Method for producing magnesium sulfate and magnesium fertilizer by utilizing alkylated waste sulfuric acid

Abstract

The invention relates to treatment of waste sulfuric acid, in particular to a method for producing a magnesium sulfate and magnesium fertilizer by utilizing alkylated waste sulfuric acid. The method comprises the following steps: (1) adding the alkylated waste sulfuric acid into a reaction kettle and preheating to 90 DEG C; (2) adding magnesite powder while stirring until no bubble occurs; (3) adding caustic-burned magnesia powder and reacting until the pH value is 6.8 to 7.0 to obtain mixed liquid; (4) performing filter-pressing separation on the mixed liquid to obtain primary mother liquid and primary waste residues; (5) adding sodium percarbonate into the primary mother liquid and stirring; (6) filter-pressing to obtain secondary mother liquid and secondary waste residues; (7) crystallizing, centrifuging and drying the secondary mother liquid to obtain magnesium sulfate heptahydrate; (8) mixing the primary waste residues and the secondary waste residues uniformly, drying and crushing to obtain silicon calcium sulfur magnesium fertilizer. The method for producing the magnesium sulfate and magnesium fertilizer by utilizing the alkylated waste sulfuric acid, provided by the invention, is simple in process and low in cost, and avoids secondary pollution.

Description

technical field [0001] The invention relates to a treatment of waste sulfuric acid, in particular to a method for producing magnesium sulfate and magnesium fertilizer by using alkylation waste sulfuric acid. Background technique [0002] The raw material magnesia used in the production of magnesium sulfate by alkylation of waste sulfuric acid contains 85% to 90% of available magnesia, and about 10 to 15% of insoluble matter, the main components of which are silicon dioxide and calcium oxide. These insolubles are eventually brought into the residue after reacting with sulfuric acid. Therefore, the main components of the residue are: silicon dioxide, calcium sulfate, magnesium sulfate brought by the mother liquor, plant fiber brought by the catalyst, adsorbent activated carbon and other components. [0003] At present, the use of silicon fertilizer, silicon-calcium fertilizer, silicon-calcium-magnesium fertilizer, and sulfur-magnesium fertilizer in China is relatively common....

AI Technical Summary

Problems solved by technology

Magnesium oxide residue is rich in silicon, calcium, magnesium, and sulfur, and the particles are small and highly active. However, there is no technology to use magnesium oxide residue to produce silicon, calcium, sulfur, and magnesium fertilizers.