CN115838233A - A method for comprehensive utilization of red mud - Google Patents

Abstract

The invention discloses a method for comprehensively utilizing red mud, which comprises the following steps: s1, preprocessing, dealkalizing and modifying the red mud, and performing acid-base neutralization reaction on multiphase acidic waste and the red mud; s2, primary separation, namely performing solid-liquid-gas separation on the product after the acid-base neutralization reaction of the red mud and the multiphase acidic waste; s3, carrying out secondary separation on the solid and the liquid separated in the step S2, separating the solid into a metal object and a nonmetal object, and separating the liquid into the metal object, the nonmetal and purified water; s4, respectively carrying out pyrolysis reaction on the metal object and the nonmetal object; s5, performing fine separation on the metal object after the pyrolysis reaction, and separating metal components and non-metal components in the metal object; and S6, activating the non-metal object after the pyrolysis reaction in the step S4 and the non-metal component in the step S5. The method has the advantages of fully treating the red mud, utilizing multiphase acid wastes to achieve the purpose of waste treatment, solving the problem of high efficiency of red mud treatment, being environment-friendly and saving resources.

Description

A method for comprehensive utilization of red mud

technical field

The invention relates to the technical field of coal gasification ash treatment, in particular to a method for comprehensive utilization of red mud.

Background technique

Red mud is the polluting waste that is removed when the aluminum industry extracts alumina. Generally, for every 1 ton of alumina produced, 1.0 to 2.0 tons of red mud is incidentally produced.

Many research institutions at home and abroad are actively carrying out research and development on the comprehensive utilization of red mud, and have also achieved some results, but so far none of the results can truly achieve large-scale industrial application, let alone any results that are beneficial to red mud. The utilization of mud exceeds 30%. One of the main reasons is that the alkali content of red mud is too high. There are three methods of processing red mud in the prior art, namely Bayer method, sintering method and sintering-Bayer combined method. The three processing methods are to add alkali to red mud, so during the red mud treatment process produces The Na ₂ O content (mass fraction) is as high as 9-11%, which is a high-risk pollutant. So high alkalinity is the bottleneck of red mud development and utilization.

Contents of the invention

The purpose of the present invention is to provide a method for comprehensive utilization of red mud, which has the advantages of being able to fully treat red mud, and utilizing multi-phase acidic waste to achieve waste treatment, solving the problem of efficient treatment of red mud, being friendly to the environment and saving resources.

In order to achieve the above object, the technical solution adopted in the present invention is: a method for comprehensive utilization of red mud, comprising the following steps:

S1, pretreatment, carry out dealkalization modification on red mud, and carry out acid-base neutralization reaction between multiphase acidic waste and red mud;

S2, primary separation, the solid-liquid-gas separation of the product after the acid-base neutralization reaction between the red mud and the multi-phase acidic waste;

S3. The solid and liquid separated in step S2 are separated twice through the electromagnetic separator and re-selector, and the solid is separated into metal and non-metal, and the liquid is divided into metal, non-metal and purified water. ;

S4, performing pyrolysis reactions on metals and non-metals respectively;

S5. Finely separate the metal objects after the pyrolysis reaction through an electromagnetic separator and a gravity separator, and separate the metal components and non-metal components in the metal objects;

S6, performing activation treatment on the non-metallic substance after the pyrolysis reaction in step S4 and the non-metallic component in step S5.

The multiphase acid waste in the step S1 is acid waste gas, acid waste liquid and acid solid waste.

The temperature of the pyrolysis reaction in the step S4 is 400-1200 degrees Celsius, and the reaction time is 40-240 minutes.

The activation treatment in step S6 is activation-petrochemical. After activating the non-metal, a binder is added to make the activated non-metal coagulate into an ore body.

The activation treatment in step S6 is activation-carbonization. After the non-metallic substance is activated, high-temperature anaerobic treatment is performed, so that oxygen and hydrogen elements in the non-metallic substance are precipitated.

Compared with the prior art, the present invention has the advantages of: adopting the electromagnetism synergistic supergravity technology to separate and recover metal components such as iron, aluminum, sodium salt, rare earth, etc., with a recovery rate greater than 90%; Large-scale green building materials and roadbed industrial applications such as cement, ceramics and additives, bricks and permeable bricks, artificial sand and gravel. Among them, the large-scale application of artificial sand and gravel is of great significance, and it can also reverse the passive situation of my country spending a large amount of foreign exchange to import sand and gravel. situation.

Detailed ways

The present invention will be further described below.

Embodiment: a method for comprehensive utilization of red mud, comprising the following steps:

S1, pretreatment, carry out dealkalization modification on the red mud, put the red mud into the reaction tank, and put the multi-phase acid waste into the reaction tank, so that the red mud and the multi-phase acid waste undergo acid-base neutralization reaction; the multiphase acid waste is acid waste gas, acid waste liquid and acid solid waste, wherein the acid waste gas can be unpurified acid waste gas in the chemical industry, carbon dioxide discharged, etc., such as coal-fired power stations, coal-fired blast furnaces , coal-fired boilers and other exhaust gases that have not been dedusted, desulfurized, and denitrated. At the same time, due to the porous red mud, it can absorb dust, sulfur ions, and nitrate ions in the exhaust gas, which greatly reduces the cost of treating exhaust gas in the chemical industry. Another On the one hand, the use of CO ₂ in exhaust gas is of great significance to the carbon emission reduction of the chemical industry.

