CN1115774A

CN1115774A - Prepn of silica white with opal and diatomite

Info

Publication number: CN1115774A
Application number: CN 95102423
Authority: CN
Inventors: 郑水林; 李杨; 董文; 夏巧玲; 杜玉成
Original assignee: BEIJING GRADUATE STUDENT DEPARTMENT WUHAN POLYTECHNICAL UNIV
Current assignee: BEIJING GRADUATE STUDENT DEPARTMENT WUHAN POLYTECHNICAL UNIV
Priority date: 1995-03-17
Filing date: 1995-03-17
Publication date: 1996-01-31
Anticipated expiration: 2015-03-17
Also published as: CN1055296C

Abstract

Opal or diatomite powder reacts with caustic soda under the condition of heating to produce sodium silicate, which is filtered to remove residues, mixed with sodium salt, to which water is added to regulate concentration. The product is then neutralized with acid and aged, filtered, washed and desiccated to obtain silica white. Compared with conventional water glass process, the said prepn process has the merits of readily available raw material, simple process, low energy consumption and low cost.

Description

A process for preparing white carbon black from opal and diatomite.

The invention relates to a method for preparing white carbon black by using opal (stone) anddiatomite, belonging to the field of chemical engineering.

The existing white carbon black production methods comprise a deposition method and a gas phase method, wherein the gas phase method uses silicon tetrachloride, oxygen (or air) and hydrogen as raw materials and prepares the white carbon black through high-temperature reaction, the product is pure, the cost is high, and the white carbon black is used in places with high requirements. The most comparable technology to the technology is a deposition method, which is prepared by using water glass as a raw material and reacting with acid (hydrochloric acid, sulfuric acid and nitric acid) or various ammonium salts, and the water glass is neutralized by hydrochloric acid at present, wherein the reaction formula is as follows:

because the water glass is prepared by the melting reaction of the soda ash and the quartz sand at high temperature or the boiling reaction of the soda ash at high pressure, the production cost of the existing precipitated white carbon black production process taking the water glass as the raw material is higher, and the energy consumption is high.

The invention aims at the defects of the two methods for preparing the white carbon black, and provides a method for directly preparing high-quality precipitated white carbon black by taking siliceous minerals such as opal (stone), diatomite and the like as raw materials, wherein a two-step method is changed into a one-step method, the production process can be simplified, and the energy consumption and the cost are reduced.

The present invention relates to a method for directly preparing white carbon black by using opal or diatomite ore powder and caustic soda to react, and then using acid to neutralize.

The process comprises the following steps:

reacting opal or diatomite ore powder with caustic soda under heating to generate sodium silicate, wherein the reaction formula is as follows:

………(1)

the reaction product is filtered to remove solid residue, then sodium salt is added, and water is added to adjust to a suitable concentration, and neutralized with acid, which has the following reaction formula:

…(2)

and filtering, washing and drying the reaction product to obtain the white carbon black product.

M in the reaction formula (2) is SiO in sodium silicate₂With Na₂The ratio of O (Si/Na) to SiO in ore powder₂Content and caustic sodaThe charge ratio of (A) is related.

The opal (stone) or diatomite ore powder is a siliceous mineral and has a main chemical composition of SiO₂.nH₂O, and other impurities, SiO₂70-95%, the method requires that the mineral powder contains SiO₂More than or equal to 70 percent, and the fineness is less than 150 mu m.

In the step (2), sulfuric acid or hydrochloric acid can be used for neutralization by acid, for example, hydrochloric acid, and the sodium salt added in advance is sodium chloride.

The formula and the process conditions of the invention are as follows:

the weight ratio of [ 1]ore powder to causticsoda is 1: 0.2-0.9, preferably 1: 0.3-0.7

The reaction temperature of the ore powder and caustic soda is 80-120 ℃;

the reaction time of the ore powder and caustic soda is 0.5 to 4 hours;

the conditions for neutralization with sulfuric acid are: the temperature is 30-90 ℃;

adding water before neutralization to adjust the concentration of sodium silicate to Be 8-18 degrees Be';

the amount of sulfuric acid used during neutralization is 1: 0.3-1.0 (weight ratio) of the mineral powder to sulfuric acid, and the optimal ratio is 1: 0.4-0.8;

neutralizing with sulfuric acid, adding sodium sulfate before neutralization or filtering mother liquor, wherein the amount of the mother liquor is that mineral powder and sodium sulfate are 1: 0.5-0.8 (weight ratio)

The process flow chart of the invention is shown in figure 1

The performance indexes of the white carbon black prepared by the method are shown in table 1, and the column 3 in the table is the technical index of the latest national standard (GB 10517-89).

Compared with the water glass method, the method has the advantages of cheap and easily available raw materials, simple process, good product quality, low energy consumption and low production cost. From the comparison of the performance data listed in Table 1 with the national standard GB10517-89, the products of the process meet and exceed the national standard.

The examples are as follows:

① powdered egg white (200mesh fineness, SiO content)₂87%) of the white carbon black, adding 15kg of industrial caustic soda and 150kg of water, stirring and reacting for 1.5hr (reaction temperature is 100 ℃) in a reaction pot, filtering to remove solid residues, adding 15kg of industrial sodium sulfate, diluting to 14 ℃ Be', neutralizing with 17kg of 30% sulfuric acid solution (reaction temperature is 50 ℃), ageing the reaction product for 38min, filtering, washing and drying to obtain the white carbon black product.

