Method of recycling residual alkali from sodium tungstate solution in tungsten smelting

Abstract

The invention discloses a method of recycling residual alkali from sodium tungstate solution in tungsten smelting, which comprises the steps of: performing liquid-solid separation on mixed material solution discharged from a pressure cooking kettle through a press filter, pumping the filtrate into a three-effect evaporation crystallizer through a pump, firstly preheating the filtrate in a first preheating pipe, then conveying the filtrate into a first-effect evaporation crystallizer, using the secondary vapor generated by first-effect evaporation concentration as a heat source of second-effect evaporation concentration, and conveying sodium tungstate crystals separated out from a second-effect evaporation crystallizer into a plate-and-frame filter press to perform solid-liquid separation; conveying the concentrated solution into a third-effect concentrator, and performing solid-liquid separation on the sodium tungstate crystals separated out from a crystallization kettle of the third-effect evaporation crystallizer; performing solid-liquid separation on the crystals separated out by the second-effect evaporation crystallizer and the third-effect evaporation crystallizer in the plate-and-frame filter press; and conveying the filtrate into a storage tank to return to the pressure cooking procedure to prepare alkali, and discharging the filter residues in a dissolving tank. The method disclosed by the invention is mature in technique and equipment, high in automation degree, high in utilization rate of effective resources, good in energy-saving effect and high in recycled economic benefit, and the method is an important comprehensive recycling component in tungsten smelting.

Description

technical field [0001] The invention belongs to tungsten hydrometallurgy, in particular to a method for recovering residual alkali from sodium tungstate solution in tungsten smelting. Background technique [0002] my country is a country rich in tungsten resources, and tungsten resources mainly exist in the form of wolframite and scheelite. With the decreasing amount of wolframite resources, mining scheelite resources has become the main mineral of tungsten resources. In the past, scheelite was a raw material that was difficult to mine and smelt in tungsten smelting, and scheelite resources still remained in the resource reserves. With the breakthrough of scheelite smelting technology and the realization of high excess alkali pressure leaching process, The production capacity and scale of scheelite smelting have been greatly improved, and the technology has been further matured. Due to the excessive alkali process, although a large part of the alkali is consumed in the leac...

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Problems solved by technology

[0004] Residual alkali recovery is the process of solution evaporation concentration and crystallization, which is mainly energy consumption. However, due to the current situation of rising energy prices, enterprises pay attention to the relationship between recovery income and cost. When the concentration of residual alkali is lower than a certain value, alkali recovery Most tungsten smelting enterprises will not consider recycling residual alkali when the income and energy consumption are equal or negative

At present, the actual recovery of residual alkali is mainly aimed at enterprises that deal with low-grade tungsten miscellaneous materials or adopt high-excess alkali leaching technology. Usually, the concentration of residual alkali in the solution is above 100 g / L, and these alkali recovery methods mainly adopt traditional methods. Single-pot intermittent evaporation and concentration equipment, this method has many prominent problems such as high energy consumption, low degree of automation, and low marginal income.

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