Method for cooperatively treating inorganic hazardous waste in cement kiln
Technical Field
The invention relates to the field of environmental protection, in particular to a method for cooperatively treating inorganic hazardous waste by using a cement kiln.
Background
With the rapid development of the industry in China, various industries come from petrochemical industry, surface treatment, electroplating, electronics, environmental protection treatment and the like, the yield of inorganic hazardous wastes containing heavy metals such as nickel, tin, zinc, cadmium, chromium, lead, mercury, arsenic and the like is continuously increased, and if the wastes are not properly treated, the inorganic hazardous wastes containing various heavy metals threaten the whole ecological system through a food chain.
CN109402414A provides a process for coupling utilization and co-disposal of organic and inorganic hazardous wastes, comprising the following steps: 1) pretreating raw materials; 2) matching and feeding; 3) smelting in a smelting furnace; 4) and (4) flue gas treatment. Various organic and inorganic hazardous wastes are pretreated and matched and then are sent into a smelting furnace to be treated together, the effective utilization of resources is realized to the greatest extent by coupling utilization and cooperative treatment of the organic hazardous wastes and the inorganic hazardous wastes, and the purposes of treating pollution without producing pollution, utilizing wastes without producing wastes are achieved; meanwhile, the smelting furnace adopts an oxygen-enriched reinforced smelting process, a single system can process 10 million t/a of various inorganic hazardous wastes and 10 million t/a of various organic hazardous wastes, the total processing capacity is 20 million t/a, and the aim of cooperatively processing various organic and inorganic hazardous wastes in a large batch and in multiple varieties is fulfilled.
CN107557583A relates to a method for biologically leaching and circularly enriching valuable metals in fluorine-containing inorganic hazardous waste, belonging to the technical field of hazardous solid waste recycling treatment. The method solves the key common problem of leaching and enrichment failure caused by fluoride ion accumulation in the bioleaching and cyclic enrichment processes of fluoride-containing inorganic hazardous metal through mutation breeding of a fluoride-resistant acidophilic pyrite oxidizing strain, alkali addition in the leaching solution and complex fluorine removal. The oxidation activity and the growth characteristic of the acidophilic ferrosulfurous oxidation resistant mixed flora obtained by mutation breeding are kept unchanged under the concentration of 120mg/L fluorine ions; the residual fluorine ion of the defluorination failure leachate obtained by the series connection of the processes of adding alkali for defluorination and complexing for defluorination or the independent treatment is less than 120mg/L, thereby ensuring more than 10 times of leachate regeneration and cyclic enrichment. The beneficial effects of the invention are: through breeding fluorine-resistant strains and a fluorine removal process in the development process, the green, safe, economic and rapid leaching and cyclic enrichment of valuable metals in fluorine-containing inorganic hazardous waste are realized.
CN107500734A relates to a ceramic water permeable brick using industrial inorganic hazardous waste and low-grade aluminum-silicon mineral as raw materials and a preparation method thereof, and is characterized in that: the ceramic aggregate is prepared from 85-95 wt% of ceramic aggregate, 1-7 wt% of industrial inorganic hazardous waste fine powder with the particle size less than or equal to 200 meshes and 1-8 wt% of bonding agent; the ceramic aggregate is prepared from 70-90 wt% of low-grade aluminum-silicon mineral, 3-15 wt% of industrial inorganic hazardous waste and 1-15 wt% of natural quartz. The method improves the utilization rate of the low-grade aluminum-silicon minerals while realizing the direct recycling of industrial inorganic hazardous solid wastes, obtains the ceramic water permeable bricks with stable quality, high compressive strength and good water permeability, meets the requirement of circular economy development, and can generate positive promotion effect on the protection of the ecological environment.
The invention and the prior art are lower than the blast furnace which is mainly used for processing inorganic hazardous wastes at high temperature, the processing technology has the defects of large consumption of fuel coke, complex control regulation, high labor intensity and low equipment running rate, the sulfur content and heavy metal leaching amount of a sintering block are easy to exceed the standard, and the pressure of environmental protection and discharge is very large.
Disclosure of Invention
In order to solve the problems, the invention provides a method for cooperatively treating inorganic hazardous waste by using a cement kiln.
