CN112358279A

CN112358279A - Method for preparing ultra-light ceramsite by using heavy organic contaminated soil and nonferrous metal smelting slag

Info

Publication number: CN112358279A
Application number: CN202011191406.4A
Authority: CN
Inventors: 陈辉霞; 佟雪娇; 王源; 胡大海; 黄涛; 宋庆赟; 徐红彬; 张奇
Original assignee: Yuhuan Environment Technology Co ltd; Institute of Process Engineering of CAS
Current assignee: Yuhuan Environment Technology Co ltd; Institute of Process Engineering of CAS
Priority date: 2020-10-30
Filing date: 2020-10-30
Publication date: 2021-02-12
Anticipated expiration: 2040-10-30
Also published as: CN112358279B

Abstract

The invention relates to a method for preparing ultra-light ceramsite by using heavy organic contaminated soil and nonferrous metal smelting slag. The preparation method of the ultra-light ceramsite comprises the following steps: (1) proportionally mixing the heavy organic contaminated soil and the nonferrous metal smelting slag to obtain a mixed material; (2) and (2) granulating and roasting the mixed material obtained in the step (1) to obtain the ultra-light ceramsite. The invention can realize that the ultra-light ceramsite which has low bulk density, low water absorption rate and meets the requirements of both the organic matter content and the heavy metal content of the leachate by taking the heavy organic polluted soil and the nonferrous metal smelting slag as raw materials, mixing, granulating, drying, roasting, cooling and the like, and controlling the raw material and auxiliary material proportion and the roasting process parameters, thereby realizing the harmlessness and reclamation of the two wastes.

Description

Method for preparing ultra-light ceramsite by using heavy organic contaminated soil and nonferrous metal smelting slag

Technical Field

The invention belongs to the technical field of soil remediation, and particularly relates to a method for preparing ultralight ceramsite by using heavy organic contaminated soil and nonferrous metal smelting slag.

Background

Along with the transformation and upgrading of economic development in recent years, the optimization and adjustment of industrial structure and layout, the 'two-in three' of economic structure, the 'garden entering and zone entering' of industrial enterprises, especially the vigorous promotion of structural reform on the supply side, a large amount of backward capacity elimination, the continuous generation of industrial polluted sites due to the removal or closing of traditional polluted enterprises such as chemical engineering, metallurgy and the like, a large amount of polluted soil in China is urgently needed to be repaired, and the problem of soil pollution in some regions is serious. The organic pollutants in the soil of China mainly comprise volatile and semi-volatile organic compounds, and the main types comprise: petroleum hydrocarbon pollutants, benzene series pollutants, halogenated hydrocarbon pollutants, pesticide pollutants, polycyclic aromatic hydrocarbons, polychlorinated biphenyl, dioxin and other organic pollutants. The volatile organic pollutants can directly damage the normal functions of the soil, thereby further harming the health of human bodies.

The technology for restoring the soil polluted by the organic matters comprises the following steps: chemical oxidation technology, thermal desorption technology, soil elution technology, cement kiln cooperative treatment technology, phytoremediation technology, bioremediation technology, gas stripping technology and the like. Except for the heat desorption and cement kiln cooperative treatment technology, the other repairing technologies have limited effect on treating semi-volatile high-toxicity organic pollution and are difficult to achieve a low-concentration repairing target value. The ceramsite is a light raw material with wide application range and good market at present, can be prepared by proportioning clay-containing soil, municipal domestic garbage, fly ash, municipal sludge and the like and then roasting, and the related technology is mature day by day and becomes a novel environment-friendly process for consuming part of solid wastes.

CN 201510419907.6 discloses a method for restoring organic contaminated soil by a ceramsite preparation process, which comprises the steps of preparing a ceramsite product by using the organic contaminated soil and fly ash as raw materials; CN 201710287802.9 discloses a method for preparing ceramsite by utilizing polluted soil and industrial sludge. The lightweight aggregate for building materials is the most main application field of ceramsite. When used as a light aggregate for buildings, the ceramsite used as the light aggregate is required to have certain strength, low bulk density and low water absorption. The existing method for preparing the ceramsite by taking the organic polluted soil as the raw material mainly takes fly ash and sludge as ingredients, and the report of preparing the ceramsite by taking nonferrous metal smelting slag as an ingredient is less, so that the ceramsite prepared by taking the nonferrous metal smelting slag and the organic polluted soil as the raw material can meet the use requirement of building light aggregate, and the risk of releasing pollutants such as heavy metal, dioxin and the like in the technical process of preparing the ceramsite and the residual heavy metal in the ceramsite is controllable.

The non-ferrous metal smelting slag is waste slag generated in the smelting process of non-ferrous metal ores, such as copper slag, lead slag, zinc slag, nickel slag and the like. When nonferrous metal smelting slag and organic contaminated soil are used as raw materials, how to realize the fixation of heavy metals in the nonferrous metal smelting slag and the decomposition of organic matters in the organic contaminated soil through the control of ingredients and temperature to prepare the ceramsite with certain strength, low stacking density and low water absorption rate, and the problem to be solved is that the ceramsite is environment-friendly in the preparation process and the ceramsite product is environment-friendly.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide the ultra-light ceramsite and the preparation method and the application thereof. The invention can realize the preparation of the organic heavy polluted soil and industrial solid wastes by using the raw materials, mixing, granulating, drying, roasting, cooling and other steps and controlling the raw material and auxiliary material proportion and roasting process parameters, thereby having low bulk density, low water absorption and sulfur contentAnd the ultra-light ceramsite with the water-soluble substance content meeting the requirement, so that the harmlessness and the recycling of two industrial wastes are realized. The ultra-light ceramsite disclosed by the invention is a light aggregate with the bulk density meeting the requirements of GB/T17431.1-2010 light aggregate and the test method thereof part 1, namely the ultra-light aggregate specified in 3.7 in the light aggregate, and the bulk density is not more than 500kg/m³The ceramsite is prepared.

