Method for separating and enriching lithium, aluminum and silicon from fly ash

Abstract

The invention discloses a method for separating and enriching lithium, aluminum and silicon from fly ash. The method comprises the following steps: (1) pretreating fly ash; (2) carrying out low-temperature alkali dip reaction on the treated fly ash, aids and a sodium hydroxide solution, and filtering; (3) washing the filter residue, removing the impurities, filtering, and drying to obtain calcium silicate; (4) regulating the pH value of the filtrate to alkalinity, separating the lithium / aluminum-containing filtrate to obtain a sodium metaaluminate concentrated solution and a lithium-rich solution, carrying out reverse osmosis on the lithium-rich solution to obtain a lithium concentrated solution, and mixing the sodium metaaluminate concentrated solution with the lithium / aluminum-containing filtrate to obtain a refined solution; (5) precipitating the sodium metaaluminate refined solution, filtering to obtain aluminum hydroxide, and calcining to obtain the aluminum oxide finished product; (6) treating the lithium-rich solution to obtain a lithium-rich concentrated solution and fresh water; and (7) carrying out carbonating precipitation on the lithium-rich concentrated solution, filtering, and drying to obtain the lithium carbonate finished product. The method is a short-stage extraction process, reduces the lithium loss, and implements separation, enrichment and extraction of calcium silicate, aluminum oxide and lithium carbonate.

Description

technical field

[0001] The invention belongs to the field of resource utilization of solid waste, relates to a separation and enrichment extraction method for lithium, aluminum and silicon in fly ash, relates to a short-flow extraction process, reduces lithium loss, separates and enriches to extract calcium silicate, oxidizes Aluminum, lithium carbonate method. Background technique

[0002] my country is a large coal-producing and coal-burning country. Coal is the main energy source of my country's industry. A considerable part of coal resources is used for thermal power generation, resulting in a large amount of fly ash, which has become the largest single pollution source of China's industrial bulk solid waste. Fly ash The effects of stacking, leaching, and dust escaping have brought great potential harm to the ecological environment. At the same time, fly ash is also a waste with strong resource utilization. Its main constituent elements are Si, Al, etc., and the oxides o...

Images