Preparation method for sludge baked brick resisting leaching of heavy metal

Abstract

The invention relates to a preparation method for a sludge baked brick resisting leaching of heavy metal. The preparation method includes the steps as follows: (1) adding boric acid in water glass and stirring to obtain sodium borosilicate ternary sol original solution; and then adding water for mixture to obtain sodium borosilicate ternary sol diluted solution; (2) adding the diluted solution in sludge, wherein the added diluted solution accounts for 8%-15% sludge in quantity, stirring, and standing for 12-24 hours; and (3) baking according to conventional flow, so that the sludge baked brick can be obtained. The preparation method is simple, convenient and feasible, and suitable for industrial production; and in the treated sludge baked brick, the leaching of chromium is lowered by 40% minimally and the leaching of arsenic is lowered by 60% minimally.

Description

technical field [0001] The invention belongs to the field of preparation of silt sintered bricks, in particular to a preparation method of silt sintered bricks resistant to leaching of heavy metals. Background technique [0002] Severe silt accumulation in rivers and lakes will lead to reduced flood control and storage capacity, reduced drought resistance, deterioration of water environment, shrinking of shipping, etc., endangering local environmental harmony, social security and economic growth. The results of years of research and exploration have led people to find that the best way to solve the problem of silt is to use it as a building material, mainly for the preparation of fired bricks. For example, Changde City in Hunan Province and Nantong City in Jiangsu Province have formed a mud brick-making industrial system with local characteristics. As the economic and social benefits of using silt as a building material are more and more accepted by people, sintered bricks ...

AI Technical Summary

Problems solved by technology

However, during the long-term use of silt sintered bricks, heavy metals in silt bricks will slowly leach out under the action of the environment.

Although the leaching amount of most heavy metals after sludge sintering is very low, the leaching amount of chromium and metalloid arsenic will increase significantly compared with that before sintering (Table 1), resulting in secondary pollution of sludge building material products, which seriously endangers the Residential health and life

In addition, because brick-making enterprises do not measure the content of heavy metals in the sludge before each production, and the sludge in some areas will be enriched and the content of heavy metals is high, so that the leaching of heavy metals in the product reach a dangerous level

At present, China has not paid enough attention to this aspect, and has not consciously controlled and improved it in the production process.

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