Brine refinement technique

Abstract

The invention relates to a brine preparation technique, particularly a brine refinement technique. The technique comprises the following steps: adding crude brine, lime milk and a sodium sulfate solution into a primary reactor, and mixing to react in the reactor; sending the reaction solution in the primary reactor to a primary brine settling tank through a chute, carrying out solid-liquid separation on primary refined brine and brine sludge in the primary brine settling tank, sending the clear primary refined brine from the upper part of the primary settling tank to a secondary refinement reactor to perform calcium removal; sending the brine sludge discharged from the top of the primary brine settling tank and silt discharged from the primary reactor into a sludge washing barrel to be washed, and recovering raw salt; and when different degrees of calcium sulfate scales are formed on the equipment and pipelines after the sulfate content in the sodium sulfate solution increases, adding causticized low-concentration alkali liquor into the primary brine settling tank to eliminate the scales. The technique avoids the scales of the production equipment system and improves the lime-sodium carbonate brine refinement method from sodium carbonate by an ammonia soda process.

Description

technical field [0001] The invention relates to a brine preparation process, in particular to a brine refining process. Background technique [0002] Brine refining is an important process of soda ash production, the main purpose is to remove impurities such as calcium, magnesium and silt in crude brine. Commonly used brine refining methods mainly include lime-soda ash method, lime-ammonium carbonate method, ammonium carbonate method and lime-glauber's salt method. [0003] The lime-soda ash method is widely used. Lime is used to remove magnesium and soda ash to remove calcium. The refining efficiency is high, but a large amount of soda ash product is consumed, and the refining cost is high. It is suitable for the brine refining system with low impurity content; the lime-ammonium carbonate method uses lime Removing magnesium and using carbonization tail gas to remove calcium, the refining cost is relatively low, but the secondary brine contains equivalent fixed ammonium to ...

AI Technical Summary

Problems solved by technology

[0003]The lime-soda ash method is widely used. Lime is used to remove magnesium and soda ash to remove calcium. It has high refining efficiency but consumes a lot of soda ash products, and the refining cost is high. It is suitable for impurities Brine refining system with low content; the lime-ammonium carbonate method uses lime to remove magnesium and carbonized tail gas to remove calcium. Carbonization conversion rate, followed by decalcification and magnesium removal, complex process, many equipment, large investment, large ammonia loss, serious scarring of decalcification tower and equipment; ammonium carbonate method uses carbonized tail gas to refine brine, and the efficiency of magnesium removal is poor , the ammonia absorption system is still seriously blocked; while the lime-glauber's salt method uses a large amount of thenardite and is expensive, and the refined brine contains a high concentration of SO 4 2- , resulting in ammonia evaporation The system is severely scarred

[0004]The above four methods have their own advantages and disadvantages. When using seawater salt or raw salt with poor quality to make coarse brine with high calcium and magnesium content, choose any of the above refining methods One, neither can guarantee the refining efficiency without increasing the refining cost

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