Process for extracting calcium chloride from waste incineration fly ash

A waste incineration fly ash and calcium chloride technology, applied in the direction of alkali metal chloride, calcium/strontium/barium chloride, calcium/strontium/barium halide, etc., can solve the problem of low economic value and high processing cost of calcium carbonate , comprehensive operating costs and other issues, to achieve the effect of reducing operating costs, reducing processing costs, and reducing equipment investment

Pending Publication Date: 2021-02-19
河北金坦化工装备有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

A large amount of sodium carbonate is consumed in the decalcification process, the treatment cost is high, and

Method used

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  • Process for extracting calcium chloride from waste incineration fly ash

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[0038] Example 1

[0039] 1) Use evaporative condensed water as washing water to carry out countercurrent washing for waste incineration fly ash three times, and then separate the washed aqueous solution into solid-liquid to obtain dechlorinated ash residue and washing water.

[0040] 2), adding a heavy metal removal agent to the washing water, and performing solid-liquid separation again to remove heavy metal precipitation.

[0041] 3), adding hydrochloric acid to adjust the pH value to pH=7, and then sending it to the subsequent evaporation process.

[0042] 4), evaporating concentrated solution, to the calcium chloride concentration of concentrated solution is concentrated to 40% (wt.), sodium chloride and potassium chloride crystallization, adopt the solid mixed salt of filtering solid-liquid separation sodium chloride, potassium chloride and calcium chloride solution. The condensed water obtained when the concentrated liquid is evaporated is returned to step 1 for reuse...

Example Embodiment

[0044] Example 2

[0045] 1) Use evaporative condensed water as washing water to carry out countercurrent washing for waste incineration fly ash three times, and then separate the washed aqueous solution into solid-liquid to obtain dechlorinated ash residue and washing water.

[0046] 2), adding a heavy metal removal agent to the washing water, and performing solid-liquid separation again to remove heavy metal precipitation.

[0047] 3), adding hydrochloric acid to adjust the pH value to pH=8, and then sending it to the subsequent evaporation process.

[0048] 4), evaporate concentrated solution, to the calcium chloride concentration of concentrated solution is concentrated to 38% (wt.), sodium chloride and potassium chloride crystallization, adopt the solid mixed salt of filtering solid-liquid separation sodium chloride, potassium chloride and calcium chloride solution. The condensed water obtained when the concentrated liquid is evaporated is returned to step 1 for reuse a...

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Abstract

The invention relates to a process for extracting calcium chloride from waste incineration fly ash, and belongs to the technical field of chemical engineering. The process comprises the following steps: 1) washing waste incineration fly ash by using evaporation condensate water, and carrying out solid-liquid separation to obtain dechlorinated ash residues and washing water; 2) adding a heavy metalremoval agent into the washing water, and removing heavy metal precipitates through solid-liquid separation; 3) adding hydrochloric acid to adjust the pH value, and then feeding into a subsequent evaporation process; 4) carrying out evaporating concentration on the solution, and carrying out solid-liquid separation on the concentrated solution to obtain sodium chloride, potassium chloride solid salt and a calcium chloride solution; and 5) concentrating, cooling and crystallizing the calcium chloride solution to obtain a hydrated calcium chloride product, or directly drying the calcium chloride solution to obtain an anhydrous calcium chloride product. According to the process, sodium chloride, potassium chloride and calcium chloride are recycled in a multi-time solid-liquid separation andevaporation concentration mode, and heavy metals are removed, so that the environmental protection property is good.

Description

technical field [0001] The invention relates to a process for extracting calcium chloride from waste incineration fly ash, which belongs to the technical field of chemical industry. Background technique [0002] The resource utilization of domestic waste incineration fly ash is currently a hot spot. The fly ash after water washing and dechlorination treatment is sent to cement kiln for co-processing and sintered light bone material treatment is the main way of resource utilization of fly ash. Fly ash washing water contains a large amount of calcium, potassium, sodium, chloride, a small amount of magnesium ions and trace amounts of heavy metal ions. In the prior art, the water washing liquid is treated by adding a large amount of sodium carbonate to the water washing liquid for calcium removal treatment to obtain a solution of potassium chloride and sodium chloride, and then performing evaporation and crystallization separation and purification of potassium chloride and sodi...

Claims

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Application Information

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IPC IPC(8): C01F11/24C01D3/08
CPCC01F11/24C01D3/08C01P2004/82
Inventor 闫永娟张海春程萍张涛
Owner 河北金坦化工装备有限公司
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