CN1159425A

CN1159425A - Clean production technology for manganese carbonate

Info

Publication number: CN1159425A
Application number: CN 96118059
Authority: CN
Inventors: 周良才
Original assignee: Changsha Environmental Protection Industry Coordination Management Station; Hunan chemical reagent general factory; INST OF ENVIRONMENTAL PROTECTION CHANGSHA CITY
Current assignee: Changsha Environmental Protection Industry Coordination Management Station; Hunan chemical reagent general factory; INST OF ENVIRONMENTAL PROTECTION CHANGSHA CITY
Priority date: 1996-03-11
Filing date: 1996-03-11
Publication date: 1997-09-17

Abstract

The present invention relates to a clean production process for preparing manganese carbonate. It is made up by using manganous sulfate and ammonium carbonate as raw material through double decomposition reaction in water-phase. It is characterized by that tightening up the control of compounding procedure; reducing water-soluble manganese contained in discharged waste liquor as far as possible; using distillation process to recover a large quantity of ammonium nitrogen discharged with compounded supernatant; using physico-chemical method to recover suspensoid and dissolution manganese salt discharged with compounded waste liquor and washing water. After treatment, the manganese content in the waste water can be up to the national standard on waste water discharge, and ammonium nitrogen discharge load also can be greatly reduced.

Description

Clean production process of manganese carbonate

The invention relates to a preparation method of carbonate in the field of inorganic chemistry, in particular to a clean production process of manganese carbonate.

Manganese carbonate is an important inorganic chemical product and has wide application in the electronic and metal surface treatment industry. The product is prepared by taking manganese sulfate and ammonium bicarbonate as raw materials and carrying out double decomposition reaction in a water phase, and the chemical reaction formula is as follows:

in the traditional production process widely adopted at present, the recovery rate of manganese is only about 95%, about 5% of manganese is discharged along with wastewater, and a byproduct ammonium sulfate generated by double decomposition reaction is completely lost, so that precious resources are wasted, and serious environmental pollution is caused. Taking an enterprise producing ten thousand tons of manganese carbonate every year as an example, the loss of manganese is about 500 tons of manganese carbonate and 500 ten thousand yuan, the loss of ammonium is about 21000 tons of ammonium carbonate and 1400 ten thousand yuan, and the concentrations of ammonium and manganese in the wastewater exceed the permitted discharge standard of a house by hundreds of times.

The invention aims to provide a clean production process for producing manganese carbonate, which can recover most of manganese salt and ammonium sulfate lost along with wastewater at present, so that the manganese content in the treated wastewater reaches the national wastewater discharge standard, and the pollution discharge load of ammonium nitrogen is greatly reduced.

The solution of the process of the invention is as follows. The method still uses a manganese sulfate solution and an ammonium bicarbonate solution as raw materials, carries out double decomposition reaction in a water phase, and obtains a manganese carbonate product through conventional procedures of clarification, cleaning, liquid-solid separation, drying, crushing, packaging and the like, and is characterized in that the process control of a chemical combination procedure is enhanced, and the water-soluble manganese in the discharged waste liquid is reduced as much as possible; treating the separated manganese-containing and ammonium-containing supernatant liquid after combination by adopting a distillation method so as to recover a large amount of ammonium nitrogen discharged along with the combined waste liquid; and recovering the suspended and soluble manganese salt discharged along with the chemical combination waste liquid and the cleaning water by a physical and chemical method. So as to ensure that the content of manganese in the discharged wastewater reaches the national discharge standard.

By adopting the clean production and wastewater comprehensive treatment process, the manganese content in the discharged wastewater can reach the discharge standard of the surrounding households. Under the condition of strictly controlling the distillation process, the ammonia nitrogen in the discharged distillation waste liquid can be less than 25-100 mg/L, so that the pollution discharge load of ammonia is greatly reduced. Taking one million tons of manganese carbonate production enterprises produced every year as an example, the comprehensive utilization yield can approach 2000 ten thousand yuan, and the method has remarkable social, environmental and economic benefits.

The method of the present invention is described in further detail below with reference to the accompanying drawings.

FIG. 1 is a process flow diagram of the method of the present invention.

Referring to fig. 1, the key points of the process of the invention are as follows:

(1) the process control of the chemical combination procedure is enhanced, and the water-soluble manganese in the discharged waste liquid is reduced as much as possible so as to reduce the loss of manganese and the cost of further treating the waste liquid and the waste water;

(2) the supernatant containing manganese and ammonium separated after combination (clarified again if necessary to recover the lost suspended manganese carbonate product) is sent to an ammonium distillation tower, and gaseous ammonia is distilled under the conditions of steam heating and lime milk alkalization. The gaseous ammonia can be sent into a carbonating tower to prepare ammonium bicarbonate solution with proper concentration for reuse in production, and can be electrically compressed to prepare liquid ammonia or other ammonium-containing products.

After the alkaline waste liquid containing calcium discharged from the ammonium steaming tower is subjected to liquid-solid separation, waste residue taking calcium sulfate as a main component can be comprehensively utilized or stockpiled, and the alkaline waste water can be discharged after neutralization or used for boiler flue gas desulfurization.

(3) The washing water of the clarified and recovered manganese carbonate product is reused for production (used as absorption liquid of a carbonating tower or used for preparing other raw material liquid) as much as possible, and the discharged part is treated by physical and chemical methods such as flocculation precipitation, filtration and the like so as to ensure that the manganese content in the discharged wastewater reaches the national discharge standard.

Claims

1. A clean production process for preparing manganese carbonate is characterized in that a manganese carbonate product is obtained by carrying out double decomposition combination reaction on a manganese sulfate solution and an ammonium carbonate solution which serve as raw materials in a water phase and carrying out the working procedures of clarification, cleaning, liquid-solid separation, drying, crushing and packaging, and the process is characterized in that a distillation method is adopted to treat a supernatant containing manganese and ammonium which are separated after combination so as to recover a large amount of ammonium nitrogen discharged along with a combination waste liquid; and recovering the suspended and soluble manganese salt discharged along with the chemical combination waste liquid and the cleaning water by a physical and chemical method.