A method for cooperatively treating inorganic hazardous waste by a cement kiln mainly comprises the following steps:
firstly, drying inorganic hazardous waste, crushing and crushing the inorganic hazardous waste by a crusher, and conveying the crushed inorganic hazardous waste to a powder bin;
step two, inorganic hazardous waste is pre-decomposed; conveying inorganic hazardous waste powder in a powder bin to a rotary kiln for incineration disposal, wherein the incineration temperature of the rotary kiln is 1300-1600 ℃, and the total retention time is 20-30 s;
thirdly, solidifying heavy metals, namely, after gas-solid separation is carried out on the burned flue gas and inorganic micropowder ash, the gas enters the upper multi-stage cyclone preheater and is discharged after gas-solid separation, 10 to 25 percent of heavy metal curing agent is added into solid slag, and the mixture is uniformly mixed and treated at 80 to 120 ℃ for 10 to 20 min;
and step four, mixing materials, namely mixing the treated solid slag with cement clinker to form a part of the cement clinker.
The heavy metal curing agent is an inorganic cementing curing material, and silane-succinic acid starch is prepared by adopting vinyl tetramethyl disilane and sodium starch octenyl succinate;
the heavy metal curing agent is an inorganic cementing curing material, the surface grafted nano magnesium oxide and silane-succinic acid starch are subjected to copolymerization reaction,
the preparation method of the silane-succinic acid starch comprises the following steps:
adding 20-53 parts of vinyl tetramethyl disilane, 0.05-2 parts of platinum carbon catalyst and 300-355 parts of white oil into a reaction kettle according to the mass parts, stirring for 100-200min under the protection of nitrogen, then slowly adding 40-65 parts of sodium starch octenyl succinate into a high-pressure reaction kettle, heating to 80-92 ℃, controlling the pressure of the reaction kettle to be 0.5-1MPa, carrying out heat preservation reaction for 60-180min, finishing the reaction, carrying out vacuum distillation to remove the white oil, filtering and drying to obtain silane-starch succinate;
the step is a hydrosilylation reaction, wherein partial reaction is shown as follows:
the heavy metal curing agent is an inorganic cementing curing material, and the preparation method comprises the following steps:
according to the mass parts, 54-68 parts of nano magnesium oxide, 100-200 parts of water, 2-6 parts of 3- (methacryloyloxy) propyl trimethoxy silane are added into a reaction kettle, stirred for 100-200min at 50-71 ℃, filtered, dried, then 8-23 parts of silane-succinic acid starch, 2-5 parts of benzoyl peroxide and 15-28 parts of potassium sulfate are added into a multistage grinding machine after being uniformly mixed, and the mixture is ground for 60-200min at 100-120 ℃ to obtain the inorganic cementing curing material.
Hydroxyl on the surface of the nano magnesium oxide is grafted with 3- (methacryloyloxy) propyl trimethoxy silane, wherein partial reaction is shown as follows:
further, during the heating and grinding process, the nano magnesium oxide grafted on the surface is subjected to copolymerization reaction with silane-succinic acid starch, wherein partial reaction is shown as follows:
the diameter of the steel ball in the multi-stage grinder bin grinder is 36-55 mm.
The water content of the inorganic hazardous waste is 1-5% after drying, and the kiln tail hot air is used for drying treatment.
The particle size of the crushed inorganic hazardous waste is 0.01-0.1 mm.
And the powdery inorganic hazardous wastes are conveyed to the rotary kiln through a metering reamer.
The mass ratio of the solid slag to the cement clinker is 0.18-0.54: 1.
The invention relates to a method for cooperatively treating inorganic hazardous waste by a cement kiln, and provides a method for cooperatively treating inorganic hazardous waste by a cement kiln, wherein the method is used for incinerating the inorganic hazardous waste at high temperature in a rotary kiln of the cement kiln, so that not only is the energy consumption saved, but also the sulfur content of solid slag can be effectively reduced; the invention provides an inorganic cementing and curing material as a curing agent for heavy metal in solid slag, which mainly comprises a potassium magnesium phosphate cementing and curing material, wherein nano magnesium oxide grafted on the surface is subjected to copolymerization reaction with silane-succinic acid starch, so that the inorganic cementing and curing material has a good curing and stabilizing effect on various heavy metal elements and can effectively reduce the heavy metal precipitation rate in the solid slag; the invention utilizes the resources of the inorganic hazardous waste to change waste into valuable, utilizes the kiln tail hot air to dry the inorganic hazardous waste, is beneficial to improving the energy utilization efficiency, simplifying equipment and saving energy, and the final product of the invention is cement, does not generate secondary residue, does not generate fly ash and has no environment-friendly discharge pressure.
Drawings
FIG. 1 is a Fourier infrared spectrum of a sample of the inorganic cementitious cured material prepared in example 2.
