Comprehensive utilization method of refining slag

Abstract

The invention discloses a comprehensive utilization method of refining slag, which comprises the following steps: dissolving the refining slag in hydrochloric acid to obtain a refining slag pickle liquor; filtering the refining slag pickle liquor to obtain first filtrate and filter residues, and washing the filter residues to obtain first solid and first washing liquor; combining the first washing liquid and the first filtrate to obtain a second mixed solution; and adding an oxidizing agent into the second mixed solution to obtain a first precipitate. According to the method, the refining slag is subjected to acid leaching with hydrochloric acid, the PH value of the solution is adjusted, silicon dioxide, aluminum hydroxide, ferric hydroxide, calcium chloride or calcium oxide and recycled hydrochloric acid are obtained, the accumulated refining slag is decomposed into various new substances in the process reaction, the method is simple, the substance purity is high, the refining slag is recycled, and large economic value can be created; and meanwhile, mining of various resources is reduced. And a new direction is found for comprehensive utilization of the refining slag.

Description

Technical Field

[0001] The present invention relates to the technical field of comprehensive utilization of iron and steel solid waste, and particularly to a method for comprehensive utilization of refining slag. Background Art

[0002] Refining slag refers to a technology in which raw materials are mixed in a certain proportion and particle size, heated below the melting point of the raw materials to sinter the raw materials together, and then crushed into particle size for use. Refining slag is the waste slag generated in the steelmaking refining process of iron and steel. In the steelmaking refining process, slag-making agents such as calcium oxide and calcium-aluminum wire are added to the molten steel to remove harmful substances such as silicon and sulfur elements in the molten steel. The formed refining slag mainly contains calcium, aluminum, silicon, and iron elements. In the prior art, refining slag is stacked as steel slag solid waste, resulting in a waste of resources.

[0003] Therefore, how to provide a method for recycling refining slag is an urgent technical problem to be solved by those skilled in the art. Summary of the Invention

[0004] The present invention provides a method for comprehensive utilization of refining slag.

[0005] The present invention provides the following solutions:

[0006] A method for comprehensive utilization of refining slag, comprising:

[0007] Dissolving the refining slag in hydrochloric acid to obtain a refining slag acid leaching solution;

[0008] Filtering the refining slag acid leaching solution to obtain a first filtrate and a filter residue, and washing the filter residue with water to obtain a first solid and a first washing solution;

[0009] Combining the first washing solution and the first filtrate to obtain a second mixed solution;

[0010] Adding an oxidant to the second mixed solution to obtain a first precipitate, filtering and washing the first precipitate to obtain a second solid, a second washing solution, and a second filtrate;

[0011] Combining the second washing solution and the second filtrate to obtain a third mixed solution;

[0012] Adding limestone and quicklime to the third mixed solution, reacting to generate a first gas and a second precipitate, filtering and washing the second precipitate to obtain a third solid, a third washing solution, and a third filtrate;

[0013] Combining the third washing solution and the third filtrate to obtain a fourth mixed solution, and recovering the first gas;

[0014] The fourth mixed solution is subjected to evaporation treatment to obtain a fourth solid, and the fourth solid is subjected to spray high-temperature treatment to obtain a fifth solid and a second gas.

[0015] Preferably, the concentration of the hydrochloric acid is 20%.

[0016] Preferably, the refined slag acid leaching solution includes aluminum chloride, calcium chloride, and SiO2 flocculent precipitate.

[0017] Preferably, the first solid includes SiO2 solid.

[0018] Preferably, the oxidant is used to oxidize Fe in the second mixed solution 2+ to Fe 3+ , the first precipitate includes Fe(OH)3 precipitate, and the second solid includes Fe(OH)3 solid.

[0019] Preferably, the oxidant includes 10% hydrogen peroxide.

[0020] Preferably, the first gas includes CO2 gas, and the third solid includes Al(OH)3 solid.

[0021] Preferably, the evaporation treatment includes evaporation treatment at 200 °C, and the spray high-temperature treatment includes high-temperature treatment under conditions greater than 800 °C.

[0022] Preferably, the fourth solid includes calcium chloride and magnesium chloride containing crystal water.

[0023] Preferably, the fifth solid includes calcium chloride and magnesium chloride without crystal water, and the second gas includes hydrogen chloride gas.

