Cleaning method of concentration system for wet process phosphoric acid purifying process

Abstract

The invention discloses a cleaning method of a concentration system for a wet process phosphoric acid purifying process. The cleaning method comprises the following steps: connecting a cleaning liquidpipe to a circulating pipe at the inlet of a circulating pump; arranging a cleaning liquid delivery pump and a valve on the cleaning liquid pipe; preparing a cleaning liquid and connecting the cleaning liquid to the cleaning liquid pipe; opening the valve to start the cleaning liquid delivery pump, wherein the cleaning liquid enters an evaporating room; when the cleaning liquid in the evaporatingroom reaches a preset liquid level, closing the valve on the cleaning liquid pipe and starting the circulating pump; after the cleaning liquid flows circularly in the concentration system for 10-15 min, opening a discharging valve, and starting a discharging pump to discharge the cleaning liquid to finish cleaning. The cleaning liquid is a mixed solution containing sulfuric acid, fluosilicic acid, a pickling corrosion inhibitor, sodium molybdate, a penetrant and sulfamic acid. The method disclosed by the invention is simple and convenient to operate, saves the labor force, cleans the concentration system effectively, so that the cleaning time is shortened, damage of scale blocks hit to fall off to concentration equipment in a conventional method is avoided, too, and the operating rate ofthe equipment is guaranteed.

Description

technical field [0001] The invention relates to a cleaning method for a concentration system used in a wet-process phosphoric acid purification process, and belongs to the technical field of fine chemicals. Background technique [0002] Phosphoric acid is the core of the phosphorus chemical industry. In my country, the phosphate industry is formed by obtaining yellow phosphorus from electrolytic phosphate rock to produce thermal phosphoric acid, and the phosphate fertilizer industry is formed by using sulfuric acid to decompose phosphate rock to produce wet process phosphoric acid. Compared with thermal phosphoric acid, wet-process phosphoric acid has lower energy consumption and less pollution, and has significant advantages in energy, environment and cost. However, wet-process phosphoric acid contains more impurities and requires higher purification technology. Therefore, domestic wet-process phosphoric acid is currently mainly used for the production of phosphorus compou...

AI Technical Summary

Problems solved by technology

Since the dilute phosphoric acid processed by the concentration system contains calcium, magnesium, potassium salt and other media, as the cycle time prolongs, scaling will occur in the system, especially the scaling on the inner wall of the heat exchanger tube will reduce the heat transfer efficiency and affect the system. load, so it needs to be regularly descaled

The existing descaling method is physical cleaning, which is to use a high-pressure water gun to make the water form a jet state to strike the scale and make the scale fall off the inner wall of the tube. This method has high safety risks, high cost, long time-consuming and complicated operation

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