At 508cm-1The absorption peak of magnesium oxide exists nearby and is 3223cm-1A stretching absorption peak of hydroxyl exists nearby, which indicates that the nano magnesium oxide participates in the reaction; at 1478cm-1An antisymmetric telescopic absorption peak of borate ions exists nearby, which indicates that borax participates in the reaction; at 1735cm-1The absorption peak of the ester carbonyl group is found near 1063cm-1An antisymmetric telescopic absorption peak of ester carbon-oxygen single bond exists nearby and is 2962cm-1A telescopic absorption peak of carbon hydrogen exists nearby, which indicates that silane-succinic acid starch participates in the reaction; at 1012/868cm-1The anti-symmetric stretching/stretching absorption peak of the silicon oxygen exists nearby, and is at 761cm-1A stretching absorption peak of silicon carbon exists nearby, and the 3- (methacryloyloxy) propyl trimethoxy silane participates in the reaction.
Detailed Description
The invention is further illustrated by the following specific examples:
the cement prepared in the experiment is added with water and stirred into mortar, then the mortar is poured into a mold with the size of 700mm multiplied by 700mm, and then the mortar is cured for 2 days at the temperature of 20 ℃ and under the environment with the relative humidity of 80 percent, and the performance is tested after the mortar is cured for 28 days under the standard condition; contaminant leaching test: carrying out a pollutant leaching test by adopting a method 1311TCLP of the United states environmental protection agency, oscillating 20 times of leaching solution with the pH value of 2.88 +/-0.05 for 20 hours at normal temperature, filtering by using a glass fiber filter membrane, and then measuring the concentrations of heavy metals of lead and chromium by using an atomic absorption spectrophotometry, wherein the leaching standards of the heavy metals of lead and chromium are respectively 3.5mg/L and 8 mg/L; sulphur content was measured according to the tube furnace combustion-potassium iodate titration method of GB/T3286.7-2014.
Example 1
A method for cooperatively treating inorganic hazardous waste by a cement kiln mainly comprises the following steps:
firstly, drying inorganic hazardous waste, crushing and crushing the inorganic hazardous waste by a crusher, and conveying the crushed inorganic hazardous waste to a powder bin;
step two, inorganic hazardous waste is pre-decomposed; conveying inorganic hazardous waste powder in a powder bin to a rotary kiln for incineration disposal, wherein the incineration temperature of the rotary kiln is 1300 ℃, and the total retention time is 20 s;
thirdly, solidifying heavy metals, namely, after gas-solid separation is carried out on the burned flue gas and inorganic micropowder ash, the gas enters the upper multi-stage cyclone preheater and is discharged after gas-solid separation, 10 percent of heavy metal curing agent is added into solid slag, and the mixture is uniformly mixed and treated at 80 ℃ for 10 min;
and step four, mixing materials, namely mixing the treated solid slag with cement clinker to form a part of the cement clinker.
The preparation method of the silane-succinic acid starch comprises the following steps:
adding 20kg of vinyl tetramethyl disilane and 0.05kg of platinum-carbon catalyst into a reaction kettle, stirring for 100min under the protection of nitrogen, slowly adding 40kg of sodium starch octenyl succinate into a high-pressure reaction kettle, heating to 80 ℃, controlling the pressure of the reaction kettle to be 0.5MPa, carrying out heat preservation reaction for 60min, finishing the reaction, carrying out vacuum distillation to remove white oil, filtering and drying to obtain silane-starch succinate;
the heavy metal curing agent is an inorganic cementing curing material, and the preparation method comprises the following steps:
adding 54kg of nano magnesium oxide, 100kg of water and 2kg of 3- (methacryloyloxy) propyl trimethoxy silane into a reaction kettle, stirring for 100min at 50 ℃, filtering, drying, adding 8kg of silane-succinic starch, 2kg of benzoyl peroxide and 15kg of potassium sulfate, uniformly mixing, adding into a multistage grinding machine, and grinding for 60min at 100 ℃ to obtain the inorganic cementing curing material.
The diameter of the steel ball in the multi-stage grinder bin grinder is 36 mm.
The water content of the inorganic hazardous waste after drying is 1%, and kiln tail hot air is used for drying treatment.
The particle size of the inorganic hazardous waste crushed is 0.01 mm.
And the powdery inorganic hazardous wastes are conveyed to the rotary kiln through a metering reamer.
The mass ratio of the solid slag to the cement clinker is 0.18: 1.
