CN104138887B - A method for solidifying chromium in polluted acid slag - Google Patents

Abstract

The present invention relates to a kind of method for solidifying chromium in waste acid slag.It is characterized in, comprises the following steps：Modification metal magnesium slag is added in waste acid slag first after drying grinding, then obtained block is put into sintering furnace and is incubated 48 hours at 800 1300 DEG C by compound stalk forming after being well mixed, and cooling is taken out and carries out dry grinding into powdered.The inventive method has advantages below:The present invention is a kind of environment-friendly treatment method for solidifying the heavy metal Cr in stable waste acid slag, and the heavy metal in the stable waste acid slag of solidification is realized with the sintered processing of modification reducing slag of magnesium metal smelting, the purpose of the treatment of wastes with processes of wastes against one another is reached.Therefore the solidification and stabilization process is not required to use expensive material, low raw-material cost；Make full use of modification magnesium slag；Waste acid slag curing process is simple, easy engineering construction thus industrial operation can be realized；Secondary residue, waste water are not produced during solidification stabilizing heavy metal.

Description

A method for solidifying chromium in polluted acid slag

technical field

The invention relates to a method for solidifying chromium in polluted acid slag.

Background technique

Non-ferrous metal smelting is a heavily polluting industry that plays a pivotal role in my country's economic development. However, the long-term accumulation of waste residues in the non-ferrous metal smelting industry has led to serious pollution of groundwater, posing major safety hazards, and severely restricting the sustainable development of the non-ferrous metal industry. Two types of society" construction.

The lead and zinc industry is an important representative of non-ferrous metal smelting in my country. The bulk industrial solid waste in my country's lead and zinc industry mainly comes from metallurgical slag and acidic water treatment slag (polluted acid slag), and the annual industrial waste slag is estimated to exceed 6 million tons. Taking Qingshuitang Industrial Zone in Zhuzhou as an example, millions of tons of various industrial wastes are discharged every year, and their stockpiles have increased year by year. The solid waste such as acid waste slag and the storage yard covering an area of nearly 100 mu are shocking. If the heavy metal elements in the heavy metal polluted acid waste residue cannot be stably stored in the polluted acid residue, it will easily flow to the environment and cause serious harm to the human body and the surrounding environment; in terms of harm to the human body, on the one hand, direct drinking will cause heavy metal poisoning and damage human health. On the other hand, it indirectly pollutes agricultural and aquatic products, posing a threat to human health through the food chain. The chromium element in the environment, especially the hexavalent chromium ion, is a pollutant with strong toxic effects on human health, and there are major safety hazards. It is urgent to develop and use industrialized technology for harmless treatment and reduction.

Contents of the invention

The purpose of the present invention is to provide a method for solidifying chromium in polluted acid slag, which can solidify and stabilize the heavy metal Cr in polluted acid slag.

A method for solidifying chromium in polluted acid slag, which is particularly characterized in that it comprises the following steps: firstly, adding modified metal magnesium slag to the dried and ground polluted acid slag, mixing evenly, and then briquetting the obtained The block is put into the sintering furnace and kept at 800-1300°C for 4-8 hours, cooled and taken out.

Further, include the following steps:

(1) drying: collect dirty acid slag and dry;

(2) Grinding: dry-grind the dried dirty acid slag into powder, and simultaneously take the modified magnesium slag and carry out ultrafine grinding to make the particle size less than 100 mesh;

(3) Mixing: adding superfine pulverized modified magnesium slag to the ground polluted acid slag powder for mixing, wherein the added amount of magnesium slag accounts for 50-80% of the total weight;

(4) Sample pressing: briquetting the uniformly mixed slag into blocks;

(5) Sintering: Put the briquetting block into a sintering furnace at 800-1300°C, keep it warm for 4-8 hours, and take it out after natural cooling.

In step (1), the drying temperature is 100-110° C., the drying time is 8-12 hours, and the drying is performed until the moisture content is ≤5%.

The dry grinding in step (2) is carried out in a vibration mill, and the grinding time is 3-10 minutes; the grinding time of ultrafine grinding is 3-10 minutes.

The mixing time in step (3) is 10-40min.

In step (4), a universal hydraulic press is used for briquetting.

After the step (5), the slag obtained after sintering should be dry-ground, and the dry-grinding is carried out in a vibration mill, and the grinding time is 3-10 minutes.

