag in power plants" (publication number: CN117447103A), Chinese patent application "A production process for preparing rock wool using hot blast furnace slag" (publication number: CN117361890A) and Chinese patent application "A method for preparing photocatalytic permeable bricks using high-titanium blast furnace slag doped with vanadium" (publication number: CN117510184A); however, in the above-mentioned existing process of developing high value-added products using blast furnace slag, the utilization rate of blast furnace slag is low, the utilization cost is high, and it is not suitable for large-scale industrial production. Summary of the invention

[0004] In view of the technical problems existing in the prior art, the present invention provides a method for preparing nano calcium carbonate by resource utilization of blast furnace slag, so as to solve the technical problems that in the existing process of developing high value-added products using blast furnace slag, the utilization rate of blast furnace slag is low, the utilization cost is high, and it is not suitable for large-scale industrial production.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is: The present invention provides a method for preparing nano calcium carbonate by resource utilization of blast furnace slag, comprising: Chemically leaching blast furnace slag to obtain a leaching solution rich in calcium ions; wherein the blast furnace slag is blast furnace slag produced when smelting pig iron; Carbon dioxide is introduced into the calcium ion-rich leaching solution for reaction, and after the reaction, screening, washing and drying are performed to obtain nano calcium carbonate; wherein the carbon dioxide is carbon dioxide gas captured by organic amines during the purification process of blast furnace gas.

[0006] Further, the blast furnace slag is subjected to chemical leaching treatment to obtain a leaching solution rich in calcium ions, as follows: mixing blast furnace slag with blast furnace slag leaching solution to obtain a leaching system; The pH value of the leaching system is adjusted by using the evaporated ammonia waste liquid, and the mixture is allowed to stand for reaction to obtain a mixed solution rich in calcium ions.

[0007] Furthermore, the blast furnace slag leachate is an ammonium chloride solution or an ammonium nitrate solution; wherein the liquid-to-solid ratio of the blast furnace slag leachate to the blast furnace slag is: (100-150) mL: (10-15) g, and the mass fraction of the ammonium chloride solution or the ammonium nitrate solution is 5%-10%.

[0008] Furthermore, when the pH value of the leaching system is adjusted by using the evaporated ammonia waste liquid, the temperature is 30-40°C.

[0009] Furthermore, the ammonia evaporation waste liquid is ammonia water recovered from the coking section of the factory or the factory waste water through the ammonia evaporation process, and the effective ammonia water content in the ammonia evaporation waste liquid is 15%-20%.

[0010] Furthermore, the process of introducing carbon dioxide into the calcium ion-rich extract to react, and then filtering, washing and drying the extract after the reaction to obtain nano calcium carbonate is as follows: adding sodium citrate to the calcium ion-rich extract to obtain a reaction system; The reaction system is placed in a homogenizer, and an organic amine is used to capture carbon dioxide gas in the blast furnace gas during the blast furnace gas purification process, and a homogenization and dispersion reaction is performed to obtain a reaction product; The reaction product is subjected to screening, alcohol washing and drying treatment to obtain nano-scale calcium carbonate.

[0011] Furthermore, the sodium citrate is of industrial grade, and the amount of sodium citrate added is 0.05%-0.15% of the mass of the calcium ion-rich extract.

[0012] Furthermore, in the process of capturing carbon dioxide gas in blast furnace gas by organic amine during blast furnace gas purification, the carbon dioxide content in the carbon dioxide gas is greater than 98%, and the inlet flow rate of the carbon dioxide gas is 40-60 mL / min.

[0013] Furthermore, the temperature of the homogeneous dispersion reaction is 18-22°C.

[0014] Furthermore, the alcohol washing process is: washing with anhydrous ethanol; the drying process is: vacuum drying at a temperature of 80-100° C. for 1-4 hours.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The invention provides a method for preparing nano calcium carbonate by resource utilization of blast furnace slag. The method comprises the following steps: carbon dioxide gas captured by organic amine in the process of blast furnace gas purification is reacted with a calcium ion-rich leaching solution obtained by chemically leaching the blast furnace slag to prepare the nano calcium carbonate. The preparation process is simple and the blast furnace slag in the factory is fully utilized. The carbon dioxide in the blast furnace gas is utilized to further improve the calorific value of the blast furnace gas, reduce the emission of carbon dioxide, and realize the recycling of factory materials. Secondly, the prepared nano calcium carbonate has high purity and high particle size concentration, and can be used as an additive for rubber, plastic, papermaking and coating, and the product has high added value. The invention has the advantages of strong process operability, easy industrialization and low cost.