Acid waste liquid can be waste acid liquid and acid waste water produced by various industries; acid solid waste can be unpurified acid waste residue and acid slag in chemical industry, mining and other industries; through rational use of multiphase acid waste to realize Large-scale and low-cost dealkalization modification treatment of mud, and realize waste treatment by waste treatment, which reduces the treatment cost of red mud and industrial waste.

S2. Primary separation. The product after the acid-base neutralization reaction is separated into solid, liquid and gas, and separated into three substances: solid, liquid and gas. The separated gas is collected and purified by a gas purification device before being discharged.

S3. The solid and liquid separated in step S2 are separated twice through the electromagnetic separator and re-selector, and the solid is separated into metal and non-metal, and the liquid is divided into metal, non-metal and purified water. , in which metal objects mainly contain metal ions such as iron and aluminum, and both metal objects and non-metal objects are solid.

S4. Carry out pyrolysis reaction on the metal object and the non-metal object respectively, the temperature of the pyrolysis reaction is 400-1200 degrees Celsius, and the reaction time is 40-240 minutes.

S5. Finely separate the metal objects after the pyrolysis reaction through an electromagnetic separator and a gravity separator, and separate the metal components in the metal objects from the non-metal components; the metal components are iron, aluminum, sodium salt, rare earth, etc. and the metal The components are sorted and recovered, and the recovery rate is greater than 90%, and the remaining non-metallic component residues are transferred to non-metallic substances for further processing.

S6, performing activation treatment on the non-metallic substance after the pyrolysis reaction in step S4 and the non-metallic component in step S5. Among them, the activation treatment is divided into activation-petrochemical and activation-carbonization; activation-petrochemical is a technology that uses binders to naturally condense complex component powders and liquids into high-strength ore bodies without heating. High-value components (such as aluminum, calcium and other metal ions) are made into cement, ceramics and additives, bricks and permeable bricks, artificial sand and other large-scale green building materials and roadbed industrial applications. Among them, artificial sand Large-scale application is of great significance, and it can also reverse the passive situation that my country spends a large amount of foreign exchange to import sand and gravel; the adhesive includes natural adhesives and synthetic adhesives, wherein natural adhesives are derived from substances in nature. Including starch, protein, dextrin, animal glue, shellac, hide glue, rosin and other biological adhesives; also including asphalt and other mineral adhesives; synthetic adhesives refer to artificially synthesized substances, including inorganic adhesives such as water glass agent, and organic adhesives such as synthetic resin and synthetic rubber.

Activation-carbonization is to activate the non-metallic substance and perform high-temperature anaerobic, so that the oxygen and hydrogen elements in the non-metallic substance are precipitated, so that the non-metallic substance is made into functional materials, including environmentally friendly functional materials and catalyst functional materials, among which environmental protection Functional materials are widely used in the treatment of three wastes and soil restoration and improvement. Catalyst functional materials are used in the hydrogenation saturation reaction of coal, biomass, oil shale, certain organic compounds and petroleum residue. In another embodiment, non-metallic objects can also be subjected to high-temperature activation treatment with a temperature greater than 80 degrees Celsius. After the non-metallic objects are activated and harmless at high temperature, they can be directly used as soil for construction land. Farming waste such as orange stalks, livestock and poultry manure, kitchen waste, sewage plant sludge, food production leftovers and waste residues and other organic wastes, after high temperature activation, they can be used for land restoration and reclamation in red mud and other waste residue dumps, or Land improvement, or recultivation of saline-alkali land and desertification land.

In this paper, specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; meanwhile, for those of ordinary skill in the art, according to the present invention Thoughts, there will be changes in the specific implementation and scope of application, and changes and improvements to the present invention will be possible without going beyond the concept and scope specified in the appended claims. In summary, this specification The content should not be construed as a limitation of the invention.

Claims (5)

1. A method for comprehensive utilization of red mud, characterized in that: comprises the following steps: S1, pretreatment, carry out dealkalization modification on red mud, and carry out acid-base neutralization reaction between multiphase acidic waste and red mud; S2, primary separation, the solid-liquid-gas separation of the product after the acid-base neutralization reaction between the red mud and the multi-phase acidic waste; S3. The solid and liquid separated in step S2 are separated twice through the electromagnetic separator and re-selector, and the solid is separated into metal and non-metal, and the liquid is divided into metal, non-metal and purified water. ; S4, performing pyrolysis reactions on metals and non-metals respectively; S5. Finely separate the metal objects after the pyrolysis reaction through an electromagnetic separator and a gravity separator, and separate the metal components and non-metal components in the metal objects; S6, performing activation treatment on the non-metallic substance after the pyrolysis reaction in step S4 and the non-metallic component in step S5. 2. The method for comprehensive utilization of red mud according to claim 1, characterized in that: the multiphase acid waste in the step S1 is acid waste gas, acid waste liquid and acid solid waste. 3. The method for comprehensive utilization of red mud according to claim 1, characterized in that: the temperature of the pyrolysis reaction in the step S4 is 400-1200 degrees Celsius, and the reaction time is 40-240 minutes. 4. A method for comprehensive utilization of red mud according to claim 1, characterized in that: the activation treatment in step S6 is activation-petrochemical, after activating non-metallic objects, adding a binder to make the activated non-metallic Condensed into ore bodies. 5. A method for comprehensive utilization of red mud according to claim 1, characterized in that: the activation treatment in step S6 is activation-carbonization, after activating non-metallic objects, high-temperature anaerobic is performed, so that the non-metallic objects Oxygen and hydrogen elements are precipitated.