② powdered egg white (200 mesh fineness, SiO content)₂86%) of the white carbon black, adding 13kg of industrial caustic soda and 120kg of water, stirring and reacting for 2 hours in a reaction pot (reaction temperature is 100 ℃), filtering to remove unreacted solid residues, adding 13kg of industrial sodium sulfate, diluting to 12-DEG Be', neutralizing with 15kg of 30% sulfuric acid solution (reaction temperature is 60 ℃), ageing the reaction product for 30min, filtering, washing and drying to obtain the white carbon black product.

③ diatomaceous earth powder (fineness of 100 meshes, containing SiO)₂1.50 percent of water content, 26 percent of water content), adding 0.35kg of industrial caustic soda and 4kg of water, stirring and reacting for 1.5 hours (reaction temperature is 100 ℃) in a reaction pot, filtering and removing residues, adding 0.5kg of industrial sodium sulfate, diluting to 13 DEG Be', neutralizing with 0.4kg of 40 percent sulfuric acid solution (reaction temperature is 70 ℃), aging the reaction product for 0.5 hour, filtering, washing and drying to obtain the white carbon black product.

The analysis and detection results of the white carbon black products of the examples are shown in the attached table 2.

TABLE 1

Item	Technical index^*	BG10517-89
Item	Technical index^*	BG10517-89	Silicon dioxide content%	91.53	≥90
Colour(s)	Is superior to the standard sample	Better than or equal to the standard sample	Silicon dioxide content%	91.53	≥90
Colour(s)	Is superior to the standard sample	Better than or equal to the standard sample	Percent of sieve residue (45 μm)%	Is free of	≤0.5
Is heated to reduce weight%	4.29	4.0～8.0	Percent of sieve residue (45 μm)%	Is free of	≤0.5
Is heated to reduce weight%	4.29	4.0～8.0	Reduced on ignition,%	4.55	≤7.0
PH	8.0	5.0～8.0	Reduced on ignition,%	4.55	≤7.0
PH	8.0	5.0～8.0	Total copper content, mg/kg	5	≤30
Total manganese content, mg/kg	2	≤50	Total copper content, mg/kg	5	≤30
Total manganese content, mg/kg	2	≤50	Total iron content mg/kg	190	≤1000
Specific surface area, m²/g	145～220 Average 180	A＞190 B：161～190 C：136～160 D106～135 E：71～105 F：＜71	Total iron content mg/kg	190	≤1000

Table 2 detection and analysis results of white carbon black products in examples

Item	Example 1	Example 2	Example 3
Item	Example 1	Example 2	Example 3	Silicon dioxide content%	91.63	91.59	92.50
Percent of sieve residue (45 μm)%	Is free of	Is free of	Is free of	Silicon dioxide content%	91.63	91.59	92.50
Percent of sieve residue (45 μm)%	Is free of	Is free of	Is free of	Is heated to reduce weight%	4.32	4.26	4.60
Reduced on ignition,%	4.50	4.01	6.64	Is heated to reduce weight%	4.32	4.26	4.60
Reduced on ignition,%	4.50	4.01	6.64	PH	7.5	7.0	6.5
Total copper content, mg/kg	6	5	Is free of	PH	7.5	7.0	6.5
Total copper content, mg/kg	6	5	Is free of	Total manganese content, mg/kg	2	3	Is free of
Total iron content, mg/kg	380	360	90	Total manganese content, mg/kg	2	3	Is free of
Total iron content, mg/kg	380	360	90	Specific surface area, m²/g	145	210	198

Claims

1. A method for preparing white carbon black by using opal (stone) and diatomite is characterized by comprising the following process steps:

reacting the opal or diatomite ore powder with caustic soda under heating to generate sodium silicate, wherein the reaction formula is as follows:

the reaction product is filtered to remove solid residue, then inorganic sodium salt is added, water is added to adjust to proper concentration, and neutralization is carried out by acid, and the reaction formula is as follows:

and aging, filtering, washing and drying the reaction product to obtain the white carbon black product.

2. The method for preparing silica white from opal and diatomite as claimed in claim 1, wherein said opal or diatomite ore powder contains SiO₂Not less than 70 percent (weight percentage), and sieving with a 100-mesh sieve.

3. The process for preparing silica white from opal and diatomite as claimed in claim 1, wherein the neutralizing acid is hydrochloric acid, in which case the sodium chloride is added in advance.

4. The method for preparing white carbon black from opal (stone) and diatomite as claimed in claim 1, wherein the formula and process conditions are as follows:

1, 1: 0.2-0.9 (weight) of mineral powder and caustic soda;

the reaction temperature of the ore powder and caustic soda is 80-120 ℃;

the reaction time of the ore powder and caustic soda is 0.5 to 4 hours;

the neutralization condition with sulfuric acid is 30-90 deg.C;

adding water to adjust the concentration of the sodium silicate to Be 8-18 degrees Be' before neutralization;

the amount of sulfuric acid used in neutralization is 1: 0.3-1.0 (weight ratio) of mineral powder to sulfuric acid;

sodium sulfate is added before the neutralization with sulfuric acid or the mother liquor after the neutralization reaction product is filtered, and the dosage of the mother liquor is 1: 0.5-0.8 (weight ratio) of the mineral powder and the sodium sulfate.

5. The method for preparing silica white from opal (stone) or diatomite as claimed in claim 4, wherein the optimum ratio of the mineral powder to the caustic soda is 1: 0.3-0.7.

6. The method for preparing silica white from opal or diatomite as claimed in claim 4, wherein the optimum amount of sulfuric acid for neutralizing the reaction solution is 1: 0.4-0.8.