[0016] Furthermore, during the chemical leaching process of blast furnace slag, the pH value of the leaching system is adjusted by using evaporated ammonia waste liquid, which solves the storage problem of the factory's ammonia waste liquid; the wet leaching process can efficiently and quickly extract calcium oxide, which has the advantages of strong selectivity, few impurities and high purity.

[0017] Furthermore, when reacting with carbon dioxide to produce nano-calcium carbonate, a homogenizer plus circulating water is used. The process is simple, and the high-speed mixing uniformity of the homogenizer provides good reaction conditions for the generation of high-purity nano-calcium carbonate. The drying time is short and the process is simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The present invention provides a flow chart of a method for preparing nano-calcium carbonate by resource utilization of blast furnace slag. DETAILED DESCRIPTION

[0019] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail in the following specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0020] As attached Figure 1 As shown, the present invention provides a method for preparing nano calcium carbonate by resource utilization of blast furnace slag, comprising the following steps: Step 1, collecting blast furnace slag produced during the smelting of pig iron, treating the blast furnace slag by a water quenching process, and then crushing it to obtain fine-grained slag mainly composed of glass; drying the fine-grained slag mainly composed of glass, crushing it, ball milling it, and sieving it through a 150-mesh standard sieve to obtain blast furnace slag powder.

[0021] Step 2: chemically leaching the blast furnace slag powder to obtain a leaching solution rich in calcium ions. The specific implementation process of obtaining the leaching solution rich in calcium ions is as follows: Step 21, mixing the blast furnace slag powder with a blast furnace slag leaching solution to obtain a leaching system. The blast furnace slag leaching solution is an ammonium chloride solution or an ammonium nitrate solution; the liquid-solid ratio of the blast furnace slag leaching solution to the blast furnace slag is (100-150) mL: (10-15) g, and the mass fraction of the ammonium chloride solution or the ammonium nitrate solution is 5%-10%.

[0022] Step 22: Under the temperature condition of 30-40° C., the pH value of the leaching system is adjusted to 11.0-12.0 using the ammonia evaporation waste liquid, and the reaction is allowed to stand to obtain a leaching solution rich in calcium ions; wherein the ammonia evaporation waste liquid is ammonia water recovered from the coking section of the factory or the factory waste water through the ammonia evaporation process, and the effective ammonia water content in the ammonia evaporation waste liquid is 15%-20%; the CaCl in the leaching solution rich in calcium ions is 1.0-12.0; wherein the ammonia evaporation waste liquid ... 2 The mass concentration of NH 4 The mass concentration of Cl is 4.0%-5.0%, and the mass concentration of ammonia water is 2%-3%.

[0023] Step 3: introducing carbon dioxide into the calcium ion-rich extract to react, and then filtering, washing and drying the extract to obtain nano calcium carbonate. Specifically, the implementation process is as follows: Step 31, transferring the calcium ion-rich extract to a homogenizer, and adding sodium citrate to obtain a reaction system; wherein the sodium citrate is industrial grade, and the amount of sodium citrate added is 0.05%-0.15% of the mass of the calcium ion-rich extract.

[0024] Step 32, start the homogenizer, control the speed at 500-800r / min, disperse for 5-10min, introduce the carbon dioxide gas in the blast furnace gas using organic amines in the blast furnace gas purification process, carry out homogenous dispersion reaction, and obtain a reaction product; wherein the carbon dioxide content in the carbon dioxide gas is greater than 98%, and the flow rate of the carbon dioxide gas is 40-60mL / min; the temperature of the homogenous dispersion reaction is controlled at 18-22°C, and the reaction is stopped when the pH of the reaction system reaches 7.0.

[0025] Step 33, using a 200-mesh sieve to filter the reaction product to obtain a sieved product; using anhydrous ethanol to wash the sieved product, and after alcohol washing, placing it in a vacuum drying oven at a temperature of 80-100° C. for 1-4 hours to obtain nano-scale calcium carbonate, that is, obtaining the nano calcium carbonate.

