CN1911801A

CN1911801A - Technology for preparating boric acid, magnesium carbonate and sodium sulphate by combined method

Info

Publication number: CN1911801A
Application number: CN 200610127337
Authority: CN
Inventors: 沙文斌
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-09-14
Filing date: 2006-09-14
Publication date: 2007-02-14
Anticipated expiration: 2026-09-14
Also published as: CN100532259C

Abstract

The process of co-producing boric acid, magnesium carbonate and sodium sulfate includes the first reaction step of reacting ascharite with 85 % concentration sulfuric acid to obtain wet boric acid and filtering to obtain filtrate; and the second reaction step of reacting the filtrate and sodium carbonate solution inside a reaction pond, filtering to obtain magnesium carbonate, concentrating the filtrate in a directly burning evaporator and hot filtering to obtain anhydrous sodium sulfate.

Description

Combined process for preparing boric acid, magnesium carbonate and sodium sulfate

The technical field is as follows:

the invention relates to the technical field of boron ore processing.

Background

At present, the domestic method for producing boric acid from boron-magnesium ore mainly adopts sulfuric acid to decompose boron-magnesium ore, and after the boric acid is prepared, the boric acid and magnesium sulfate in mother liquor reach a common saturation point. The mother liquor is treated in two ways, namely, the mother liquor is discharged to seriously pollute the environment; and secondly, magnesium sulfate is recovered, but the magnesium sulfate has boric acid, so that the product quality cannot reach the product standard, and the benefit is poor. The process seeks a processing method of the boron-magnesium ore, which can solve the problem of processing the mother liquor in the process and can comprehensively utilize the effective components in the boron-magnesium ore. The final product of the invention obtains boric acid, magnesium carbonate and sodium sulfate. Boric acid is used in the glass industry, enamel and ceramic industry, alkali-free glass fiber industry, metallurgical industry, electrical engineering industry, electroplating, electrolysis industry, pharmaceutical industry, rubber industry, wood preservation, soap manufacturing industry, leather industry, photography, fire-resistant fabrics, synthetic gemstones, dyes, perfume manufacturing, organic synthesis, electrical appliance manufacturing, agriculture, etc., and as a raw material for the production of various boron compounds. Magnesium carbonate is mainly used in rubber industry, dye industry, plastic industry, electronic industry, refractory materials, etc., and is used as a raw material for producing various magnesium compounds and magnesium. The anhydrous sodium sulfate is mainly used as raw material for vinylon, dye, synthetic detergent, glass, paper making, inorganic salt and other industries.

Disclosure of Invention

The method for preparing boric acid by the combined method comprises two steps, namely: after reacting the boron-magnesium ore with sulfuric acid, separating boric acid; the second step of reaction: after boric acid is separated, sodium carbonate is added into the mother liquor for continuous reaction to produce hydrated magnesium carbonate, after the hydrated magnesium carbonate is filtered, the mother liquor is evaporated to separate anhydrous sodium sulfate, and the filtrate is reused.

The first step of reaction:

the second step of reaction:

the process is as follows: the first step of reaction: adding the boron-magnesium ore (fine powder) and 85% sulfuric acid into a reaction tank according to a proportion, wherein the weight ratio of the boron-magnesium ore to the 85% sulfuric acid is 1-3: 0.5-2, adding water, and continuously stirring for reaction at 80-115 ℃. Filtering when the reaction is complete while the reaction is hot, feeding the filtrate into a cooling crystallizer, and cooling and crystallizing under stirring. Separating with a centrifugal separator to obtain wet boric acid, washing, and drying to obtain the final product. And (5) the filtrate enters a second-step reaction tank. The second step of reaction: adding the dissolved sodium carbonate solution into the filtrate obtained in the first step of reaction process, wherein the weight ratio of the boron-magnesium ore to the sodium carbonate is 1-3: 0.5-1, controlling the temperature at 40-70 ℃, and reacting under the condition of continuous stirring. Filtering after the reaction is completed to obtain magnesium carbonate, washing and drying to obtain the finished product. Concentrating the filtrate in a direct combustion evaporator, filtering while the filtrate is hot to obtain anhydrous sodium sulfate product, washing, and drying to obtain the final product. The filtrate is used for the first step of reaction process burdening.

Compared with the traditional one-step method for preparing the boric acid, the process has the advantages that:

1. the problem of low yield of the traditional process is solved, the product yield is improved, and mineral resources are saved;

2. the method is carried out at normal temperature and normal pressure, so that investment, production and management are facilitated, and the operation cost is reduced;

3. the process adopts a direct fuel gas evaporation technology,improves the evaporation efficiency and saves energy;

4. the process has no waste gas and waste water discharge, and is favorable for environmental protection;

5. the waste residue contains boron fertilizer, and can be mixed with phosphate fertilizer to be processed into compound fertilizer;

6. the processing range of the boron-magnesium ore is expanded, and the processing of mineral products with higher magnesium content can be met;

7. the gas source is the self-developed gas producer, and can meet the requirement of fuels in a wider range.

The specific implementation mode is as follows:

the first step of reaction: 2.00 tons of fine powder boron-magnesium ore and 0.75 tons of 85 percent sulfuric acid are added into a reaction tank, water is added, and the mixture is continuously stirred and reacted at 95 ℃. Filtering when the reaction is complete while the reaction is hot, feeding the filtrate into a cooling crystallizer, and cooling and crystallizing under stirring. Separating with a centrifugal separator to obtain wet boric acid, washing, and drying to obtain the final product. And (5) the filtrate enters a second-step reaction tank. The second step of reaction: and adding the dissolved sodium carbonate solution into the filtrate obtained in the first step of reaction process, wherein the amount of the added sodium carbonate is 0.83 ton, the temperature is controlled to be about 55 ℃, and the reaction is carried out under the condition of continuous stirring. Filtering after the reaction is completed to obtain magnesium carbonate, washing and drying to obtain the finished product. And (3) filtering magnesium carbonate, concentrating the filtrate in a direct-fired evaporator, filtering while the filtrate is hot to obtain an anhydroussodium sulfate product, washing and drying to obtain a finished product. The filtrate is used for the first step of reaction process burdening. The resulting product meets the following specifications: boric acid in product specification: GB538-82, hydrated basic magnesium carbonate: HG/T2959-2000 anhydrous sodium sulfate: HG 1-520-80.

Claims

1. A method for preparing boric acid, magnesium carbonate and sodium sulfate is characterized in that: in the first step of reaction, adding fine powder boron-magnesium ore and 85% sulfuric acid into a reaction tank in proportion, adding water, continuously stirring and reacting at 80-115 ℃, filtering while the reaction is complete, feeding the filtrate into a cooling crystallizer, cooling and crystallizing while stirring, separating by using a centrifugal separator to obtain wet boric acid, washing and drying to obtain a finished product; and (2) the filtrate after centrifugal separation enters a second-step reaction tank, in the second-step reaction, the filtrate obtained after the first-step reaction process is added with a dissolved sodium carbonate solution, the temperature is controlled to be 40-70 ℃, the reaction is carried out under continuous stirring, the reaction is completed, the filtrate is filtered to obtain magnesium carbonate, the magnesium carbonate is washed and dried to obtain a finished product, the filtrate obtained after the magnesium carbonate is filtered enters a direct-fired evaporator for concentration, the filtrate is filtered while hot to obtain an anhydrous sodium sulfate product, and the finished product is washed and dried.

2. The method of claim 1, wherein: the weight ratio of the boron-magnesium ore to 85% sulfuric acid is 1-3: 0.5-2, and the weight ratio of the boron-magnesium ore to sodium carbonate is 1-3: 0.5-1.