阅读说明：本技术 稀糖汁除钙的方法 (Method for removing calcium from thin sugar juice ) 是由 邹传军 于 2020-12-16 设计创作，主要内容包括：本发明公开一种稀糖汁除钙的方法,该方法首先将稀糖汁经过二次饱充后,过滤,得到处理后的稀糖汁；将草酸和氢氧化钠混合均匀,得到pH值为5-9的混合物；向处理后的稀糖汁中加入混合物反应,得到反应后的稀糖汁；将反应后的稀糖汁过滤,得到除掉了钙离子的稀糖汁。本发明使用草酸-氢氧化钠混合物除掉稀糖汁的钙离子,方法简单可靠,避免了常规方法--离子交换法投资大、废水多、运行成本高的缺点。(The invention discloses a method for removing calcium from dilute sugar juice, which comprises the steps of firstly, carrying out secondary saturation on the dilute sugar juice, and filtering to obtain treated dilute sugar juice; uniformly mixing oxalic acid and sodium hydroxide to obtain a mixture with a pH value of 5-9; adding the mixture into the treated dilute sugar juice for reaction to obtain reacted dilute sugar juice; and filtering the reacted dilute sugar juice to obtain the dilute sugar juice without calcium ions. The method uses the oxalic acid-sodium hydroxide mixture to remove calcium ions in the dilute sugar juice, is simple and reliable, and avoids the defects of large investment, more waste water and high operation cost of the conventional method, namely an ion exchange method.)

1. A method for removing calcium from thin sugar juice is characterized in that: the method comprises the following steps:

1) after the dilute sugar juice is saturated for the second time, filtering to obtain the treated dilute sugar juice;

2) uniformly mixing oxalic acid and sodium hydroxide to obtain a mixture with a pH value of 5-9;

3) adding the mixture into the treated dilute sugar juice for reaction to obtain reacted dilute sugar juice;

4) and filtering the reacted dilute sugar juice to obtain the dilute sugar juice without calcium ions.

2. The method for removing calcium from dilute sugar juice according to claim 1, wherein: and in the step 3), adding the mixture while or after the treated dilute sugar juice is subjected to sulfur bleaching to obtain the reacted dilute sugar juice.

3. The method for removing calcium from dilute sugar juice according to claim 1, wherein: in the mixture, the weight ratio of oxalic acid to sodium hydroxide is 5:1-1.5, and the pH value of the mixture is 6-8.

4. A method of decalcifying dilute sugar juice according to claim 3 wherein: the pH value of the mixture is 6.5-7.5.

5. The method for removing calcium from dilute sugar juice according to claim 1, wherein: in the step 4), before filtering, the reacted dilute sugar juice is concentrated to 55-65%.

Technical Field

The invention relates to the field of sugar production, in particular to a method for removing calcium from dilute sugar juice.

Background

Sugar is the most important carbohydrate source for human beings, the commonly used sugar-making raw materials are sugar cane and sugar beet, the commonly used production process is squeezing sugar cane or boiling sugar beet in water to obtain sugar juice, filtering to remove impurities, adding a proper amount of lime water into the filtrate, filtering again to remove precipitates, introducing carbon dioxide into the filtrate to precipitate the lime water into calcium carbonate, and filtering again to obtain the filtrate which is the aqueous solution of sugar, wherein the concentration is generally 10-20%. The sugar solution is put into a vacuum container for reduced pressure evaporation, concentration and cooling, reddish brown slightly sticky crystals are separated out, and the sugar is the sugar, and sticky molasses which cannot be crystallized is obtained. Because sugar cane and beet are crops, the obtained sugar juice contains a lot of salt, and lime is used for processing the sugar juice in the sugar making process, so that the calcium content of the sugar juice is very high, and a large amount of calcium-containing compound precipitates, namely the scale formation which is often called in the subsequent evaporation and concentration stages can be generated. After the equipment is scaled, the heat exchange efficiency of the equipment can be influenced, and the heat energy consumption is increased. To solve this problem, sugar factories usually perform decalcification treatment before concentrating sugar solutions, that is, ion exchange resins are used to remove most of the calcium ions from sugar solutions.

