Process for preparing potassium fluoride and co-producing white carbon black from fluosilicic acid

Abstract

The invention discloses a process for preparing potassium fluoride and co-producing white carbon black from fluosilicic acid. The process comprises the following steps of: 1, ammonolysis: sequentially adding ammonia gas and ammonia water in the fluosilicic acid with the mass concentration of 20-45 percent, stirring for reacting for 25-35min, and then filtering and washing to obtain a silica sediment and an ammonium fluoride solution; 2, alkaline hydrolysis: adding potassium hydroxide in the ammonium fluoride solution obtained in the step 1 under the condition that the mol ratio of the potassium hydroxide to the ammonium fluoride solution is (1.05-1.10):1.00, reacting the ammonium fluoride with the potassium hydroxide to generate potassium fluoride, evaporating and concentrating until the mass concentration of the potassium fluoride is not less than 35 percent, and spraying the potassium fluoride solution to be dried to obtain a potassium fluoride product; and 3, drying the silica sediment to obtain the white carbon black. The process has the advantages of low production cost and good product quality.

Description

technical field [0001] The invention relates to a process for preparing potassium fluoride and co-producing white carbon black with fluosilicic acid. Background technique [0002] Fluosilicic acid is a by-product produced during the production of phosphate fertilizers and anhydrous hydrofluoric acid. At present, the silicon dioxide content in acid-grade fluorite powder is 1.0-1.6%. Every ton of anhydrous hydrogen fluoride produced will produce 0.2t of fluorosilicic acid by-product. (33.5%). Compared with the by-product of phosphate fertilizer, fluosilicic acid, its impurity content is lower, and the concentration of fluosilicic acid is higher, which has higher recycling value. However, the products produced with fluosilicic acid as raw materials generally have the problem that the silicon content in the product is too high and the product quality is not high, which seriously affects the recycling of fluosilicic acid. In this way, not only will it cause a serious waste of fl...

AI Technical Summary

Problems solved by technology

Its production cost is relatively low, but due to the low reaction rate, the silicon in potassium fluorosilicate cannot be effectively removed, resulting in high silicon dioxide content and poor product quality in the resulting potassium fluoride product