Old brine solution purification treatment method

Abstract

The invention provides a purification treatment method for an old brine solution. A filter aid adding technology is adopted; the large-particle magnesium hydroxide is selected as a filter aid, an oldbrine solution is pumped into a filter aid adding tank 1, the filter aid is added, fully stirred and mixed after being metered in proportion, the fully stirred solution is fed into a filter 3 througha feeding pump 2, the solution is filtered in the filter 3, and a filtrate obtained after filtration serves as a purification pretreatment solution and enters a subsequent procedure. By adding the large-particle magnesium hydroxide filter aid, parameter liquid channels are distributed in a filter cake, and the filtering efficiency is improved.

Description

Technical field [0001] The invention relates to an old brine solution purification treatment method, in particular to a method for pretreating old brine containing high-concentration magnesium chloride to remove impurities. Background technique [0002] In the process of potash fertilizer production, for every ton of potassium chloride potash fertilizer produced, about 7-10 tons of potash fertilizer tail liquid and brine are discharged, which is about 5-9 cubic meters of solution. Potassium fertilizer tail liquor old brine (hereinafter referred to as old brine) is a mixture of magnesium chloride-based solution, the color is yellow-green, containing 28-30% magnesium chloride (mass fraction), 0.5% sodium chloride, 0.24% potassium chloride, 0.01 % Of calcium, 0.9% of sulfate, 0.13% of lithium chloride, 0.10 of boron, and a small amount of solid insolubles. Chaerhan Salt Lake, a typical potash fertilizer production area in my country, has a potash fertilizer production capacity of a...

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Problems solved by technology

However, this kind of metal mesh accessories is extremely expensive and needs to be imported, and it is easy to be worn and corroded, and the cost of use is high

[0008] In summary, when using old brine or old brine crystallization solutions as raw materials to develop resources such as magnesium and lithium, the existing treatment methods for old brine solutions have problems such as unstable purification solution quality and high maintenance costs for production equipment.

The content of magnesium chloride in the solution of old brine or old brine crystals is usually 30% or even higher, and the viscosity of the solution is extremely high. The precipitate generated by chemical methods cannot be clarified by itself, and impurities such as clay cannot be clarified, and mechanical pressure filtration is required. , due to the existence of substances with small particle sizes in the solution, when the filter is used for a long time, the substances with small particle sizes will bond together to form a very dense filter cake, and the flow rate of the liquid cannot be guaranteed

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