[0024] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0025] Through the present invention, a comprehensive utilization method of refining slag can be realized. In one implementation, the method may include dissolving the refining slag in hydrochloric acid to obtain a pickling solution of the refining slag; filtering the pickling solution of the refining slag to obtain a first filtrate and a filter residue, and washing the filter residue with water to obtain a first solid and a first washing solution; combining the first washing solution and the first filtrate to obtain a second mixed solution; adding an oxidant to the second mixed solution to obtain a first precipitate, filtering and washing the first precipitate to obtain a second solid, a second washing solution and a second filtrate; combining the second washing solution and the second filtrate to obtain a third mixed solution; adding limestone and quicklime to the third mixed solution to react to generate a first gas and a second precipitate, filtering and washing the second precipitate to obtain a third solid, a third washing solution and a third filtrate; combining the third washing solution and the third filtrate to obtain a fourth mixed solution, and recovering the first gas; performing evaporation treatment on the fourth mixed solution to obtain a fourth solid, and performing spray high-temperature treatment on the fourth solid to obtain a fifth solid and a second gas. This method acid-leaches the refining slag with hydrochloric acid and adjusts the pH value of the solution to obtain silicon dioxide, aluminum hydroxide, iron hydroxide, calcium chloride or calcium oxide respectively, and recovers hydrochloric acid. This process reaction decomposes the accumulated refining slag into new various substances. The method is simple, the substance purity is high, the refining slag is recycled, and it can create great economic value, while reducing the exploitation of various resources. It finds a new direction for the comprehensive utilization of refining slag.

[0026] Of course, it is not necessary for any product implementing the present invention to achieve all the above advantages simultaneously. Detailed implementation manners

[0027] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Apparently, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention belong to the protection scope of the present invention.

[0028] Embodiment

[0029] The embodiment of the present invention provides a comprehensive utilization method of refining slag, and the method may include:

[0030] Dissolving the refining slag in hydrochloric acid to obtain a pickling solution of the refining slag; specifically, the concentration of the hydrochloric acid is 20%. The pickling solution of the refining slag includes aluminum chloride, calcium chloride and SiO2 flocculent precipitate. Dissolving the refining slag in hydrochloric acid to obtain a mixed solution mainly composed of aluminum chloride and calcium chloride, and a pickling solution of the refining slag with SiO2 flocculent precipitate.

[0031] Filter the acid-leached solution of the refined slag to obtain a first filtrate and a filter residue, and wash the filter residue with water to obtain a first solid and a first washing solution; specifically, the first solid includes SiO2 solid.

[0032] Combine the first washing solution and the first filtrate to obtain a second mixed solution;

[0033] Add an oxidizing agent to the second mixed solution to obtain a first precipitate, and filter and wash the first precipitate to obtain a second solid, a second washing solution, and a second filtrate; specifically, the oxidizing agent is used to oxidize Fe 2+ in the second mixed solution to Fe 3+ , the first precipitate includes Fe(OH)3 precipitate, and the second solid includes Fe(OH)3 solid. The oxidizing agent may include 10% hydrogen peroxide.

[0034] Combine the second washing solution and the second filtrate to obtain a third mixed solution;

[0035] Add limestone and quicklime to the third mixed solution, react to generate a first gas and a second precipitate, and filter and wash the second precipitate to obtain a third solid, a third washing solution, and a third filtrate; specifically, the first gas includes CO2 gas, and the third solid includes Al(OH)3 solid.

[0036] Combine the third washing solution and the third filtrate to obtain a fourth mixed solution, and recover the first gas;

[0037] Perform evaporation treatment on the fourth mixed solution to obtain a fourth solid, and perform spray high-temperature treatment on the fourth solid to obtain a fifth solid and a second gas. Specifically, the evaporation treatment includes evaporation treatment at 200 °C, and the spray high-temperature treatment includes high-temperature treatment under conditions greater than 800 °C. The fourth solid includes calcium chloride and magnesium chloride containing crystal water. The fifth solid includes calcium chloride and magnesium chloride without crystal water, and the second gas includes hydrogen chloride gas. In order to facilitate the collection of hydrogen chloride gas, the embodiments of the present application may also provide that the hydrogen chloride gas is absorbed by water to obtain hydrochloric acid liquid.

[0038] The main components of the refined slag are as follows:

[0039] Composition <![CDATA[SiO2]]> CaO MgO <![CDATA[Al2O3]]> TFe Total Mass percentage (%) 5.26 48.39 8.00 35.12 1.20 97.97

[0040] The composition of the refining slag has relatively high contents of calcium and aluminum elements, followed by silicon and magnesium elements. The comprehensive utilization method of the refining slag provided by the embodiment of the present application acid-leaches the refining slag with hydrochloric acid and adjusts the pH value of the solution to obtain silicon dioxide, aluminum hydroxide, iron hydroxide, calcium chloride or calcium oxide, and recycled hydrochloric acid respectively. This technological reaction decomposes the accumulated refining slag into various new substances. The method is simple, the purity of the substances is high, enabling the recycling of the refining slag, creating greater economic value, and reducing the exploitation of various resources at the same time. It finds a new direction for the comprehensive utilization of the refining slag.

