Resource utilization method of titanium chloride slag and device thereof

Abstract

The invention relates to a resource utilization method of titanium chloride slag and a device thereof and belongs to the chemical field of titanium dioxide. The method comprises the following steps: S1, carrying out alkaline leaching to form slag slurry; S2, carrying out solid-liquid separation on the slag slurry; S3, washing the separated solid in the step 2 again; S5, second settlement: adjusting the pH to 9-10 of the filtrate after solid-liquid separation in the step 2 with sodium carbonate and sodium hydroxide jointly, and carrying out settlement to remove heavy metal ions therein to formsecondary slag slurry; and S6, filtering the secondary slag slurry with a ceramic film, wherein solid-liquid separation is carried out on concentrated liquor and washing slag slurry through a plate-and-frame filter press or a centrifugal machine; and the clean liquor is deeply treated by a membrane separation technology to prepare salt dissolving light salt brine for a chlor-alkali process. The method converts environment-harmful titanium chloride slag into harmless building raw material and light salt brine for the chlor-alkali process, and turns wastes into wealth, so that the method has obvious economical and environmental benefits.

Description

technical field [0001] The invention relates to a new method and device for resource utilization of titanium chloride slag, in particular to a device for recovering and utilizing chloride ions and heavy metal ions in titanium chloride slag by using alkali leaching, water washing and membrane separation deep treatment processes A new method for solid slag belongs to the field of titanium dioxide chemical industry. Background technique [0002] At present, the methods for producing titanium dioxide mainly include sulfuric acid method and chloride method. Due to the long process of the sulfuric acid method, serious pollution and poor product quality, it was gradually replaced by the chlorination method. [0003] In the current production of titanium dioxide by chloride method, its main process is: [0004] a. Mix titanium raw material (such as: high titanium slag) and reducing agent (such as: petroleum coke) evenly, then send it into the chlorination furnace, and feed chlorin...

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Problems solved by technology

The idea of ​​this process is very good, but there are two disadvantages: first, roasting requires a lot of energy, and hydrochloric acid is very corrosive, and the equipment investment is large; second, the conversion rate of chloride salt is not high, and the heavy metals in the slag are converted The rate is above 80%, and there are still 20% that cannot be handled

But there are three problems: one is that a large amount of slag is produced after acid dissolution, and the filtration effect is not good due to too strong adhesion and compactness during the press filtration process, and even the problem of not being able to press water; The pH is directly neutralized to above 12 and filtered. Under such high alkaline conditions, amphoteric substances such as aluminum and silicon will dissolve in the alkali solution. With the interception of the nanofiltration membrane, the concentration will become higher and higher, and hydrolysis and precipitation will occur on the membrane. On the surface, it affects the smooth progress of the membrane process, and the result of the high concentration of aluminum and silicon in the nanofiltration feed will lead to high content of aluminum and silicon in the nanofiltration liquid, which cannot meet the requirements of the salt and light brine of the chlor-alkali process ; The third is to mix the neutralization filtrate and washing water filtrate into the ultrafiltration system

This method not only reduces the concentration of salt in the filtrate, but also greatly increases the processing capacity of the membrane system, increasing investment and operating costs

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