Methods To manufacture alkaline waste neutralizer of solids containing large amounts of active calcium oxide by mixing raw lime with bauxite residues and neutralizing sulfuric acid as industrial materials such as cement condensation retardant

摘要

In the present invention, in a method of manufacturing an alkali waste acid neutralizer capable of stably and economically neutralizing waste acids generated in various industries, and by-products generated after neutralizing sulfuric acid waste acid in the waste acid neutralizer, a method of replacing gypsum for a cement setting delay agent, Mixing step of causing a hydration exothermic reaction by mixing the bauxite residue with a moisture content of 20% or more and quicklime (CaO 85% or more) in a weight ratio of 1: 0.25 to 0.7; An aging drying step of converting the mixture into calcium oxide (CaO) → calcium hydroxide (Ca(OH) ₂ ) and giving time to reduce moisture due to heat generation; A pulverizing step of pulverizing the mixture of the aging drying step to 200 μm or less in order to increase reactivity with waste acid; Neutralization step of neutralizing the mixture of the pulverization step by mixing waste sulfuric acid in a weight ratio of 1.0: 0.5 to 1.5; Neutralization aging step for stabilizing the pH of the neutralized product and reducing additional moisture in the neutralization step; In the preparation of the alkali waste acid neutralizer, since the amount of active calcium oxide (CaO) is increased to increase the amount of the neutralization reaction of the waste acid, the amount of by-products is economically treated, and the by-product after neutralization is sulfur trioxide (SO ₃ ) content. As a form of dihydrated gypsum containing 25% or more, it can be used as a cement setting delay agent and as a substitute resource for gypsum, reducing the cost of landfilling and treatment of by-products, and it can be sold as a product by secondary processing of crushing or molding by-products. In addition, the alkaline waste acid neutralizer containing a large amount of active calcium oxide can be used as a neutralizing agent for waste acids such as hydrochloric acid, nitric acid, hydrofluoric acid and phosphoric acid. It has an excellent effect of allowing it to solve secondary environmental problems caused by elution during landfill.