[0041] The chemical equations involved in the method provided by the embodiment of the present application include:

[0042] CaO·Al2O3 + 8HCl = CaCl2 + 2AlCl3 + 4H2O

[0043] Fe2O3 + 6HCl = 2FeCl3 + 3H2O

[0044] FeCl3 + 3H2O = Fe(OH)3↓ + 3HCl

[0045] CaCO3 + 2HCl = CaCl2 + CO2↑ + H2O

[0046] CaO + H2O = Ca(OH)2

[0047] Ca(OH)2 + AlCl3 = Al(OH)3↓ + CaCl2

[0048] The following conducts experimental phenomena and component analysis on the method provided by the embodiment of the present application:

[0049] 1. Dissolve 50 grams of refining slag in 500 ml of 20% excessive hydrochloric acid to obtain a brownish-red acid-leached solution L1 of the refining slag; the acid-leached solution L1 of the refining slag includes a mixed solution mainly composed of aluminum chloride and calcium chloride, and SiO2 flocculent precipitates.

[0050] 2. Filter the acid-leached solution L1 of the refining slag, wash the filter residue with water to obtain a brownish-red solid S1, and combine the washing liquid and the filtrate to obtain a mixed solution L2; the brownish-red solid S1 includes SiO2 solid.

[0051] 3. Add an oxidant (10% hydrogen peroxide) to the mixed solution L2 to obtain brownish-red precipitates, filter and wash with water to obtain a brownish-red solid S2, and combine the washing liquid and the filtrate to obtain a mixed solution L3; Fe in the mixed solution L2 2+ is oxidized to Fe 3+ , producing Fe(OH)3 precipitates, filtering and washing with water to obtain Fe(OH)3 solid S2, and combining the washing liquid and the filtrate to obtain a mixed solution L3.

[0052] 4. Add limestone and quicklime to the mixed liquid L3, generating gas G1 and a green precipitate simultaneously. Filter and wash with water to obtain solid S3, and combine the washing liquid and the filtrate to get the mixed liquid L4;

[0053] 4. Treat the mixed liquid L4 according to Method 1, the 200°C evaporation treatment method, to obtain solid S4;

[0054] 5. Treat the mixed liquid L4 according to Method 2, the high-temperature treatment method for the solution. Spray the mixed liquid L4 for high-temperature treatment (above 800°C) to obtain solid S5 and gas G2. Absorb gas G2 with water to obtain liquid L5 for system reuse.

[0055] The components of the separated substances are analyzed as follows:

[0056]

[0057]

[0058] It should be noted that in this text, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0059] The above is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included within the protection scope of the present invention.

Claims

1. A method for comprehensive utilization of refining slag, characterized in that, Including: Dissolve the refining slag in hydrochloric acid to obtain a pickling solution of the refining slag. Filter the pickling solution of the refining slag to obtain a first filtrate and a filter residue, and wash the filter residue with water to obtain a first solid and a first washing solution. Combine the first washing solution and the first filtrate to obtain a second mixed solution. Add an oxidant to the second mixed solution to obtain a first precipitate, and filter and wash the first precipitate to obtain a second solid, a second washing solution, and a second filtrate. Combine the second washing solution and the second filtrate to obtain a third mixed solution. Add limestone and quicklime to the third mixed solution, react to generate a first gas and a second precipitate, and filter and wash the second precipitate to obtain a third solid, a third washing solution, and a third filtrate. Combine the third washing solution and the third filtrate to obtain a fourth mixed solution, and recover the first gas. Perform evaporation treatment on the fourth mixed solution to obtain a fourth solid, and perform spray high-temperature treatment on the fourth solid to obtain a fifth solid and a second gas.

2. The comprehensive utilization method of refining slag according to claim 1, wherein, The concentration of the hydrochloric acid is 20%.

3. The comprehensive utilization method of refining slag according to claim 1, characterized in that The pickling solution of the refining slag includes aluminum chloride, calcium chloride, and a flocculent precipitate of SiO2.

4. The comprehensive utilization method of refining slag according to claim 1, characterized in that The first solid includes a SiO2 solid.

5. The comprehensive utilization method of refining slag according to claim 1, characterized in that The oxidant is used to oxidize Fe in the second mixed solution 2+ to Fe 3+ . The first precipitate includes Fe(OH)3 precipitate, and the second solid includes Fe(OH)3 solid.

6. The comprehensive utilization method of refining slag according to claim 1, characterized in that The oxidant includes 10% hydrogen peroxide.

7. The comprehensive utilization method of refining slag according to claim 1, characterized in that, The first gas includes CO2 gas, and the third solid includes an Al(OH)3 solid.

8. The comprehensive utilization method of refining slag according to claim 1, characterized in that, The evaporation treatment includes evaporation treatment at 200°C, and the spray high-temperature treatment includes high-temperature treatment under conditions greater than 800°C.

9. The comprehensive utilization method of refining slag according to claim 1, characterized in that, The fourth solid includes calcium chloride and magnesium chloride containing crystal water.

10. The comprehensive utilization method of refined slag according to claim 9, characterized in that The fifth solid includes calcium chloride and magnesium chloride without crystal water, and the second gas includes hydrogen chloride gas.

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