[0026] Resource utilization principle: The method for preparing nano calcium carbonate by resource utilization of blast furnace slag of the present invention uses blast furnace slag produced during pig iron smelting as raw material, performs chemical leaching treatment on the blast furnace slag, and obtains a leaching solution rich in calcium ions; then, carbon dioxide in blast furnace gas at the smelting site is used for reaction to obtain high-purity nano calcium carbonate with a particle size of less than 100 nm, which can be used in rubber, plastic, papermaking and coating industries; the preparation process is simple, and the blast furnace slag of the factory can be treated on site and fully utilized; the ammonia water obtained in the ammonia distillation section of the factory and the carbon dioxide in the blast furnace gas are used to fix the calcium ions, which solves the storage problem of the ammonia water in the factory, further improves the calorific value of the blast furnace gas, reduces the emission of carbon dioxide, and realizes the recycling of factory materials.

[0027] Specifically, calcium oxide can be extracted and utilized from blast furnace slag through process innovation, and carbon dioxide captured from existing waste gas of metallurgical plants can be fixed to produce nano-scale calcium carbonate. The product has high added value, high purity, and high particle size concentration, which meets the needs of rubber, plastic, papermaking and coating industries, and has the characteristics of high blast furnace slag utilization rate and large product added value; secondly, the wet leaching process can be used to efficiently and quickly extract calcium oxide, which has the advantages of strong selectivity, few impurities and high purity; the raw materials used are all from the existing resources and recycling equipment of the factory, the cost can be greatly reduced, and it is convenient for industrial promotion; the reaction with carbon dioxide to produce nano high-purity calcium carbonate adopts a homogenizer plus circulating water process, and the high-speed mixing uniformity of the homogenizer provides good reaction conditions for the generation of high-purity nano calcium carbonate, short drying time, simple process, strong operability, easy industrialization and low cost.

[0028] Example 1 This embodiment 1 provides a method for preparing nano calcium carbonate by resource utilization of blast furnace slag, comprising the following steps: Step 1: After treating blast furnace slag by water quenching process, crushing it to obtain fine-grained slag mainly composed of glass; after drying the fine-grained slag mainly composed of glass, crushing and ball milling it, and sieving it through a 150-mesh standard sieve to obtain blast furnace slag powder.

[0029] Step 2: Add 12 g of the blast furnace slag powder to 140 g of 5% ammonium chloride solution, and adjust the pH value of the leaching system to 11.0 using 18 g of ammonia evaporation waste liquid at a temperature of 37° C., allow the mixture to react to obtain a calcium ion-rich leaching solution; wherein the ammonia evaporation waste liquid is ammonia water recovered from factory wastewater through an ammonia evaporation process, and the effective ammonia water content in the ammonia evaporation waste liquid is 15%.

[0030] Step 3, transferring the calcium ion-rich extract to a homogenizer, and adding sodium citrate to obtain a reaction system; wherein the sodium citrate is industrial grade, and the amount of sodium citrate added is 0.15% of the mass of the calcium ion-rich extract; starting the homogenizer, controlling the speed at 800r / min for dispersion for 10min, introducing the carbon dioxide gas in the blast furnace gas purification process using organic amine to capture the blast furnace gas, and performing a homogenous dispersion reaction to obtain a reaction product; wherein the carbon dioxide content in the carbon dioxide gas is greater than 98%, and the flow rate of the carbon dioxide gas is 60mL / min; the temperature of the homogenous dispersion reaction is controlled to 20°C, and the reaction is stopped when the pH of the reaction system reaches 7.0.

[0031] Step 4: sieve the reaction product with a 200-mesh sieve to obtain a sieved product; wash the sieved product with anhydrous ethanol, and after washing, place it in a vacuum drying oven at 90° C. for 3 hours to obtain nano calcium carbonate.

[0032] Example 2 This embodiment 2 provides a method for preparing nano calcium carbonate by resource utilization of blast furnace slag, comprising the following steps: Step 1: After treating blast furnace slag by water quenching process, crushing it to obtain fine-grained slag mainly composed of glass; after drying the fine-grained slag mainly composed of glass, crushing and ball milling it, and sieving it through a 150-mesh standard sieve to obtain blast furnace slag powder.

[0033] Step 2: adding 12 g of the blast furnace slag powder to 130 g of an ammonium chloride solution with a mass fraction of 8%, and adjusting the pH value of the leaching system to 11.0 using 18 g of ammonia evaporation waste liquid at a temperature of 35° C., allowing the mixture to react to obtain a leaching solution rich in calcium ions; wherein the ammonia evaporation waste liquid is ammonia water recovered from the ammonia evaporation process in the coking section of the factory, and the effective ammonia water content in the ammonia evaporation waste liquid is 16%.