In order to achieve the purpose, the invention adopts the following technical scheme:

one of the purposes of the invention is to provide a preparation method of ultra-light ceramsite, which is characterized by comprising the following steps:

(1) proportionally mixing the heavy organic contaminated soil and the non-ferrous metal smelting waste residues to obtain a mixed material; in the mixed material, the content of heavy organic polluted soil is 50-70 wt%, and the balance is non-ferrous metal smelting slag;

(2) and (2) granulating and roasting the mixed material obtained in the step (1) to obtain the ultra-light ceramsite.

According to the invention, the characteristics that the smelting slag of nonferrous metals contains more silicon dioxide and aluminum oxide and heavy organic polluted soil contains a large amount of organic matters are combined, the decomposition gas production of the organic matters in the heavy organic polluted soil is utilized by adjusting the component ratio of the raw materials and the roasting process, so that the sintering and burning expansion process of the ceramsite, the high-temperature decomposition process of the organic matters and the reaction process of alkali metals are regulated and controlled, on one hand, the super-light ceramsite with a hard glaze layer on the surface and a large amount of closed micropores in the interior can be obtained, on the other hand, most of the organic matters are decomposed into carbon dioxide and water, and the heavy metals are generated into water-insoluble substances, so that the decomposition of the organic matters in the heavy organic polluted soil and the fixation of the heavy metals in the smelting waste slag of the nonferrous metals³The water absorption rate of 1 hour is 0.5-15.0%, the cylinder pressure strength is 0.5-5.0 MPa, the organic content TOC in the ceramsite water extract (1: 10) is lower than 0.5mg/L, and the heavy metal concentration is lower than the limit of hazardous waste identification standard leaching toxicity identification, so that the method meets the requirements of GB/T17431.1-2010 light aggregate and the test method part 1 thereof: light-weight ceramsite required by the light aggregate.

Preferably, the content of the heavy organic contaminated soil in the mixed material is 50-70 wt%, such as 52wt%, 55wt%, 58wt%, 60wt%, 62wt%, 65wt% or 70 wt%.

The content of the heavy organic polluted soil is less than 50wt%, and the bulk density and the water absorption of the obtained ceramsite do not meet the performance requirements of GB/T17431.1-2010 on the ultra-light aggregate; the content of the heavy organic polluted soil is more than 70wt%, and the obtained ceramsite bulk density, water absorption and cylinder pressure strength do not meet the performance requirements of GB/T17431.1-2010 on the ultra-light aggregate.

Preferably, the content of the non-ferrous metal smelting slag in the mixed material is 30-50 wt%, such as 32wt%, 35wt%, 36wt%, 38wt%, 40wt%, 42wt%, 45wt%, 46wt% or 50 wt%.

Preferably, the particle size of the mixed material is not more than 80 meshes, preferably 80-200 meshes, such as 80 meshes, 100 meshes, 120 meshes, 140 meshes, 160 meshes, 180 meshes or 200 meshes.

The chemical composition (calculated by oxide) of the raw material for preparing the ceramsite is mainly SiO₂、Al₂O₃、Fe₂O₃、CaO、MgO、K₂O、Na₂O and the like, and the chemical components and the relative content thereof can have important influence on whether the ceramsite can be burnt and expanded and the performance of the prepared ceramsite. According to the existing research reports, the performance of the ceramsite is influenced by the combination of the acidic oxide and the basic oxide. Wherein the acidic oxide is SiO₂And Al₂O₃The mullite ceramic grain is reacted at high temperature to generate mineral phases such as mullite and the like, so that the strength of the ceramic grain is improved; basic oxides, e.g. Fe₂O₃、CaO、MgO、K₂O、Na₂O and the like, which can play a role in fluxing by reducing the sintering temperature in the process of firing the ceramsite. According to the Riley phase diagram, the chemical composition range of the raw material of the sintered and expanded ceramsite is SiO₂: 53%-79%、Al₂O₃10-25 percent of flux and 13-26 percent of fluxing agent.

The granularity of the raw materials influences the sintering process of the ceramsite, further influences the performance of the ceramsite, and the invention comprehensively considers the performance of the ceramsite and the production cost and determines the proper granularity range.

PreferablySiO in the heavy organic contaminated soil in the step (1)₂The content of (B) is 30 to 60wt%, for example 32wt%, 35wt%, 38wt%, 40wt%, 42wt%, 45wt%, 48wt%, 50wt%, 52wt%, 55wt% or 58 wt%.

Preferably, Al is contained in the heavy organic contaminated soil in the step (1)₂O₃The content is 5 to 15wt%, for example, 5wt%, 6wt%, 8wt%, 10wt%, 12wt%, 13wt%, or 14 wt%.

