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CN-115650539-B - Sludge solidification molding process containing hazardous waste

CN115650539BCN 115650539 BCN115650539 BCN 115650539BCN-115650539-B

Abstract

The invention relates to the technical field of hazardous waste treatment, and particularly discloses a sludge solidification molding process containing hazardous waste, which comprises the steps of uniformly mixing sludge with a sludge dehydrating agent, performing filter pressing treatment to obtain a filter cake, uniformly mixing and stirring the filter cake with aluminum ash, an alkali-activated agent and asbestos, then adding bentonite and sulfonated asphalt, further mixing and stirring uniformly to obtain a mixed material, wherein the mass ratio of the filter cake, the aluminum ash, the alkali-activated agent, the asbestos, the bentonite and the sulfonated asphalt is 100:5-10:1-3:3-5:1-3:1-2, and curing and molding the mixed material at a dry and ventilated place. The invention ensures that the sludge has compressive strength, shearing strength and tensile strength at the same time after solidification and forming, greatly improves the solidification and forming effect of the sludge, effectively improves the stability of landfill stacks, reduces leakage, improves safety, accords with the environment-friendly concept of treating waste with waste, saves production cost and effectively increases dangerous waste disposal benefit.

Inventors

  • PEI JUNHUI
  • LI MIAO
  • CHEN HAO
  • LU WENTAO
  • WANG LONG

Assignees

  • 湖南瀚洋环保科技有限公司

Dates

Publication Date
20260505
Application Date
20221026

Claims (9)

  1. 1. The sludge solidification molding process containing hazardous waste is characterized by comprising the following steps of: uniformly mixing sludge and a sludge dehydrating agent, and then conveying the mixture to a plate-and-frame filter press for filter pressing treatment to obtain a filter cake, wherein the material pressing pressure of the plate-and-frame filter press is 15-20 MPa; mixing and stirring the filter cake, the pretreated secondary aluminum ash, the alkali-activated agent and the asbestos uniformly, and then adding bentonite and sulfonated asphalt, further mixing and stirring uniformly to obtain a mixed material, wherein the mass ratio of the filter cake to the pretreated secondary aluminum ash to the alkali-activated agent to the asbestos to the bentonite to the sulfonated asphalt is 100:5-10:1-3:3-5:1-3:1-2; The secondary aluminum ash is the residue of the primary aluminum ash after being roasted and recovered, and the main components of the secondary aluminum ash comprise aluminum oxide, aluminum nitride, aluminum carbide, a small amount of metal aluminum and a certain amount of fluoride, and the pretreatment method of the secondary aluminum ash comprises the steps of adding water into the secondary aluminum ash, reacting for 1-3 hours at the temperature of 75-85 ℃, and drying and ball milling to 100-200 meshes for standby after the reaction is completed; The alkali-activated agent is one of calcium oxide, calcium hydroxide and carbide slag; and (3) placing the mixed material at a dry and ventilated place for curing and molding.
  2. 2. The hazardous waste-containing sludge solidification molding process according to claim 1, wherein the mass ratio of the sludge to the sludge dewatering agent is 100:0.5-1.5.
  3. 3. The hazardous waste-containing sludge solidification molding process according to claim 1, wherein the particle size of the polycarboxylate water reducer is 100-200 meshes.
  4. 4. The hazardous waste-containing sludge solidification molding process according to claim 1, wherein the sludge is mixed with a sludge dehydrating agent and then is conveyed to a plate-and-frame filter press by a slurry pump, and the feeding pressure of the slurry pump is 0.6-0.8 MPa.
  5. 5. The hazardous waste-containing sludge solidification molding process according to claim 1, wherein the mass ratio of the filter cake, the pretreated secondary aluminum ash, the alkali-activated agent, the asbestos, the bentonite, and the sulfonated asphalt is in a range of 100:8:2:4:2:1.
  6. 6. The hazardous waste-containing sludge solidification molding process according to claim 1, wherein the particle size of the alkali-activated agent is 100-200 mesh.
  7. 7. The process for solidifying and molding sludge containing hazardous waste according to claim 1, wherein the asbestos is one or more of waste asbestos, waste rock wool and waste glass wool, and the asbestos pretreatment method comprises the steps of wetting asbestos with water and crushing the asbestos into a strip-shaped structure for later use.
  8. 8. The hazardous waste-containing sludge solidification molding process according to claim 1, wherein the bentonite pretreatment method is that bentonite is ball-milled to 100-200 meshes and then dried for 0.5-1.5 h under the condition of 100-200 ℃.
  9. 9. The hazardous waste-containing sludge solidification molding process of claim 1, wherein the sulfonated asphalt has a particle size of 100-200 mesh.

