Treatment method of waste iron oxide desulfurizer

Abstract

The invention relates to the field of waste iron oxide desulfurizer resource utilization, and discloses a waste iron oxide desulfurizer treatment method, which comprises: (1) crushing a waste iron oxide desulfurizer to obtain waste iron oxide desulfurizer powder; (2) heating the waste iron oxide desulfurizer powder obtained in the step (1), and respectively condensing elemental sulfur and benzene naphthalene organic matters generated by heating to obtain a mixture of liquid elemental sulfur and liquid benzene naphthalene organic matters; and (3) preparing the heated waste iron oxide desulfurizer powder into a cementing material or concrete. According to the treatment method disclosed by the invention, 100% resource utilization of the waste iron oxide desulfurizer is realized through the processes of crushing, sulfur removal, admixture and the like.

Description

Technical Field

[0001] The invention relates to the field of resource utilization of waste iron oxide desulfurizing agents, and in particular to a method for treating waste iron oxide desulfurizing agents. Background Art

[0002] In the manufacturing industry, industries with high requirements for coal gas or natural gas usually carry out fine desulfurization. Commonly used desulfurizers include iron-based desulfurizers, activated carbon desulfurizers, zinc-based desulfurizers, etc. Among them, the iron oxide desulfurizer in the iron-based desulfurizer becomes ineffective due to the reduction of sulfur capacity after long-term use and becomes a waste desulfurizer. The waste desulfurizer contains some benzene, naphthalene and sulfur, and its accumulation will cause pollution to soil and water quality.

[0003] Domestic treatment methods for waste desulfurizers mainly include incineration, deep burial, chemical treatment and sintering. Among them, the incineration method produces sulfur dioxide that needs to be treated, the deep burial method pollutes land resources, and the sintering process of steel enterprises is a long process and produces sulfur dioxide that needs to be treated. At present, there is no 100% resource utilization method for waste iron oxide desulfurizers.

[0004] Application No. 201910187755.X discloses a method for separating waste iron oxide desulfurizer from sulfur, comprising the following steps: mixing the sulfur-containing iron oxide desulfurizer with a solvent, and performing solid-liquid separation to obtain a sulfur-containing solution and a sulfur-free iron oxide desulfurizer, regenerating and recycling the waste desulfurizer, and obtaining high-purity sulfur as an industrial product. The method is simple and operable, but does not take into account that the waste desulfurizer cannot be simply regenerated and reused after sulfur is extracted, and even after regeneration, the use effect is not good.

[0005] Application No. 201810663638.1 discloses a method for treating waste desulfurizer, which includes the following steps: mixing waste desulfurizer, iron ore powder, solid fuel, flux and return ore to obtain a sintering mixture; adding water to the sintering mixture and mixing and granulating to obtain a granulated material; sintering the granulated material to obtain sintered ore and sintering flue gas; and desulfurizing and denitrifying the sintering flue gas and then discharging it into the atmosphere. Although this process recovers the beneficial elements in the waste desulfurizer, it still produces sulfur dioxide that needs to be removed, and the sulfur element is not recycled.

[0006] Application No. 202210449471.5 discloses a harmless treatment method and application of waste desulfurizer from coke oven gas, which uses high temperature to remove elemental sulfur in the waste desulfurizer and collect it, uses hydrochloric acid to dissolve iron oxide, calcium carbonate and other impurities in the waste desulfurizer, separates calcium sulfate for use in the gypsum industry, and the solution is roasted at high temperature to form a mixture of iron oxide and calcium oxide, which is used as a sintering raw material. The gas is absorbed to form hydrochloric acid, thereby achieving harmless treatment of the waste desulfurizer. Although this method makes full use of the components in the waste desulfurizer, the process is complicated.

[0007] Application No. 202111385736.1 discloses a method for disposing of waste iron oxide desulfurizer, which includes pre-treatment of the waste desulfurizer before removal, transportation to the power plant, blending into coal, high-temperature combustion purification, etc., to synergistically dispose of the waste desulfurizer. This method uses the coal-fired system of the power plant to treat the waste desulfurizer, but the sulfur in the desulfurizer is converted into sulfur dioxide and removed again, and the process is complicated.