After adopting the method of the invention, the leaching content of the heavy metal element Cr in the polluted acid slag can be effectively reduced, and more heavy metal Cr can be solidified and stabilized in the polluted acid slag. The method of the present invention also has the following advantages: the present invention is an environmental protection treatment method for solidifying and stabilizing the heavy metal Cr in the polluted acid slag, and the modified reducing slag smelted with metal magnesium is sintered to realize the solidification and stabilization of the heavy metal in the polluted acid slag, achieving The purpose of treating waste with waste. Therefore, the solidification and stabilization process does not need expensive materials, and the cost of raw materials is low; the modified magnesium slag is fully utilized; the solidification process of the polluted acid slag is simple and easy to implement, so it can realize industrial operation; no secondary waste residue is produced in the process of solidifying and stabilizing heavy metals , Waste water.

Description of drawings

Accompanying drawing 1 is the process flow chart of embodiment 1 of the present invention.

detailed description

Example 1

(1) The modified metal magnesium slag in the raw materials is the magnesium smelting slag of Ningxia Huiye Magnesium Industry Group Co., Ltd., and the polluted acid slag is the slag of the lead-zinc smelting enterprise (Zhuzhou Smelting Group Co., Ltd.).

Chemical composition of polluted acid slag (%)

Chemical composition of modified magnesium slag (%)

(2) Drying: collect the dirty acid slag and dry it at 110°C until the moisture content is ≤3%;

(3) Grinding: put the dried dirty acid slag into a vibrating mill for dry grinding, and the grinding time is 8 minutes. At the same time, take the modified metal magnesium slag and carry out ultrafine grinding, and use a vibrating mill for grinding for 5 minutes;

(4) Mixing: add ultra-finely pulverized modified magnesium slag to the ground polluted acid slag and mix for 40 minutes, wherein the added amount of magnesium slag accounts for 70% of the total weight of the mixed sample;

(5) Sample pressing: the uniformly mixed slag is formed into a briquetting block (2cm*2cm*2cm) by a universal hydraulic press;

(6) Sintering: put the briquetting block into a sintering furnace and keep it warm at 1200°C for 6 hours; then take it out after cooling naturally with the furnace.

(7) Grinding: put the slag obtained after sintering into a vibration mill for dry grinding, and the grinding time is 4 minutes.

(8) Prepare the extraction agent with pH=3.20±0.05; take 200g of each sample to be tested and pour it into the roller bottle and mark it well, pour 2000mL of the extraction agent into each roller bottle according to the solid-to-liquid ratio of 1:10 After sealing it well, place it on the rolling machine and roll it; take off the roller bottle after 18±2h, stand still for 1.5h-2.0h, use a pipette to take 100ml supernatant into the volumetric flask to obtain the leaching solution; for leaching solution detection ICP-7000.

The result of using the above method is as follows:

The experimental data before sintering are shown in Table 1, and the experimental data after sintering are shown in Table 2.

Table 1 The data and results of the toxicity leaching test before burning

Table 2 The data and results of the toxicity leaching test after burning

Since sintering at 1200°C may volatilize the easily volatile components in the slag, the Cr content in the slag is different before and after sintering for the same proportion of polluted acid slag and modified magnesium slag. It can be seen from the experimental data that sintering The Cr content in the slag increases. After the sintering treatment, the Cr content in the leaching solution can be reduced from 1050mg/L to 99.94mg/L. Although the leaching amount is still relatively large, the reduction of the leaching amount is very large, which shows that the method for sintering treatment of the present invention can be greatly improved. Reduce the leaching of heavy metal element Cr in heavy metal waste slag.

Claims (1)

1. a method for solidifying chromium in dirty acid slag, is characterized in that, comprises the steps: (1) drying: collect dirty acid slag and dry; (2) Grinding: dry-grind the dried dirty acid slag into powder, and simultaneously take the modified magnesium slag and carry out ultrafine grinding to make the particle size less than 100 mesh; (3) Mixing: adding superfine pulverized modified magnesium slag to the ground polluted acid slag powder for mixing, wherein the added amount of magnesium slag accounts for 70% of the total weight; (4) Sample pressing: briquetting the uniformly mixed slag into blocks; (5) Sintering: Put the briquetting block into a sintering furnace at 1200°C, keep it warm for 6 hours, and take it out after natural cooling; In step (1), the drying temperature is 110°C, the drying time is 8-12 hours, and the drying time is until the moisture content is ≤3%; In the step (2), the dry grinding is carried out in a vibration mill, and the grinding time is 8 minutes; the grinding time of the ultrafine grinding is 5 minutes; Mixing time 40min in the step (3); In the step (4), the briquette forming adopts a universal hydraulic press; After step (5), the slag material obtained after sintering is also dry-ground, and the dry grinding is carried out in a vibration mill, and the grinding time is 4 minutes; The modified magnesium slag includes CaO, SiO ₂ , MgO, Fe ₂ O ₃ and Al ₂ O ₃ ; the CaO is 42.35%, the SiO ₂ is 25.34%, the MgO is 5.12%, and the Fe _{2 O3} is 5.46%, and the _Al2O3 is _1.02 %.