Method for production of acid from phosphogypsum by utilizing electrolytic-aluminium waste cathode carbon blocks

Abstract

The invention discloses a method for applying electrolytic-aluminium waste cathode carbon blocks in combined production of sulfuric acid and cement from phosphogypsum. The method comprises the following steps: smashing the phosphogypsum, carrying out drying and dehydrating so as to obtain hemihydrate gypsum, crushing the electrolytic-aluminium waste cathode carbon blocks into a powder material, mixing the powder material with the hemihydrate gypsum, clay and bauxite, carrying out on-line drying, after completion of drying, carrying out integrated grinding so as to obtain a phosphogypsum cementraw material, preheating the raw material, delivering the preheated raw material into a hollow rotary kiln for decomposition and calcination, subjecting generated SO2-containing gas to gas-solid separation, carrying out dedusting and purifying, then delivering obtained gas into a sulfuric acid system so as to prepare a finished sulfuric acid product, subjecting the raw material to high-temperature calcination so as to obtain a cement clinker, blending the cement clinker with certain amounts of coal cinder and fly ash, and carrying out grinding with a ball mill so as to obtain the cement. Themethod provided by the invention realizes reutilization of the electrolytic-aluminium waste cathode carbon blocks and the phosphogypsum, eliminates the influence of wastes on the environment, saves the cost of occupied land, seepage prevention treatment and the like for waste residue storage at the same time, and has significant economic and environmental benefits.

Description

technical field [0001] The invention relates to a method for producing cement, in particular to a method for producing cement and sulfuric acid with phosphogypsum. Background technique [0002] Phosphogypsum is the industrial waste slag discharged during the wet production of phosphoric acid. For every 1t of phosphoric acid produced, about 4.5t-5t of phosphogypsum is produced. my country's phosphate fertilizer production is increasing at a rate of more than 10% per year, which will lead to an increase in the discharge of phosphogypsum year by year. Long-term accumulation of large amounts of phosphogypsum not only wastes land resources, but also easily causes soil and water pollution, threatening human health. [0003] At present, the reuse of phosphogypsum is mainly through the co-production of cement technology through the production of sulfuric acid from phosphogypsum. The main process of this technology is as follows: firstly, phosphogypsum is dried to remove the crystal...

AI Technical Summary

Problems solved by technology

However, the flotation method and sulfuric acid decomposition method cannot remove the cyanide in the waste cathode carbon block, and the cyanide and some fluoride enter the waste liquid and easily cause secondary pollution; the carbon in the waste cathode carbon block is recovered as fuel by the roasting method and burned The heat generated is difficult to use effectively, resulting in a large amount of energy waste, and cannot meet the requirements of strict temperature control in the roasting process

In view of the problems of low recovery rate, serious energy waste, and high recycling cost of the existing waste cathode carbon block recovery methods, it is extremely necessary to study a high-efficiency, energy-saving, and environmentally friendly electrolytic aluminum waste cathode carbon block recycling process.