[0008] The current disposal methods of waste iron oxide desulfurizers generally have the following problems: first, the degree of resource utilization is insufficient, the process flow is complicated, and the cost is high; second, when sintering and other pyrometallurgical processes are used for disposal, sulfur dioxide is still generated and enters the flue gas, which needs to be removed. Summary of the invention

[0009] The purpose of the present invention is to overcome the problems of the existing waste iron oxide desulfurizer disposal methods, such as complex process flow, safety and environmental protection problems, and the beneficial components of the waste desulfurizer are not effectively utilized. A treatment method for waste iron oxide desulfurizer is provided, which has simple process, feasible method, low cost, high degree of resource utilization, and achieves the maximum resource utilization of the waste desulfurizer.

[0010] In order to achieve the above object, the present invention provides a method for treating waste iron oxide desulfurizer, the method comprising the following steps:

[0011] (1) crushing the waste iron oxide desulfurizer to obtain waste iron oxide desulfurizer powder;

[0012] (2) heating the waste iron oxide desulfurizer powder obtained in step (1), and condensing the sulfur element and benzene naphthalene organic matter generated by the heating, respectively, to obtain a mixture of liquid sulfur element and liquid benzene naphthalene organic matter;

[0013] (3) The heated waste iron oxide desulfurizer powder is prepared into a cementitious material or concrete.

[0014] The waste iron oxide desulfurizer of the invention comes from the waste iron oxide desulfurizer produced by the fine desulfurization of coke oven gas and the fine desulfurization of blast furnace gas.

[0015] Among them, the waste iron oxide desulfurizer contains CaSO 4 The content of is 30-80wt%, the content of S is 0.5-40wt%, and the content of Fe is 2 O 3 The content of CaCO is 5-30wt%, 3 The content of is 0.2-15wt%, and other unavoidable impurities (such as Al 2 O 3 、SiO 2 , MgO, K 2 O、Na2 O, etc.) is 0.5 to 5 wt%.

[0016] In a specific embodiment, the waste iron oxide desulfurizer in the present invention is first transported to a raw material bin for storage, and the waste iron oxide desulfurizer stored in the raw material bin is continuously fed into a pulverizer for pulverization to obtain waste iron oxide desulfurizer powder, which is stored in a powder bin, and then the waste iron oxide desulfurizer powder in the powder bin is transported to a heating kiln for heating.

[0017] Furthermore, in step (1) of the present invention, the particle size of the waste iron oxide desulfurizer powder is less than 250 μm, of which the weight of particles less than 75 μm accounts for no less than 50 wt%, and the weight of particles less than 150 μm accounts for no less than 80 wt%; controlling the particle size within these ranges is beneficial to the volatilization of sulfur and benzene-naphthalene organic matter when the waste iron oxide desulfurizer is heated, as well as the subsequent resource utilization of the waste iron oxide desulfurizer powder.

[0018] In a preferred case, when the waste iron oxide desulfurizer is stored in the raw material bin and the waste iron oxide desulfurizer powder is in the powder bin, protective gas needs to be introduced into the raw material bin and the powder bin for protection to prevent the waste iron oxide desulfurizer from spontaneous combustion due to excessive temperature.

[0019] Among them, when the waste iron oxide desulfurizer powder in the powder bin is transported to the heating kiln, the waste iron oxide desulfurizer powder can be directly fed into the heating kiln, and the feeding speed is controlled to be 0.1-10 tons / hour; the waste iron oxide desulfurizer powder can also be sprayed into the heating kiln, and the spraying speed is also controlled to be 0.1-10 tons / hour. Because too low a speed will lead to low production efficiency, too high a speed will lead to insufficient addition of waste iron oxide desulfurizer powder, resulting in insufficient volatilization of sulfur and benzene naphthalene organic matter, so it is more appropriate to control the speed within the above range.

[0020] Furthermore, in step (2), a protective gas is introduced into the heating furnace used for heating or a vacuum state is maintained to isolate the air.

[0021] In step (2), the heating method of the heating kiln can be ordinary electric heating, gas heating, microwave heating or electromagnetic induction heating, etc.; the heating kiln can be a conventional kiln such as a rotary kiln or an ordinary kiln with an internal conveyor belt.

[0022] Among them, when the heating kiln used is a rotary kiln, the rotation speed of the rotary kiln is 0.5 to 2 revolutions per minute; when the heating kiln used is an ordinary kiln with an internal conveyor belt, the speed of the conveyor belt is 0.1 to 3 meters per minute.

[0023] Furthermore, in step (2), when the heating furnace used for heating is maintained in a vacuum state, the vacuum degree is not less than 0.05 MPa, and more preferably 0.05 to 0.5 MPa.

[0024] Preferably, in step (2), in order to ensure that the sulfur element and benzene-naphthalene organic matter in the waste iron oxide desulfurizer powder can be fully heated and volatilized, the heating conditions include: a temperature of 400-700° C. and a time of 5-60 minutes.

