Method of utilizing dicyandiamide waste residues and carbide slag to produce lime

Abstract

A method of utilizing dicyandiamide waste residues and carbide slag to produce lime comprises the following steps: evenly mixing and stirring the dicyandiamide waste residues and the carbide slag according to a scheduled weight ratio, obtaining blank through compression moulding, wherein the scheduled weight ratio is 95 to 39 percent of the dicyandiamide waste residues and 5 to 70 percent of the carbide slag; sending the pressed blank into a carbonization furnace, passing tail gas into the carbonization furnace to conduct carbonization and drying, wherein carbonization time is 4 to 8 hours, moisture of the dried blank is less than 5 percent; and sending the carbonized and dried blank to a lime kiln to conduct calcination to obtain lime, wherein calcination temperature is 800 to 1000 DEG C. The dicyandiamide waste residues and the carbide slag can be utilized to produce lime with high purity through the method of utilizing the dicyandiamide waste residues and the carbide slag to produce lime.

Description

Technical field: [0001] The invention relates to the technical field of industrial waste slag reuse, in particular to a method for producing lime by using dicyandiamide waste slag and carbide slag. Background technique: [0002] At present, limestone is fired into lime, which is widely used as the basic raw material in the construction industry, and the process of producing dicyandiamide products is lime-calcium carbide-lime nitrogen-dicyandiamide-a large amount of waste residue, the existing production Manufacturers of dicyandiamide products produce a large amount of dicyandiamide waste residue in the production process, which piles up like mountains and occupies a lot of land. At the same time, the waste residue contains certain harmful substances and has a certain impact on the surrounding environment. For example, drinking water is polluted , crops are endangered, etc. [0003] Although the prior art has utilized dicyandiamide waste slag and anthracite to produce lime t...

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Problems solved by technology

But there is following problem in above-mentioned prior art: dicyandiamide waste slag is a kind of very loose powdery substance, is extremely difficult to molding, and its main component is calcium carbonate, and content is 85%, even if molding is superimposed successively in vertical kiln will make The formed billet is crushed, and the ash after burning the anthracite is mixed with the burned lime, which reduces the purity of the lime; in addition, because a large amount of sulfur is produced during the combustion of the anthracite, the sulfur reacts with the oxygen in the air to form sulfur dioxide, sulfur dioxide It reacts with calcium carbonate at a moisture content of 18-20% to form calcium sulfate. Further, because the dicyandiamide waste residue and anthracite particles are superimposed, the sulfur dioxide produced continues to react with a part of the calcium carbonate in the upper layer to form calcium sulfate. Calcium sulfate forms gypsum at high temperature, and the gypsum is mixed into the lime, which reduces the purity of the produced lime

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