Description

Sludge solidification molding process containing hazardous waste Technical Field The invention relates to the technical field of hazardous waste treatment, in particular to a sludge solidification molding process containing hazardous waste. Background Most of the waste treated by the hazardous waste landfill is sludge, including surface treatment sludge, electroplating sludge, heavy metal sludge and the like. Because most of the solid-liquid separation equipment of the waste production unit is mainly plate-frame filter pressing, the water content of the sludge is 60% -80%, and in practice, the process control of the waste production unit is unstable, so that the water content of the sludge actually entering the factory is larger than 80%. Too high water content leads to the sludge not to be formed, easily leads to the pile body unstable, is difficult to meet the requirements of the pollution control standard of hazardous waste landfill, too high water content of the sludge can also produce too much percolate, the operation cost is increased, and meanwhile, after the sludge solidified by cement is flushed or soaked by the percolate in the landfill pile body, the solidified body easily forms small gaps, the structure of the solidified body is damaged, the pile body is easily subjected to uneven sedimentation, and the pile body is unstable. At present, the medicament for improving the solidification and forming effects of wastes in the dangerous waste landfill is mainly cement, free water of the cement and the sludge is subjected to hydration gelation reaction, the free water of the sludge is reduced, and the compressive strength of the sludge is improved, in the mode, the cement addition amount needs to reach about 30%, however, the large amount of cement addition is easy to lead the leaching corrosiveness of the wastes to be more than 12, the requirement of the GB18598-2019 dangerous waste landfill pollution control standard is exceeded, the cement addition only has gelation, the formability is poor, the shearing resistance is insufficient after forming, the pile lifting is unstable, and landslide is easy to occur. Meanwhile, the dangerous waste landfill is used as a terminal disposal site for dangerous waste, the nature of the dangerous waste for landfill disposal is complex and various, once leakage occurs, the environmental risk which is difficult to estimate is caused, and therefore, the pile stability of the dangerous waste landfill is an important object of attention. The existing sludge forming process in the prior art is difficult to be suitable for high-water-content sludge containing hazardous wastes, or the condition that the stability is reduced due to flushing or soaking of percolate after the sludge is buried is not considered, or the shearing strength of the sludge is not considered. For example, chinese patent CN102503053a proposes an early-strength sludge modifier, which is used for dewatering sludge with high water content by using polycarboxylic acid, carbide slag and the like after being regulated, so that the water content of the sludge can be reduced to about 52%, and the compressive strength is about 72kPa, however, the shearing strength of the sludge and whether the sludge still has strong compressive strength after being soaked are not considered, so practical application is still limited. In summary, the invention aims to develop a novel sludge solidification molding process containing hazardous wastes, so as to further reduce the water content and the generation of landfill leachate, improve the stability and the safety and reduce the operation cost. Disclosure of Invention The invention solves the technical problem of providing a sludge solidification molding process containing hazardous waste, so as to further reduce the water content and improve the stability and safety. The technical problems solved by the invention are realized by adopting the following technical scheme: A sludge solidification molding process containing hazardous waste comprises the steps of uniformly mixing sludge and a sludge dehydrating agent, performing filter pressing treatment to obtain a filter cake, mixing and uniformly stirring the filter cake, aluminum ash, an alkali exciting agent and asbestos, then adding bentonite and sulfonated asphalt, further mixing and uniformly stirring to obtain a mixed material, wherein the mass ratio of the filter cake, the aluminum ash, the alkali exciting agent, the asbestos, the bentonite and the sulfonated asphalt is 100:5-10:1-3:3-5:1-3:1-2, and curing and molding the mixed material at a dry and ventilated place. Further, the mass ratio of the sludge to the sludge dehydrating agent is 100:0.5-1.5. Further, the sludge dehydrating agent is a polycarboxylate water reducer, and the particle size of the polycarboxylate water reducer is 100-200 meshes. Further, after being mixed with a sludge dehydrating agent, the sludge is conveyed into a plate-and-frame filter press thr