[0025] A graded condenser is also connected to the upper part of one side of the heating kiln, and the gaseous sulfur and a very small amount of gaseous benzene and naphthalene organic matter generated during the heating process enter the graded condenser, and are condensed at different parts of the graded condenser to obtain liquid sulfur and a mixture of liquid benzene and naphthalene organic matter; the liquid sulfur (sulfur) obtained after condensation has a sulfur content of ≥90wt%, and is collected by a sulfur collector and used for industrial or agricultural sulfur production; the liquid benzene and naphthalene organic matter mixture obtained by condensation is collected by a naphthalene-benzene collector and returned to the coking enterprise for comprehensive utilization or sold to other fuel fields for use.

[0026] Specifically, the gaseous substances generated after the waste iron oxide desulfurizer powder is heated in the heating kiln need to be guided to the graded condenser for condensation using an induced draft fan.

[0027] Wherein, in step (2), the condensation temperature of the sulfur element produced by heating is 130-180°C; the condensation temperature of the benzene-naphthalene organic matter produced by heating is ≤80°C, further 25-80°C.

[0028] The graded condenser in the present invention adopts circulating water condensation or other conventional condensation methods.

[0029] Furthermore, in a preferred embodiment, the end of the heating furnace can also be designed with a device for spraying to remove impurities or other gases according to actual conditions.

[0030] The protective gas described in the present invention is selected from one or more of nitrogen, helium, neon, argon, krypton and xenon. In a specific embodiment, the protective gas used is nitrogen.

[0031] In a specific implementation, the heated waste iron oxide desulfurizer powder enters a slag powder bin and is then transported to a blending bin of a concrete production enterprise. The waste desulfurizer slag powder is added to a concrete mixer as needed to prepare concrete; or the heated waste iron oxide desulfurizer powder is used to prepare a cementitious material.

[0032] Among them, the methods for preparing concrete and preparing cementitious materials are both conventional methods in the field. On this basis, the present invention further adds heated waste iron oxide desulfurizer powder; the present invention further prepares the heated waste iron oxide desulfurizer powder into cementitious material or concrete, thereby improving the strength of the material.

[0033] Further in step (3), when the heated waste iron oxide desulfurizer powder is used to prepare cementitious material, the amount of the heated waste iron oxide desulfurizer powder does not exceed 3wt% of the total weight of the cementitious material, and further is 0.1-3wt% of the total weight of the cementitious material; wherein the heated waste iron oxide desulfurizer powder is used to replace part of the gypsum and is ground together with the clinker to prepare the cementitious material.

[0034] In step (3), when the heated waste iron oxide desulfurizer powder is used to prepare concrete, the amount of the heated waste iron oxide desulfurizer powder does not exceed 10wt% of the amount of the cementitious material, and further is 1-10wt% of the amount of the cementitious material.

[0035] In a specific implementation manner, the transportation method in the process may include a tank truck, a dump truck, etc.

[0036] The treatment method of the present invention fully considers that the waste iron oxide desulfurizer contains sulfur resources, and also contains calcium sulfate, iron oxide, calcium carbonate and other ingredients that are beneficial to improving the performance of concrete. The sulfur and a very small amount of benzene naphthalene in the waste iron oxide desulfurizer are graded and collected, and the elemental sulfur is used for industrial or agricultural sulfur production, and the benzene naphthalene is returned to the coking enterprise for comprehensive utilization or sold to other fuel fields. The slag powder left after the waste iron oxide desulfurizer is desulfurized can be used as an admixture for concrete production. The treatment method is a means of resource utilization of waste iron oxide desulfurizer, with a simple process, a feasible method, low cost, and a high degree of resource utilization. The calcium sulfate and calcium carbonate in the waste iron oxide desulfurizer can improve the strength of concrete.

[0037] The treatment method of the invention achieves 100% resource utilization of the waste iron oxide desulfurizer through processes such as crushing, desulfurization, and using as an admixture. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a process flow chart of the method for treating waste iron oxide desulfurizer of the present invention. DETAILED DESCRIPTION

[0039] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific implementation described herein is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0040] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0041] The process flow of the method for treating the waste iron oxide desulfurizer of the present invention is as follows: Figure 1 shown.

