Production process of active lime

Abstract

The invention discloses a production process of active lime. The process comprises the following steps of (1) screening and pretreatment of limestone, (2) mixing, (3) preheating, (4) calcining, (5) cooling and (6) post-treatment. Firstly, an additive used in the production process reduces underfiring and overburning of the lime, increases the decomposition speed of CaCO3, shortens the calcining time, correspondingly reduces the energy consumption and is beneficial to industrial popularization. Furthermore, carbon is also added, decompression operation is adopted after preheating and before cooling separately, correspondingly the elements sulfur and carbon which remain in lime raw materials can be volatilized out more thoroughly, and the recombination of the elements with calcium oxide is avoided, so that the purity of the active lime is improved, and the activity degree of quicklime is further improved.

Description

technical field [0001] The invention relates to the technical field of active lime preparation, in particular to an active lime production process. Background technique [0002] Active lime is a kind of high-quality light burnt lime, which has fine grains (0.1-3μm), high porosity (50%), and large specific surface area (1.5-2.0m 2 / kg), small bulk density: (1.5~1.7g / cm 3 ), high activity (≥300ml), residual CO 2 Low content (≤2%) and other advantages. Activated lime is mainly used as a "slagging agent" for steelmaking, and is also widely used in environmental protection fields such as wet flue gas desulfurization and acidic industrial wastewater, as well as light calcium carbonate, calcium carbide, briquette binder, epichlorohydrin, Sintered alumina and other chemical production processes. [0003] Activated lime is made by calcining limestone to make calcium carbonate (CaCO 3 ) obtained by thermal decomposition. When the limestone is calcined by the traditional process,...

AI Technical Summary

Problems solved by technology

When the limestone is calcined by the traditional process, due to the large particle size range of the limestone, the heat transfer rate of the lime is much lower than that of the limestone during the calcining process. As the outer lime layer becomes thicker, the inner limestone particles The heat transfer rate will become slower and slower, and the calcination time will be longer, and the long-term high temperature will make the surface of the limestone over-fired and "ceramized", and the CO generated during calcination will 2 The gas is difficult to discharge, the decarburization is not complete, and a raw burn is formed

This not only wastes energy, but also affects the quality of low-carbon high-activity lime

[0004] In addition, limestone contains a small amount of sulfur, usually in the form of CaSO 4 The form exists, while CaSO 4 The decomposition temperature of calcium carbonate is above 1200°C, and the decomposition process must be carried out completely at 1350-1400°C, which is much higher than the decomposition temperature of calcium carbonate, and because of its low content in limestone, there are few in the prior art. Process for treating sulfur in limestone