[0034] Step 3, transferring the calcium ion-rich extract to a homogenizer, and adding sodium citrate to obtain a reaction system; wherein the sodium citrate is industrial grade, and the amount of sodium citrate added is 0.1% of the mass of the calcium ion-rich extract; starting the homogenizer, controlling the speed at 600r / min for dispersion for 7min, introducing the carbon dioxide gas in the blast furnace gas using organic amines during the blast furnace gas purification process, and performing a homogenous dispersion reaction to obtain a reaction product; wherein the carbon dioxide content in the carbon dioxide gas is greater than 98%, and the flow rate of the carbon dioxide gas is 50mL / min; the temperature of the homogenous dispersion reaction is controlled to 19°C, and the reaction is stopped when the pH of the reaction system reaches 7.0.

[0035] Step 4: sieve the reaction product with a 200-mesh sieve to obtain a sieved product; wash the sieved product with anhydrous ethanol, and after washing, place it in a vacuum drying oven at 85° C. for 2 hours to obtain nano calcium carbonate.

[0036] Example 3 This embodiment 3 provides a method for preparing nano calcium carbonate by resource utilization of blast furnace slag, comprising the following steps: Step 1: After treating blast furnace slag by water quenching process, crushing it to obtain fine-grained slag mainly composed of glass; after drying the fine-grained slag mainly composed of glass, crushing and ball milling it, and sieving it through a 150-mesh standard sieve to obtain blast furnace slag powder.

[0037] Step 2: adding 10 g of the blast furnace slag powder to 100 g of 5% ammonium nitrate solution by mass, and adjusting the pH value of the leaching system to 12 with 18 g of ammonia evaporation waste liquid at a temperature of 38° C., allowing the reaction to stand to obtain a leaching solution rich in calcium ions; wherein the ammonia evaporation waste liquid is ammonia water recovered from the ammonia evaporation process in the coking section of the factory, and the effective ammonia water content in the ammonia evaporation waste liquid is 19%.

[0038] Step 3, transferring the calcium ion-rich extract to a homogenizer, and adding sodium citrate to obtain a reaction system; wherein the sodium citrate is industrial grade, and the amount of sodium citrate added is 0.1% of the mass of the calcium ion-rich extract; starting the homogenizer, controlling the speed at 600r / min for dispersion for 8min, introducing the carbon dioxide gas in the blast furnace gas purification process using organic amine to capture the blast furnace gas, and performing a homogenous dispersion reaction to obtain a reaction product; wherein the carbon dioxide content in the carbon dioxide gas is greater than 98%, and the flow rate of the carbon dioxide gas is 40mL / min; the temperature of the homogenous dispersion reaction is controlled to 20°C, and the reaction is stopped when the pH of the reaction system reaches 7.0.

[0039] Step 4: sieve the reaction product with a 200-mesh sieve to obtain a sieved product; wash the sieved product with anhydrous ethanol, and after washing, place it in a vacuum drying oven at 80° C. for 1 hour to obtain nano calcium carbonate.

[0040] Example 4 This embodiment 4 provides a method for preparing nano calcium carbonate by resource utilization of blast furnace slag, comprising the following steps: Step 1: After treating blast furnace slag by water quenching process, crushing it to obtain fine-grained slag mainly composed of glass; after drying the fine-grained slag mainly composed of glass, crushing and ball milling it, and sieving it through a 150-mesh standard sieve to obtain blast furnace slag powder.

[0041] Step 2: adding 12 g of the blast furnace slag powder to 140 g of a 6% ammonium chloride solution by mass, and adjusting the pH value of the leaching system to 12.0 using 18 g of ammonia evaporation waste liquid at a temperature of 38° C., allowing the reaction to stand to obtain a leaching solution rich in calcium ions; wherein the ammonia evaporation waste liquid is ammonia water recovered from the ammonia evaporation process in the coking section of the factory, and the effective ammonia water content in the ammonia evaporation waste liquid is 15%.