[0042] The waste iron oxide desulfurizer used in the following examples comes from the waste iron oxide desulfurizer produced by coke oven gas desulfurization and blast furnace gas desulfurization, wherein CaSO 4 The content of is 63.5wt%, the content of S is 15.1wt%, and the content of Fe 2 O 3 The content of CaCO is 16.2wt%, 3 The content of is 2.1wt%, and the content of other inevitable impurities is 3.1wt%.

[0043] Example 1

[0044] (1) The waste iron oxide desulfurizer is transported to a raw material warehouse by a tank truck and filled with nitrogen for protection. The waste iron oxide desulfurizer stored in the raw material warehouse is continuously fed into a pulverizer for pulverization to obtain waste iron oxide desulfurizer powder. The particle size of the waste iron oxide desulfurizer powder is less than 250 μm, of which the weight proportion of particles less than 75 μm is 60wt%, and the weight proportion of particles less than 150 μm is 90wt%; the waste iron oxide desulfurizer powder is stored in a powder warehouse, and the powder warehouse is filled with nitrogen for protection;

[0045] (2) Spraying the waste iron oxide desulfurizer powder stored in the powder silo onto the conveyor belt of the electric heating kiln at a speed of 2 tons / hour for heating. The heating temperature is 450°C, the heating time is 20 minutes, and the conveyor belt speed is 0.5 m / minute. Nitrogen is introduced into the heating kiln for protection. The sulfur element and benzene and naphthalene organic matter generated by heating are guided to the graded condenser through the induced draft fan and condensed at different parts of the graded condenser. The condensation temperature of the sulfur element generated by heating is 150°C, and the condensation temperature of the benzene and naphthalene organic matter generated by heating is 80°C. The sulfur content of the liquid sulfur element (sulfur) obtained after condensation is 96wt%, and it is collected by the sulfur collector and used for industrial or agricultural sulfur production; the liquid benzene and naphthalene organic matter mixture obtained by condensation is collected by the naphthalene and benzene collector and returned to the coking enterprise for comprehensive utilization or sold to other fuel fields for use;

[0046] (3) The heated waste iron oxide desulfurizer powder obtained in step (2) is sent to a slag powder bin, transported to a blending bin of a concrete production enterprise by a tank truck, and then added to a concrete mixer for preparing concrete, wherein the amount of the heated waste iron oxide desulfurizer powder is 1wt% of the amount of the cementitious material, and the strength grade of the obtained concrete is C45.

[0047] Example 2

[0048] (1) The waste iron oxide desulfurizer is transported to a raw material warehouse by a tank truck and filled with nitrogen for protection. The waste iron oxide desulfurizer stored in the raw material warehouse is continuously fed into a pulverizer for pulverization to obtain waste iron oxide desulfurizer powder. The particle size of the waste iron oxide desulfurizer powder is less than 250 μm, of which the weight proportion of particles less than 75 μm is 55 wt%, and the weight proportion of particles less than 150 μm is 85 wt%; the waste iron oxide desulfurizer powder is stored in a powder warehouse, and the powder warehouse is filled with nitrogen for protection;

[0049] (2) feeding the waste iron oxide desulfurizer powder stored in the powder bin into a microwave-heated rotary kiln at a rate of 5 tons / hour for heating at a temperature of 500°C for 25 minutes and a rotation speed of 1 revolution / minute. Nitrogen is introduced into the heating kiln for protection. The sulfur element and benzene-naphthalene organic matter generated by heating are guided to a graded condenser through an induced draft fan and condensed at different parts of the graded condenser. The condensation temperature of the sulfur element generated by heating is 131°C and the condensation temperature of the benzene-naphthalene organic matter generated by heating is 75°C. The sulfur content of the liquid sulfur element (sulfur) obtained after condensation is 95wt%, and it is collected by a sulfur collector and used for industrial or agricultural sulfur production. The liquid benzene-naphthalene organic matter mixture obtained by condensation is collected by a naphthalene-benzene collector and returned to the coking enterprise for comprehensive utilization or sold to other fuel fields for use.

[0050] (3) The heated waste iron oxide desulfurizer powder obtained in step (2) is sent to a slag powder bin, transported to a blending bin of a concrete production enterprise by a tank truck, and then added to a concrete mixer for preparing concrete, wherein the amount of the heated waste iron oxide desulfurizer powder is 5wt% of the amount of the cementitious material, and the strength grade of the obtained concrete is C50.

