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Pre-treatment method for preparing ceramsites from heavy metal contaminated soil before entering kiln

A technology for polluted soil and heavy metals, applied in the field of polluted soil reuse, can solve the problems of blindness and process feasibility analysis in heavy metal polluted soil, and achieve the effects of low heavy metal release, low chemical dosage and strong solidification ability.

Active Publication Date: 2020-10-09
ENVIRONMENTAL SCI RES & DESIGN INST OF ZHEJIANG PROVINCE
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, due to the lack of relevant technical guidelines and standards in the country, there is still blindness in the process of utilizing heavy metal-contaminated soil as building materials
For example, in the process of building material utilization, there is basically no process feasibility analysis based on the heavy metal content in the polluted soil

Method used

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  • Pre-treatment method for preparing ceramsites from heavy metal contaminated soil before entering kiln

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] Take the decommissioned soil of an electroplating factory, the heavy metal copper content is 8321mg / kg, and the zinc content is 4390mg / kg. After being treated according to the general ceramsite preparation process, the release concentration of heavy metals from ceramsite is lower than that of the original soil, but copper and zinc can still be detected in the leachate (see Table 1).

[0048] This soil reference figure 1 The process shown, after the three-step pretreatment of "removal of foreign matter→addition of 1% calcium oxide→adding water (water content 45%)→mixing kaolin with ball mill for 3 times", the "Solid Waste Leaching Toxic Leaching Method Sulfuric Acid Nitric Acid Method" ( HJT299-2007) test results show that the leaching concentration of copper and zinc exceeds the relevant limit of Class III surface water.

[0049] Subsequently, ceramsite was prepared according to direct granulation, and the original soil was re-according to "removing foreign matter → ad...

Embodiment 2

[0056] Take the soil of a decommissioned plot of a metal pipe drawing factory, and its heavy metal nickel content is 1400mg / kg. According to the traditional ceramsite preparation process and the matching pretreatment process ("removing foreign matter → adding 1% calcium oxide → adding water (moisture content 50%) → roasting ceramsite kiln once (gradually heating up from 400°C to 1150°C, the whole time 45min) → mixed kaolin ball mill grinding 3 times (to the silicon dioxide content in the soil reaches 65%) → granulation to prepare ceramsite) The ceramsite preparation process respectively processes the heavy metal polluted soil, in this embodiment, granulation prepares ceramsite The process is specifically the same as in Example 1. The results are shown in Table 2.

[0057] Table 2 Concentration of heavy metals released under acid rain leaching of materials before and after the process (mg / L)

[0058] test group Nickel concentration original soil 2.07 No ...

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Abstract

The invention discloses a pre-treatment method for preparing ceramsites from heavy metal contaminated soil before entering a kiln. The pre-treatment method includes first step: impurity removing, screening and crushing are carried out; second step: calcium oxide is added to the soil, the water is added, and even stirring is carried out; third step: the obtained mixture is fed into a ball mill, andclay minerals are added at the same time; fourth step: heavy metal leaching concentration is determined, and if the leaching concentration does not exceed a concentration limit of type III surface water pollutants, the pre-treatment process is over; fifth step: if the leaching concentration is still higher than the concentration limit of the type III surface water pollutants, the process is returned to the first step, after the first step and the second step treatment are repeated in sequence, then the obtained object is directly send to a ceramsite kiln in a non-granulation mode, and high-temperature roasting is carried out according to the operation procedure of the ceramsite kiln; and six step: the third step is repeated, and the pre-treatment is completed. The pre-treatment method aims to effectively reduce the heavy metal release risk of ceramsite products, and the problem of heavy metal excessive release of the high and low heavy metal polluted soil ceramsites under the currentsituation is solved.

Description

technical field [0001] This application relates to the field of reuse of polluted soil, and specifically relates to a pretreatment process before entering the kiln to strengthen the stability of heavy metals of ceramsite developed for the preparation of ceramsite from heavy metal-contaminated soil. Background technique [0002] my country's industrial industry has experienced long-term extensive development. During this process, due to poor management, hardware and technology, some enterprises have caused soil pollution at the original site of the factory. Among the various types of polluted sites, heavy metal polluted sites are more difficult to remediate and remediate such polluted soil due to their large number, various types of heavy metal pollutants, deep pollution, and difficult decomposition of pollutants. [0003] For heavy metal-contaminated soil, there are currently two main remediation ideas: in-situ treatment and ex-situ treatment. Due to the high demand for the...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B28B17/02C04B33/132C04B33/13B09B3/00B09B5/00
CPCB28B17/026B28B17/02C04B33/1327C04B33/13C04B33/131B09B3/00B09B5/00C04B2235/3208C04B2235/656C04B2235/6567B09B3/40Y02P40/60
Inventor 冯一舰钟重张弛赵浙卿严韵致杨晓丹
Owner ENVIRONMENTAL SCI RES & DESIGN INST OF ZHEJIANG PROVINCE
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