CN-121976039-A - Self-heating extraction system for valuable elements of coal gangue

CN121976039ACN 121976039 ACN121976039 ACN 121976039ACN-121976039-A

Abstract

The invention relates to the field of fuel and boiler systems, in particular to a gangue valuable element self-heating extraction system which comprises feeding, crushing, decarburization and activation and valuable element extraction modules, wherein the modules are sequentially linked to form a closed loop. The feeding module is combined with screw feeding, the crushing module crushes the coal gangue to a particle size below 2cm by using a jaw crusher, the temperature of the decarburization activation furnace is controlled to be 750-850 ℃, the coal gangue decarburization, ash activation and rare earth calcination are realized, the flue gas is subjected to heat exchange to generate high-temperature steam energy of 300-450 ℃, and the bottom slag is ground to a particle size below 200 meshes for standby. The valuable element extraction comprises submodules of magnetic separation, iron removal, hydrochloric acid leaching and the like, and the system adopts step energy consumption (high temperature, medium temperature, low temperature steam for acid leaching, aluminum chloride hexahydrate crystallization, extraction and white carbon black preparation respectively). The system realizes the utilization of the whole components of coal gangue carbon, aluminum and the like, produces high-value products of gallium metal, rare earth oxide and the like, reduces the energy consumption by self-heating, is matched with an environment-friendly treatment unit, and is suitable for different coal gangue components, and the energy efficiency and the economy are good.

Inventors

WANG XUEBIN
ZHANG XIAOPAN
PU JING
YU WEI
MA DAOYANG
LI RUI
Wu Dongken
ZHANG YILI

Assignees

西安交通大学

Dates

Publication Date: 20260505
Application Date: 20251230

Claims (10)

1. The self-heating extraction system for the valuable elements of the coal gangue is characterized by comprising a feeding module, a crushing module, a decarburization activation module and a valuable element extraction module, wherein the modules are sequentially linked to form a closed-loop process system; The feeding module adopts a combined structure of belt feeding and spiral feeding, the belt feeding is connected to the rear end of the crushing module, and the spiral feeding is respectively arranged at the rear end of the crushing module, the front end of the decarburization activation module, the rear end of the bottom slag hopper and the front end of the ball mill, so that continuous conveying of materials is realized; the crushing module adopts a jaw crusher to crush the coal gangue to a particle size below 2 cm; The equipment main body of the decarburization activation module is a decarburization activation furnace, the furnace temperature is controlled to be 750-850 ℃, the equipment main body is used for realizing combustion decarburization and ash activation of coal gangue and simultaneously carrying out calcination of rare earth enrichment; The valuable element extraction module comprises a magnetic separation iron removal module, a hydrochloric acid leaching module, a white carbon black preparation module, a gallium extraction module, a rare earth extraction module and an aluminum chloride hexahydrate preparation module which are sequentially linked; the system heat utilization adopts a cascade utilization mode, namely high-temperature steam at 300-450 ℃ is firstly introduced into a hydrochloric acid leaching module, the temperature is reduced to 200-300 ℃ after heat exchange to become medium-temperature steam, the medium-temperature steam is introduced into an aluminum chloride hexahydrate crystallization preparation module, the temperature is reduced to 130-140 ℃ after heat exchange to become low-temperature steam, and the low-temperature steam is introduced into a gallium extraction module, an extraction link of a rare earth extraction module and a white carbon black preparation module, so that the system has the functions of heat supply and stirring mixing.
2. The self-heating extraction system of valuable elements of coal gangue is characterized in that the pressure of an acid leaching reaction kettle of a hydrochloric acid leaching module is kept at 0.1-0.6 MPa, the temperature is controlled at 140-180 ℃, the solid-liquid ratio is 1:4-1:10, the reaction time is 1-10 h, and the concentration of hydrochloric acid is 10-25 wt%.
3. The self-heating extraction system of valuable elements in coal gangue is characterized in that in a gallium extraction module, the volume ratio of an extractant to hydrochloric acid leaching solution is 1:10-1:50, the extraction temperature is 40-70 ℃, the hydrochloric acid concentration in the extraction process is 1-6 mol/L, a gallium solution with the gallium concentration of 20-50 g/L is obtained after back extraction and washing, and metal gallium is obtained through electrolysis for 2-6 hours in an acid system with the pH value of 1-3.
4. The self-heating extraction system for valuable elements of coal gangue is characterized in that in a rare earth extraction module, the volume ratio of an extractant to hydrochloric acid leaching solution is 1:1-1:10, the extraction temperature is 20-50 ℃, the extraction pH is 1-5, a stripping agent adopts 1-3 mol/L nitric acid or hydrochloric acid solution, a precipitant adopts one or more of oxalic acid, potassium oxalate, sodium oxalate and calcium oxalate, and the rare earth oxide is obtained by placing the rare earth extraction module into a decarburization activation furnace after precipitation and filtration and calcining the rare earth oxide at 700-800 ℃ for 2-3 hours.
5. The self-heating extraction system of valuable elements in coal gangue is characterized in that the aluminum chloride hexahydrate preparation module concentrates aluminum chloride leaching solution to be 30-45wt% of AlCl 3 through a multi-effect evaporator, transfers the aluminum chloride leaching solution into a crystallization reactor, carries out programmed cooling to 20-40 ℃ at a rate of 10-30 ℃ per hour, carries out aging crystallization for 2-8 hours, and obtains aluminum chloride hexahydrate crystals through filtration, ethanol washing and vacuum drying.
6. The self-heating extraction system for valuable elements of coal gangue is characterized in that a white carbon black preparation module adopts 5-20wt% of sodium hydroxide solution, the solid-to-liquid ratio is 1:2-1:5, alkali dissolution is carried out for 2-6 hours, then sodium silicate solution is obtained through filtration, 10-20wt% of sulfuric acid solution is added to adjust the final pH value to 7-10, reaction is carried out for 0.5-2 hours to form silica precipitation, the temperature of slurry is raised to 80-95 ℃ and curing is carried out for 0.5-1 hour, and an active white carbon black product is obtained through filtration, washing and drying.
7. The self-heating extraction system of valuable elements from coal gangue according to claim 1, wherein the decarburization activation furnace is provided with a zoned atmosphere control structure, the burning decarburization zone maintains an oxidizing atmosphere, and the rare earth calcining zone maintains a neutral or weak reducing atmosphere.
8. The self-heating extraction system for valuable elements of coal gangue, which is disclosed in claim 1, is characterized in that a reaction kettle and a heat exchanger of the hydrochloric acid leaching module are made of hastelloy or enamel corrosion resistant materials, and the system further comprises an HCl waste gas washing tower, an acid-base waste water neutralization tank and an ethanol distillation recovery device.
9. The self-heating extraction system of valuable elements in coal gangue according to claim 1, wherein an acid dissolving and impurity removing unit is additionally arranged behind the magnetic separation and iron removing module.
10. The self-heating extraction system for valuable elements of coal gangue is characterized in that a drying pretreatment unit is additionally arranged at the front end of a feeding module, the water content of the coal gangue is regulated to be less than 5wt%, and the heat exchange area of a heat exchanger is adapted to the transmission flow requirement of high-temperature steam at 300-450 ℃.

