CN-121994009-A - Continuous arsenic sulfide slag drying treatment system and method for corrosive waste gas filtration

CN121994009ACN 121994009 ACN121994009 ACN 121994009ACN-121994009-A

Abstract

The invention discloses a continuous arsenic sulfide slag drying treatment system and method for corrosive waste gas filtration, which belong to the technical field of hazardous waste treatment, wherein the system comprises a box body, the box body is internally provided with a closed feeding unit, a sectional low-temperature drying unit and a discharging unit, and the sectional low-temperature drying unit is circularly communicated with the corrosion protection unit and the heating air supply unit; the corrosion protection unit comprises a dry type filtering unit, a wet type filtering unit, a condenser and a steam preheating recoverer, realizes the graded purification, condensation dehumidification and heat energy recovery of corrosive waste gas, and the heating air supply unit supplies heated circulating air to the drying unit, and the sectional type low-temperature drying unit adopts a PVC+nylon corrosion-resistant net belt and a dust removal scraping belt to realize the airtight drying and anti-spillage dust removal of materials. The method realizes the full-flow airtight drying of the arsenic sulfide slag, has the weight reduction rate of more than 40 percent, the corrosive gas removal rate of more than 98 percent and high energy utilization rate, and is suitable for the large-scale treatment of the arsenic sulfide slag in the nonferrous metal smelting industry.

Inventors

ZHAO ZHIXIAO
WANG XIANGLI

Assignees

中融(天津)环境科技有限公司

Dates

Publication Date: 20260508
Application Date: 20260310

Claims (10)