The sulfur content of the cement material prepared by the experiment is 0.34%, and the leaching concentrations of heavy metals of lead and chromium are 1.57mg/L and 0.12mg/L respectively.
Example 2
A method for cooperatively treating inorganic hazardous waste by a cement kiln mainly comprises the following steps:
firstly, drying inorganic hazardous waste, crushing and crushing the inorganic hazardous waste by a crusher, and conveying the crushed inorganic hazardous waste to a powder bin;
step two, inorganic hazardous waste is pre-decomposed; conveying inorganic hazardous waste powder in a powder bin to a rotary kiln for incineration treatment, wherein the incineration temperature of the rotary kiln is 1450 ℃, and the total retention time is 25 s;
thirdly, solidifying heavy metals, namely, after gas-solid separation is carried out on the burned flue gas and inorganic micropowder ash, the gas enters the upper multi-stage cyclone preheater and is discharged after gas-solid separation, 18 percent of heavy metal curing agent is added into solid slag, and the mixture is uniformly mixed and treated for 15min at 100 ℃;
the preparation method of the silane-succinic acid starch comprises the following steps:
adding 53kg of vinyl tetramethyl disilane, 2kg of platinum-carbon catalyst and 355kg of white oil into a reaction kettle, stirring for 200min under the protection of nitrogen, then slowly adding 65kg of sodium starch octenyl succinate into a high-pressure reaction kettle, heating to 92 ℃, controlling the pressure of the reaction kettle to be 1MPa, carrying out heat preservation reaction for 180min, after the reaction is finished, carrying out vacuum distillation to remove the white oil, filtering and drying to obtain silane-starch succinate;
the heavy metal curing agent is an inorganic cementing curing material, and the preparation method comprises the following steps:
adding 68kg of nano magnesium oxide, 200kg of water and 6kg of 3- (methacryloyloxy) propyl trimethoxy silane into a reaction kettle, stirring for 200min at 71 ℃, filtering, drying, adding 23kg of silane-succinic starch, 5kg of benzoyl peroxide and 28kg of potassium sulfate, uniformly mixing, adding into a multistage grinding machine, and grinding for 200min at 120 ℃ to obtain the inorganic cementing and curing material.
The diameter of the steel ball in the multi-stage grinder bin grinder is 45 mm.
The water content of the inorganic hazardous waste after drying is 3%, and kiln tail hot air is used for drying treatment.
The particle size of the inorganic hazardous waste crushed is 0.05 mm.
And the powdery inorganic hazardous wastes are conveyed to the rotary kiln through a metering reamer.
The mass ratio of the solid slag to the cement clinker is 0.36: 1.
The content of sulfur in the cement material prepared by the experiment is 0.27%, and the leaching concentrations of heavy metals of lead and chromium are 1.24mg/L and 0.08mg/L respectively.
Example 3
A method for cooperatively treating inorganic hazardous waste by a cement kiln mainly comprises the following steps:
firstly, drying inorganic hazardous waste, crushing and crushing the inorganic hazardous waste by a crusher, and conveying the crushed inorganic hazardous waste to a powder bin;
step two, inorganic hazardous waste is pre-decomposed; conveying inorganic hazardous waste powder in a powder bin to a rotary kiln for incineration disposal, wherein the incineration temperature of the rotary kiln is 1600 ℃, and the total retention time is 30 s;
thirdly, heavy metal solidification, namely, after gas-solid separation is carried out on the burned flue gas and inorganic micropowder ash, the gas enters the upper multi-stage cyclone preheater and is discharged after gas-solid separation, 25 percent of heavy metal curing agent is added into solid slag, and the mixture is uniformly mixed and treated at 120 ℃ for 20 min;
and step four, mixing materials, namely mixing the treated solid slag with cement clinker to form a part of the cement clinker.
The preparation method of the silane-succinic acid starch comprises the following steps:
adding 53kg of vinyl tetramethyl disilane, 2kg of platinum-carbon catalyst and 355kg of white oil into a reaction kettle, stirring for 200min under the protection of nitrogen, then slowly adding 65kg of sodium starch octenyl succinate into a high-pressure reaction kettle, heating to 92 ℃, controlling the pressure of the reaction kettle to be 1MPa, carrying out heat preservation reaction for 180min, after the reaction is finished, carrying out vacuum distillation to remove the white oil, filtering and drying to obtain silane-starch succinate;
the heavy metal curing agent is an inorganic cementing curing material, and the preparation method comprises the following steps:
adding 68kg of nano magnesium oxide, 200kg of water and 6kg of 3- (methacryloyloxy) propyl trimethoxy silane into a reaction kettle, stirring for 200min at 71 ℃, filtering, drying, adding 23kg of silane-succinic starch, 5kg of benzoyl peroxide and 28kg of potassium sulfate, uniformly mixing, adding into a multistage grinding machine, and grinding for 200min at 120 ℃ to obtain the inorganic cementing and curing material.