The prior art has the defects that: the method adopts ion exchange resin to decalcify, has large investment, needs to regenerate the resin in the using process, namely removes calcium ions absorbed by the resin, adopts NaOH and NaCL in the existing regeneration method, has high regeneration liquid cost, generates a large amount of waste water, has limited using period of the ion exchange resin, needs to replace the resin periodically, needs not only investment, but also the replaced resin is waste which is very difficult to treat.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a method for removing calcium from thin sugar juice.

In order to achieve the purpose, the invention designs a method for removing calcium from thin syrup, which comprises the following steps:

1) after the dilute sugar juice is saturated for the second time, filtering to obtain the treated dilute sugar juice;

2) uniformly mixing oxalic acid and sodium hydroxide to obtain a mixture with a pH value of 5-9;

3) adding the mixture into the treated dilute sugar juice for reaction to obtain reacted dilute sugar juice;

4) and filtering the reacted dilute sugar juice to obtain the dilute sugar juice without calcium ions.

Further, in the step 3), the mixture is added while or after the treated dilute sugar juice is subjected to sulfur bleaching, so as to obtain the reacted dilute sugar juice.

Still further, in the mixture, the weight ratio of oxalic acid to sodium hydroxide is 5:1-1.5, and the pH value of the mixture is 6-8.

Still further, in the mixture, the most preferable pH value is 6.5 to 7.5

Still further, in the step 4), before filtering, the reacted dilute sugar juice is concentrated to 55-65%.

The principle of the invention is as follows:

1. the calcium oxalate formed by oxalic acid and calcium ions in the dilute sugar juice is the most stable calcium salt with the least solubility;

2. the filtering method can adopt various modes such as plate-and-frame filtering and the like, and can remove calcium oxalate precipitates;

3. the dilute sugar juice has low concentration of only 12-20%, so that its volume is large, and at the same time its calcium oxalate content is very low, it can be concentrated to 55-65%, then filtered.

The invention has the beneficial effects that:

the method uses the oxalic acid-sodium hydroxide mixture to remove calcium ions in the dilute sugar juice, is simple and reliable, and avoids the defects of large investment, more waste water and high operation cost of the conventional method, namely an ion exchange method.

Detailed Description

The present invention is described in further detail below with reference to specific examples so as to be understood by those skilled in the art.

Example 1

The method for removing calcium from the dilute sugar juice in the sugar making process comprises the following steps:

1) after the dilute sugar juice is saturated for the second time, filtering, and performing a conventional sulfur bleaching process;

2) uniformly mixing oxalic acid and sodium hydroxide according to the weight ratio of 5:1-1.5 to obtain a mixture (oxalic acid-sodium hydroxide mixture) with the pH value of 6-8;

3) adding an oxalic acid-sodium hydroxide mixture while or after the dilute sugar juice is subjected to sulfur bleaching;

4) filtering the dilute sugar juice to obtain the dilute sugar juice without calcium ions.

Example 2

The method for removing calcium from the dilute sugar juice in the sugar making process comprises the following steps:

1) after the dilute sugar juice with the concentration of 12-20% is saturated for the second time, filtering, which is a conventional step;

2) uniformly mixing oxalic acid and sodium hydroxide according to the weight ratio of 5:1-1.5 to obtain a mixture (oxalic acid-sodium hydroxide mixture) with the pH value of 6-8;

3) adding a proper amount of oxalic acid-sodium hydroxide mixture into the dilute sugar juice;

4) concentrating the dilute sugar juice to 55-65%, and filtering to obtain dilute sugar juice without calcium ions.

Other parts not described in detail are prior art. Although the present invention has been described in detail with reference to the above embodiments, it is only a part of the embodiments of the present invention, not all of the embodiments, and other embodiments can be obtained without inventive step according to the embodiments, and the embodiments are within the scope of the present invention.