Preferably, the content of calcium oxide in the heavy organic contaminated soil in the step (1) is 5-20 wt%, such as 6wt%, 8wt%, 10wt%, 12wt%, 15wt%, 18wt%, 20wt% and the like.

Preferably, the content of magnesium oxide in the heavy organic contaminated soil in the step (1) is 2-20 wt%, such as 3wt%, 6wt%, 8wt%, 10wt%, 12wt%, 15wt%, 18wt%, 20wt% and the like.

Preferably, the content of iron oxide in the heavy organic contaminated soil in the step (1) is 4-15 wt%, such as 5wt%, 8wt%, 10wt%, 12wt%, 15wt%, 18wt%, 20wt% and the like.

Preferably, in the heavy organic contaminated soil in the step (1), K₂O and Na₂The total O content is 1 to 10wt%, for example, 2wt%, 4wt%, 6wt%, 8wt%, 10wt%, etc.

Preferably, in the heavy organic polluted soil in the step (1), the organic matter type is pollutants such as organic pesticides, petroleum hydrocarbons, polycyclic aromatic hydrocarbons, polychlorinated biphenyl and the like;

preferably, in the heavy organic contaminated soil in the step (1), the content of the organic pesticide is 500-10000 mg/kg, such as 1000mg/kg, 2000mg/kg, 3000mg/kg, 4000mg/kg, 5000mg/kg, 6000mg/kg, 7000mg/kg, 8000mg/kg, 9000mg/kg and the like;

preferably, the content of petroleum hydrocarbon in the heavy organic contaminated soil in the step (1) is 10000-50000 mg/kg, such as 10000mg/kg, 20000mg/kg, 30000mg/kg, 40000mg/kg, 50000mg/kg and the like;

preferably, in the heavy organic contaminated soil in the step (1), the content of polycyclic aromatic hydrocarbon is 500-10000 mg/kg, such as 1000mg/kg, 2000mg/kg, 3000mg/kg, 4000mg/kg, 5000mg/kg, 6000mg/kg, 7000mg/kg, 8000mg/kg, 9000mg/kg and the like;

preferably, the content of polychlorinated biphenyl in the heavy organic contaminated soil in the step (1) is 50-500 mg/kg, such as 100mg/kg, 200mg/kg, 300mg/kg, 400mg/kg, 500mg/kg and the like;

preferably, the non-ferrous metal smelting slag in the step (1) is a mixture of copper slag, lead slag, zinc slag, nickel slag and the like;

preferably, the content of copper in the non-ferrous metal smelting slag in the step (1) is controlled to be less than 10000mg/kg, the content of lead is controlled to be less than 1200mg/kg, the content of zinc is controlled to be less than 10000mg/kg, and the content of nickel is controlled to be less than 300 mg/kg.

Preferably, SiO in the non-ferrous metal smelting slag of the step (1)₂The content of (B) is not less than 50wt%, preferably 50 to 70wt%, for example 52wt%, 54wt%, 55wt%, 56wt%, 58wt%, 60wt%, 62wt%, 65wt%, 66wt% or 68 wt%.

Preferably, in the non-ferrous metal smelting slag of the step (1), Al₂O₃The content of (B) is not less than 15wt%, preferably 15 to 30wt%, for example 16wt%, 18wt%, 20wt%, 22wt%, 25wt%, 26wt% or 28 wt%.

Preferably, in the non-ferrous metal smelting slag of the step (1), Fe₂O₃、CaO、MgO、K₂O and Na₂The total content of O is 15 to 30wt%, for example 16wt%, 18wt%, 20wt%, 22wt%, 25wt%, 26wt%, or 28 wt%.

Preferably, the granulation process of step (2) comprises: and mixing the mixed material, water and the binder, and granulating by using granulation equipment to obtain the raw material balls.

Preferably, in the granulation process, the amount of water added is 10-40 wt% of the mass of the pellet, such as 12wt%, 15wt%, 16wt%, 18wt%, 20wt%, 22wt%, 25wt%, 28wt%, 30wt%, 32wt%, 35wt%, 38wt%, etc.

Preferably, the granulating device is a disk granulator or a round pan granulator.

The equipment for the granulating process is not limited to a disk granulator or a round pan granulator, and the equipment for granulating can be selected by a person skilled in the art according to actual needs. When a disk or round pot granulator is used for granulation, firstly, the powdery raw materials are added, then water is sprayed to form a ball core, then, the powdery raw materials are added, and water is sprayed until the diameter of a material ball reaches a certain degree, and discharging is carried out; and (3) using an extrusion granulation machine, uniformly mixing the raw materials and water, and granulating, wherein the adding amount of the water is 10-40 wt% of the mass of the pellets.

The invention can control the particle size of the ceramsite raw material ball by adjusting the inclination angle and the rotating speed of the disc (round pot), thereby meeting the requirements of different use occasions on the particle size of the ceramsite.

Preferably, the diameter of the raw meal ball is 2-15 mm. Such as 4mm, 6mm, 8mm, 10mm, 12mm, 14mm, etc.

Preferably, after the granulation and before the roasting, a process of drying the raw material balls obtained by the granulation is also included.

