Manufacturing AHF Products By Utilizing BOE waste liquid, Generated By Chip Manufacturers.

Fluorine-containing waste liquid (also called "BOE waste liquid") should be discharged in the process of chip production. See the following table for the components of the waste liquid.

A small amount of 98% sulfuric acid is consumed with BOE waste liquid as raw material to produce anhydrous hydrogen fluoride (AHF), and by-product liquid ammonia (NH₃) or ammonia water (NH₃∙H₂O).

Flow Chart:

1. BOE is pumped from storage tank into intermediate homogeneous tank; React with ammonia gas (or ammonia water) to form ammonium fluoride solution.

2. The ammonium fluoride solution enters the electrodialysis membrane group after precise filtration, where it is decomposed into HF dilute solution and NH₃ dilute solution.

3. The HF dilute solution is distilled and concentrated to obtain concentrated hydrofluoric acid with a concentration of 25-35wt%. The evaporated steam is converted into the water through the condenser, which is used in the sewage treatment station.

4. Concentrated hydrofluoric acid is resolved into HF gas and dilute sulfuric acid solution in an HF resolution tower. Hydrogen fluoride gas is condensed into hydrogen fluoride liquid. The product of hydrogen fluoride (AHF) is obtained after rectification and degassing.

5. Dilute sulfuric acid solution is concentrated into concentrated sulfuric acid, which is returned to the HF analysis tower to absorb water. Wastewater (H₂SO₄≤1.0%) is delivered to sewage treatment station.

6. The dilute NH₃ solution is stripped to become concentrated ammonia water (NH₃≥20~25%). It could be sold as a product.

7. The concentrated ammonia water (NH3≥20~25%) continues to evaporate ammonia at high pressure, and liquid ammonia (NH₃≥99.6%) can be obtained.

8. The tail gas of each process enters the tail gas absorption system, and it can be discharged up to the standard after multi-stage absorption.

Process Features:

1. It is in line with the concept of developing a circular economy to produce industrial products with industrial waste.

2. This process is clean and environmentally friendly, and this technology has reached the international advanced level.

3. The production device adopts a continuous and closed design, which is energy-saving, efficient and pollution-free.

4. The negative pressure process is carried out during the whole system. The pipeline of liquid raw materials adopts double casing, pump valve box, automatic liquid leakage alarm and other structures, so as to ensure the safety of the production process.

5. Advanced DCS control system and high-definition video monitoring system are adopted for production control, and the whole process is automatic and unmanned on site.

6. The quality of hydrogen fluoride products meets the index of superior products, and can be used as raw materials for various fluorine chemical products. In case an electronic hydrofluoric acid production line is added, BOE can be directly prepared and returned to the chip production line for use.

7. The product quality of liquid ammonia (or ammonia water) meets the index of superior products and can be sold as a product. In case an electronic ammonia production line is added, BOE can be directly prepared and returned to the chip production line for use.