Method for extracting amphoteric heavy metal by adopting incineration fly ash as low-grade heavy metal

A technology for incinerating fly ash and heavy metals, applied in the direction of improving process efficiency, etc., can solve the problems of lack of universal applicability in incinerating fly ash, limited improvement of heavy metal fixation rate, inability to break dioxin, etc., and achieve good universal applicability and low cost Low, easy-to-select effects

Inactive Publication Date: 2012-08-01
SHENYANG AEROSPACE UNIVERSITY
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Problems solved by technology

[0004] Since incineration fly ash is defined as hazardous waste, current research focuses on the control technology of heavy metal pollutants, including thermochemical treatment technology and conventional chemical treatment technology. Conventional chemical treatment technology includes cement solidification, chemical stabilization and acid or other solvents The disadvantage of the extraction method is that it can only solve the problem of heavy metals, but cannot break the dioxin
Thermochemical treatment technology, including melting treatment, calcination treatment and cement kiln co-processing technology, has been paid attention to because of its high temperature can destroy dioxins, but the disadvantage is that heavy metals volatilize seriously
In order to improve the fixation rate of heavy metals in slag, it is usually improved by adding additives such as waste glass powder and borax, but the disadvantages are: 1) the improvement of the fixation rate of heavy metals is limited, 2) the incineration fly ash with very different properties is not widely used applicability

Method used

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  • Method for extracting amphoteric heavy metal by adopting incineration fly ash as low-grade heavy metal
  • Method for extracting amphoteric heavy metal by adopting incineration fly ash as low-grade heavy metal

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Experimental program
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Effect test

Embodiment 1

[0022] Low chlorine content incineration fly ash samples, the composition is shown in Table 1, take incineration fly ash 100g, after adding different proportions of NaCl (5%, 10% (calculated according to the weight % of Cl)), and then in the box-shaped resistance furnace The sample was roasted at a constant temperature of 1000°C and 1100°C for 4 hours, and the sample was cooled naturally in the air, and then the extraction rate of amphoteric heavy metals was analyzed. When the NaCl content was 0, 5% and 10%, the extraction rate of Cd was 86.9%, 97.6% and 100% at the calcination temperature of 1000℃. When the calcination temperature is 1100℃, they are 90.1%, 93.2% and 100%, respectively. The extraction rate of Pb increased from 85.7% to 100% at the calcination temperature of 1000°C. When the calcination temperature is 1100℃, it increases from 90.8% to 100% respectively. The extraction rate of Zn increased from 23.9% to 73.8% at the calcination temperature of 1000℃. It increa...

Embodiment 2

[0026] Incineration fly ash samples are shown in Table 1, and different proportions of CaCl were added 2 After (5%, 10% (calculated according to the weight % of Cl)), the implementation method is shown in Example 1.

[0027] When CaCl 2 When the contents are 0, 5% and 10% respectively, the extraction rate of Cd is 86.9%, 91.6% and 100% at the calcination temperature of 1000℃. The extraction rates of Pb were 85.7%, 91.4% and 100% respectively at the calcination temperature of 1000°C. The extraction rate of Zn increased from 23.9% to 72.3% at the calcination temperature of 1000℃.

Embodiment 3

[0029] The samples of incineration fly ash with high chlorine content are shown in Table 2. 100g of fly ash was placed in a corundum porcelain boat (the composition is Al 2 o 3 , the length, width and height are 10cm×10cm×1.2cm), the corundum porcelain boat is placed in a fixed furnace that has reached a predetermined temperature for firing experiments. The preset temperature is 900°C and 1100°C, and the atmosphere is air atmosphere. The roasting time is 12.5min, 30min, 60min, 1.5h, 2h, 3h. When the Cl content in the original incineration fly ash is high, that is, 14.22%, there is no need to add inorganic chlorinating agents to the incineration fly ash. At 900°C and the roasting time is 1 hour, the extraction rate of Pb is about 80%, and the extraction rate of Cu is about 80%. The extraction rate reached 50%, and after the roasting temperature was increased to 1100°C, the roasting time was only 12.5 minutes, and the extraction rate of Pb was over 90%, and the extraction rate...

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Abstract

The invention relates to a method for extracting amphoteric heavy metal by adopting incineration fly ash as low-grade heavy metal. The method is applicable to the incineration fly ash of high-concentration amphoteric heavy metal. An inorganic chloride-contained medium is added into the incineration fly ash, and the amphoteric heavy metal is selectively and high-efficiently extracted from the incineration fly ash by adjusting the inorganic chloride-contained medium and a calcination temperature under the condition with appropriate calcination temperature and an appropriate time. The heavy metal contains lead (Pb), cadmium (Cd), copper (Cu) and zinc (Zn), the inorganic chloride-contained medium is sodium chloride (NaCl), potassium chloride (KCl) and calcium chloride (CaCl2), and a formulation of the inorganic chloride-contained medium contains NaCl, KCl, CaCl2, NaCl + KCl, NaCl + CaCl2, KCl + CaCl2 and NaCl + KCl + CaCl2. According to the method, Pb and Cd can be completely extracted, and a majority of Zn and Cu can be extracted. The extracted product has high purity, the cost of the inorganic chlorinating agent is low, good universal applicability to the incineration fly ash with complicated and variable properties can be achieved, Dioxin can be eliminated, the incineration fly ash is converted from dangerous waste into ordinary waste after chlorinating calcinating and extracting the amphoteric heavy metal, and the incineration fly ash after being calcinated in a chlorinating way and the amphoteric heavy metal is extracted not only can enter a municipal solid waste landfill but also can be recycled for building skeletons.

Description

technical field [0001] The invention belongs to the technical field of hazardous waste treatment and disposal, and in particular relates to a purification technology for hazardous waste containing high-concentration amphoteric heavy metals as a secondary ore of amphoteric heavy metals. Background technique [0002] The output of municipal solid waste is huge, with an annual growth rate of 8-10%. The removal volume in 2002 and 2004 was 136.5 million tons and 155 million tons respectively. The incineration treatment of domestic waste has achieved rapid development in my country in recent years, and its proportion has also increased year by year. In 2004, the capacity of waste incinerators in operation and under construction nationwide was 7.3 million tons per year, accounting for 9.0% of the total waste, and in 2005 it was 10 million tons per year. The "National Eleventh Five-Year Plan for the Construction of Harmless Treatment Facilities for Municipal Domestic Waste" pointed...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B7/02C22B1/08C22B13/00C22B15/00C22B17/00C22B19/00
CPCY02P10/20
Inventor 王雷李润东李彦龙
Owner SHENYANG AEROSPACE UNIVERSITY
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