Preferably, the drying temperature is 80-120 ℃, such as 85 ℃, 88 ℃, 90 ℃, 92 ℃, 95 ℃, 98 ℃, 100 ℃, 105 ℃, 110 ℃ or 115 ℃.

In the invention, the raw material balls are fully dried, the water content of the raw material balls is reduced, and the raw material balls are prevented from being cracked due to direct roasting.

Preferably, the drying time is 1-4 h, such as 1.2h, 1.5h, 1.8h, 2h, 2.2h, 2.5h, 2.8h, 3h, 3.2h, 3.5h or 3.8 h.

Preferably, the roasting process in the step (2) comprises the following steps: the temperature is increased to a first temperature at a first temperature increase rate and then increased to a second temperature at a second temperature increase rate.

The invention can adjust the decomposition of organic matters in soil, the reaction of alkali metals and the sintering and burning expansion of material balls by adjusting the heating rate, the heat preservation temperature and the time of the two-stage roasting.

Preferably, the first temperature rise rate is 5-30 ℃/min, such as 6 ℃/min, 8 ℃/min, 10 ℃/min, 12 ℃/min, 15 ℃/min, 18 ℃/min, 20 ℃/min, 22 ℃/min, 25 ℃/min or 28 ℃/min, and the like.

The first temperature rise rate is too low, the gas production component loss is more, and the later expansion of the ceramsite is not facilitated; the first heating rate is too high, and the material balls are easy to crack.

Preferably, the first temperature is less than or equal to 600 ℃, preferably 250 to 500 ℃, such as 280 ℃, 320 ℃, 350 ℃, 380 ℃, 400 ℃, 420 ℃, 450 ℃, 480 ℃ and the like.

The first temperature is too low to effectively remove free water and bound water in the raw materials; the first temperature is too high, the loss of gas production components in the raw materials is more, and the later expansion of the ceramsite is not facilitated.

Preferably, the holding time at the first temperature is 10-35 min, such as 12min, 15min, 18min, 20min, 24min, 26min, 28min, 30min, 35min, and the like.

Preferably, the second heating rate is 5-20 ℃/min, such as 6 ℃/min, 8 ℃/min, 10 ℃/min, 12 ℃/min, 15 ℃/min, 16 ℃/min or 18 ℃/min.

The second heating rate is too low, and excessive gas is released, so that the expansion of the material balls is not facilitated; and the second temperature rising rate is too high, so that gas is released rapidly, and the material balls are easy to crack.

Preferably, the second temperature is not less than 1000 ℃, preferably 1100 to 1250 ℃, such as 1120 ℃, 1150 ℃, 1180 ℃, 1200 ℃, 1120 ℃, 1140 ℃ and the like.

The second temperature is too low, the sintering degree of the material balls is too low, and the bulk density and the water absorption are too high; and when the second temperature is too high, the pellets are easy to over-burn, and the pellets are melted and adhered.

Preferably, the holding time at the second temperature is 10-35 min, such as 12min, 15min, 18min, 20min, 24min, 26min, 28min, 30min, 35min, and the like.

Preferably, the roasting process further comprises a cooling process;

preferably, the cooling is naturally carried out to room temperature, and the room temperature is 0-40 ℃.

The invention adopts a temperature reduction system of discharging the ceramsite after the ceramsite is cooled to room temperature along with the furnace, thereby avoiding the occurrence of fine cracks on the surface of the ceramsite caused by temperature shrinkage stress generated inside and on the surface of the ceramsite during rapid temperature reduction, and further improving the strength of the ceramsite.

As a preferred technical scheme, the method for preparing the ultralight ceramsite by using the heavy organic contaminated soil and the nonferrous metal smelting slag comprises the following steps:

(1) mixing materials: mixing 50-70 wt% of heavy organic contaminated soil and 30-50 wt% of industrial solid waste to obtain a mixed material with the granularity of less than or equal to 80 meshes;

(2) and (3) granulation: mixing the mixed material obtained in the step (1) with water, and granulating by using granulation equipment to obtain raw material balls, wherein the adding amount of the water is 10-40 wt% of the mass of the raw material balls;

(3) and (3) drying: drying the raw material balls obtained by granulation at the temperature of 80-120 ℃ for 1-4 h to obtain dry material balls;

(4) roasting: raising the temperature of the dry material balls to 250-500 ℃ at a heating rate of 5-30 ℃/min, preserving heat for 10-35 min, then raising the temperature to 1100-1250 ℃ at a heating rate of 5-20 ℃/min, and preserving heat for 10-35 min;

(5) and (3) cooling: and naturally cooling the roasted product to obtain the ultralight ceramsite.

After mixing, granulating, drying, roasting and cooling, the ultra-light ceramsite can be obtained.

The invention also aims to provide the ultra-light ceramsite, which is obtained by the preparation method.

Preferably, the bulk density of the ultra-light ceramsite is 500-650 kg/m³For example 520kg/m³、550kg/m³、580kg/m³、600kg/m³、620kg/m³、650kg/m³And the like.

Preferably, the water absorption rate of the ultra-light ceramsite is 0.5-15% within 1 hour, such as 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13% or 14%.

Preferably, the cylinder pressure strength of the ultra-light ceramsite is 0.5-5.0 MPa, such as 0.5MPa, 1MPa, 1.5MPa, 2MPa, 2.5MPa, 3MPa, 3.5MPa, 4MPa, 4.5MPa or 5 MPa.