[0042] Step 3, transferring the calcium ion-rich extract to a homogenizer, and adding sodium citrate to obtain a reaction system; wherein the sodium citrate is industrial grade, and the amount of sodium citrate added is 0.05% of the mass of the calcium ion-rich extract; starting the homogenizer, controlling the speed at 700r / min for dispersion for 10min, introducing the carbon dioxide gas in the blast furnace gas using organic amines during the blast furnace gas purification process, and performing a homogenous dispersion reaction to obtain a reaction product; wherein the carbon dioxide content in the carbon dioxide gas is greater than 98%, and the flow rate of the carbon dioxide gas is 50mL / min; the temperature of the homogenous dispersion reaction is controlled to 22°C, and the reaction is stopped when the pH of the reaction system reaches 7.0.

[0043] Step 4: sieve the reaction product with a 200-mesh sieve to obtain a sieved product; wash the sieved product with anhydrous ethanol, and after washing, place it in a vacuum drying oven at 90° C. for 2 hours to obtain nano calcium carbonate.

[0044] Example 5 This embodiment 5 provides a method for preparing nano calcium carbonate by resource utilization of blast furnace slag, comprising the following steps: Step 1: After treating blast furnace slag by water quenching process, crushing it to obtain fine-grained slag mainly composed of glass; after drying the fine-grained slag mainly composed of glass, crushing and ball milling it, and sieving it through a 150-mesh standard sieve to obtain blast furnace slag powder.

[0045] Step 2: Add 13 g of the blast furnace slag powder to 150 g of a 10% ammonium chloride solution, and adjust the pH value of the leaching system to 11.0 using 18 g of ammonia evaporation waste liquid at a temperature of 40° C., allow the mixture to react to obtain a leaching solution rich in calcium ions; wherein the ammonia evaporation waste liquid is ammonia water recovered from the ammonia evaporation process in the coking section of the factory, and the effective ammonia water content in the ammonia evaporation waste liquid is 19%.

[0046] Step 3, transferring the calcium ion-rich extract to a homogenizer, and adding sodium citrate to obtain a reaction system; wherein the sodium citrate is industrial grade, and the amount of sodium citrate added is 0.1% of the mass of the calcium ion-rich extract; starting the homogenizer, controlling the speed at 600r / min for dispersion for 5min, introducing the carbon dioxide gas in the blast furnace gas using organic amines during the blast furnace gas purification process, and performing a homogenous dispersion reaction to obtain a reaction product; wherein the carbon dioxide content in the carbon dioxide gas is greater than 98%, and the flow rate of the carbon dioxide gas is 50mL / min; the temperature of the homogenous dispersion reaction is controlled to 20°C, and the reaction is stopped when the pH of the reaction system reaches 7.0.

[0047] Step 4: sieve the reaction product with a 200-mesh sieve to obtain a sieved product; wash the sieved product with anhydrous ethanol, and place it in a vacuum drying oven at a temperature of 100° C. for 2 hours to obtain nano calcium carbonate.

[0048] Example 6 This embodiment 6 provides a method for preparing nano calcium carbonate by resource utilization of blast furnace slag, comprising the following steps: Step 1: After treating blast furnace slag by water quenching process, crushing it to obtain fine-grained slag mainly composed of glass; after drying the fine-grained slag mainly composed of glass, crushing and ball milling it, and sieving it through a 150-mesh standard sieve to obtain blast furnace slag powder.

[0049] Step 2: adding 14 g of the blast furnace slag powder to 140 g of 5% ammonium nitrate solution by mass, and adjusting the pH value of the leaching system to 12.0 with 18 g of ammonia evaporation waste liquid at a temperature of 35° C., allowing the reaction to stand to obtain a leaching solution rich in calcium ions; wherein the ammonia evaporation waste liquid is ammonia water recovered from the ammonia evaporation process in the coking section of the factory, and the effective ammonia water content in the ammonia evaporation waste liquid is 15%.

[0050] Step 3, transferring the calcium ion-rich extract to a homogenizer, and adding sodium citrate to obtain a reaction system; wherein the sodium citrate is industrial grade, and the amount of sodium citrate added is 0.1% of the mass of the calcium ion-rich extract; starting the homogenizer, controlling the speed at 500r / min for dispersion for 10min, introducing the carbon dioxide gas in the blast furnace gas using organic amines during the blast furnace gas purification process, and performing a homogenous dispersion reaction to obtain a reaction product; wherein the carbon dioxide content in the carbon dioxide gas is greater than 98%, and the flow rate of the carbon dioxide gas is 60mL / min; the temperature of the homogenous dispersion reaction is controlled to 18°C, and the reaction is stopped when the pH of the reaction system reaches 7.0.

