Method for treating waste liquid containing magnesium and/or calcium in rare earth smelting separation course

Abstract

The invention relates to a method for treating waste liquid containing magnesium and / or calcium in the rare earth smelting separation course. The treating method comprises the following steps of performing pyrolysis on the waste liquid containing magnesium and / or calcium to obtain solid magnesium oxide and / or solid calcium oxide and gas containing hydrogen chloride, wherein after acid making, theobtained gas containing hydrogen chloride is returned for rare earth mine acid dissolution or rare earth extraction and separation, and the obtained magnesium oxide and / or calcium oxide can be directly returned for rare earth extraction and separation or be subjected to size mixing, carbonization and refining to be used as an organic pretreating agent for rare earth extraction and separation according to a specific technological process. The treating method disclosed by the invention is short in technological process and low in energy consumption; besides, the obtained products and by-productsare mutually combined with the rare earth smelting separation course, so that resource cyclic utilization is realized; and the whole course is fundamentally free from discharging of waste water and waste gas.

Description

technical field [0001] The invention belongs to the field of waste liquid treatment, and in particular relates to a treatment method for waste liquid containing magnesium and / or calcium in a rare earth smelting and separation process. Background technique [0002] my country is recognized as a major country with the richest rare earth resources in the world. After nearly 50 years of continuous development, China has established the world's largest rare earth industry system and has become the world's largest producer, exporter and consumer of rare earths. At the same time, my country's rare earth smelting and separation industry has also realized the transformation from small to large, from weak to strong. China's rare earth production was only a few thousand tons in 1980. By 2016, the output had reached 105,000 tons, accounting for 83% of the world's total production. In the industrial production of rare earths, the processes of acid dissolution, extraction and separation ...

AI Technical Summary

Problems solved by technology

At present, ammonia water, liquid caustic soda or solid calcium oxide are mainly used as saponification agents. Among them, the ammonia water saponification extraction process consumes more than 1 ton of liquid ammonia for separating 1 ton of ion ore, and all of them enter the discharge wastewater, which brings serious ammonia nitrogen pollution problems; liquid caustic soda Replacing ammonia water will more than double the cost of saponification, and discharge a large amount of sodium chloride high-salt wastewater; the solid-liquid reaction between solid calcium oxide, aqueous phase and organic phase is slow and the activity is low, resulting in incomplete reaction and precipitation of three-phase substances , affect the operation of the extraction process, and calcium oxide contains a small amount of iron, aluminum and other impurities that are extracted and enriched, affecting the rare earth extraction capacity and product quality

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