Preferably, in the ultra-light ceramsite, the TOC concentration of organic matters in the ceramsite water extract (1: 10) is less than 0.5mg/L, such as 0.1mg/L, 0.2mg/L, 0.3mg/L, 0.4mg/L and the like.

Preferably, the concentration of heavy metals in the leaching solution of the ultra-light ceramsite is lower than the limit of 'standard leaching toxicity identification for hazardous waste identification', namely Cu is less than 100mg/L, Pb is less than 5mg/L, Zn is less than 100mg/L, and Ni is less than 5 mg/L.

The third purpose of the invention is to provide the use of the ultra-light ceramsite described in the second purpose, wherein the ultra-light ceramsite is used in the field of building materials, preferably any one or a combination of at least two of heat insulating materials, sound insulating materials, heat insulating materials and fire resisting materials in the field of building materials.

Compared with the prior art, the invention has the following beneficial effects:

(1) the raw materials used in the invention are all wastes, so that the harmlessness and the resource utilization of the heavy organic polluted soil and the nonferrous metal smelting slag are realized, the natural resources are saved, and the production cost is reduced.

(2) The method combines the characteristics that the smelting slag of nonferrous metals contains more silicon dioxide and aluminum oxide, and the heavy organic polluted soil contains a large amount of organic matters, regulates the mixture ratio of the components in the raw materials and the roasting process, utilizes the decomposed gas of the organic matters in the heavy organic polluted soil, further regulates and controls the sintering and sintering process of the ceramsite, the high-temperature decomposition process of the organic matters and the reaction process of alkali metals, is favorable for obtaining the ultra-light ceramsite which has a hard glaze layer on the surface and a large amount of closed micropores in the interior, promotes most of the organic matters to be decomposed into carbon dioxide and water, and ensures that heavy metals generate water-insoluble substances, thereby realizing the decomposition of the organic matters in the heavy organic polluted soil and the fixation of heavy metals in the smelting waste slag of the.

(3) The bulk density of the ceramsite obtained by the method is 500-650 kg/m³The water absorption rate of 1 hour is 0.5-15.0%, the cylinder pressure strength is 0.5-5.0 MPa, the organic content TOC in the ceramsite water extract (1: 10) is lower than 0.5mg/L, and the heavy metal concentration is lower than the limit of hazardous waste identification standard leaching toxicity identification, so that the method meets the requirements of GB/T17431.1-2010 light aggregate and the test method part 1 thereof: light aggregate is required.

Drawings

FIG. 1 is a schematic view of the process for preparing ultra-light ceramsite.

Detailed Description

To facilitate understanding of the present invention, the present invention is exemplified below with reference to fig. 1. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.

Example 1

A method for preparing ultra-light ceramsite by using heavy organic contaminated soil and nonferrous metal smelting slag comprises the following steps:

the heavy organically-polluted soil used in this example had the following inorganic matter composition (inorganic matter is calculated as oxide) and organic matter pollutant content: SiO 2₂59.23wt% of Al₂O₃14.36 wt.% of Fe₂O₃0.76wt% of CaO, 10.86wt% of MgO, 7.15wt% of K₂O content 0.68wt%, Na₂The O content is 1.22wt%, the organic pesticide content is 9850mg/kg, the petroleum hydrocarbon content is 48901mg/kg, the polycyclic aromatic hydrocarbon content is 8964mg/kg, and the polychlorinated biphenyl content is 483 mg/kg. The inorganic matter composition (all calculated by oxide) of the copper smelting tailings is as follows: SiO 2₂51.26wt% of Al₂O₃24.18 wt.% of Fe₂O₃8.85wt%, CaO 13.74wt%, MgO 1.22wt%, K₂O content 1.66wt%, Na₂The O content was 12.16wt%, and the copper content was 9460 mg/kg.

(1) Mixing materials: mixing 70wt% of heavy organic contaminated soil and 30wt% of industrial solid waste to obtain a mixed material with the granularity of 80 meshes;

(2) and (3) granulation: mixing the mixed material obtained in the step (1) with water, and granulating by using granulation equipment to obtain raw material balls, wherein the addition amount of the water is 40wt% of the mass of the raw material balls, and the diameter of each raw material ball is 2 mm;

(3) and (3) drying: drying the raw material balls obtained by granulation at 120 ℃ for 3.5 hours to obtain dry material balls;

(4) roasting: heating the dry material ball to 500 ℃ at the heating rate of 30 ℃/min, preserving heat for 35min, then heating to 1250 ℃ at the heating rate of 20 ℃/min, and preserving heat for 35 min;

(5) and (3) cooling: and naturally cooling the roasted product to room temperature to obtain the ultralight ceramsite.