[0051] Example 3

[0052] (1) The waste iron oxide desulfurizer is transported to a raw material warehouse by a tank truck and filled with nitrogen for protection. The waste iron oxide desulfurizer stored in the raw material warehouse is continuously fed into a pulverizer for pulverization to obtain waste iron oxide desulfurizer powder. The particle size of the waste iron oxide desulfurizer powder is less than 250 μm, of which the weight proportion of particles less than 75 μm is 55 wt%, and the weight proportion of particles less than 150 μm is 85 wt%; the waste iron oxide desulfurizer powder is stored in a powder warehouse, and the powder warehouse is filled with nitrogen for protection;

[0053] (2) The waste iron oxide desulfurizer powder stored in the powder bin is fed to the conveyor belt of the electromagnetic induction heating furnace at a speed of 8 tons / hour for heating. The heating temperature is 550°C, the heating time is 40 minutes, the conveyor belt speed is 0.3 m / min, and the heating furnace is kept in a vacuum state with a vacuum degree of 0.05 MPa. The sulfur element and benzene and naphthalene organic matter generated by heating are guided to the graded condenser through the induced draft fan, and condensed at different parts of the graded condenser respectively. The condensation temperature of the sulfur element generated by heating is 178°C, and the condensation temperature of the benzene and naphthalene organic matter generated by heating is 70°C. The sulfur content of the liquid sulfur element (sulfur) obtained after condensation is 93wt%, and it is collected by the sulfur collector and used for industrial or agricultural sulfur production; the liquid benzene and naphthalene organic matter mixture obtained by condensation is collected by the naphthalene and benzene collector and returned to the coking enterprise for comprehensive utilization or sold to other fuel fields for use;

[0054] (3) The heated waste iron oxide desulfurizer powder obtained in step (2) is sent to a slag powder bin, transported to a blending bin of a concrete production enterprise by a tank truck, and then added to a concrete mixer for preparing concrete, wherein the amount of the heated waste iron oxide desulfurizer powder is 8wt% of the amount of the cementitious material, and the strength grade of the obtained concrete is C55.

[0055] According to the above results, it can be seen that the treatment method of the present invention can achieve 100% resource utilization of waste iron oxide desulfurizer, and the strength of the obtained concrete is relatively high.

[0056] It should be understood that parts not elaborated in detail in this specification belong to the prior art.

[0057] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for treating waste iron oxide desulfurizer, characterized in that: The processing method comprises the following steps: (1) crushing the waste iron oxide desulfurizer to obtain waste iron oxide desulfurizer powder; (2) heating the waste iron oxide desulfurizer powder obtained in step (1), and condensing the sulfur element and benzene naphthalene organic matter generated by the heating, respectively, to obtain a mixture of liquid sulfur element and liquid benzene naphthalene organic matter; (3) The heated waste iron oxide desulfurizer powder is prepared into a cementitious material or concrete.

2. The processing method according to claim 1, characterized in that: The waste iron oxide desulfurizer contains 30-80wt% CaSO4, 0.5-40wt% S, 5-30wt% Fe2O3, 0.2-15wt% CaCO3 and 0.5-5wt% other inevitable impurities.

3. The processing method according to claim 1 or 2, characterized in that: In step (1), the particle size of the waste iron oxide desulfurizer powder is less than 250 μm, of which the weight of particles smaller than 75 μm accounts for no less than 50 wt%, and the weight of particles smaller than 150 μm accounts for no less than 80 wt%.

4. The processing method according to claim 1 or 2, characterized in that: In step (2), a protective gas is introduced into the heating furnace used for heating or a vacuum state is maintained.

5. The processing method according to claim 4, characterized in that: In step (2), when the heating furnace used for heating is maintained in a vacuum state, the vacuum degree is not less than 0.05 MPa.

6. The processing method according to claim 1, characterized in that: In step (2), the heating conditions include: a temperature of 400 to 700° C. and a time of 5 to 60 minutes.

7. The processing method according to claim 1 or 6, characterized in that: In step (2), the condensation temperature of the sulfur element produced by heating is 130-180°C.

8. The processing method according to claim 1 or 6, characterized in that: In step (2), the condensation temperature of the benzene-naphthalene organic matter generated by heating is ≤80°C.

9. The processing method according to claim 1, characterized in that: In step (3), when the heated waste iron oxide desulfurizer powder is used to prepare a cementitious material, the amount of the heated waste iron oxide desulfurizer powder does not exceed 3 wt % of the total weight of the cementitious material.

10. The processing method according to claim 1 or 9, characterized in that: In step (3), when the heated waste iron oxide desulfurizer powder is used to prepare concrete, the amount of the heated waste iron oxide desulfurizer powder does not exceed 10 wt % of the amount of the cementitious material.

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