Acid pickling and waste acid treatment process for improving purity of powdery quartz sand

Abstract

The invention provides an acid pickling and waste acid treatment process for improving purity of powdery quartz sand. The process includes the steps: putting the powdery quartz sand in an acid pickling purification device, and using an acid pump for pumping acid pickling solution into the acid pickling purification device, wherein the acid pickling solution is composed of hydrofluoric acid, fluorosilicic acid, oxalic acid and water or composed of fluorosilicic acid, oxalic acid and water; removing the acid pickling solution after acid pickling, and collecting; delivering the powdery quartz sand to a washing device by clear water after acid pickling, washing to neutral, and dewatering to obtain a finished product of powdery quartz sand; transferring waste acid into a neutralization tank for neutralization, delivering into a sedimentation tank by the pump, and allowing calcium fluosilicate and calcium oxalate to precipitate; delivering the clear water into a regulation tank after precipitation to realize pH adjustment for precipitation of iron ions; using oxalic acid or fluorosilicic acid to adjust pH, precipitating calcium fluosilicate and calcium oxalate again, filtering to obtain clear water, and delivering the clear water to a workshop for recycling. The acid pickling and waste acid treatment process for improving purity of the powdery quartz sand has the advantages of remarkable purity improvement and impurity reduction and simplicity and convenience in subsequent treatment.

Description

technical field [0001] The invention provides a pickling and waste acid treatment process for improving the purity of quartz sand powder, relates to the formulation of pickling solution, pickling purification process and treatment process of waste water after pickling, and belongs to the technical field of non-metallic ore deep processing and environmental protection . Background technique [0002] Quartz sand is one of the important inorganic non-metallic materials. It is widely used in glass, ceramics, cement, refractory materials and other industries; the grade (purity) and value of quartz sand mainly depend on the metal impurities in the quartz sand itself. The amount of mineral content, especially the content of metal minerals represented by impurity iron, determines the value and use value of quartz sand. In order to effectively reduce the content of iron elements in quartz sand, people generally adopt the method of strong magnetic separation to remove iron in the pro...

AI Technical Summary

Problems solved by technology

Nowadays, most of the acid solutions used for the purification of quartz sand use strong acids such as: hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid and other acid solutions and their compound acid solutions; the acid-containing waste acids produced by these acid solutions (except sulfuric acid) ) If you want to achieve complete recycling, you need to invest in huge environmental protection systems and equipment, which is very difficult for enterprises with large production volumes

[0003] Compound acid solutions in this field are as follows: hydrofluoric acid, fluorosilicic acid and sulfuric acid; Hydrofluoric acid, fluorosilicic acid and nitric acid; Hydrofluoric acid, fluorosilicic acid and hydrochloric acid can either improve silicon content, but the removal of iron cannot meet the requirements; either the removal of iron meets the requirements, but the purity of silica cannot be improved; The salt content in the quartz sand is too high, and the purity of the final silica has not reached the expected purpose