1. The continuous arsenic sulfide slag drying treatment system for corrosive waste gas filtration is characterized by comprising a box body, wherein a feeding unit, a sectional low-temperature drying unit and a discharging unit which form a full-flow closed passage are sequentially arranged from a feeding end to a discharging end in the box body, and the sectional low-temperature drying unit is also used for gas filtration and is circularly communicated with a corrosion protection unit and a heating air supply unit; The corrosion protection unit comprises a dry type filtering unit, a wet type filtering unit, a condenser and a steam preheating recoverer which are sequentially arranged from an air inlet end to an air outlet end, wherein the air inlet end of the dry type filtering unit is communicated with the inside of a box body to suck corrosive high-temperature steam generated by drying arsenic sulfide slag on a sectional type low-temperature drying unit, the steam preheating recoverer is heated by hot steam in the box body communicated with the steam preheating recoverer, the air outlet end of the steam preheating recoverer is communicated with a heating air supply unit and supplies preheated drying air for the heating air supply unit, and the heating air supply unit supplies heated drying air for the arsenic sulfide slag on the sectional type low-temperature drying unit to accelerate drying of the arsenic sulfide slag.
2. The continuous arsenic sulfide sludge drying treatment system for corrosive waste gas filtration according to claim 1, wherein the dry filtration unit comprises a housing and a plurality of functional chambers arranged in the housing, and the functional chambers comprise a first filtration chamber, a dust collection chamber, a medicament chamber, a reaction chamber and a second filtration chamber in sequence along the gas flow direction; The first filtering chamber is positioned at the gas inlet end and is internally filled with a first filtering material, and the first filtering material is used for carrying out preliminary filtering on dust-containing high-humidity acid gas; The dust collection chamber is communicated with the first filtering chamber, and the cross-sectional area of the dust collection chamber is larger than that of the exhaust end of the first filtering chamber so as to reduce the gas flow rate by utilizing the Bernoulli principle and enable large particles to be deposited; The medicament chamber is communicated with the dust collecting chamber and is internally filled with an alkaline medicament, and the alkaline medicament reacts with hydrogen chloride, hydrogen fluoride, sulfur dioxide and sulfur trioxide acidic corrosive gases in the gas; The reaction chamber is communicated with the medicament chamber to provide a sufficient reaction space between the gas and the medicament and enhance the acid gas removal effect; The second filtering chamber is communicated with the reaction chamber and is internally filled with a second filtering material so as to further filter the reacted gas and prevent the medicament from losing; A plurality of detachable grid plates which divide the internal space of the shell into a plurality of functional chambers are arranged in the shell.
3. The continuous arsenic sulfide slag drying treatment system for corrosive waste gas filtration, as set forth in claim 1, wherein the wet filtration unit comprises a reaction dust removal water tank, a spray dust removal device and a plurality of water curtain dust removal partition plates arranged in a bending manner, the spray device sprays acid and dust removal agents to the dry filtration unit at the air inlet end of the wet filtration unit, the water curtain dust removal partition plates are airtight solid plates, the interior of the wet filtration unit is divided into a plurality of gas flow passages which are bent up and down in a reciprocating manner by the plurality of water curtain dust removal partition plates, and the lower parts of the plurality of water curtain dust removal partition plates are inserted below the acid and dust removal agents filled in the reaction dust removal water tank.
4. The continuous arsenic sulfide slag drying treatment system for corrosive waste gas filtration according to claim 1, wherein the wet filtration unit comprises a reaction dust removal water tank, a spray dust removal device and a plurality of water curtain dust removal partition plates which are arranged in parallel, the spray device sprays acid and dust removal agents to the water curtain dust removal partition plates, the water curtain dust removal partition plates are breathable sieve plates, the interior of the wet filtration unit is divided into a plurality of layers of parallel gas flow channels by the plurality of water curtain dust removal partition plates, and the lower parts of the plurality of water curtain dust removal partition plates extend above the liquid level of the acid and dust removal agents filled in the reaction dust removal water tank.
5. The continuous arsenic sulfide residue drying treatment system for corrosive waste gas filtration according to claim 1, wherein the tube side cooling channel of the steam preheating recoverer is communicated with the inside of the box body to introduce hot steam generated by arsenic sulfide residue drying, and the shell side heating channel of the steam preheating recoverer is communicated with the exhaust end of the condenser and the air inlet end of the heating air supply unit.
6. The continuous arsenic sulfide slag drying treatment system for corrosive waste gas filtration according to claim 1, wherein the cooling water pipeline inside the condenser is communicated with an external cooling tower, and the gas passage outside the condenser is communicated with the exhaust end of the wet-type filtering unit and the gas inlet end of the steam preheating recoverer, so that the temperature of the filtered steam is further reduced by the condenser, and the moisture content in the steam is reduced.
7. The continuous arsenic sulfide residue drying treatment system for corrosive waste gas filtration according to claim 1, wherein the sectional type low-temperature drying unit comprises multi-stage conveying belts which are sequentially connected with arsenic sulfide residues from end to end, the multi-stage conveying belts are parallel to each other and have a height drop so that different surfaces of the blocky arsenic sulfide residues fully contact hot air in the box body when the blocky arsenic sulfide residues are transported between the multi-stage conveying belts, and the sectional type low-temperature drying unit further comprises an ash removing scraping belt which is arranged below the multi-stage conveying belts and conveys the arsenic sulfide residues falling from the multi-stage conveying belts to the discharging unit.
8. The continuous arsenic sulfide slag drying treatment system for corrosive waste gas filtration according to claim 1, wherein the heating air supply unit comprises a plurality of groups of fans and heating pipes, wherein the heating pipes are communicated with an external heat source, the air inlet ends of the fans are communicated with the air outlet ends of steam preheating recoverers in the corrosion protection unit, and the air outlet ends of the fans face the heating pipes and output heated drying air to the sectional type low-temperature drying unit.
9. A method of treating a continuous arsenic sulfide residue drying treatment system for corrosive exhaust gas filtration as claimed in claim 1, comprising the steps of: s1, feeding and granulating, namely feeding arsenic sulfide slag with the water content of 55-65% into a feeding unit, conveying the arsenic sulfide slag to a granulating and forming unit in a sealing manner through the feeding unit, extruding the arsenic sulfide slag into strip-shaped particles through a cutter of a strip cutting machine, and increasing the drying contact area; S2, sectional low-temperature drying, namely, enabling strip arsenic sulfide slag particles to enter a PVC+nylon composite anti-corrosion net belt of a sectional low-temperature drying unit, drying materials to reach 10-30% of water content through sectional low-temperature drying of a 70-75 ℃ preheating section, a 75-80 ℃ constant-speed drying section and a 70-75 ℃ speed reduction drying section, and outputting dried arsenic sulfide slag to a discharging unit through a final-stage conveying net belt of the sectional low-temperature drying unit, wherein corrosive waste gas containing hydrogen chloride, hydrogen fluoride and arsenic dust is generated in the drying process; S3, anti-spillage ash removal and discharging, namely an ash removal scraping belt is arranged below the last-stage conveying mesh belt and is contacted with the bottom of the last-stage conveying mesh belt to clean the mesh belt ash deposit so as to receive spilled arsenic sulfide slag and convey the spilled arsenic sulfide slag to a discharging unit.
10. The method for treating the continuous arsenic sulfide residue drying treatment system for filtering corrosive exhaust gas according to claim 1, wherein the step S2 comprises the following steps: The corrosive waste gas is purified in a grading way, namely the corrosive waste gas generated by the sectional low-temperature drying unit enters the corrosion protection unit and sequentially passes through the dry type filtering unit and the wet type filtering unit, and the hydrogen chloride, the hydrogen fluoride and the fine particle dust in the waste gas are deeply removed through primary filtration, gravity dust collection, neutralization reaction of alkaline composite particle medicament and grading treatment of medium-efficiency filtration; The method comprises the steps of condensing, dehumidifying and heat energy recovery, namely, enabling purified waste gas to enter a condenser, performing tubular heat exchange and condensing, dehumidifying, converting water vapor in the waste gas into condensed water, collecting the condensed water and discharging the condensed water to a wastewater treatment system, enabling dehumidified dry and cold air to enter a steam preheating recoverer, preheating by utilizing waste heat of the steam condensed water in a box body, heating to 70-80 ℃ by a heating air supply unit, and then sending the preheated steam into a sectional low-temperature drying unit again to realize recycling of hot air; the steam heating module of the sectional type low-temperature drying unit in the step S2 adopts 3.0-3.5bar low-pressure steam, the temperature of the whole drying process is less than or equal to 80 ℃, arsenic trioxide generated by oxidizing and volatilizing arsenic sulfide slag is avoided, and the volatilizing amount of corrosive gas is reduced.