Description

Self-heating extraction system for valuable elements of coal gangue Technical Field The invention relates to the field of fuel and boiler systems, in particular to a self-heating extraction system for valuable elements of coal gangue. Background The prior treatment technology has the obvious defects in the links of heat treatment and resource utilization of the coal gangue, such as difficulty in stabilizing direct combustion of the coal gangue due to a large amount of non-combustible matters, low heat efficiency, low product strength and easiness in weathering due to high residual carbon content, unactivated clay minerals, low extraction rate due to insufficient activation of valuable elements, poor comprehensive benefit, independent supply of heat sources of each utilization unit, systematic and efficient utilization of the heat energy value of the coal gangue carbon component, removal of impurities only, low system energy efficiency, and low specific components only focused on by the conventional high-value utilization technology, and a large number of valuable elements are not effectively treated. Therefore, development of an integrated system with low cost and high energy efficiency is needed to realize the full-component utilization of carbon, aluminum, silicon, gallium and rare earth in the gangue, and the bottlenecks of low extraction rate, secondary pollution and high energy consumption in the prior art are overcome. Disclosure of Invention The invention aims to overcome the defect of high cost of separating and upgrading coal gangue carbon ash in the prior art, and provides a self-heating extraction system for valuable elements of coal gangue, which realizes ash activation by accurately regulating and controlling the temperature of a decarburization hearth synchronously, drives the extraction flow of the valuable elements by utilizing heat generated by decarburization of the coal gangue, reduces energy consumption and cost, and realizes comprehensive and high-value utilization of solid wastes. The invention solves the technical problems by adopting the technical scheme that the self-heating extraction system for valuable elements of coal gangue comprises a feeding module, a crushing module, a decarburization activation module and a valuable element extraction module, wherein the modules are sequentially linked to form a closed-loop process system; The feeding module adopts a combined structure of belt feeding and spiral feeding, the belt feeding is connected to the rear end of the crushing module, and the spiral feeding is respectively arranged at the rear end of the crushing module, the front end of the decarburization activation module, the rear end of the bottom slag hopper and the front end of the ball mill, so that continuous conveying of materials is realized; the crushing module adopts a jaw crusher to crush the coal gangue to a particle size below 2 cm; The equipment main body of the decarburization activation module is a decarburization activation furnace, the furnace temperature is controlled to be 750-850 ℃, the equipment main body is used for realizing combustion decarburization and ash activation of coal gangue and simultaneously carrying out calcination of rare earth enrichment; The valuable element extraction module comprises a magnetic separation iron removal module, a hydrochloric acid leaching module, a white carbon black preparation module, a gallium extraction module, a rare earth extraction module and an aluminum chloride hexahydrate preparation module which are sequentially linked; the system heat utilization adopts a cascade utilization mode, namely high-temperature steam at 300-450 ℃ is firstly introduced into a hydrochloric acid leaching module, the temperature is reduced to 200-300 ℃ after heat exchange to become medium-temperature steam, the medium-temperature steam is introduced into an aluminum chloride hexahydrate crystallization preparation module, the temperature is reduced to 130-140 ℃ after heat exchange to become low-temperature steam, and the low-temperature steam is introduced into a gallium extraction module, an extraction link of a rare earth extraction module and a white carbon black preparation module, so that the system has the functions of heat supply and stirring mixing. Specifically, the pressure of an acid leaching reaction kettle of the hydrochloric acid leaching module is kept at 0.1-0.6 MPa, the temperature is controlled at 140-180 ℃, the solid-liquid ratio is 1:4-1:10, the reaction time is 1-10 h, and the concentration of hydrochloric acid is 10-25 wt%. The gallium extraction module comprises a gallium extraction module, a gallium solution, a metal gallium and a metal gallium, wherein the volume ratio of an extracting agent to hydrochloric acid leaching solution is 1:10-1:50, the extraction temperature is 40-70 ℃, the hydrochloric acid concentration in the extraction process is 1-6 mol/L, the gallium solution with the gallium concentration of 20-50