Example 2

the heavy organically-polluted soil used in this example had the following inorganic matter composition (inorganic matter is calculated as oxide) and organic matter pollutant content: SiO 2₂32.46wt% of Al₂O₃6.48wt% of Fe₂O₃4.59wt%, CaO 5.97wt%, MgO 2.64wt%, K₂O content 0.78wt%, Na₂The O content is 1.67wt%, the organic pesticide content is 4951mg/kg, the petroleum hydrocarbon content is 38942mg/kg, the polycyclic aromatic hydrocarbon content is 7968mg/kg, and the polychlorinated biphenyl content is 408 mg/kg. The inorganic matter composition (all calculated by oxides) of the lead smelting tailings is as follows: SiO 2₂67.48wt% of Al₂O₃24.58 wt.% of Fe₂O₃8.64wt%, CaO 14.58wt%, MgO 1.06wt%, K₂O content 1.42wt%, Na₂The O content was 7.48wt%, and the lead content was 1198 mg/kg.

(1) Mixing materials: mixing 60wt% of heavy organic contaminated soil and 40wt% of industrial solid waste to obtain a mixed material with the granularity of 100 meshes;

(2) and (3) granulation: mixing the mixed material obtained in the step (1) with water, and granulating by using granulation equipment to obtain raw material balls, wherein the addition amount of the water is 30wt% of the mass of the raw material balls, and the diameter of each raw material ball is 15 mm;

(3) and (3) drying: drying the raw material balls obtained by granulation at 80 ℃ for 4h to obtain dry material balls;

(4) roasting: heating the dry material ball to 500 ℃ at the heating rate of 5 ℃/min, preserving heat for 10min, then heating to 1250 ℃ at the heating rate of 5 ℃/min, and preserving heat for 10 min;

Example 3

the heavy organically-polluted soil used in this example had the following inorganic matter composition (inorganic matter is calculated as oxide) and organic matter pollutant content: SiO 2₂45.89wt% of Al₂O₃8.45wt% of Fe₂O₃9.45wt%, CaO 14.15wt%, MgO 10.46wt%, K₂O content 1.05wt%, Na₂The O content is 1.46wt%, the organic pesticide content is 8912mg/kg, the petroleum hydrocarbon content is 41320mg/kg, the polycyclic aromatic hydrocarbon content is 8612mg/kg, and the polychlorinated biphenyl content is 316 mg/kg. The inorganic matter composition (all calculated by oxide) of the zinc smelting tailings is as follows: SiO 2₂61.46wt% of Al₂O₃21.46wt% of Fe₂O₃10.46wt%, CaO 4.75wt%, MgO 1.58wt%, K₂O content 0.42wt%, Na₂The O content was 1.48wt% and the zinc content was 8941 mg/kg.

(1) Mixing materials: mixing 50wt% of heavy organic contaminated soil and 50wt% of industrial solid waste to obtain a mixed material with the granularity of 200 meshes;

(2) and (3) granulation: mixing the mixed material obtained in the step (1) with water, and granulating by using granulation equipment to obtain raw material balls, wherein the addition amount of the water is 15wt% of the mass of the raw material balls, and the diameter of each raw material ball is 10 mm;

(3) and (3) drying: drying the raw material balls obtained by granulation at 100 ℃ for 2h to obtain dry material balls;

(4) roasting: heating the dry material ball to 400 ℃ at the heating rate of 15 ℃/min, preserving heat for 20min, then heating to 1200 ℃ at the heating rate of 15 ℃/min, and preserving heat for 25 min;

Example 4

the heavy organically-polluted soil used in this example had the following inorganic matter composition (inorganic matter is calculated as oxide) and organic matter pollutant content:SiO₂40.16wt% of Al₂O₃10.46wt% of Fe₂O₃10.78wt%, CaO 14.16wt%, MgO 10.32wt%, K₂O content 2.16wt%, Na₂The O content is 1.74wt%, the organic pesticide content is 9146mg/kg, the petroleum hydrocarbon content is 16430mg/kg, the polycyclic aromatic hydrocarbon content is 5497mg/kg, and the polychlorinated biphenyl content is 104 mg/kg. The inorganic matter composition (all calculated by oxide) of the nickel smelting tailings is as follows: SiO 2₂68.26wt% of Al₂O₃29.47 wt.% Fe₂O₃7.89wt%, CaO 6.58wt%, MgO 4.35wt%, K₂O content 1.56wt%, Na₂The O content was 1.48wt%, and the nickel content was 284 mg/kg.

(1) Mixing materials: mixing 40wt% of heavy organic contaminated soil and 60wt% of industrial solid waste to obtain a mixed material with the granularity of 120 meshes;

(2) and (3) granulation: mixing the mixed material obtained in the step (1) with water, and granulating by using granulation equipment to obtain raw material balls, wherein the addition amount of the water is 25wt% of the mass of the raw material balls, and the diameter of each raw material ball is 5 mm;

(3) and (3) drying: drying the raw material balls obtained by granulation at 90 ℃ for 4 hours to obtain dry material balls;

(4) roasting: heating the dry material ball to 400 ℃ at the heating rate of 25 ℃/min, preserving the heat for 30min, then heating to 1200 ℃ at the heating rate of 20 ℃/min, and preserving the heat for 30 min;

Example 5

the composition of the heavy organic contaminated soil and the copper smelting tailings used in this example were the same as in example 1.

(2) and (3) granulation: mixing the mixed material obtained in the step (1) with water, and granulating by using granulation equipment to obtain raw material balls, wherein the addition amount of the water is 10wt% of the mass of the raw material balls, and the diameter of each raw material ball is 2 mm;

Example 6

the composition of the heavy organic contaminated soil and the lead smelting tailings used in this example were the same as those of example 2.