[0051] Step 4: sieve the reaction product with a 200-mesh sieve to obtain a sieved product; wash the sieved product with anhydrous ethanol, and after washing, place it in a vacuum drying oven at 90° C. for 3 hours to obtain nano calcium carbonate.

[0052] Example 7 This embodiment 7 provides a method for preparing nano calcium carbonate by resource utilization of blast furnace slag, comprising the following steps: Step 1: After treating blast furnace slag by water quenching process, crushing it to obtain fine-grained slag mainly composed of glass; after drying the fine-grained slag mainly composed of glass, crushing and ball milling it, and sieving it through a 150-mesh standard sieve to obtain blast furnace slag powder.

[0053] Step 2: adding 15 g of the blast furnace slag powder to 120 g of 9% ammonium chloride solution by mass, and adjusting the pH value of the leaching system to 11.0 with 18 g of ammonia evaporation waste liquid at a temperature of 35° C., allowing the reaction to stand to obtain a leaching solution rich in calcium ions; wherein the ammonia evaporation waste liquid is ammonia water recovered from the ammonia evaporation process in the coking section of the factory, and the effective ammonia water content in the ammonia evaporation waste liquid is 20%.

[0054] Step 3, transferring the calcium ion-rich extract to a homogenizer, and adding sodium citrate to obtain a reaction system; wherein the sodium citrate is industrial grade, and the amount of sodium citrate added is 0.15% of the mass of the calcium ion-rich extract; starting the homogenizer, controlling the speed at 600r / min for dispersion for 8min, introducing the carbon dioxide gas in the blast furnace gas purification process using organic amine to capture the blast furnace gas, and performing a homogenous dispersion reaction to obtain a reaction product; wherein the carbon dioxide content in the carbon dioxide gas is greater than 98%, and the flow rate of the carbon dioxide gas is 55mL / min; the temperature of the homogenous dispersion reaction is controlled to 20°C, and the reaction is stopped when the pH of the reaction system reaches 7.0.

[0055] Step 4: sieve the reaction product with a 200-mesh sieve to obtain a sieved product; wash the sieved product with anhydrous ethanol, and after washing, place it in a vacuum drying oven at a temperature of 95° C. and vacuum dry it for 4 hours to obtain nano calcium carbonate.

[0056] Example 8 This embodiment 8 provides a method for preparing nano calcium carbonate by resource utilization of blast furnace slag, comprising the following steps: Step 1: After treating blast furnace slag by water quenching process, crushing it to obtain fine-grained slag mainly composed of glass; after drying the fine-grained slag mainly composed of glass, crushing and ball milling it, and sieving it through a 150-mesh standard sieve to obtain blast furnace slag powder.

[0057] Step 2: adding 12 g of the blast furnace slag powder to 140 g of 5% ammonium nitrate solution by mass, and adjusting the pH value of the leaching system to 11.0 with 18 g of ammonia evaporation waste liquid at a temperature of 30° C., allowing the reaction to stand to obtain a leaching solution rich in calcium ions; wherein the ammonia evaporation waste liquid is ammonia water recovered from the ammonia evaporation process in the coking section of the factory, and the effective ammonia water content in the ammonia evaporation waste liquid is 15%.

[0058] Step 3, transferring the calcium ion-rich extract to a homogenizer, and adding sodium citrate to obtain a reaction system; wherein the sodium citrate is industrial grade, and the amount of sodium citrate added is 0.1% of the mass of the calcium ion-rich extract; starting the homogenizer, controlling the speed at 700r / min for dispersion for 10min, introducing the carbon dioxide gas in the blast furnace gas using organic amines in the blast furnace gas purification process, and performing a homogenous dispersion reaction to obtain a reaction product; wherein the carbon dioxide content in the carbon dioxide gas is greater than 98%, and the flow rate of the carbon dioxide gas is 50mL / min; the temperature of the homogenous dispersion reaction is controlled to 21°C, and the reaction is stopped when the pH of the reaction system reaches 7.0.

[0059] Step 4: sieve the reaction product with a 200-mesh sieve to obtain a sieved product; wash the sieved product with anhydrous ethanol, and after washing, place it in a vacuum drying oven at 90° C. for 2 hours to obtain nano calcium carbonate.