The diameter of the steel ball in the multi-stage grinder bin grinder is 55 mm.
The water content of the inorganic hazardous waste after drying is 5%, and kiln tail hot air is used for drying treatment.
The particle size of the inorganic hazardous waste crushed is 0.1 mm.
And the powdery inorganic hazardous wastes are conveyed to the rotary kiln through a metering reamer.
The mass ratio of the solid slag to the cement clinker is 0.54: 1.
The content of sulfur in the cement material prepared by the experiment is 0.21%, and the leaching concentrations of heavy metals of lead and chromium are 1.20mg/L and 0.07mg/L respectively.
Comparative example 1
A method for cooperatively treating inorganic hazardous waste by a cement kiln mainly comprises the following steps:
the heavy metal curing agent is an inorganic cementing curing material, and the preparation method comprises the following steps:
54kg of nano magnesium oxide, 100kg of water and 2kg of 3- (methacryloyloxy) propyl trimethoxy silane are stirred for 100min when the temperature is 50 ℃, filtered and dried, then 2kg of benzoyl peroxide and 15kg of potassium sulfate are added, mixed evenly and then added into a multistage grinding machine, and ground for 60min at 100 ℃ to obtain the inorganic cementing curing material.
The rest of the process is the same as that of the embodiment 1,
the content of sulfur in the cement material prepared by the experiment is 0.51%, and the leaching concentrations of heavy metals of lead and chromium are 2.87mg/L and 3.26mg/L respectively.
Comparative example 2
A method for cooperatively treating inorganic hazardous waste by a cement kiln mainly comprises the following steps:
firstly, drying inorganic hazardous waste, crushing and crushing the inorganic hazardous waste by a crusher, and conveying the crushed inorganic hazardous waste to a powder bin;
step two, inorganic hazardous waste is pre-decomposed; conveying inorganic hazardous waste powder in a powder bin to a rotary kiln for incineration disposal, wherein the incineration temperature of the rotary kiln is 1300 ℃, and the total retention time is 20 s;
and step three, solidifying heavy metals, namely, performing gas-solid separation on the burnt smoke and inorganic micropowder ash, allowing the gas to enter the upper multistage cyclone preheater and discharging the gas after the gas-solid separation, and mixing solid slag with cement clinker to form part of the cement clinker.
The water content of the inorganic hazardous waste after drying is 1%, and kiln tail hot air is used for drying treatment.
The particle size of the inorganic hazardous waste crushed is 0.01 mm.
And the powdery inorganic hazardous wastes are conveyed to the rotary kiln through a metering reamer.
The mass ratio of the solid slag to the cement clinker is 0.18: 1.
The sulfur content of the cement material prepared by the experiment is 1.53%, and the leaching concentrations of heavy metals of lead and chromium are 6.87mg/L and 18.47mg/L respectively.
Comparative example 3
The preparation method of the silane-succinic acid starch comprises the following steps:
adding 20kg of vinyl tetramethyl disilane and 0.05kg of platinum-carbon catalyst into a reaction kettle, stirring for 100min under the protection of nitrogen, slowly adding 40kg of sodium starch octenyl succinate into a high-pressure reaction kettle, heating to 80 ℃, controlling the pressure of the reaction kettle to be 0.5MPa, carrying out heat preservation reaction for 60min, finishing the reaction, carrying out vacuum distillation to remove white oil, filtering and drying to obtain silane-starch succinate;
the heavy metal curing agent is an inorganic cementing curing material, and the preparation method comprises the following steps:
and uniformly mixing 54kg of nano magnesium oxide, 8kg of silane-succinic acid starch, 2kg of benzoyl peroxide and 15kg of potassium sulfate, adding the mixture into a multistage grinding machine, and grinding for 60min at 100 ℃ to obtain the inorganic cementing curing material.
The rest of the process is the same as that of the embodiment 1,
the content of sulfur in the cement material prepared by the experiment is 0.41%, and the leaching concentrations of heavy metals of lead and chromium are 2.29mg/L and 1.57mg/L respectively.