(2) and (3) granulation: mixing the mixed material obtained in the step (1) with water, and granulating by using granulation equipment to obtain raw material balls, wherein the addition amount of the water is 10wt% of the mass of the raw material balls, and the diameter of each raw material ball is 15 mm;

(3) and (3) drying: drying the raw material balls obtained by granulation at 120 ℃ for 1h to obtain dry material balls;

(4) roasting: heating the dry material ball to 500 ℃ at the heating rate of 30 ℃/min, preserving heat for 10min, then heating to 1250 ℃ at the heating rate of 20 ℃/min, and preserving heat for 10 min;

Example 7

the composition of the heavy organic contaminated soil and the zinc smelting tailings used in this example were the same as in example 3.

(2) and (3) granulation: mixing the mixed material obtained in the step (1) with water, and granulating by using granulation equipment to obtain raw material balls, wherein the addition amount of the water is 40wt% of the mass of the raw material balls, and the diameter of each raw material ball is 10 mm;

Example 8

the composition of the heavy organic contaminated soil and the nickel smelting tailings used in this example were the same as in example 4.

(1) Mixing materials: mixing 50wt% of heavy organic contaminated soil and 50wt% of industrial solid waste to obtain a mixed material with the granularity of 120 meshes;

(2) and (3) granulation: mixing the mixed material obtained in the step (1) with water, and granulating by using granulation equipment to obtain raw material balls, wherein the addition amount of the water is 40wt% of the mass of the raw material balls, and the diameter of each raw material ball is 5 mm;

Example 9

The difference from the embodiment 1 is that the weight percentage of the heavy organic polluted soil and the copper smelting tailings is 40: 60.

Example 10

The difference from the embodiment 1 is that the weight percentage of the heavy organic polluted soil and the copper smelting tailings is 90: 10.

Example 11

The difference from example 1 is that the two-stage firing in step (4) is replaced by one-stage firing: and (3) raising the temperature of the dry material ball to 1150 ℃ at the heating rate of 10 ℃/min, and preserving the temperature for 20 min.

Example 12

The difference from example 1 is that the first temperature in step (4) is 800 ℃.

Example 13

The difference from example 1 is that the second temperature in step (4) is 900 ℃.

And (3) performance testing:

the prepared ultra-light ceramsite is subjected to the following performance tests:

(1) bulk density: according to GB/T17431.2-2010 lightweight aggregate and test method part 2: the test is carried out according to the specification of ' 6 bulk density ' in the test method of light aggregate ';

(2) water absorption for 1 h: according to GB/T17431.2-2010 lightweight aggregate and test method part 2: the test is carried out according to the regulation of '11 water absorption rate' in the test method of light aggregate;

(3) barrel pressure strength: according to GB/T17431.2-2010 lightweight aggregate and test method part 2: the test is carried out according to the specification of '9 cylinder pressure strength' in the test method of light aggregate;

(4) TOC concentration in the aqueous extract (1: 10): the test was carried out according to the solid waste leaching toxicity leaching method horizontal shaking method (HJ 557-2010);

(5) leaching concentration of heavy metal: the test was carried out according to the regulations of the solid waste leaching toxicity leaching method horizontal oscillation method (HJ 557-.

The bulk density of the ceramsite obtained by the method is 500-650 kg/m³The water absorption rate of 1 hour is 0.5-15.0%, the cylinder pressure strength is 0.5-5.0 MPa, the TOC content of organic matters in the ceramsite water extract (1: 10) is lower than 0.5mg/L, and the concentration of heavy metals is lower than the leaching toxicity of the hazardous waste identification standardThe restriction of the identification document meets the GB/T17431.1-2010 part 1 of lightweight aggregate and test method thereof: light aggregate is required.

TABLE 1

As can be seen from table 1, compared with example 1, when the heavy organic contaminated soil is out of the range of 50 to 70wt% (examples 9 and 10), the obtained ceramsite has high bulk density and water absorption and low cylinder pressure strength, which are caused by different sintering degrees and expansion degrees of materials in different raw material ratios, so that the product performance is different, and in the preparation method of the present invention, the heavy organic contaminated soil is preferably in the range of 50 to 70 wt%.

It can be seen from table 1 that, when two-stage roasting is changed into one-stage roasting (example 11), the bulk density and water absorption of the ceramsite are increased, the cylinder pressure strength is reduced, and the TOC concentration and heavy metal leaching toxicity in the leachate exceed the standards, because of the adoption of the one-stage roasting, when the temperature reaches the first temperature in the heating process, enough heat preservation time is not provided for adjusting the proportion of gas-generating components in the raw materials, so that the performance difference of the ceramsite is caused; the first temperature is higher than 500 ℃ (example 12), the obtained ceramsite has higher bulk density and water absorption, because the first temperature is too high, gas production components in the raw materials are more lost, and the later expansion of the ceramsite is not facilitated; when the second temperature is lower than 1100 ℃ (example 13), the sintering degree of the pellets is too low, so that the bulk density and the water absorption of the obtained ceramsite are increased, the cylinder pressure strength is reduced, and the TOC concentration and the leaching toxicity of heavy metals in the leachate are over-standard.