[0060] Comparative Example 1 The method for preparing calcium carbonate by resource utilization of blast furnace slag provided in this comparative example 1 comprises the following steps: Step 1: After treating blast furnace slag by water quenching process, crushing it to obtain fine-grained slag mainly composed of glass; after drying the fine-grained slag mainly composed of glass, crushing and ball milling it, and sieving it through a 150-mesh standard sieve to obtain blast furnace slag powder.

[0061] Step 2: Add 30 g of the blast furnace slag powder to 244 g of 5% acetic acid solution, and adjust the pH value of the leaching system to 11.0 with 56 g of 25% ammonia water at a temperature of 35° C., let the reaction stand, and obtain a leaching solution.

[0062] Step 3, transferring the extract to a homogenizer, and adding sodium citrate to obtain a reaction system; wherein the sodium citrate is industrial grade, and the amount of sodium citrate added is 0.1% of the mass of the calcium ion-rich extract; starting the homogenizer, controlling the speed at 600r / min for dispersion for 10min, introducing carbon dioxide gas, performing a homogenous dispersion reaction, and obtaining a reaction product; wherein the content of carbon dioxide in the carbon dioxide gas is greater than 98%, and the introduction flow rate of the carbon dioxide gas is 50mL / min; the temperature of the homogenous dispersion reaction is controlled at 20°C, and the reaction is stopped when the pH of the reaction system reaches 7.0.

[0063] Step 4: sieve the reaction product with a 200-mesh sieve to obtain a sieved product; wash the sieved product with anhydrous ethanol, and after washing, place it in a vacuum drying oven at 90° C. for 8 hours to obtain calcium carbonate.

[0064] Comparative Example 2 The method for preparing calcium carbonate by resource utilization of blast furnace slag provided in this comparative example 2 comprises the following steps: Step 1: After treating blast furnace slag by water quenching process, crushing it to obtain fine-grained slag mainly composed of glass; after drying the fine-grained slag mainly composed of glass, crushing and ball milling it, and sieving it through a 150-mesh standard sieve to obtain blast furnace slag powder.

[0065] Step 2: Add 30 g of the blast furnace slag powder to 244 g of 5% ammonium acetate solution, and adjust the pH value of the leaching system to 11.0 with 56 g of 25% ammonia water at a temperature of 35° C., let the reaction stand, and obtain a leaching solution.

[0066] Step 3, transferring the extract to a homogenizer, and adding sodium citrate to obtain a reaction system; wherein the sodium citrate is industrial grade, and the amount of sodium citrate added is 0.1% of the mass of the calcium ion-rich extract; starting the homogenizer, controlling the speed at 600r / min for dispersion for 10min, introducing the carbon dioxide gas in the blast furnace gas using organic amines during the blast furnace gas purification process, and performing a homogenous dispersion reaction to obtain a reaction product; wherein the carbon dioxide content in the carbon dioxide gas is greater than 50%, and the flow rate of the carbon dioxide gas is 50mL / min; the temperature of the homogenous dispersion reaction is controlled to 20°C, and the reaction is stopped when the pH of the reaction system reaches 7.0.

[0067] Step 4: sieve the reaction product with a 200-mesh sieve to obtain a sieved product; wash the sieved product with anhydrous ethanol, and after washing, place it in a vacuum drying oven at 90° C. for 2 hours to obtain calcium carbonate.

[0068] Test result description: The quality, purity, whiteness and particle size of the nano calcium carbonate prepared in the above Examples 1-8 and the calcium carbonate prepared in Comparative Examples 1-2 were tested, and the carbon dioxide consumed in the preparation process was recorded; wherein, the whiteness test was conducted with reference to the general method for determining the whiteness of inorganic chemical products GB / T 23774-2009, and the particle size test was conducted using the calcium carbonate analysis method GB / T 19281-2014 standard; specifically, the above test and recorded results are shown in Table 1 below.

[0069] Table 1 Test results of nano calcium carbonate prepared in Examples 1-8 and light calcium carbonate prepared in Comparative Examples 1-2

[0070] As can be seen from Table 1 above, the nano calcium carbonate prepared in the above Examples 1-8 meets the national nano calcium carbonate standards and can be used in industries such as rubber, plastics, sealants, adhesives, offset inks and coatings; while the calcium carbonate prepared in Comparative Examples 1-2 is light calcium carbonate.