Description

Continuous arsenic sulfide slag drying treatment system and method for corrosive waste gas filtration Technical Field The invention relates to the technical field of hazardous waste treatment, in particular to a continuous arsenic sulfide slag drying treatment system and method for corrosive waste gas filtration. Background Arsenic sulfide slag is a typical hazardous waste generated in the nonferrous metal smelting (especially copper smelting) process, contains highly toxic arsenic element, has poor stability and is difficult to degrade, and is listed as national hazardous solid waste. The water content of the waste residue after plate and frame filter pressing still reaches 55% -65%, the particle size is small (the particle size below 15 mu m is more than 99% of the whole), the waste residue is acidic (the pH value is about 3-4), the adhesiveness is strong, various impurities such as fluorine, chlorine, lead and zinc are contained, the highly corrosive acid gas such as hydrogen chloride and hydrogen fluoride can be volatilized in the drying process, and a large amount of arsenic dust is easily generated. At present, enterprises mostly adopt ton bag packaging outsourcing treatment for treating arsenic sulfide slag, the treatment cost per ton is about 2000 yuan, the economic burden is heavy, and when the traditional general drying equipment (a belt drier, a box drier, a negative pressure drier, an ultrahigh pressure drier and the like) is used for treating the arsenic sulfide slag, a plurality of technical defects which are difficult to solve exist: The equipment corrosion is serious, namely acid gases such as hydrogen chloride, hydrogen fluoride and the like volatilized in the arsenic sulfide slag drying process grow exponentially along with the temperature rise, chloride ions are easy to enrich to cause pitting corrosion and penetrating corrosion, the service life of metal parts (a fin heat exchanger, a mesh belt, a bearing, a sensor and the like) of the traditional drying equipment is extremely short, the service life of most of the equipment is not more than half a year, and the service life of vulnerable parts such as a humidity sensor and the like is even less than 30 days; The waste gas treatment effect is poor, the traditional dry dust removal can only filter dust, acid molecules such as hydrogen chloride, hydrogen fluoride and the like can not be removed, the wet dust removal equipment has huge volume, needs to treat sewage secondarily, has high energy consumption and complex maintenance, is easy to cause the unorganized emission of harmful gas containing arsenic, and violates the environmental protection standard; the material scattering and dust pollution are that arsenic sulfide slag has small particle diameter and strong adhesiveness, the problems of material leakage and scattering easily occur in the traditional conveying and drying links, the dust quantity after drying is large, the dust removing operation environment is bad, and occupational disease risks are easily caused; The drying efficiency is low, the automation degree is poor, materials of the traditional equipment are easy to harden, so that the materials are heated unevenly, the air flow direction is unreasonably designed, the water volatilization efficiency is low, manual on-duty parameter adjustment is needed, internal pressure unbalance is easy to occur after the sealing performance is reduced, and the drying efficiency is further reduced; the energy utilization rate is low, the traditional steam heat source drying equipment can only utilize steam heat once, and the waste heat of steam condensate water is directly discharged, so that a large amount of energy is wasted, and the drying operation cost is improved. Meanwhile, in the existing waste gas treatment technology of arsenic sulfide slag drying: The dry dust removal mainly adopts plate type or bag type dust removal equipment. The device has simple structure, convenient maintenance and operation and wide application. However, when acid waste gas containing high chloride ions and fluoride ions, such as generated in the sludge drying industry, is treated, the traditional dry filter has obvious defects that firstly, dust can be filtered, a large amount of volatilized acid corrosive gases such as HCl, HF and the like along with the temperature and humidity increase can not be effectively removed, the gases can seriously corrode metal parts such as a heat pump system, an electric heating system, a cold and hot water coil pipe and the like of equipment, so that the equipment efficiency is low and even safety accidents are caused, and secondly, when the filter is purged by compressed air during maintenance, the attached dust can be blown away into the air, so that secondary pollution is caused, and the health of workers is endangered. Although most dust and acid gas can be removed by wet dedusting, the equipment is huge in size, secondary treatment is needed for the reacted sewage, co