As can be seen from Table 1, the proportion and the roasting system of the heavy organic contaminated soil and the nonferrous metal smelting slag influence the sintering process and the sintering degree of the ceramsite, thereby influencing the expansion performance of the ceramsite and further influencing the performance of the ceramsite.

The applicant states that the present invention is illustrated by the above examples to show the detailed process equipment and process flow of the present invention, but the present invention is not limited to the above detailed process equipment and process flow, i.e. it does not mean that the present invention must rely on the above detailed process equipment and process flow to be implemented. It should be understood by those skilled in the art that any modification of the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.

Claims

1. A method for preparing ultra-light ceramsite by using heavy organic contaminated soil and nonferrous metal smelting slag is characterized by comprising the following steps:

(1) proportionally mixing the heavy organic contaminated soil and the nonferrous metal smelting slag to obtain a mixed material, wherein the content of the heavy organic contaminated soil is 50-70 wt%, and the balance is the nonferrous metal smelting slag;

2. The method of claim 1,

SiO in the heavy organic contaminated soil in the step (1)₂The content of (A) is 30-60 wt%; al (Al)₂O₃The content is 5-15 wt%; the content of calcium oxide is 5-20 wt%; the content of magnesium oxide is 2-15 wt%; the content of ferric oxide is 4-15 wt%; k₂O and Na₂The total content of O is 1-10 wt%; the organic matter is organic pesticide, petroleum hydrocarbon, polycyclic aromatic hydrocarbon and polychlorinated biphenyl pollutant;

the non-ferrous metal smelting slag in the step (1) is a mixture of stone coal vanadium extraction tailings, copper slag, lead slag, zinc slag, chromium slag and nickel slag;

the mixing in the step (1) is grinding and mixing; the particle size of the mixed material is less than or equal to 80 meshes.

3. The method of claim 1, wherein the particle size of the mixed material is 80 to 200 mesh;

in the heavy organic polluted soil in the step (1), the content of organic pesticides is 500-10000 mg/kg, the content of petroleum hydrocarbons is 10000-50000 mg/kg, the content of polycyclic aromatic hydrocarbons is 500-10000 mg/kg, and the content of polychlorinated biphenyl is 50-500 mg/kg;

controlling the copper content in the non-ferrous metal smelting slag in the step (1) to be less than 10000mg/kg, controlling the lead content to be less than 1200mg/kg, controlling the zinc content to be less than 10000mg/kg, controlling the chromium content to be less than 2500mg/kg, and controlling the nickel content to be less than 300 mg/kg;

SiO in the non-ferrous metal smelting slag of the step (1)₂The content of (A) is more than or equal to 50 wt%;

in the non-ferrous metal smelting slag of the step (1), Al₂O₃The content of (A) is more than or equal to 15 wt%;

in the non-ferrous metal smelting slag of the step (1), Fe₂O₃、CaO、MgO、K₂O and Na₂The total content of O is 15-30 wt%.

4. The method according to claim 3, wherein SiO is contained in the non-ferrous metal smelting slag of the step (1)₂The content of (A) is 50-70 wt%;

in the non-ferrous metal smelting slag of the step (1), Al₂O₃The content of (B) is 15-30 wt%.

5. The method of any one of claims 1-4, wherein the granulation process of step (2) comprises: mixing the mixed material with water, and granulating by using granulation equipment to obtain raw material balls;

in the granulation process, the adding amount of water is 10-40 wt% of the mass of the pellet;

the granulating equipment is a disk granulator or a round pan granulator;

the diameter of the raw material ball is 2-15 mm;

after the granulation and before the roasting, the process of drying the raw material balls obtained by the granulation is also included; the drying temperature is 80-120 ℃; the drying time is 1-4 h.

6. The method of any one of claims 1-4, wherein the firing of step (2) comprises: increasing the temperature to a first temperature at a first temperature-increasing rate, and then increasing the temperature to a second temperature at a second temperature-increasing rate;

the first heating rate is 5-30 ℃/min;

the first temperature is 250-500 ℃;

the heat preservation time at the first temperature is 10-35 min;

the second heating rate is 5-20 ℃/min;

the second temperature is 1100-1250 ℃;

the heat preservation time at the second temperature is 10-35 min;

the process of cooling is also included after roasting;

and the cooling is natural cooling and the temperature is reduced to the room temperature.

7. The method according to any one of claims 1 to 4, comprising the steps of:

8. An ultra-light ceramsite, characterized in that the ultra-light ceramsite is obtained by the preparation method of any one of claims 1 to 6.

9. The ultra-light ceramsite of claim 8, wherein the ultra-light ceramsite has a bulk density of 500-650 kg/m³；

The water absorption rate of the ultra-light ceramsite is 0.5-15.0% after 1 hour;

the cylinder pressure strength of the ultra-light ceramsite is 0.5-5.0 MPa;

in the ultra-light ceramsite, the organic matter content TOC in the ceramsite water extract is less than 0.5mg/L in a ratio of 1: 10;

in the ultra-light ceramsite, the concentration of heavy metals in the leaching solution is lower than the limit of 'standard leaching toxicity identification for hazardous waste identification'.

10. The use of the ultra-light ceramsite according to claim 9, wherein the ultra-light ceramsite is used in the field of building materials, and is any one or a combination of at least two of heat insulating materials, sound insulating materials, heat insulating materials and fire resisting materials in the field of building materials.