Method for treating ammonium chloride in sodium bicarbonate mother solution at normal temperature

Abstract

The invention relates to a method for treating ammonium chloride in a sodium bicarbonate mother solution at normal temperature, which comprises the following steps: adding saturated brine into a double decomposition kettle, adding ammonium bicarbonate to carry out double decomposition reaction so as to generate sodium bicarbonate, filtering the sodium bicarbonate, dehydrating and drying to obtain the sodium bicarbonate; filtering the sodium bicarbonate mother solution, and dehydrating with a centrifugal machine, cooling to normal temperature, and adding hydrochloric acid to control the content of free ammonia in the sodium bicarbonate mother solution at less than 1.3% and the pH value at 6.5-7.1; adding ammonium sulfate or ammonium nitrate which accounts for 8-11 wt% of the total salt amount in the sodium bicarbonate mother solution, as an anion accelerator; evenly adding solid sodium chloride which accounts for 100% of the content of the ammonium chloride in the sodium bicarbonate mother solution, so that the ammonium chloride crystallizes and precipitates under the action of the anion accelerator, and the sodium chloride is quickly dissolved in water to generate brine, until the ammonium chloride completely precipitates and the brine becomes saturated; and carrying out liquid solid separation with a centrifugal machine to obtain the ammonium chloride. The invention ensures the recycling of water, and has the advantages of obvious environmental-protection benefit, high utilization ratio of ammonia, and obvious energy-saving effect.

Description

technical field [0001] The present invention relates to a kind of metathesis method to produce baking soda (NaHCO 3 ) method, especially a method for treating ammonium chloride in baking soda mother liquor at normal temperature, without concentration at normal temperature, and directly crystallizing ammonium chloride by using an anion stimulant. Background technique [0002] Existing production of baking soda (NaHCO 3 ) process such as figure 1 As shown, add the purified saturated brine (NaCl) into the metathesis reaction kettle, raise the temperature to 33-38°C, and then add ammonium bicarbonate (NH 4 HCO 3 ) for metathesis reaction to generate baking soda, then filter the baking soda, and use saturated soda water (Na 2 CO 3 ) to remove chloride ions (Cl - ), dehydrated and dried by a centrifuge to obtain baking soda; the free ammonia generated during the metathesis reaction and the drying process is emptied; the filtered and dehydrated baking soda mother liquor conta...

AI Technical Summary

Problems solved by technology

[0003] 1. After concentrating and recovering ammonium chloride and sodium chloride, the mother liquor still needs to be discharged, which cannot fundamentally solve the problem of environmental pollution caused by waste water discharge;

[0004] 2. Despite the adoption of energy-saving multi-effect evaporation, 0.3-0.5 tons of standard coal is still needed to produce one ton of ammonium chloride, and the cost of each ton of product is increased by 200 to 300 yuan, which increases the cost of the enterprise, the efficiency of the enterprise is low, and the saturated brine must be processed first. After purification, the metathesis reaction with ammonium bicarbonate can be carried out, which increases the production cost;

[0005] 3. Since the content of ammonium chloride in the solution is only 12% to 18%, the evaporative cooling time is long, usually 6-8 hours, and 8-10 firemen and evaporative cooling workers must be added, which is time-consuming and labor-intensive. High labor cost and low production efficiency

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