Method of cement kiln co-processing for calcium-added and passivated town sludge

A co-processing and cement kiln technology, applied in water/sludge/sewage treatment, sludge treatment, chemical instruments and methods, etc., can solve the problems of lack of targeted treatment technology, consumption, serious secondary pollution, etc. Achieve the effect of resource utilization, cost reduction and landfill avoidance

Active Publication Date: 2012-10-10
南京希捷环保科技有限公司
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AI Technical Summary

Problems solved by technology

[0005] (2) The source and nature of sewage are unstable: the influent of small and medium-sized cities and towns includes industrial sewage and domestic sewage, and the proportion of industrial wastewater is relatively high.
[0007] (4) There are many kinds of heavy metals in sludge, and the content differences are significant: due to the high proportion of industrial sewage in the influent water, and the nature of industrial enterprises is significantly different, resulting in a wide variety of heavy metals in sludge, and the content differences are significant, As, Cd , Ni, Pb, Cr, Cu, and Zn vary greatly, with a range of up to several thousand mg / kg, which leads to serious environmental pollution and high-concentration heavy metal leachate and secondary pollution in the process of sludge treatment and disposal. serious
[0008] These characteristics of urban sludge severely limit the use of existing sludge treatment technologies, and the low organic matter content makes composting unfavorable for smooth development. The high heavy metal concentration limits the agricultural use and landfill treatment of sludge composting products, and also makes incineration. The secondary pollution of the process is serious, and the low volatile matter, high ash content and low received basis heat value cause the incineration process to consume more fuel
[0009] The environmental problems caused by urban sludge have not yet attracted enough attention, and targeted treatment technologies are also very scarce

Method used

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  • Method of cement kiln co-processing for calcium-added and passivated town sludge
  • Method of cement kiln co-processing for calcium-added and passivated town sludge
  • Method of cement kiln co-processing for calcium-added and passivated town sludge

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] A kind of urban sludge with a moisture content of 78.2%, a volatile content of 18.1%, and the contents of heavy metals Zn, Cu, Cr, and Ni are 1046mg / kg, 293mg / kg, 244mg / kg and 221mg / kg respectively, Sr, Mn The contents of, Ba are 766mg / kg, 535mg / kg and 386mg / kg respectively. Add 10% (mass percentage) waste lime, use a screw conveyor to transport it to the sludge mixing mixer, fully stir, and pile it naturally for 7 days under direct sunlight. The moisture content of the sludge and waste lime is 40%. Mix with raw meal (see Table 1 for composition) at a replacement ratio of 2% (calculated based on the dry weight of sludge and waste lime) to meet the requirements of SM = 2.5, IM = 1.5, and KH = 0.9 for clinker. The clinker calcination method is as follows: a uniform mixture of sludge and waste lime is uniformly mixed with cement raw material, and water is pressed to form a φ100mm×15mm green sheet. After drying at 105°C for 24 hours, it was heated to 1450°C at a heating rat...

Embodiment 2

[0041] The properties of urban sludge are the same as in Example 1. Add 15% (mass percentage) waste lime, use a screw conveyor to transport it to the sludge mixing mixer for full mixing, and pile it naturally for 7 days under direct sunlight. The moisture content of the sludge and waste lime is 38%. Mix with raw meal (see Table 1 for composition) at a replacement ratio of 5% (calculated based on the dry weight of sludge and waste lime) to meet the SM=2.4, IM=1.5, and KH=0.9 of clinker. The clinker calcination method is the same as in Example 1.

[0042] The Portland cement clinker after calcination is tested. The four main components of the clinker are tricalcium silicate (C 3 S), dicalcium silicate (C 2 S), tricalcium aluminate (C 3 A) and tetracalcium iron aluminate (C 4 The content of AF) was 56%, 20%, 7.9% and 9.2, respectively.

[0043] The 1d, 3d and 28d compressive strengths of the calcined ordinary Portland cement are 11MPa, 22MPa and 54MPa respectively. Other indicators ...

Embodiment 3

[0046] The properties of urban sludge are the same as in Example 1. Add 20% (mass percentage) waste lime, use a screw conveyor to transport to the sludge mixing mixer, fully stir, and pile up naturally for 7 days under direct sunlight. The moisture content of the sludge and waste lime is 30%. Mix with raw meal (see Table 1 for composition) at a replacement ratio of 10% (calculated based on the dry weight of sludge and waste lime) to satisfy the SM=2.5, IM=1.5, and KH=0.9 of the clinker. The clinker calcination method is the same as in Example 1.

[0047] The Portland cement clinker after calcination is tested. The four main components of the clinker are tricalcium silicate (C 3 S), dicalcium silicate (C 2 S), tricalcium aluminate (C 3 A) and tetracalcium iron aluminate (C 4 The content of AF) was 53%, 20%, 8.1% and 9.0, respectively.

[0048] The 1d, 3d and 28d compressive strengths of the calcined ordinary Portland cement are 10MPa, 21MPa and 51MPa respectively. Other indicators...

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Abstract

The invention discloses a method of cement kiln co-processing for calcium-added and passivated town sludge and solves the technical problems that the content of organic matters in the town sludge is lower while the content of heavy metals in the town sludge is higher, the nature of the sludge is not stable, the moisture content of the sludge is high and the sludge is difficult to transport. The implementation steps of the method are as follows: firstly, the constituents and the moisture content of the town sludge are tested, the pH value of the town sludge is usually between 6 and 8, and when the sludge meets leachate within the pH value range or in the landfilling state, the heavy metals are dissolved out easily, and the increasing of the pH value of the sludge is beneficial for passivation of the heavy metals and reduction of dissolution of the heavy metals; the town sludge is mixed with waste lime to ensure that the pH value of the mixture is between 9 and 10, and the mixture is kept stable at room temperature for 2-7 days; and the mixture enters a novel dry-process cement kiln from below a predecomposition furnace, silicon and calcium in the sludge and calcium in the lime can be used to produce silicate cement, and the organic matters in the sludge can be burnt so as to replace partial cement kiln fuel. The method of the cement kiln co-processing for the calcium-added and passivated town sludge is an economical, fuel-saving and low-pollution method for resource utilization of the town sludge.

Description

Technical field [0001] The invention relates to a method for co-processing of urban sludge after calcium increase and passivation in a cement kiln, in particular to a method for harmless and resource utilization of urban sludge containing heavy metals, and belongs to the technical field of solid waste treatment. Background technique [0002] my country's urban sewage treatment facilities have formed a large-scale treatment capacity after high-speed construction during the "10th Five-Year Plan" and "Eleventh Five-Year Plan" periods. As of the end of September 2010, the accumulated sewage treatment capacity of cities, counties and some key organizational towns (hereinafter referred to as "towns") nationwide has reached 169 million m2. 3 / d; Among them, 36 large and medium-sized cities (municipalities directly under the Central Government, provincial capital cities and cities under separate state planning) have built 376 sewage treatment plants with a processing capacity of 43.68 mil...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F11/00C04B7/24
CPCY02P40/10Y02W10/37
Inventor 王雷李润东魏砾宏李彦龙徐杰贺业光孙洋杨天华刘耀鑫
Owner 南京希捷环保科技有限公司
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