[0071] In the present invention, the existing carbon dioxide resources of the factory are utilized, which are obtained from the treatment of the blast furnace gas of the factory, which not only increases the content of carbon monoxide, but also increases the calorific value of the blast furnace gas; the captured carbon dioxide can be used as a raw material for production, reducing carbon emissions, and being environmentally friendly and low-carbon; the ammonia water comes from the recovered ammonia water in the ammonia distillation section, and the special approach has higher efficiency in the extract, and can be used on-site, reducing production costs, and solving the ammonia water storage problem of the factory; the method has the characteristics of blast furnace slag resource utilization, environmental protection, low carbon, and turning waste into treasure; the nano-scale calcium carbonate produced by the present invention has high added value, high purity, and high particle size concentration, and meets the needs of the rubber, plastic, papermaking and coating industries.

[0072] The above embodiment is only one of the implementation methods that can realize the technical solution of the present invention. The scope of protection claimed by the present invention is not limited only to this embodiment, but also includes changes, replacements and other implementation methods that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention.

Claims

1. A method for preparing nano calcium carbonate by recycling blast furnace slag, characterized in that: include: Chemically leaching blast furnace slag to obtain a leaching solution rich in calcium ions; wherein the blast furnace slag is blast furnace slag produced when smelting pig iron; Carbon dioxide is introduced into the calcium ion-rich leaching solution for reaction, and after the reaction, screening, washing and drying are performed to obtain nano calcium carbonate; wherein the carbon dioxide is carbon dioxide gas captured by organic amines during the purification process of blast furnace gas.

2. The method for preparing nano calcium carbonate by recycling blast furnace slag according to claim 1, wherein: The process of chemically leaching blast furnace slag to obtain a leaching solution rich in calcium ions is as follows: mixing blast furnace slag with blast furnace slag leaching solution to obtain a leaching system; The pH value of the leaching system is adjusted by using the evaporated ammonia waste liquid, and the mixture is allowed to stand for reaction to obtain a mixed solution rich in calcium ions.

3. The method for preparing nano calcium carbonate by recycling blast furnace slag according to claim 2, characterized in that: The blast furnace slag leachate is an ammonium chloride solution or an ammonium nitrate solution; wherein the liquid-solid ratio of the blast furnace slag leachate to the blast furnace slag is: (100-150) mL: (10-15) g, and the mass fraction of the ammonium chloride solution or the ammonium nitrate solution is 5%-10%.

4. The method for preparing nano calcium carbonate by recycling blast furnace slag according to claim 2, characterized in that: When the pH value of the leaching system is adjusted by using the evaporated ammonia waste liquid, the temperature is 30-40°C.

5. The method for preparing nano calcium carbonate by recycling blast furnace slag according to claim 2, characterized in that: The ammonia evaporation waste liquid is ammonia water recovered from the coking section of the factory or the factory waste water through the ammonia evaporation process, and the effective ammonia water content in the ammonia evaporation waste liquid is 15%-20%.

6. The method for preparing nano calcium carbonate by recycling blast furnace slag according to claim 1, characterized in that: The process of introducing carbon dioxide into the calcium ion-rich extract to react, and then filtering, washing and drying the extract to obtain nano calcium carbonate is as follows: adding sodium citrate to the calcium ion-rich extract to obtain a reaction system; The reaction system is placed in a homogenizer, and an organic amine is used to capture carbon dioxide gas in the blast furnace gas during the blast furnace gas purification process, and a homogenization and dispersion reaction is performed to obtain a reaction product; The reaction product is subjected to screening, alcohol washing and drying treatment to obtain nano-scale calcium carbonate.

7. The method for preparing nano calcium carbonate by recycling blast furnace slag according to claim 6, characterized in that: The sodium citrate is of industrial grade, and the amount of sodium citrate added is 0.05%-0.15% of the mass of the calcium ion-rich extract.

8. The method for preparing nano calcium carbonate by recycling blast furnace slag according to claim 6, characterized in that: In the process of using organic amine to capture carbon dioxide gas in blast furnace gas during blast furnace gas purification, the carbon dioxide content in the carbon dioxide gas is greater than 98%, and the inlet flow rate of the carbon dioxide gas is 40-60mL / min.

9. The method for preparing nano calcium carbonate by recycling blast furnace slag according to claim 6, characterized in that: The temperature of the homogeneous dispersion reaction is 18-22°C.

10. The method for preparing nano calcium carbonate by recycling blast furnace slag according to claim 6, wherein: The alcohol washing process is: washing with anhydrous ethanol; the drying process is: vacuum drying at a temperature of 80-100° C. for 1-4 hours.

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